Sample records for rock slope stability

  1. Constitutive models in stability analysis of rock slope

    言志信; 段建; 王后裕


    Equivalent Mohr-Coulomb yield criterion was established,and the relationship between different constitutive models was studied.The application of equivalent Mohr-Coulomb yield criterion in Ansys was achieved by means of transforming material parameters.The stability research aiming at the most common rock slope without conspicuous slide surface was accomplished,the methods of measurably assessing the stability of rock slope without conspicuous slide surface were explored,and the disadvantages of method of minimum slide-resisted reserve as dangerous slide path were pointed out.The results show that through the calculation and analysis of cases,the conception that measurable assessment of the stability of rock slope without conspicuous slide surface can be achieved under condition that equivalent Mohr-Coulomb yield criterion is validated.Its safety parameter formula is explicit in theory and credible in results.The results obtained are approximate to those obtained by using finite element intensity reducing method.

  2. Rock mass characterisation and stability analyses of excavated slopes

    Zangerl, Christian; Lechner, Heidrun


    Excavated slopes in fractured rock masses are frequently designed for open pit mining, quarries, buildings, highways, railway lines, and canals. These slopes can reach heights of several hundreds of metres and in cases concerning open pit mines slopes larger than 1000 m are not uncommon. Given that deep-seated slope failures can cause large damage or even loss of life, the slope design needs to incorporate sufficient stability. Thus, slope design methods based on comprehensive approaches need to be applied. Excavation changes slope angle, groundwater flow, and blasting increases the degree of rock mass fracturing as well as rock mass disturbance. As such, excavation leads to considerable stress changes in the slopes. Generally, slope design rely on the concept of factor of safety (FOS), often a requirement by international or national standards. A limitation of the factor of safety is that time dependent failure processes, stress-strain relationships, and the impact of rock mass strain and displacement are not considered. Usually, there is a difficulty to estimate the strength of the rock mass, which in turn is controlled by an interaction of intact rock and discontinuity strength. In addition, knowledge about in-situ stresses for the failure criterion is essential. Thus, the estimation of the state of stress of the slope and the strength parameters of the rock mass is still challenging. Given that, large-scale in-situ testing is difficult and costly, back-calculations of case studies in similar rock types or rock mass classification systems are usually the methods of choice. Concerning back-calculations, often a detailed and standardised documentation is missing, and a direct applicability to new projects is not always given. Concerning rock mass classification systems, it is difficult to consider rock mass anisotropy and thus the empirical estimation of the strength properties possesses high uncertainty. In the framework of this study an approach based on

  3. Simulation analysis of construction process of high rock slope's stabilization

    ZHU Zhan-yuan; LING Xian-zhang; WANG Xuan-qing; ZOU Zu-yin


    A self-developed elasto-plastic finite element program was used to analyze the construction sequence of high rock slope' s stabilization in a coal-coking plant, and the result was compared with that employing the ultimate equilibrium method. Based on the results of finite element analysis, the stress contour graphs and dis-placement vector graphs at different construction steps were obtained, and the behavior of the slope during stabi-lization construction process was analyzed quantitatively. Based on the analysis of safety factors of three different schemes of stabilization and two different construction schemes, the assessment of stability and bracing design of the construction process were performed. The results show that the original reinforcement design is improper;the stability of the rock slope is controlled by a developed structural plane, the stability factor after excavation is less than 1, and the free surface should be braced in time ; for stability, the construction sequence should adopt that bracing follows excavation step by step up to down; the local slide occurred during the construction process agrees with the dangerous slide determined by the numerical analysis, which proves the validity and rationality of the adopted method.

  4. The Dynamic Evaluation of Rock Slope Stability Considering the Effects of Microseismic Damage

    Xu, N. W.; Dai, F.; Liang, Z. Z.; Zhou, Z.; Sha, C.; Tang, C. A.


    A state-of-the-art microseismic monitoring system has been implemented at the left bank slope of the Jinping first stage hydropower station since June 2009. The main objectives are to ensure slope safety under continuous excavation at the left slope, and, very recently, the safety of the concrete arch dam. The safety of the excavated slope is investigated through the development of fast and accurate real-time event location techniques aimed at assessing the evolution and migration of the seismic activity, as well as through the development of prediction capabilities for rock slope instability. Myriads of seismic events at the slope have been recorded by the microseismic monitoring system. Regions of damaged rock mass have been identified and delineated on the basis of the tempo-spatial distribution analysis of microseismic activity during the periods of excavation and consolidation grouting. However, how to effectively utilize the abundant microseismic data in order to quantify the stability of the slope remains a challenge. In this paper, a rock mass damage evolutional model based on microseismic data is proposed, combined with a 3D finite element method (FEM) model for feedback analysis of the left bank slope stability. The model elements with microseismic damage are interrogated and the deteriorated mechanical parameters determined accordingly. The relationship between microseismic activities induced by rock mass damage during slope instability, strength degradation, and dynamic instability of the slope are explored, and the slope stability is quantitatively evaluated. The results indicate that a constitutive relation considering microseismic damage is concordant with the simulation results and the influence of rock mass damage can be allowed for its feedback analysis of 3D slope stability. In addition, the safety coefficient of the rock slope considering microseismic damage is reduced by a value of 0.11, in comparison to the virgin rock slope model. Our results

  5. Stability Analysis for Loosened Rock Slope of Jinyang Grand Buddha in Taiyuan, China

    SUN, Jinzhong; TIAN, Xiaofu; GUAN, Xudong; YU, Yonggui; YANG, Xiusheng

    On the basis of the status quo of Jinyang Grand Buddha in Taiyuan, some factors such as topography, geological structures, climate, hydrology, and engineering geology that influence the stability of the Buddha slope are considered, and several working situations of the slope that possibly suffered are presented in this article. The Buddha slope stands upright and the rock masses are composed of thick Permian sandstone, which dips slightly inward to the slope. Affected by both the incision of regional joints and the load relief to the free surface, the rock mass of the Buddha slope has turned into loosened blocks. Numerical stability analysis by FLAC-2D on the basis of the strength reduction method reveals that the localized deformation of the rock masses near the vertical surface of the slope may trigger reversing of rock beddings making the back dip slope convert into a dip slope with the possibility of plane sliding failure. Furthermore, the pseudostatic method for the dynamic process and limit equilibrium method for the static process are applied to different working situations of the Buddha slope. The analytical results illustrate that plane sliding failure will not occur when the slope is affected only by seism. However, water filling in the cracks of the loosened rock mass may greatly contribute to the potential plane sliding failure. When horizontal seism-force and hydrostatic pressure are coupled, the Buddha slope can hardly keep stable. Additionally, the loosened rock masses are prone to block toppling failure when influenced by the seism force.

  6. Comprehensive Stability Evaluation of Rock Slope Using the Cloud Model-Based Approach

    Liu, Zaobao; Shao, Jianfu; Xu, Weiya; Xu, Fei


    This article presents the cloud model-based approach for comprehensive stability evaluation of complicated rock slopes of hydroelectric stations in mountainous area. This approach is based on membership cloud models which can account for randomness and fuzziness in slope stability evaluation. The slope stability is affected by various factors and each of which is ranked into five grades. The ranking factors are sorted into four categories. The ranking system of slope stability is introduced and then the membership cloud models are applied to analyze each ranking factor for generating cloud memberships. Afterwards, the obtained cloud memberships are synthesized with the factor weights given by experts for comprehensive stability evaluation of rock slopes. The proposed approach is used for the stability evaluation of the left abutment slope in Jinping 1 Hydropower Station. It is shown that the cloud model-based strategy can well consider the effects of each ranking factor and therefore is feasible and reliable for comprehensive stability evaluation of rock slopes.

  7. Modified Limiting Equilibrium Method for Stability Analysis of Stratified Rock Slopes

    Rui Yong


    Full Text Available The stratified rock of Jurassic strata is widely distributed in Three Gorges Reservoir Region. The limit equilibrium method is generally utilized in the stability analysis of rock slope with single failure plane. However, the stratified rock slope cannot be accurately estimated by this method because of different bedding planes and their variable shear strength parameters. Based on the idealized model of rock slope with bedding planes, a modified limiting equilibrium method is presented to determine the potential sliding surface and the factor of safety for the stratified rock slope. In this method, the S-curve model is established to define the spatial variations of the shear strength parameters c and  φ of bedding plane and the tensile strength of rock mass. This method was applied in the stability evaluation of typical stratified rock slope in Three Gorges Reservoir Region, China. The result shows that the factor of safety of the case study is 0.973, the critical sliding surface for the potential slip surface appears at bedding plane C, and the tension-controlled failure occurs at 10.5 m to the slope face.

  8. Effects of Weak Layer Angle and Thickness on the Stability of Rock Slopes

    Garmondyu Crusoe Jr


    Full Text Available This paper researches two key factors (angle and thickness of a weak layer in relation to their influencing mechanism on slope stability. It puts forward the sliding surface angle and morphological model criteria for the control of rock slopes and realization of its failure mechanism. By comparing the Failure Modes and Safety Factors (Fs obtained from numerical analysis, the influence pattern for the weak layer angle and thickness on the stability of rock slopes is established. The result shows that the weak layer angle influences the slope by validating the existence of the “interlocking” situation. It also illustrates that as the angle of the weak layer increases, the Fs unceasingly decreases with an Fs transformation angle. The transformation interval of the Fs demonstrates the law of diminishing of a quadratic function. Analysis of the weak layer thickness on the influence pattern of slope stability reveals three decrease stages in the Fs values. The result also shows that the increase in the thickness of the weak layer increases the failure zone and influences the mode of failure. Given the theoretical and numerical analysis of a weak layer effects on the stability of rock slopes, this work provides a guiding role in understanding the influence of a weak layer on the failure modes and safety factors of rock slopes.

  9. A more general model for the analysis of the rock slope stability

    Mehdi Zamani


    The slope stability analysis has many applications in the engineering projects such as the dams, the roads and open pits structures. The method of analysis is usually based on the equilibrium conditions of the potential plane and wedge failures. The zone of the potential failure is stable whenever the stability forces dominate instability characteristics of the slope. In most of the classic methods of slope stability analysis, the joint surfaces are assumed to be continuous along the potential failure zone. These can cause an underestimated solution to the analysis. In this research the joint trace length is considered to be discontinuous across thepotential surface of failure as it happens in nature. Therefore, there exists a rock bridge between the local joint traces. Because of the numerous problems related to the rock slope stability the above assumption is satisfied and the shear strength characteristics of intact rock have taken part in the analysis. The analysis presented here gives a better concept, view, and idea of understanding the physical nature of rock slopes and includes more parameters governing the stability of the potential failure zone.

  10. Rheological Characteristics of Weak Rock Mass and Effects on the Long-Term Stability of Slopes

    Yang, Tianhong; Xu, Tao; Liu, Hongyuan; Zhang, Chunming; Wang, Shanyong; Rui, Yongqin; Shen, Li


    The creep deformation behavior of the northern slope of an open-pit mine is introduced. Direct shear creep tests are then conducted for the samples taken from the northern slope to study the rheological characteristics of the rock mass. The experimental results are analyzed afterwards using an empirical method to develop a rheological model for the rock mass. The proposed rheological model is finally applied to understand the creep behavior of the northern slope, predict the long-term stability, and guide appropriate measures to be taken at suitable times to increase the factor of safety to ensure stability. Through this study, a failure criterion is proposed to predict the long-term stability of the slope based on the rheological characteristics of the rock mass and a critical deformation rate is adopted to determine when appropriate measures should be taken to ensure slope stability. The method has been successfully applied for stability analysis and engineering management of the toppling and slippage of the northern slope of the open-pit mine. This success in application indicates that it is theoretically accurate, practically feasible, and highly cost-effective.

  11. Spatial evaluation of rock slope geometry, kinematics and stability with RSS-GIS

    Günther, A.


    A GIS-implemented, deterministic approach for the spatial evaluation of geometrical and kinematical properties of rock slope terrains is presented. Based on spatially distributed directional information on planar geological fabrics and DEM-derived topographic attribute data, the internal geometry of rock slopes can be characterized on a grid cell basis. For such computations, different approaches for the analysis and regionalization of available structural directional information applicable in specific tectonic settings are demonstrated and implemented in a GIS-environment. Simple kinematical testing procedures based on feasibility criteria can be conducted on a pixel basis to determine which failure mechanisms are likely to occur at particular terrain locations. In combination with hydraulic and strength data on geological discontinuities, scenario-based rock slope stability evaluations can be performed. For conceptual investigations on rock slope failure processes, a GIS-based specification tool for a 2-D distinct element code (UDEC) was designed to operate with the GIS-encoded spatially distributed rock slope data. The concepts of the proposed methodology for rock slope hazard assessments are demonstrated at three different test sites in Germany.

  12. Stability and reinforcement analysis of rock slope based on elasto-plastic finite element method

    刘耀儒; 武哲书; 常强; 李波; 杨强


    The rigid body limit equilibrium method (RBLEM) and finite element method (FEM) are two widely used approaches for rock slope’s stability analysis currently. RBLEM introduced plethoric assumptions; while traditional FEM relied on artificial factors when determining factor of safety (FOS) and sliding surfaces. Based on the definition of structure instability that an elasto-plastic structure is not stable if it is unable to satisfy simultaneously equilibrium condition, kinematical admissibility and constitutive equations under given external loads, deformation reinforcement theory (DRT) is developed. With this theory, plastic complementary energy (PCE) can be used to evaluate the overall stability of rock slope, and the unbalanced force beyond the yield surface could be the identification of local failure. Compared with traditional slope stability analysis approaches, the PCE norm curve to strength reduced factor is introduced and the unbalanced force is applied to the determination of key sliding surfaces and required reinforcement. Typical and important issues in rock slope stability are tested in TFINE(a three-dimensional nonlinear finite element program), which is further applied to several representatives of high rock slope’s stability evaluation and reinforcement engineering practice in southwest of China.

  13. 3D Identification and Stability Analysis of Key Surface Blocks of Rock Slope

    李明超; 周四宝; 王刚


    Complicated geological structures make it difficult to analyze the stability of rock slopes, such as faults, weak intercalated layers or joint fissures. Based on 3D geological modeling and surface block identifying methods, an integrated methodology framework was proposed and realized to analyze the stability of surface blocks in rock slopes. The surface blocks cut by geological structures, fissures or free faces could be identified subjected to the four principles of closure, completeness, uniqueness and validity. The factor of safety(FOS)of single key block was calculated by the limit equilibrium method. If there were two or more connected blocks, they were defined as a block-group. The FOS of a block-group was computed by the Sarma method. The proposed approach was applied to an actual rock slope of a hydropower project, and some possible instable blocks were demonstrated and analyzed visually. The obtained results on the key blocks or block-groups provide essential information for determining po-tential instable region of rock slopes and designing effective support scheme in advance.

  14. Effect of Surcharge on the Stability of Rock Slope under Complex Conditions

    Jiewen Tu


    Full Text Available In this paper, a general analytical expression for the factor of safety of the rock slope against plane failure is proposed, incorporating most of the practically occurring under complex conditions such as depth of tension crack, depth of water in tension crack, seismic loads and surcharge. Several special cases of this expression are established, which can be found similarly to those reported in the literature. A detailed parametric analysis is presented to study the effect of surcharge on the stability of the rock slope for practical ranges of main parameters such as depth of tension crack, depth of water in tension crack, the horizontal seismic coefficient and the vertical seismic coefficient. The parametric analysis has shown that the factor of safety of the rock slope decreases with increase in surcharge for the range of those parameters in this paper. It is also shown that the horizontal seismic coefficient is the most important factor which effects on the factor of safety in the above four influence factors. The general analytical expression proposed in this paper and the results of the parametric analysis can be used to carry out a quantitative assessment of the stability of the rock slopes by engineers and researchers.

  15. Determination of stability of epimetamorphic rock slope using Minimax Probability Machine

    Manoj Kumar


    Full Text Available The article employs Minimax Probability Machine (MPM for the prediction of the stability status of epimetamorphic rock slope. The MPM gives a worst-case bound on the probability of misclassification of future data points. Bulk density (d, height (H, inclination (β, cohesion (c and internal friction angle (φ have been used as input of the MPM. This study uses the MPM as a classification technique. Two models {Linear Minimax Probability Machine (LMPM and Kernelized Minimax Probability Machine (KMPM} have been developed. The generalization capability of the developed models has been checked by a case study. The experimental results demonstrate that MPM-based approaches are promising tools for the prediction of the stability status of epimetamorphic rock slope.

  16. Structure, stability and tsunami hazard associated with a rock slope in Knight Inlet, British Columbia

    D. P. van Zeyl


    Full Text Available Rockfalls and rockslides during the past 12 000 years have deposited bouldery debris cones on the seafloor beneath massive rock slopes throughout the inner part of Knight Inlet. The 885 m high rock slope situated across from the Kwalate site, a former First Nations village destroyed in the late 1500s by a slide-induced wave, exposes the contact between a Late Cretaceous dioritic pluton and metamorphic rocks of the Upper Triassic Karmutsen Formation. The pluton margin is strongly foliated in parallel with primary and secondary fabrics in the metamorphic rocks, resulting in highly persistent brittle structures. Other important structures include a set of sheeting joints and highly persistent mafic dykes and faults. Stability analysis identified the potential for planar and wedge failure. We made empirical estimates of impulse waves generated by potential slides ranging in size from 0.5 to 3.5 Mm3, with results suggesting mid-inlet wave heights in the order of 6 to 26 m. As several similar rock slopes fronted by large submarine debris cones exist in the inner part of Knight Inlet, it is clear that tsunami hazards should be considered in coastal infrastructure development and land-use planning in this area.

  17. Using a Remotely Piloted Aircraft System (RPAS) to analyze the stability of a natural rock slope

    Salvini, Riccardo; Esposito, Giuseppe; Mastrorocco, Giovanni; Seddaiu, Marcello


    This paper describes the application of a rotary wing RPAS for monitoring the stability of a natural rock slope in the municipality of Vecchiano (Pisa, Italy). The slope under investigation is approximately oriented NNW-SSE and has a length of about 320 m; elevation ranges from about 7 to 80 m a.s.l.. The hill consists of stratified limestone, somewhere densely fractured, with dip direction predominantly oriented in a normal way respect to the slope. Fracture traces are present in variable lengths, from decimetre to metre, and penetrate inward the rock versant with thickness difficult to estimate, often exceeding one meter in depth. The intersection between different fracture systems and the slope surface generates rocky blocks and wedges of variable size that may be subject to phenomena of gravitational instability (with reference to the variation of hydraulic and dynamic conditions). Geometrical and structural info about the rock mass, necessary to perform the analysis of the slope stability, were obtained in this work from geo-referenced 3D point clouds acquired using photogrammetric and laser scanning techniques. In particular, a terrestrial laser scanning was carried out from two different point of view using a Leica Scanstation2. The laser survey created many shadows in the data due to the presence of vegetation in the lower parts of the slope and limiting the feasibility of geo-structural survey. To overcome such a limitation, we utilized a rotary wing Aibotix Aibot X6 RPAS geared with a Nikon D3200 camera. The drone flights were executed in manual modality and the images were acquired, according to the characteristics of the outcrops, under different acquisition angles. Furthermore, photos were captured very close to the versant (a few meters), allowing to produce a dense 3D point cloud (about 80 Ma points) by the image processing. A topographic survey was carried out in order to guarantee the necessary spatial accuracy to the process of images exterior

  18. Effect of rock mass structure and block size on the slope stability--Physical modeling and discrete element simulation

    LI; Shihai; LIAN; Zhenzhong; J.; G.; Wang


    This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

  19. Microseismic monitoring and numerical simulation on the stability of high-steep rock slopes in hydropower engineering

    Chun’an Tang; Lianchong Li; Nuwen Xu; Ke Ma


    abstract For high-steep slopes in hydropower engineering, damage can be induced or accumulated due to a series of human or natural activities, including excavation, dam construction, earthquake, rainstorm, rapid rise or drop of water level in the service lifetime of slopes. According to the concept that the progressive damage (microseismicity) of rock slope is the essence of the precursor of slope instability, a microseismic monitoring system for high-steep rock slopes is established. Positioning accuracy of the monitoring system is tested by fixed-position blasting method. Based on waveform and cluster analyses of micro-seismic events recorded during test, the tempo-spatial distribution of microseismic events is analyzed. The deformation zone in the deep rock masses induced by the microseismic events is preliminarily delimited. Based on the physical information measured by in situ microseismic monitoring, an evaluation method for the dynamic stability of rock slopes is proposed and preliminarily implemented by combining microseismic monitoring and numerical modeling. Based on the rock mass damage model obtained by back analysis of microseismic information, the rock mass elements within the microseismic damage zone are automatically searched by finite element program. Then the stiffness and strength reductions are performed on these damaged elements accordingly. Attempts are made to establish the correlation between microseismic event, strength deterioration and slope dynamic instability, so as to quantitatively evaluate the dynamic stability of slope. The case studies about two practical slopes indi-cate that the proposed method can reflect the factor of safety of rock slope more objectively. Numerical analysis can help to understand the characteristics and modes of the monitored microseismic events in rock slopes. Microseismic monitoring data and simulation results can be used to mutually modify the sensitive rock parameters and calibrate the model. Combination

  20. Microseismic monitoring and numerical simulation on the stability of high-steep rock slopes in hydropower engineering

    Chun'an Tang


    Full Text Available For high-steep slopes in hydropower engineering, damage can be induced or accumulated due to a series of human or natural activities, including excavation, dam construction, earthquake, rainstorm, rapid rise or drop of water level in the service lifetime of slopes. According to the concept that the progressive damage (microseismicity of rock slope is the essence of the precursor of slope instability, a microseismic monitoring system for high-steep rock slopes is established. Positioning accuracy of the monitoring system is tested by fixed-position blasting method. Based on waveform and cluster analyses of microseismic events recorded during test, the tempo-spatial distribution of microseismic events is analyzed. The deformation zone in the deep rock masses induced by the microseismic events is preliminarily delimited. Based on the physical information measured by in situ microseismic monitoring, an evaluation method for the dynamic stability of rock slopes is proposed and preliminarily implemented by combining microseismic monitoring and numerical modeling. Based on the rock mass damage model obtained by back analysis of microseismic information, the rock mass elements within the microseismic damage zone are automatically searched by finite element program. Then the stiffness and strength reductions are performed on these damaged elements accordingly. Attempts are made to establish the correlation between microseismic event, strength deterioration and slope dynamic instability, so as to quantitatively evaluate the dynamic stability of slope. The case studies about two practical slopes indicate that the proposed method can reflect the factor of safety of rock slope more objectively. Numerical analysis can help to understand the characteristics and modes of the monitored microseismic events in rock slopes. Microseismic monitoring data and simulation results can be used to mutually modify the sensitive rock parameters and calibrate the model

  1. Numerical probabilistic analysis for slope stability in fractured rock masses using DFN-DEM approach

    Alireza Baghbanan


    Full Text Available Due to existence of uncertainties in input geometrical properties of fractures, there is not any unique solution for assessing the stability of slopes in jointed rock masses. Therefore, the necessity of applying probabilistic analysis in these cases is inevitable. In this study a probabilistic analysis procedure together with relevant algorithms are developed using Discrete Fracture Network-Distinct Element Method (DFN-DEM approach. In the right abutment of Karun 4 dam and downstream of the dam body, five joint sets and one major joint have been identified. According to the geometrical properties of fractures in Karun river valley, instability situations are probable in this abutment. In order to evaluate the stability of the rock slope, different combinations of joint set geometrical parameters are selected, and a series of numerical DEM simulations are performed on generated and validated DFN models in DFN-DEM approach to measure minimum required support patterns in dry and saturated conditions. Results indicate that the distribution of required bolt length is well fitted with a lognormal distribution in both circumstances. In dry conditions, the calculated mean value is 1125.3 m, and more than 80 percent of models need only 1614.99 m of bolts which is a bolt pattern with 2 m spacing and 12 m length. However, as for the slopes with saturated condition, the calculated mean value is 1821.8 m, and more than 80 percent of models need only 2653.49 m of bolts which is equivalent to a bolt pattern with 15 m length and 1.5 m spacing. Comparison between obtained results with numerical and empirical method show that investigation of a slope stability with different DFN realizations which conducted in different block patterns is more efficient than the empirical methods.

  2. Stability of High Slope Interbedded Strata with Low Dip Angle Constituted by Soft and Hard Rock Mass

    邓荣贵; 周德培; 张倬元


    Slopes consisting of interbedded strata of soft and hard rock mass, such as purplish red mudstone and grey-brown arkosic sandstone of Jurassic age, are very common in Sichuan basin of China. The mudstone is soft while the sandstone is hard and contains many opening or closing joints with a high dip angle. Some are nearly parallel and the others are nearly decussated with the trend of the slopes. Many natural slopes are in deformation or sliding because of those reasons. The stability of cutting slopes and supporting method to be taken for their stability in civil engineering are important. In this paper, the stability and deformation of the slopes are studied. The methods of analysis and support design principle are analyzed also. Finally, the method put forward is applied to study Fengdian high cutting slope in Sichuan section of the express way from Chengdu to Shanghai. The results indicate that the method is effective.

  3. Workflow for the fast evaluation of rock mass properties and stability of rock slopes along trafficways in Lower Austria

    Straka, Wolfgang; Zangerl, Christian


    In Lower Austria there is a total of 17.000 km of provincial and 24.000 km of communal roads, to be maintained by the province and the municipalities. In addition, there are approx. 1.500 km of railroads, and the Danube as a major waterway. A large part of this infrastructure is, or is potentially, affected by various types of instability of adjacent slopes. Due to insufficient knowledge, as well as slope design and management practice in the past, every year, especially in connection to weather extremes, slopes known to be critical become active landslides again, and unexpected new ones arise, causing damage as well as financial stress. Engineering intervention, if possible, should be quick and effective. Geologists and engineers in public service, not having the means for detailed investigation in most cases, are using guidelines to assess the requirements to be met by slope design on traffic ways. But these guidelines don't reflect many of the newer scientific advances. Therefore, scientists at BOKU and backers in the administration want to gain more insight into causative factors, which, if successful, may render maintenance of traffic lines under critical conditions more effective and predictable. The specific project goal is to produce new guidelines to allow quick assessment of the most likely behaviour of rock masses common in the area, especially when cut into shape along infrastructure lines, using readily available information. The scientific investigations include simple and ready tests (like Schmidt hammer), as well as photogrammetry, laserscanning, and other complex geophysical and numerical techniques, but the final product (guidelines) is expected to work without such difficult methods. It is important to note, on the other hand, that the rock mass stability classification inherent in the new guidelines must allow distinction between conclusions which are safe, and conjectures which are in need of validation by contracted experts. It is planned to

  4. Stability analysis and optimum reinforcement design for an intense weathered rock slope

    Qi, Kuan; Tan, Zhuoying; Li, Wen


    In view of the complex structural characters of Chengmenshan copper mine slope, the slope stability should be analyzed and additional reinforcement measures need to be considered to ensure mining safety. In this paper, the slope model was built and its stability was analyzed by numerical simulation method under nature and dynamic loading state. After that the design of orthogonal experiment was discussed for the key factors which influence the reinforcement effect of anchors with SPSS software, and the primary and secondary relation of factors and the optimal combination were obtained using the range analysis method. Finally, the slope stability with optimal reinforcement measure was tested. The results show that the safety factor of slope under nature state is low and it is in the critical instability condition. Under dynamic loading state, the failure probability of slope increases from 0 to 18% as the seismic magnitude varies from 6 to 8. Primary and secondary sequence of factors that influence the anchor reinforcement effect is the bonding length, anchor installing angle, anchor length at 3rd bench, anchor length at 2nd bench and anchor length at 1st bench .The safety factor of slope reinforced with anchors is larger than 1.1, which could ensure the safety and stability of the slope.

  5. Combined rock slope stability and shallow landslide susceptibility assessment of the Jasmund cliff area (Rügen Island, Germany

    A. Günther


    Full Text Available In this contribution we evaluated both the structurally-controlled failure susceptibility of the fractured Cretaceous chalk rocks and the topographically-controlled shallow landslide susceptibility of the overlying glacial sediments for the Jasmund cliff area on Rügen Island, Germany. We employed a combined methodology involving spatially distributed kinematical rock slope failure testing with tectonic fabric data, and both physically- and inventory-based shallow landslide susceptibility analysis. The rock slope failure susceptibility model identifies areas of recent cliff collapses, confirming its value in predicting the locations of future failures. The model reveals that toppling is the most important failure type in the Cretaceous chalk rocks of the area. The shallow landslide susceptibility analysis involves a physically-based slope stability evaluation which utilizes material strength and hydraulic conductivity data, and a bivariate landslide susceptibility analysis exploiting landslide inventory data and thematic information on ground conditioning factors. Both models show reasonable success rates when evaluated with the available inventory data, and an attempt was made to combine the individual models to prepare a map displaying both terrain instability and landslide susceptibility. This combination highlights unstable cliff portions lacking discrete landslide areas as well as cliff sections highly affected by past landslide events. Through a spatial integration of the rock slope failure susceptibility model with the combined shallow landslide assessment we produced a comprehensive landslide susceptibility map for the Jasmund cliff area.

  6. Geological Control on Stability of Excavated Rock Slope at Jeruklegi Claystone Quarry, Cilacap Regency, Central Java Province, Indonesia

    Fukuoka, Hiroshi; Dok, Atitkagna; Pramumijoyo, Subagyo; Faisal Fathani, Teuku


    PT. Holcim Indonesia Tbk is a well-known company for cement production in Cilacap, Central Java, Indonesia. In cement manufacturing, certain raw materials such as limestone, claystone and other supplementary materials are required. In a mean time, the company is conducting claystone mining to support the cement industry. Currently, the exploitation has covered the area of approximately 103 ha. Due to the increment need of more claystone to achieve the expecting amount of cement production, the company plans to extend existing mining site up to 250 ha with maximum depth of +10m above the sea level. However, such development may eventually lead to major slope failures which essentially affect the sustainability and the safety of the mine. Understanding that various negative impacts may appear during the mining operation, which possibly result in personal injury, potential life loss, property damage and other socio-economic consequences, it is crucial to assess slope stability conditions of the mining pit to ensure safety of the mine. The study is mainly focused on analysis of the rock mass behaviours under specific geological control and earthquake trigger through the application of finite element method. Based on the assessment result, the zone where covered by discontinuous rock mass, absorbent lithology and steep slope geometry in combination with presence of groundwater, is estimated to be potential to slope movement in form of rock falls and/or rock slides which could be possibly predicted to occur as a consequence of heavy rainfall intensity, un-controlled slope excavation and ground vibration. And, the stable slope inclination is suggested not to be steeper than 60˚, with the maximum width of 3m and maximum height of 6m.

  7. Effect of Seismic Permanent Deformation on Safety and Stability of Earth-Rock Dam Slope

    戚蓝; 陈启振; 蔡建成


    In order to study the effect of seismic permanent deformation on the safety and stability of earth-rock dam, the permanent deformation is considered as the non-design permanent load, and the stress-strain hysteresis curve is also considered when the earth is under cyclic load. The research work can make the calculation results of plastic col-lapse more accurate by including the effect of the post-earthquake degree of plastic deformation on the stability of the earth-rock dam, and the dam safety factor decreases from 2.50 to 1.90 after the magnitude-8 earthquake. Moreover, the research work will also improve the design of the earth-rock dam under abnormal operating conditions.

  8. Analysis of microseismic signals and temperature recordings for rock slope stability investigations in high mountain areas

    C. Occhiena


    Full Text Available The permafrost degradation is a probable cause for the increase of rock instabilities and rock falls observed in recent years in high mountain areas, particularly in the Alpine region. The phenomenon causes the thaw of the ice filling rock discontinuities; the water deriving from it subsequently freezes again inducing stresses in the rock mass that may lead, in the long term, to rock falls. To investigate these processes, a monitoring system composed by geophones and thermometers was installed in 2007 at the Carrel hut (3829 m a.s.l., Matterhorn, NW Alps. In 2010, in the framework of the Interreg 2007–2013 Alcotra project no. 56 MASSA, the monitoring system has been empowered and renovated in order to meet project needs.

    In this paper, the data recorded by this renewed system between 6 October 2010 and 5 October 2011 are presented and 329 selected microseismic events are analysed. The data processing has concerned the classification of the recorded signals, the analysis of their distribution in time and the identification of the most important trace characteristics in time and frequency domain. The interpretation of the results has evidenced a possible correlation between the temperature trend and the event occurrence.

    The research is still in progress and the data recording and interpretation are planned for a longer period to better investigate the spatial-temporal distribution of microseismic activity in the rock mass, with specific attention to the relation of microseismic activity with temperatures. The overall goal is to verify the possibility to set up an effective monitoring system for investigating the stability of a rock mass under permafrost conditions, in order to supply the researchers with useful data to better understand the relationship between temperature and rock mass stability and, possibly, the technicians with a valid tool for decision-making.

  9. Methodology to evaluate rock slope stability under seismic conditions at Solà de Santa Coloma, Andorra

    O. Mavrouli


    Full Text Available An analytical methodology is presented to evaluate rock slope stability under seismic conditions by considering the geomechanical and topographic properties of a slope. The objective is to locate potential rockfall source areas and evaluate their susceptibility in terms of probability of failure. For this purpose, the slope face of a study area is discretized into cells having homogenous aspect, slope angle, rock properties and joint set orientations. A pseudostatic limit equilibrium analysis is performed for each cell, whereby the destabilizing effect of an earthquake is represented by a horizontal force. The value of this force is calculated by linear interpolation between the peak horizontal ground acceleration PGA at the base and the top of the slope. The ground acceleration at the top of the slope is increased by 50% to account for topographic amplification. The uncertainty associated with the joint dip is taken into account using the Monte Carlo method. The proposed methodology was applied to a study site with moderate seismicity in Solà de Santa Coloma, located in the Principality of Andorra. The results of the analysis are consistent with the spatial distribution of historical rockfalls that have occurred since 1997. Moreover, the results indicate that for the studied area, 1 the most important factor controlling the rockfall susceptibility of the slope is water pressure in joints and 2 earthquake shaking with PGA of ≤0.16 g will cause a significant increase in rockfall activity only if water levels in joints are greater than 50% of the joint height.

  10. Rock slope stability analysis along the North Carolina section of the Blue Ridge Parkway: Using a geographic information system (GIS) to integrate site data and digital geologic maps

    Latham, R.S.; Wooten, R.M.; Cattanach, B.L.; Merschat, C.E.; Bozdog, G.N.


    In 2008, the North Carolina Geological Survey (NCGS) completed a five-year geologic and geohazards inventory of the 406-km long North Carolina segment of the Blue Ridge Parkway (BRP). The ArcGIS??? format deliverables for rock slopes include a slope movement and slope movement deposit database and maps and site-specific rock slope stability assessments at 158 locations. Database entries for known and potential rock slope failures include: location data, failure modes and dimensions, activity dates and levels, structural and lithologic data, the occurrence of sulfide minerals and acid-producing potential test results. Rock slope stability assessments include photographs of the rock cuts and show locations and orientations of rock data, seepage zones, and kinematic stability analyses. Assigned preliminary geologic hazard ratings of low, moderate and high indicate the generalized relative probability of rock fall and/or rock slide activity at a given location. Statistics compiled based on the database indicate some general patterns within the data. This information provides the National Park Service with tools that can aid in emergency preparedness, and in budgeting mitigation, maintenance and repair measures. Copyright 2009 ARMA, American Rock Mechanics Association.

  11. Assessment of rock properties and slope stability at Pacaya Volcano, Guatemala

    Schaefer, Lauren; Kendrick, Jackie; Oommen, Thomas; Lavallee, Yan


    Pacaya is an active stratovolcano located 30 km south of Guatemala City, Guatemala. A large (0.65 km3) sector collapse of the volcano occurred 0.6 - 1.6 ka B.P., producing a debris avalanche that traveled 25 km SW of the edifice. The structural setting of the current cone, along with two recent smaller-volume collapses in 1962 and 2010, suggest gravitational instability of this volcano. Recent measurements of the geomechanical properties of lava and breccia from Pacaya are used to improve our understanding of the destabilizing potential of different volcanic processes. Room-temperature uniaxial and triaxial compressive tests, and total porosity tests, were conducted on 17 breccia and 21 lava samples. The average uniaxial compressive strength (σci) of lava rocks was moderately strong (σci = 72.4 MPa), with breccia rocks being 62.2% weaker (σci = 27.4 MPa). These values can partially be contributed to lava rock's very low porosity (0.054) and breccia rock's higher porosity (0.19). We also find an apparent rate-dependent strengthening of the samples as strain rate is increased from 10-5 to 10-1. Values of Poisson's Ratio (v) and Young's Modulus (E) calculated from triaxial tests, are v= 0.28 and E = 13.9 GPa for breccia and v= 0.31 and E = 17.6 GPa for lava. These experiments highlight the contrasting character of breccia versus lava, and suggest that sector collapse may have initiated in the weaker breccia. Additionally, cohesion (c) and friction angle (φ) calculated from triaxial tests yielded values of c = 1.8 MPa and φ = 19.4° for breccia and c = 4.0 MPa and φ = 41.4° for lava. Following sector collapse, the frictional properties of the rocks partially dictate the flow and deposition of the debris avalanche, and these were studied using high velocity rotary shear experiments on ash and lava rock. Experimental results are combined to understand the historical flank stability and assess the likelihood of future sector collapse at Pacaya.

  12. Automated sliding susceptibility mapping of rock slopes

    A. Günther


    Full Text Available We present a suite of extensions for ARCVIEW GIS™ (ESRI that allows to map the spatial distribution of first-order mechanical slope-properties in hard rock terrain, e.g. for large slope areas like water reservoir slopes. Besides digital elevation data, this expert-system includes regional continuous grid-based data on geological structures that might act as potential sliding or cutoff planes for rockslides. The system allows rapid automated mapping of geometrical and kinematical slope properties in hard rock, providing the basis for spatially distributed deterministic sliding-susceptibility evaluations on a pixel base. Changing hydrostatic slope conditions and rock mechanical parameters can be implemented and used for simple predictive static stability calculations. Application is demonstrated for a study area in the Harz Mts., Germany.

  13. Geotechnical characteristics and stability analysis of rock-soil aggregate slope at the Gushui Hydropower Station, southwest China.

    Zhou, Jia-wen; Shi, Chong; Xu, Fu-gang


    Two important features of the high slopes at Gushui Hydropower Station are layered accumulations (rock-soil aggregate) and multilevel toppling failures of plate rock masses; the Gendakan slope is selected for case study in this paper. Geological processes of the layered accumulation of rock and soil particles are carried out by the movement of water flow; the main reasons for the toppling failure of plate rock masses are the increasing weight of the upper rock-soil aggregate and mountain erosion by river water. Indoor triaxial compression test results show that, the cohesion and friction angle of the rock-soil aggregate decreased with the increasing water content; the cohesion and the friction angle for natural rock-soil aggregate are 57.7 kPa and 31.3° and 26.1 kPa and 29.1° for saturated rock-soil aggregate, respectively. The deformation and failure mechanism of the rock-soil aggregate slope is a progressive process, and local landslides will occur step by step. Three-dimensional limit equilibrium analysis results show that the minimum safety factor of Gendakan slope is 0.953 when the rock-soil aggregate is saturated, and small scale of landslide will happen at the lower slope.

  14. Assessment of Rock Slope Stability in Limestone Quarries in the Tournai's Region (Belgium) Using Structural Data

    Tshibangu, Jean-Pierre; Deloge, K. Pierre-Alexandre; Deschamps, Benoît; Coudyzer, Christophe

    The Tournais region is characterised by famous outcrops of carboniferous limestone which is mined out for cement and raw material production. The four main quarries found in the Region, i.e. Gaurain-Ramecroix, Milieu, Antoing and Lemay; are owned by the three main cement producers in Belgium: Italcimenti, Holcim and CBR. The global production of limestone is about 20 millions tons per year, giving big pits with depths up to 150 m. With the growth of the pits, the quarries are approaching each other leading to the problem of managing the reserves contained in the separating walls and their mechanical stability. The limestone deposit is composed of different seams having varying thickness, chemical com- position and even mechanical properties. The deposit has an overall horizontal dip and is intersected by two main sets of discontinuities with a spacing of about 10 m or less. It is also crossed by a set of east to west faults but the quarries are implanted in the in between areas, so to not be crossed by these faults. The layers and specially the shallow ones are characterised by a typical karstic weathering giving open or filled cavities. This paper presents the global work quarried out in order to study the stability of the Lemays quarry. First a description of the orientation and spacing of discontinuities is presented, and an attempt made to correlate to the development of weathering. Mechanical laboratory tests have been performed and a qualification of the rock mass assessed. A coupled approach is then presented using a mining planning analysis and mechanical simulation (i.e. Finite Element method).

  15. Modified hydropower slope rock mass stability rating system%改进的水电边坡岩体稳定性分级法

    张菊连; 沈明荣


    为克服现有基于边坡岩体分级SMR法的修正分级法存在的缺陷,采用较为合理的修正模型,结合36个水电工程边坡,提出了改进的水电边坡岩体分级M-CSMR法.该法使用边坡类型系数替代开挖修正得分,同时考虑了开挖、水流冲刷及掏蚀作用的影响;将坡高对边坡岩体稳定性的影响引入分级中,给出坡高分级及评分原则;对SMR法中各指标权值重新进行调整.与岩体分级RMR法、边坡岩体分级SMR法及水电边坡岩体分级CSMR法进行了比较,结果表明MCSMR分级法与经验评分最为接近,预测结果最好,最大绝对误差、平均绝对误差及剩余标准差均最小,因此M-CSMR是一种更优的水电边坡岩体分级方法.%In order to overcome the defects in the existing modified mass rating system originated from slope rock mass rating (SMR) system, a more rational correction model was adopted to establish a modified Chinese hydropower slope rock mass rating (M-CSMR) system based on thirty six hydropower slopes.The coefficients of slope types were used to take the place of excavation factor to comprehensively take into account the influences of excavation, water erosion and scour on rock mass stability; the influence of slope height on rock mass stability was introduced into this system, and its grading and rating principle were given; the weights of factors in the SMR system were re-adjusted.Compared with rock mass rating (RMR) system, slope rock mass rating (SMR) system and Chinese slope rock mass rating (CSMR) system, the M-CSMR system's evaluation results are closer to the empirical rating based on safety of factor, the prediction results are better, the maximum absolute error, the mean absolute error and the residual standard deviation are all smaller, thus MCSMR is a better hydropower slope rock mass rating system.

  16. Stability of Dolos Slopes

    Brorsen, Michael; Burcharth, Hans F.; Larsen, Torben

    The stability of dolos armour blocks against wave attack has been investigated in wave model studies.......The stability of dolos armour blocks against wave attack has been investigated in wave model studies....

  17. Motion of rock masses on slope

    Urška Petje


    Full Text Available This paper shows the different ways of how rock masses (stones, rocks, and blocks move along slopes and for each different way of motion (free fall, bouncing, rolling, sliding, slowing down, lubrication, fluidizationadequatedynamicequationsaregiven.Knowingthe kinematics and dynamics of travelling rock masses is necessary for mathematical modeling of motion and by this an assessment of maximal possible rockfall runout distances as an example of a sudden and hazardeous natural phenomenon, threatening man and his property, especially in the natural environment.

  18. Slope earthquake stability

    Changwei, Yang; Jing, Lian; Wenying, Yu; Jianjing, Zhang


    This book begins with the dynamic characteristics of the covering layerbedrock type slope, containing monitoring data of the seismic array, shaking table tests, numerical analysis and theoretical derivation. Then it focuses on the landslide mechanism and assessment method. It also proposes a model that assessing the hazard area based on the field investigations. Many questions, exercises and solutions are given. Researchers and engineers in the field of Geotechnical Engineering and Anti-seismic Engineering can benefit from it.

  19. Slope Stability Analysis Using GIS

    Bouajaj, Ahmed; Bahi, Lahcen; Ouadif, Latifa; Awa, Mohamed


    An analysis of slope stability using Geographic Information System (GIS) is presented in this paper. The methodology is based on the calculation of the safety factor in 2D and 3D using ArcGis. Hovland's Method in 3D and 2D were used in the stability analysis of the slope located at the 34 kilometer point (K.P.34) on the highway in the North of Morocco connecting Tangier to Ksar Sghir. Results shows that the safety factors obtained in 3D are always higher than those obtained in 2D and the slope becomes unstable when the water table level is less than 1 m.


    A. Bouajaj


    Full Text Available An analysis of slope stability using Geographic Information System (GIS is presented in this paper. The methodology is based on the calculation of the safety factor in 2D and 3D using ArcGis. Hovland's Method in 3D and 2D were used in the stability analysis of the slope located at the 34 kilometer point (K.P.34 on the highway in the North of Morocco connecting Tangier to Ksar Sghir. Results shows that the safety factors obtained in 3D are always higher than those obtained in 2D and the slope becomes unstable when the water table level is less than 1 m.

  1. Slope stability hazard management systems


    Weather-related geo-hazards are a major concern for both natural slopes and man-made slopes and embankments.Government agencies and private companies are increasingly required to ensure that there is adequate protection of sloping surfaces in order that interaction with the climate does not produce instability. Superior theoretical formulations and computer tools are now available to address engineering design issues related to the near ground surface soil-atmospheric interactions. An example is given in this paper that illustrates the consequences of not paying adequate attention to the hazards of slope stability prior to the construction of a highway in South America. On the other hand, examples are given from Hong Kong and Mainland China where significant benefits are derived from putting in place a hazard slope stability management system. Some results from a hazard management slope stability study related to the railway system in Canada are also reported. The study took advantage of recent research on unsaturated soil behaviour and applied this information to real-time modelling of climatic conditions. The quantification of the water balance at the ground surface, and subsequent infiltration, is used as the primary tool for hazard level assessment. The suggested hazard model can be applied at either specific high risk locations or in a more general, broad-based manner over large areas. A more thorough understanding of unsaturated soil behaviour as it applies to near ground surface soils,along with the numerical computational power of the computer has made it possible for new approaches to be used in slope hazard management engineering.

  2. Rock slope instabilities in Norway: First systematic hazard and risk classification of 22 unstable rock slopes

    Böhme, Martina; Hermanns, Reginald L.; Oppikofer, Thierry; Penna, Ivanna


    Unstable rock slopes that can cause large failures of the rock-avalanche type have been mapped in Norway for almost two decades. Four sites have earlier been characterized as high-risk objects based on expertise of few researchers. This resulted in installing continuous monitoring systems and set-up of an early-warning system for those four sites. Other unstable rock slopes have not been ranked related to their hazard or risk. There are ca. 300 other sites known of which 70 sites were installed for periodic deformation measurements using multiple techniques (Global Navigation Satellite Systems, extensometers, measurement bolts, and others). In 2012 a systematic hazard and risk classification system for unstable rock slopes was established in Norway and the mapping approach adapted to that in 2013. Now, the first 22 sites were classified for hazard, consequences and risk using this classification system. The selection of the first group of sites to be classified was based on an assumed high hazard or risk and importance given to the sites by Norwegian media and the public. Nine of the classified 22 unstable rock slopes are large sites that deform inhomogeneously or are strongly broken up in individual blocks. This suggests that different failure scenarios are possible that need to be analyzed individually. A total of 35 failure scenarios for those nine unstable rock slopes were considered. The hazard analyses were based on 9 geological parameters defined in the classification system. The classification system will be presented based on the Gamanjunni unstable rock slope. This slope has a well developed back scarp that exposes 150 m preceding displacement. The lateral limits of the unstable slope are clearly visible in the morphology and InSAR displacement data. There have been no single structures observed that allow sliding kinematically. The lower extend of the displacing rock mass is clearly defined in InSAR data and by a zone of higher rock fall activity. Yearly

  3. 基于非连续变形分析的岩质高边坡稳定性评价%The high rock slope stability evaluation based on DDA



    针对岩质高边坡的滑坡失稳的典型破坏形式,采用非连续变形分析(DDA)这一数值分析方法,结合某高速公路岩质高边坡工程实例,建立计算模型,深入研究边坡岩体的结构面参数与边坡变形的相互关系,分析不同工况下边坡块体的极限内摩擦角和稳定安全系数,进而评价边坡的稳定性,结果表明与边坡稳定实际情况基本吻合.%According to the classical damage problem of high rock slope,by use of DDA,the discontinuous deformation analysis ( DDA) model is set up,combined with a rock edge slope engineering case of the highway. The relationship between joint parameters and slope deformation is studied,and the limited internal friction angle of the sliding face of slope is obtained under some conditions,the safety factor of slope stability is calculated, and the slope stability is evaluated. Ttie results show that the actual situation with the basic agreement.

  4. Upper Bound Method of Plastic Limit Analysis Using Finite Elements for Layered Rock Slope Stability%层状岩质边坡稳定性有限元塑性极限分析上限法研究



    本文基于有限元上限法,研究了不同层理面参数、岩体容重和边坡坡高对边坡稳定性的影响,研究结果表明:随着层理面强度的增加,边坡稳定性越高;岩体容重和边坡坡高的增加,边坡越不稳定。本文研究成果可为类似工程起借鉴作用。%It researched on the different layer plane parameters,bulk density of rock and the slope height for slope stability based on the finite element of upper bound method,the results showed:With the increase of bedding surface strength,the slope stability higher;The increase of rock of bulk density and the slope height,the slope more unstable.The results of this article can be a reference for similar projects.

  5. Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes

    Okubo, C.H.; Tornabene, L.L.; Lanza, N.L.


    The value of slope stability analyses for gaining insight into the geologic conditions that would facilitate the growth of gully alcoves on Mars is demonstrated in Gasa crater. Two-dimensional limit equilibrium methods are used in conjunction with high-resolution topography derived from stereo High Resolution Imaging Science Experiment (HiRISE) imagery. These analyses reveal three conditions that may produce observed alcove morphologies through slope failure: (1) a ca >10m thick surface layer that is either saturated with H2O ground ice or contains no groundwater/ice at all, above a zone of melting H2O ice or groundwater and under dynamic loading (i.e., seismicity), (2) a 1-10m thick surface layer that is saturated with either melting H2O ice or groundwater and under dynamic loading, or (3) a >100m thick surface layer that is saturated with either melting H2O ice or groundwater and under static loading. This finding of three plausible scenarios for slope failure demonstrates how the triggering mechanisms and characteristics of future alcove growth would be affected by prevailing environmental conditions. HiRISE images also reveal normal faults and other fractures tangential to the crowns of some gully alcoves that are interpreted to be the result of slope instability, which may facilitate future slope movement. Stability analyses show that the most failure-prone slopes in this area are found in alcoves that are adjacent to crown fractures. Accordingly, crown fractures appear to be a useful indicator of those alcoves that should be monitored for future landslide activity. ?? 2010.

  6. Profile Orientation and Slope Stability Analysis

    Zhe-Ping Shen


    Full Text Available This paper presents an analysis of soil slope stability using a terrestrial laser scanner, particle swarm optimization, and the force equilibrium method. The aim of this study was to demonstrate that a slope needed to be analyzed in many different directions in order to assess its stability conclusively, rather than using just one cross-sectional profile to represent the entire slope. To achieve this purpose, this study illustrates how a particle swarm optimization algorithm can be successfully incorporated into the analysis with slope stability analysis software, STABL. This study compares results obtained with those of previous studies and makes important observations.

  7. Application of fuzzy optimal selection of similar slopes to the evaluation of slope stability

    WANG Xu-hua; CHEN Shou-yu; TANG Lie-xian; ZHANG Hou-quan


    The numerical calculation method is widely used in the evaluation of slope stability, but it cannot take the randomness and fuzziness into account that exist in rock and soil engineering objectively. The fuzzy optimization theory is thus introduced to the evaluation of slope stability by this paper and a method of fuzzy optimal selection of similar slopes is put forward to analyze slope stability. By comparing the relative membership degrees that the evaluated object sample of slope is similar to the source samples of which the stabilities are detected clearly, the source sample with the maximal relative membership degree will be chosen as the best similar one to the object sample, and the stability of the object sample can be evaluated by that of the best similar source sample. In the process many uncertain influential factors are considered and characteristics and knowledge of the source samples are obtained. The practical calculation indicates that it can achieve good results to evaluate slope stability by using this method.

  8. Fuzzy Logic System for Slope Stability Prediction

    Tarig Mohamed


    Full Text Available The main goal of this research is to predict the stability of slopes using fuzzy logic system. GeoStudio, a commercially available software was used to compute safety factors for various designs of slope. The general formulation of the software could analyze slope stability using various methods of analysis i.e. Morgenstern-Price, Janbu, Bishop and Ordinary to calculate the safety factors. After analyzing, fuzzy logic was used to predict the slope stability. Fuzzy logic is based on natural language and conceptually easy to understand, flexible, tolerant of imprecise data and able to model nonlinear functions of arbitrary complexity. Several important parameters such as height of slope, unit weight of slope material, angle of slope, coefficient of cohesion and internal angle of friction were used as the input parameters, while the factor of safety was the output parameter. A model to test the stability of the slope was generated from the calculated data. This model presented a relationship between input parameters and stability of the slopes. Results showed that the prediction using fuzzy logic was accurate and close to the target data.

  9. Physical and theoretical modeling of rock slopes against block-flexure toppling failure

    Mehdi Amini


    Full Text Available Block-flexure is the most common mode of toppling failure in natural and excavated rock slopes. In such failure, some rock blocks break due to tensile stresses and some overturn under their own weights and then all of them topple together. In this paper, first, a brief review of previous studies on toppling failures is presented. Then, the physical and mechanical properties of experimental modeling materials are summarized. Next, the physical modeling results of rock slopes with the potential of block-flexural toppling failures are explained and a new analytical solution is proposed for the stability analysis of such slopes. The results of this method are compared with the outcomes of the experiments. The comparative studies show that the proposed analytical approach is appropriate for the stability analysis of rock slopes against block-flexure toppling failure. Finally, a real case study is used for the practical verification of the suggested method.

  10. 基于三维数值模拟的土-岩复合边坡稳定性分析%Stability Analysis for Soil-rock Composite Slope Based on Three-dimensional Numerical Simulation

    田巍巍; 吴彬; 杜明亮; 王传宝


    The soil-rock composite slope stability of the joint intake of Kenswat hydro-junction engineering is simulated and analyzed here by using the strength reduction finite-difference method .The simulation results show that faint plastic displacement would occur in the superficial zone of the soil-rock composite slope’s feet and face owing to the shear stress and local tension stress.Under the slope,the rock slope of lower cretaceous Hutubi river group (k1h1)would be basical-ly in elastic deformation,and the upper gravel soil slope would form the most dangerous sliding face .From the prediction of evolution process,the unconsolidated layers of the Middle to Upper Pleistocene of Quaternary (Qal3 )and the glued layer of the Upper Pleistocene of Quaternary (Qal2-3)would cause the creep slip and be in the danger of collapse .The simula-tion results are of an important reference for the stability control of soil-rock composite slope .%运用有限差分强度折减法对肯斯瓦特水利枢纽工程联合进水口土-岩复合边坡的稳定性进行了模拟分析.模拟结果表明:联合进水口土-岩复合边坡在坡脚和坡面浅表层由于剪应力和局部的拉应力作用发生过微弱的塑性位移,下部白垩系下统呼图壁河组(k.h1)岩质边坡基本上处于弹性变形,上部卵砾石土质边坡形成最危险的滑移面;从演变过程预测,坡顶处第四系中~上更新统(Q2al-3)松散层和第四系上更新统(Q3al)胶结层会出现蠕动滑移和崩塌的危险.模拟结果将对土-岩复合边坡的稳定性控制具有重要的参考作用.

  11. Seismic response of rock slopes: Numerical investigations on the role of internal structure

    Arnold, L.; Applegate, K.; Gibson, M.; Wartman, J.; Adams, S.; Maclaughlin, M.; Smith, S.; Keefer, D. K.


    The stability of rock slopes is significantly influenced and often controlled by the internal structure of the slope created by such discontinuities as joints, shear zones, and faults. Under seismic conditions, these discontinuities influence both the resistance of a slope to failure and its response to dynamic loading. The dynamic response, which can be characterized by the slope's natural frequency and amplification of ground motion, governs the loading experienced by the slope in a seismic event and, therefore, influences the slope's stability. In support of the Network for Earthquake Engineering Simulation (NEES) project Seismically-Induced Rock Slope Failure: Mechanisms and Prediction (NEESROCK), we conducted a 2D numerical investigation using the discrete element method (DEM) coupled with simple discrete fracture networks (DFNs). The intact rock mass is simulated with a bonded assembly of discrete particles, commonly referred to as the bonded-particle model (BPM) for rock. Discontinuities in the BPM are formed by the insertion of smooth, unbonded contacts along specified planes. The influence of discontinuity spacing, orientation, and stiffness on slope natural frequency and amplification was investigated with the commercially available Particle Flow Code (PFC2D). Numerical results indicate that increased discontinuity spacing has a non-linear effect in decreasing the amplification and increasing the natural frequency of the slope. As discontinuity dip changes from sub-horizontal to sub-vertical, the slope's level of amplification increases while the natural frequency of the slope decreases. Increased joint stiffness decreases amplification and increases natural frequency. The results reveal that internal structure has a strong influence on rock slope dynamics that can significantly change the system's dynamic response and stability during seismic loading. Financial support for this research was provided by the United States National Science Foundation (NSF

  12. Thermomechanical forcing of deep rock slope deformation: 2. The Randa rock slope instability

    Gischig, Valentin S.; Moore, Jeffrey R.; Evans, Keith F.; Amann, Florian; Loew, Simon


    Deformation monitoring between 2004 and 2011 at the rock slope instability above Randa (Switzerland) has revealed an intriguing seasonal trend. Relative dislocation rates across active fractures increase when near-surface rock temperatures drop in the fall and decrease after snowmelt as temperatures rise. This temporal pattern was observed with different monitoring systems at the ground surface and at depths up to 68 m, and represents the behavior of the entire instability. In this paper, the second of two companion pieces, we interpret this seasonal deformation trend as being controlled by thermomechanical (TM) effects driven by near-surface temperature cycles. While Part 1 of this work demonstrated in a conceptual manner how TM effects can drive deep rock slope deformation and progressive failure, we present here in Part 2 a case study where temperature-controlled deformation trends were observed in a natural setting. A 2D discrete-element numerical model is employed, which allows failure along discontinuities and successfully reproduces the observed kinematics of the Randa instability. By implementing simplified ground surface temperature forcing, model results were able to reproduce the observed deformation pattern, and TM-induced displacement rates and seasonal amplitudes in the model are of the same order of magnitude as measured values. Model results, however, exhibit spatial variation in displacement onset times while field measurements show more synchronous change. Additional heat transfer mechanisms, such as fracture ventilation, likely create deviations from the purely transient-conductive temperature field modeled. We suggest that TM effects are especially important at Randa due to the absence of significant groundwater within the unstable rock mass.

  13. Stability Analysing of Unsaturated Soil Slope

    张士林; 邵龙潭


    The stability of unsaturated soil slope has been the hot point recently. Especially, the seeping rainfall makes losing stability of unsaturated soil slope, and causes enormous loss to the producation and safety of other people. The seeping rainfall makes volumetric water content of unsaturated soil slope changing, and the volumetric water content has directly relationship with matric suction. And matric suction also has directly relationship with the stability of unsaturated soil slope. So the change of matric suction influence the stability changing, that is, safety coefficient has decided relationship with volumetric water content. The profile of dangerous volumetric water content curves of unsaturated soil slope has been obtained. If a volumetric water content curve of some unsaturated soil slope belongs to one of these dongerous curves, the unsaturated soil slope could be in danger. So this is called DVWCCP(dangerous volumetric water content curves profile). By monitoring the volumetric water content curves can obtain the stability information of some soil slope to serve producing and safety.

  14. Three Practical Methods for Analyzing Slope Stability

    XU Shiguang; ZHANG Shitao; ZHU Chuanbing; YIN Ying


    Since the environmental capacity and the arable as well as the inhabitant lands have actually reached a full balance, the slopes are becoming the more and more important options for various engineering constructions. Because of the geological complexity of the slope, the design and thedecision-making of a slope-based engineering is still not ractical to rely solely on the theoretical analysis and numerical calculation, but mainly on the experience of the experts. Therefore, it hasimportant practical significance to turn some successful experience into mathematic equations. Basedupon the abundant typical slope engineering construction cases in Yunnan, Southwestern China, 3methods for yzing the slope stability have been developed in this paper. First of all, the corresponded analogous mathematic equation for analyzing slope stability has been established through case studies. Then, artificial neural network and multivariate regression analysis have alsobeen set up when 7 main influencing factors are adopted

  15. Step-path failure mode and stability calculation of jointed rock slopes%岩质边坡断续裂隙阶梯状滑移模式及稳定性计算

    岑夺丰; 黄达; 黄润秋


    Step-path failure is a kind of typical instability mode in rock slopes. Based on the summary of geological structural features of jointed rock slopes, the step-path failure mode and evolution process are studied by using the discrete element method, particle flow code in two dimensions (PFC2D). Three rock bridge failure modes in slopes can be summarized:tensile coalescence, shear coalescence and mixed tensile-shear coalescence. Through the evolution analysis of the rock mesoscopic particle bond force vector field, stress state of rock bridges and rock bridge failure, the progressive step-path failure process that rock bridge fractures one by one from the bottom up under the action of gravity is revealed, and the tensile crack development in the trailing edge of slope is due to the traction of lower part of slope. Take the slope with shallow dipping step-path parallel fissures for example (dip angle of rock bridge is 90°, and that of fissure is 30°), the step-path failure process can be distributed into four stages: elastic steady deformation of slope, failure of the lower rock bridges, failure of the upper rock bridges and development of tensile crack in the trailing edge of the slope, and the overall slipping of the slope along the failure surface. It is the critical state of instability at stage No. three that slip band sufficiently extends with micro-cracks expanding dramatically. Based on the understanding of failure modes and evolution process, three slope stability models for the step-path failure by shear coalescence, tensile coalescence and mixed tensile-shear coalescence of rock bridges are established, and the limit equilibrium formulae for the safety factor of slopes considering strength and coalescence coefficient of rock bridges are deduced.%阶梯状滑移破坏是一类典型岩质边坡破坏失稳模式。在总结断续裂隙阶梯状滑移的岩质边坡地质结构特征的基础上,利用离散元二维颗粒流程序(PFC2D)模拟研

  16. Preliminary Analysis of Slope Stability in Kuok and Surrounding Areas

    Dewandra Bagus Eka Putra


    Full Text Available The level of slope influenced by the condition of the rocks beneath the surface. On high level of slopes, amount of surface runoff and water transport energy is also enlarged. This caused by greater gravity, in line with the surface tilt from the horizontal plane. In other words, topsoil eroded more and more. When the slope becomes twice as steep, then the amount of erosion per unit area be 2.0 - 2.5 times more. Kuok and surrounding area is the road access between the West Sumatra and Riau which plays an important role economies of both provinces. The purpose of this study is to map the locations that have fairly steep slopes and potential mode of landslides. Based on SRTM data obtained,  the roads in Kuok area has a minimum elevation of + 33 m and a maximum  + 217.329 m. Rugged road conditions with slope ranging from 24.08 ° to 44.68 ° causing this area having frequent landslides. The result of slope stability analysis in a slope near the Water Power Plant Koto Panjang, indicated that mode of active failure is toppling failure or rock fall and the potential zone of failure is in the center part of the slope.

  17. NEESROCK: A Physical and Numerical Modeling Investigation of Seismically Induced Rock-Slope Failure

    Applegate, K. N.; Wartman, J.; Keefer, D. K.; Maclaughlin, M.; Adams, S.; Arnold, L.; Gibson, M.; Smith, S.


    Worldwide, seismically induced rock-slope failures have been responsible for approximately 30% of the most significant landslide catastrophes of the past century. They are among the most common, dangerous, and still today, least understood of all seismic hazards. Seismically Induced Rock-Slope Failure: Mechanisms and Prediction (NEESROCK) is a major research initiative that fully integrates physical modeling (geotechnical centrifuge) and advanced numerical simulations (discrete element modeling) to investigate the fundamental mechanisms governing the stability of rock slopes during earthquakes. The research is part of the National Science Foundation-supported Network for Earthquake Engineering Simulation Research (NEES) program. With its focus on fractures and rock materials, the project represents a significant departure from the traditional use of the geotechnical centrifuge for studying soil, and pushes the boundaries of physical modeling in new directions. In addition to advancing the fundamental understanding of the rock-slope failure process under seismic conditions, the project is developing improved rock-slope failure assessment guidelines, analysis procedures, and predictive tools. Here, we provide an overview of the project, present experimental and numerical modeling results, discuss special considerations for the use of synthetic rock materials in physical modeling, and address the suitability of discrete element modeling for simulating the dynamic rock-slope failure process.

  18. 公路岩质边坡稳定性评价的能量法研究%Study on Energy Method for Estimation of Highway Rock Slope Stability

    王根龙; 张军慧; 李巨文; 常中华; 苏天明


    Aimed at stability analysis and evaluation for highway rock slope, based on the theory of energy method and the upper bound theorem of plasticity limit analysis, a yield mechanism of planar failure surface for rock slope was established. On the assumption that the sliding mass of rock slope was treated as rigid body without internal energy dissipation while the sliding surface was treated as plastic zone where the energy dissipation mainly generates, the simplified virtual power equation in limit state was obtained by using energy method. With consideration of the hydrostatic pressure in back fissure, uplift pressure along slip surface, self-weight, horizontal seismic inertia force and anchorage force, the upper bound solution of energy method for highway rock slope stability analysis was deduced by means of strength reduction method. Through a typical case study, the computation results between the presented method and rigid body limit equilibrium method was compared.%针对公路岩质边坡稳定性分析评价问题,根据能量法原理和塑性极限分析上限定理,建立了岩质边坡平面滑动的屈服机构.在刚塑性假定条件下,视岩质边坡的滑体为刚体,没有内能耗散,视滑面为塑性区,能量耗散主要集中在滑面上,根据能量法可以得到简化后的虚功率方程.综合考虑作用在岩质边坡上的后缘裂缝静水压力、沿滑面扬压力、重力、水平地震惯性力、锚固力等外力,按照强度折减法,推导得出了公路岩质边坡稳定性评价的能量法上限解.通过典型算例,将能量法上限解和刚体极限平衡法稳定系数计算结果进行了对比分析.

  19. Quantification of rock slope terrain properties

    Volkwein, Axel; Gerber, Werner


    Rockfall trajectory simulation codes need information on the terrain properties to formulate appropriate rebound models. Usually, the manuals of rockfall simulation codes give sketches or photographs of terrain samples [1,2]. Based on these the user can select suitable terrains for the simulation area. We now would like to start a discussion whether it is possible to numerically quantify the terrain properties which would make the ground assignment more objective. Different ground properties play a role for the interaction between a falling rock and the ground: • Elastic deformation • plastic deformation • Energy absorption • friction • hardness • roughness • surface vs. underground • etc. The question is now whether it is possible to quantify above parameters and to finally provide tables that contain appropriate simulation parameters. In a first attempt we suggest different methods or parameters that might be evaluated in situ: • Small scale drop tests • Light weight deflectometer (LWD) • Particle sizes • Sliding angle • Particle distribution • Soil cover • Water content Of course, above measurements will never perfectly fit to different mountain slopes. However, if a number of measurements has been made their spreading will give an idea on the natural variability of the ground properties. As an example, the following table gives an idea on how the ME and Evd values vary for different soils. Table 1: LWD measurements on different soil types [3] Ground type Soil layer Soil humidityEvd (median)σ (median)Evd (average) Humus-carb. < 10cm dry 17.4 6.8 15.6 Regosol 10 - 30cm dry 8.6 3.9 9.4 Brownish 30 - 50cm dry 12.1 3.2 11.7 Calcaric 30 - 50cm dry 7.5 3.3 7.0 Acid brownish70 - 100cmdry 7.8 2.1 7.7 Fahlgley 10 - 30cm dry 9.2 4.0 7.7 References [1] Bartelt P et al (2016) RAMMS::rockfall user manual v1.6. SLF, Davos. [2] Dorren L.K.A., 2015. Rockyfor3D (v5.2) revealed - Transparent description of the complete 3D rockfall model. ecoris

  20. Stability Analysis of Rock Mass Slope at the LAFARGE Concrete Batching Plant in Chongqing City%重庆拉法基搅拌站岩质边坡稳定性分析

    李犇; 田小甫; 柳亚千; 杜明性


    本文研究重庆拉法基长寿智深混泥土搅拌站岩质边坡稳定问题。针对该边坡所处的地形地貌、地层岩性、地质构造和气象水文条件,分析了影响岩质边坡稳定性的主要因素,归纳了该边坡可能的主要工况类型。在此基础上,采用块体极限平衡法对边坡进行了稳定性分析,并最终提出了以下综合治理措施:“表里排水”、“削坡减载”、“坡面防护”、“锚杆格构”以及“重力式挡墙支挡”。这些措施在后期施工中得到了应用,并取得了不错的效果,可为类似工程问题的分析评价提供借鉴。%The stability of the rock mass slope at the LAFARGE Changshou Zhishen concrete batching plant in Chongqing City is studied in this paper. The main factors influencing the stability of this slope, including topography, strata litbology, geological structure, meteorological and hydrological conditions, arc analyzed. Then the typical operating modes of this slope are summarized. Furthermore, the stability of every operating mode is analyzed by the block limit equilibrium method, and the supporting measures for the slope are suggested. The study procedure can provide a reference for similar projects.

  1. Slope stability analysis using limit equilibrium method in nonlinear criterion.

    Lin, Hang; Zhong, Wenwen; Xiong, Wei; Tang, Wenyu


    In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the friction angle. Moreover, this paper investigates the impact of Hoek-Brown parameters on the safety factor of slope, which reveals that there is linear relation between equivalent cohesive strength and weakening factor D. However, there are nonlinear relations between equivalent cohesive strength and Geological Strength Index (GSI), the uniaxial compressive strength of intact rock σ ci , and the parameter of intact rock m i . There is nonlinear relation between the friction angle and all Hoek-Brown parameters. With the increase of D, the safety factor of slope F decreases linearly; with the increase of GSI, F increases nonlinearly; when σ ci is relatively small, the relation between F and σ ci is nonlinear, but when σ ci is relatively large, the relation is linear; with the increase of m i , F decreases first and then increases.

  2. On Front Slope Stability of Berm Breakwaters

    Burcharth, Hans F.


    The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison with the r......The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison...... test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height...

  3. Stability analysis of the open-pit mine slope and the study on the incensement of the slope angle

    LIU Bao-xu(刘宝许); QIAO Lan(乔兰); LAI Xing-ping(来兴平)


    Based on the exploration of the engineering geology and the rock mechanics testing, limit equilibrium analysis method was adopted to calculate the stability of the Huogeqi Copper Mine slope, the results show that the original slope angle is too conservative and the slope have the potential of more preferable slope angle. In order to discuss the possibility of slope angle enhancement, sensitivity analysis of parameters related to limit state slope was made. Quantitatively determined angle value of the adding and the optimal slope angle was obtained. The study having performed showed that it is not only useful for the safety control of open-pit mine slope but also for the open-pit mine design for the similar geological condition.

  4. Damage-based long-term modelling of a large alpine rock slope

    Riva, Federico; Agliardi, Federico; Amitrano, David; Crosta, Giovanni B.


    The morphology and stability of large alpine rock slopes result from the long-term interplay of different factors, following a complex history spanning several glacial cycles over thousands of years in changing morpho-climatic settings. Large rock slopes often experience slow long-term, creep-like movements interpreted as the macroscopic evidence of progressive failure in subcritically stressed rock masses. Slope damage and rock mass weakening associated to deglaciation are considered major triggers of these processes in alpine environments. Depending on rock mass properties, slope topography and removed ice thickness, valley flanks can progressively evolve over time into rockslides showing seasonal displacement trends, interpreted as evidence of hydro-mechanically coupled responses to hydrologic perturbations. The processes linking the long-term evolution of deglaciated rock slopes and their changing sensitivity to hydrologic triggers until rockslide failure, with significant implications in risk management and Early Warning, are not fully understood. We suggest that modelling long-term rock mass damage under changing conditions may provide such a link. We simulated the evolution of the Spriana rock slope (Italian Central Alps). This is affected by a 50 Mm3 rockslide, significantly active since the late 19th century and characterized by massive geological and geotechnical investigations and monitoring during the last decades. Using an improved version of the 2D Finite-Element, damage-based brittle creep model proposed by Amitrano and Helmstetter (2006) and Lacroix and Amitrano (2013), we combined damage and time-to-failure laws to reproduce diffused damage, strain localization and the long-term creep deformation of the slope. The model was implemented for application to real slopes, by accounting for: 1) fractured rock mass properties upscaling based on site characterization data; 2) fluid pressures in a progressive failure context, relating fluid occurrence to

  5. Three-dimensional stability study of semi-deterministic blocks in complex rock high slope%复杂岩质高边坡半确定性块体三维稳定性研究

    钟卫; 杨涛; 孔纪名


    通过工程地质学中的赤平投影原理对各个结构面产状进行统计分析,找出优势结构面组合,再对非确定位置的结构面按一定间距进行搜索,利用运动学分析方法对各个块体进行分析,确定出可能从坡体上滑出的块体.结合三维刚体极限平衡法,计算出各个可能块体组合在不同工况下的稳定系数,找出最危险滑块,进而对边坡进行稳定性评价,通过具体的工程实例进行了验证.结果表明,将工程地质学方法、运动学分析方法与刚体极限平衡法结合起来分析复杂岩质边坡可以提高边坡稳定性评价的准确性,对工程具有很好的指导意义.%Preferred structural plane combinations are determined by using stereographic projection principle in the engineering geology to statistically analyze the strike-dip of structural surfaces.And to the uncertain position surfaces, they are searched by a certain distance.Then.the kinematic analysis of every combination block is done by kinematic analysis method; and the blocks that can slide out from slope body are finally gained Combined with three-dimensional rigid limit equilibrium method the stability factor of each block in different cases is cakulated; and the most dangerous slip body is found.Furthermore, the stability evaluation is done.This method is verified by case study.The results show that this method of analyzing complex rock slope combined engineering geology with kinematic analysis and rigid limit equilibrium method can improve the accuracy of slope stability assessment.The results provide a good guidance for slope design and stability analysis.

  6. 基于刚性块体系统的岩质边坡稳定性下限法研究%Lower bound method for stability of rock slopes based on rigid block assemblages

    李泽; 张小艳; 王均星


    块状岩质边坡由岩块和结构面两部分组成,而且结构面的存在以及结构面的强度控制着岩体的强度和稳定性;将塑性极限分析下限法理论、块体离散技术以及数学规划手段结合起来,研究块状岩质边坡的稳定性。首先将边坡离散成为刚性块体系统+结构面的组合体,考虑岩块体与结构面的综合作用,然后基于塑性极限分析的下限定理,建立以边坡稳定安全系数为目标函数且同时满足平衡条件、屈服条件和边界条件的塑性极限分析下限法数学规划模型,进而提出了相应的求解策略并编制了计算程序。最后对4个经典算例进行了分析,得到了严格的下限解,并将计算结果与其他方法的结果进行了比较,验证了方法和程序的正确性。%The block rock slope is made up of blocks and structural surfaces, and the stability of the rock mass is controlled by the existence and the strength of structural surface. Researches on the stability of block rock slope are carried out by using the lower bound theorem of plastic limit analysis, block discretization technique and mathematical programming method. Firstly, the slope is discretized into block assemblages that consist of rigid blocks and structural surface, considering the integral interaction of each other. And then, regarding the safety factor of slope stability as the objective fimction, the nonlinear mathematical programming models are established based on the lower bound theorem, which satisfy the equilibrium equations, yield conditions and static boundary conditions. The solution strategies of models are put forward, and the calculation programs are compiled. Finally, four classic examples are analyzed by means of the proposed method, and the rigorous lower limit values of the strength safety coefficient of slope, and the corresponding statically admissible stress fields are obtained. The results are compared with those

  7. A gravity similitude model for studying steep rock slopes

    张永兴; FAN; Zebao


    A method of a large experimental model coupled with a smaller one and an equivalent replacement method are adopted to study the deformation and the failure mechanism of a steep rock slope,in order to solve the difficult problems in space gravity similitude of the experimental model on steep rock slope with weak layers.The experimental results on the Lianziya Precipice of the Yangtze Three Gorges are in general agreement with the field observations.The experimental method adopted is proved to be successful in molding the complex geological condition especially with the weak layers.

  8. Towards a mechanical failure model for degrading permafrost rock slopes representing changes in rock toughness and infill

    Mamot, Philipp; Krautblatter, Michael; Scandroglio, Riccardo


    The climate-induced degradation of permafrost in mountain areas can reduce the stability of rock slopes. An increasing number of rockfalls and rockslides originate from permafrost-affected rock faces. Discontinuity patterns and their geometrical and mechanical properties play a decisive role in controlling rock slope stability. Under thawing conditions the shear resistance of rock reduces due to lower friction along rock-rock contacts, decreasing fracture toughness of rock-ice contacts, diminishing fracture toughness of cohesive rock bridges and altered creep or fracture of the ice itself. Compressive strength is reduced by 20 to 50 % and tensile strength decreases by 15 to 70 % when intact saturated rock thaws (KRAUTBLATTER ET AL. 2013). Elevated water pressures in fractures can lead to reduced effective normal stresses and thus to lower shear strengths of fractures. However, the impact of degrading permafrost on the mechanical properties of intact or fractured rock still remains poorly understood. In this study, we develop a new approach for modeling the influence of degrading permafrost on the stability of high mountain rock slopes. Hereby, we focus on the effect of rock- and ice-mechanical changes along striking discontinuities onto the whole rock slope. We aim at contributing to a better rock-ice mechanical process understanding of degrading permafrost rocks. For parametrisation and subsequent calibration of our model, we chose a test site (2885 m a.s.l.) close by the Zugspitze summit in Germany. It reveals i) a potential rockslide at the south face involving 10E4m³ of rock and ii) permafrost occurrence due to ice-filled caves and fractures. Here we combine kinematic, geotechnical and thermal monitoring in the field with rock-mechanical laboratory tests and a 2D numerical failure modeling. Up to date, the following results underline the potential effects of thawing rock and fracture infill on the stability of steep rock slopes in theory and praxis: i. ERT and

  9. Relief unity emulator and slope stability simulator applied to mass movement occurrence analysis in slope evolution

    Colangelo, Antonio C.


    , effective stress, water retention factor, vegetation canopy unit weight and height. All these considering variables were calculated for each cell in the synthetic slope system, that is defined laterally by crossing of equivalence topographic belt with inter-profile space and, vertically by soil surface and potential rupture surface, that may be soil-regolith or regolith-rock transition. Therefore, with this device is possible, from a single generatrix profile, to design infinity of slope evolution ways by means of definition of boundary value of the models. When in the "potential rupture surface" is produced an "effective potential rupture surface", factor of safety less than unity, the soil fails and the slope stability simulator generate a mass movement prototype. A number of interesting and verisimilar 3D mass movement digital experiments may be performed for an inferred neogenic slope evolution time scale.

  10. Stability analysis of the sliding process of the west slope in Buzhaoba Open-Pit Mine

    Ning Fang; Ji Changsheng⇑; Garmondyu E. Crusoe Jr


    To study the stability of the west slope in Buzhaoba Open-Pit Mine and determine the aging stability coefficient during slide mass development, the deformation band of the west slope and the slide mass structure of the 34,600 profile are obtained on the basis of hydrology, geology, and monitoring data. The residual thrust method is utilized to calculate the stability coefficients, which are 1.225 and 1.00 under sound and transfixion conditions, respectively. According to the rock damage and fragmentation and the principle of mechanical parameter degradation, the mechanical models of the slide mass devel-opment of the hard and soft rock slopes are established. An integrated model for calculating the slope stability coefficient is built considering water, vibration, and other external factors that pertain to the structural plane damage mechanism and the generating mechanism of the sliding mass. The change curve of the stability coefficient in the slide mass development is obtained from the relevant analyses, and afterwards, the stability control measures are proposed. The analysis results indicate that in the cracking stage of the hard rock, the slope stability coefficient decreases linearly with the increase in the length Lb of the hard rock crack zone. The linear slope is positively correlated to rock cohesion c. In the transfixion stage of the soft rock, the decrease speed of the stability coefficient is positively correlated to the residual strength of the soft rock. When the slope is stable, the stability coefficient is in a quadratic-linear relationship with the decreased height Dh of the side slope and in a linear relationship with anchoring force P.

  11. Reinforcement mechanism of slope stability method with no cutting trees

    Yuki, Chikata; Harushige, KUSUMI; 楠見, 晴重; Katsumi, TERAOKA


    The study in this paper is the slope stability. Although many slopes are prone to collapse, countermeasures against slop failures have not been progressed yet in Japan. Most slope protection methods were to cover shotcrete on the slope in 1960’s. However, the slope covered shotcrete have been deteriorating. Therefore, the slope failures frequently occur due to the natural disaster such as heavy rainfall and earthquake. It is important to develop an effective slope stability method. Moreover, ...

  12. Numerical computation of homogeneous slope stability.

    Xiao, Shuangshuang; Li, Kemin; Ding, Xiaohua; Liu, Tong


    To simplify the computational process of homogeneous slope stability, improve computational accuracy, and find multiple potential slip surfaces of a complex geometric slope, this study utilized the limit equilibrium method to derive expression equations of overall and partial factors of safety. This study transformed the solution of the minimum factor of safety (FOS) to solving of a constrained nonlinear programming problem and applied an exhaustive method (EM) and particle swarm optimization algorithm (PSO) to this problem. In simple slope examples, the computational results using an EM and PSO were close to those obtained using other methods. Compared to the EM, the PSO had a small computation error and a significantly shorter computation time. As a result, the PSO could precisely calculate the slope FOS with high efficiency. The example of the multistage slope analysis indicated that this slope had two potential slip surfaces. The factors of safety were 1.1182 and 1.1560, respectively. The differences between these and the minimum FOS (1.0759) were small, but the positions of the slip surfaces were completely different than the critical slip surface (CSS).

  13. Numerical Computation of Homogeneous Slope Stability

    Shuangshuang Xiao


    Full Text Available To simplify the computational process of homogeneous slope stability, improve computational accuracy, and find multiple potential slip surfaces of a complex geometric slope, this study utilized the limit equilibrium method to derive expression equations of overall and partial factors of safety. This study transformed the solution of the minimum factor of safety (FOS to solving of a constrained nonlinear programming problem and applied an exhaustive method (EM and particle swarm optimization algorithm (PSO to this problem. In simple slope examples, the computational results using an EM and PSO were close to those obtained using other methods. Compared to the EM, the PSO had a small computation error and a significantly shorter computation time. As a result, the PSO could precisely calculate the slope FOS with high efficiency. The example of the multistage slope analysis indicated that this slope had two potential slip surfaces. The factors of safety were 1.1182 and 1.1560, respectively. The differences between these and the minimum FOS (1.0759 were small, but the positions of the slip surfaces were completely different than the critical slip surface (CSS.

  14. Interaction between transverse isotropy rock slope and supporting structure

    段靓靓; 方理刚


    In order to study the interaction between transverse isotropy rock mass and supporting structure,the laboratory tests for rock sampled from the slope at expressway project were carried out,and the parameters of elasticity for transverse isotropic rock were determined by the uniaxial compression tests for rock sample with different strike of stratification plane.Then,based on the relationship of stress-stain for transverse isotropic rock mass,the analytical model was established for the interaction between transverse isotropic rock mass and frame beam with pre-stressed anchor cable.Furthermore,the conception of the best anchorage-angle in pre-stressed anchor cable was proposed.At last,the parameters of the interaction between transverse isotropy rock mass and frame beam with pre-stressed anchor cable were investigated by finite element method,and the best anchorage-angle in pre-stressed anchor cable was obtained.The rules of the influence of the directivity of stratification plane on supporting structure were determined.The results show that the analytical model and numerical method on the design of pre-stressed anchor cable with frame beam supporting for transverse isotropy rock slope are reasonable and reliable in practical engineering design.

  15. 基于变形加固理论的岩土边坡稳定和加固分析%Stability and reinforcement analysis of rock and soil slope based on deformation reinforcement theory

    刘耀儒; 黄跃群; 杨强; 宋胜武; 冯学敏


    The traditional rigid-body limit equilibrium method and finite-element-based strength reduction method has some problems in stability and reinforcement analysis. Based on deformation reinforcement theory (DRT), a stability analysis method of slope is presented with elastoplastic finite element analysis. Plasticity complementary energy(PCE) is used to evaluate the whole stability of slope; and safety factor of slope can be obtained through the PCE curve with strength reduction factor. Reinforcement location and force can be determined by unbalance force distribution in the slope. Possible sliding surface also can be located on the boundary that direction reverse of unbalance force occurs. Three classical examples of slopes has been modeled and analyzed. The safety factor and reinforcement key location and force have been determined by the PCE curve and unbalance force distribution. The results indicate that the DRT based on nonlinear finite element analysis is effective in analysis of stability and reinforcement for rock and soil slopes. The failure process can be reflected by the development of unbalanced force with the strength reduction.%传统的刚体极限平衡法和强度折减法在分析边坡稳定和加固时存在一定的局限性.基于变形加固理论,建立了基于弹塑性有限元分析的边坡稳定和加固分析方法.以余能范数作为边坡整体稳定评价的指标,通过强度参数降低过程中的余能范数的变化来确定边坡的整体稳定安全系数.加固的关键部位和加固力的大小通过边坡中不平衡力的分布来确定.滑动面则 由方向相反的、成对的不平衡力的分界面来确定.针对3个经典边坡算例,分析了强度参数逐渐降低过程中的余能范数的变化和不平衡力的分布,确定了边坡的稳定安全系数以及相应的加固关键部位和加固力的大小.结果表明,变形加固理论基于岩土的三维非线性有限元分析,以此来进行边坡的

  16. Reliability analysis method applied in slope stability: slope prediction and forecast on stability analysis

    Wenjuan ZHANG; Li CHEN; Ning QU; Hai'an LIANG


    Landslide is one kind of geologic hazards that often happens all over the world. It brings huge losses to human life and property; therefore, it is very important to research it. This study focused in combination between single and regional landslide, traditional slope stability analysis method and reliability analysis method. Meanwhile, methods of prediction of slopes and reliability analysis were discussed.

  17. 降雨条件下岩体边坡稳定性数值模拟与分析%A Numerical Simulation and Analysis of Stability of Rock Slope under Rainfall Condition

    赵冰华; 沈振中


    According to the actual engineering conditions of an expressways slope, the finite dement model of the rock slope is set up under the rainfall conditions by unstable saturated-unsaturated seepage flow with rainfall infiltration. The law of the groundwater seepage field of the slope under two conditions of heavy rain in the flood seasons and continuous rainfall conditions are calculated and analyzed, and the underground water load is determined. The process of stage excavation and reinforcement of the slope are further simulated, and the stress and deformation law and displacement change of the slope during each stage are analyzed, and the stability of slope is evaluated under two conditions. The results that the minimum safety factor after rainfall is smaller than before rainfall, and the local safety factor is less than 1.0, so there is a risk of landslide. The minimum safety factor after rainfall with support of mooring wire rope is bigger than without support, and the distribution of smaller safety factors certainly decreases, so the safety factor is raised greatly, which can meet the stability demands. The results not only provide a scientific basis for the project construction, but also play an important guiding role in the slope reinforcement measures and landslide forecast.%根据某高速公路岩体边坡的实际情况和基本资料,选定典型边坡,建立降雨入渗条件下该边坡非稳定饱和一非饱和渗流分析的有限元模型,分析在汛期暴雨和平均降雨两种工况下边坡内的地下水渗流场及其变化规律,确定地下水荷载。进一步模拟边坡分级开挖、支护过程,计算分析各阶段边坡应力变形规律和位移变化,以及在2种工况下的边坡稳定性。结果表明,降雨后的最小安全系数比降雨前有所减小,局部安全系数小于1.0,有滑坡危险;锚索支护后降雨的最小安全系数比支护前要大,较小安全系数的分布范围有一定的

  18. Deep soil compaction as a method of ground improvement and to stabilization of wastes and slopes with danger of liquefaction, determining the modulus of deformation and shear strength parameters of loose rock.

    Lersow, M


    For the stabilization of dumps with the construction of hidden dams and for building ground improvement, for instance for traffic lines over dumps, nearly all applied compaction methods have the aim to reduce the pore volume in the loose rock. With these methods, a homogenization of the compacted loose rock will be obtained too. The compaction methods of weight compaction by falling weight, compaction by vibration and compaction by blasting have been introduced, and their applications and efficiencies have been shown. For the estimation of the effective depth of the compaction and for a safe planning of the bearing layer, respectively, the necessary material parameters have to be determined for each deep compaction method. Proposals for the determination of these parameters have been made within this paper. In connection with the stabilization of flow-slide-prone dump slopes, as well as for the improvement of dump areas for the use as building ground, it is necessary to assess the deformation behavior and the bearing capacity. To assess the resulting building ground improvement, deformation indexes (assessment of the flow-prone layer) and strength indexes (assessment of the bearing capacity) have to be determined with soil mechanical tests. Förster and Lersow, [Patentschrift DE 197 17 988. Verfahren, auf der Grundlage last- und/oder weggesteuerter Plattendruckversuche auf der Bohrlochsohle, zur Ermittlung des Spannungs-Verformungs-Verhaltens und/oder von Deformationsmoduln und/oder von Festigkeitseigenschaften in verschiedenen Tiefen insbesondere von Lockergesteinen und von Deponiekörpern in situ; Förster W, Lersow M. Plattendruckversuch auf der Bohrlochsohle, Ermittlung des Spannungs-Verformungs-Verhaltens von Lockergestein und Deponiematerial Braunkohle--Surface Mining, 1998;50(4): 369-77; Lersow M. Verfahren zur Ermittlung von Scherfestigkeitsparametern von Lockergestein und Deponiematerial aus Plattendruckversuchen auf der Bohrlochsohle. Braunkohle

  19. Quantification of rock fall processes on recently deglaciated rock slopes, Gepatsch glacier, Tyrol (Austria)

    Vehling, Lucas; Rohn, Joachim; Moser, Michael


    The recently deglaciated area in alpine glacier forefields is characterized by intensified mass movement processes in particular debris flows, shallow landslides and rockfalls. Due to enhanced geomorphic activity, rock slopes adjacent to shrinking glaciers contribute in a substantial way to the sediment budget. In this study, direct measurements of rock fall intensity are conducted by rock fall collector nets and natural sediment traps. The study area is a high mountain (1750-3520m a.s.l) catchment, which is recently about 30% glaciated. The extension of the Gepatsch glacier has been reducing since the little ice age maximum in the mid of the 19th century with an average annual shrinking rate of a few decameters at its tongue. The first results of the direct measurements demonstrate that on the recently deglaciated rock slopes, rock fall intensity is at least one order of magnitude higher (2,38-6,64 g/m2/d - corresponding backweathering rate: 0,3-0,9 mm/a) than on rock slopes which had has ice free since the last Pleistocene deglaciation (0,04-0,38 g/m2/d - backweathering rate: 0,005-0,05 mm/a). The highest rock fall intensity is attributed to the recent deglaciated rock slopes which are located close to larger fault systems (>60 g/m2/d - backweathering rate: >8 mm/a). Rock fall intensity shows also considerable intra-annual variations which are related to cold climate weathering processes and rainstorm activity.

  20. Influence to Stability by Thickness of Hard Rock in Slope%边坡内部硬岩厚度对稳定性的影响

    李玉蛟; 於智; 陈兵; 余成



  1. Validation of Hoek-Brown failure criterion charts for rock slopes

    A.M. Nekouei; K. Ahangari


    Although stability charts suggested by Hoek and Bray on the basis of Mohr-Coulomb criterion are used for rock slopes, but complete and precise recognition is required for distinguishing cohesive strength and Mohr-Coulomb equivalent internal friction angle for rock mass. The paper by Lia et al. [6] is the only one that introduced rock slope charts according to Hoek-Brown failure criterion. In this paper, at first, this type of charts is introduced. Then, Mohr-Coulomb failure criterion charts [2] are compared and validated with Hoek-Brown failure criterion ones [6]. Next, Bishop method utilizing Slide software is compared with Hoek-Brown failure criterion stability charts. Average standard deviation (ASD), root mean square error (RMSE) and variance account for (VAF) were used for the comparison. According to the results, because of high distribution and very low correlation among the comparisons, Hoek-Brown failure crite-rion charts are not efficient.

  2. HDMR methods to assess reliability in slope stability analyses

    Kozubal, Janusz; Pula, Wojciech; Vessia, Giovanna


    Stability analyses of complex rock-soil deposits shall be tackled considering the complex structure of discontinuities within rock mass and embedded soil layers. These materials are characterized by a high variability in physical and mechanical properties. Thus, to calculate the slope safety factor in stability analyses two issues must be taken into account: 1) the uncertainties related to structural setting of the rock-slope mass and 2) the variability in mechanical properties of soils and rocks. High Dimensional Model Representation (HDMR) (Chowdhury et al. 2009; Chowdhury and Rao 2010) can be used to carry out the reliability index within complex rock-soil slopes when numerous random variables with high coefficient of variations are considered. HDMR implements the inverse reliability analysis, meaning that the unknown design parameters are sought provided that prescribed reliability index values are attained. Such approach uses implicit response functions according to the Response Surface Method (RSM). The simple RSM can be efficiently applied when less than four random variables are considered; as the number of variables increases, the efficiency in reliability index estimation decreases due to the great amount of calculations. Therefore, HDMR method is used to improve the computational accuracy. In this study, the sliding mechanism in Polish Flysch Carpathian Mountains have been studied by means of HDMR. The Southern part of Poland where Carpathian Mountains are placed is characterized by a rather complicated sedimentary pattern of flysh rocky-soil deposits that can be simplified into three main categories: (1) normal flysch, consisting of adjacent sandstone and shale beds of approximately equal thickness, (2) shale flysch, where shale beds are thicker than adjacent sandstone beds, and (3) sandstone flysch, where the opposite holds. Landslides occur in all flysch deposit types thus some configurations of possible unstable settings (within fractured rocky

  3. Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling

    Lai, Xing-ping; Shan, Peng-fei; Cai, Mei-feng; Ren, Fen-hua; Tan, Wen-hui


    High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The physico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally; specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acoustic emission (AE) sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field photogrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model results indicated a clear correlation between the model's destabilization resulting from slope excavation and the collected monitoring information. During the model simulation, the overall angle of the slope increased by 1-6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.

  4. Consequence assessment of large rock slope failures in Norway

    Oppikofer, Thierry; Hermanns, Reginald L.; Horton, Pascal; Sandøy, Gro; Roberts, Nicholas J.; Jaboyedoff, Michel; Böhme, Martina; Yugsi Molina, Freddy X.


    Steep glacially carved valleys and fjords in Norway are prone to many landslide types, including large rockslides, rockfalls, and debris flows. Large rockslides and their secondary effects (rockslide-triggered displacement waves, inundation behind landslide dams and outburst floods from failure of landslide dams) pose a significant hazard to the population living in the valleys and along the fjords shoreline. The Geological Survey of Norway performs systematic mapping of unstable rock slopes in Norway and has detected more than 230 unstable slopes with significant postglacial deformation. This large number necessitates prioritisation of follow-up activities, such as more detailed investigations, periodic displacement measurements, continuous monitoring and early-warning systems. Prioritisation is achieved through a hazard and risk classification system, which has been developed by a panel of international and Norwegian experts ( The risk classification system combines a qualitative hazard assessment with a consequences assessment focusing on potential life losses. The hazard assessment is based on a series of nine geomorphological, engineering geological and structural criteria, as well as displacement rates, past events and other signs of activity. We present a method for consequence assessment comprising four main steps: 1. computation of the volume of the unstable rock slope; 2. run-out assessment based on the volume-dependent angle of reach (Fahrböschung) or detailed numerical run-out modelling; 3. assessment of possible displacement wave propagation and run-up based on empirical relations or modelling in 2D or 3D; and 4. estimation of the number of persons exposed to rock avalanches or displacement waves. Volume computation of an unstable rock slope is based on the sloping local base level technique, which uses a digital elevation model to create a second-order curved surface between the mapped extent of


    魏春启; 白润才


    The artificial neural network model which forecasts Open Mining Slope stability is established by neural network theory and method. The nonlinear reflection relation between stability target of open mining slope and its influence factor is described. The method of forecasting Open Mining Slope stability is brought forward.

  6. Seismic Stability of Reinforced Soil Slopes

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.


    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the impact...

  7. Analytical Study of the Mechanical Behavior of Fully Grouted Bolts in Bedding Rock Slopes

    Liu, C. H.; Li, Y. Z.


    Bolting is widely used as a reinforcement means for rock slopes. The support force of a fully grouted bolt is often provided by the combination of the axial and shear forces acting at the cross section of the bolt, especially for bedding rock slopes. In this paper, load distribution and deformation behavior of the deflecting section of a fully grouted bolt were analyzed, and a structural mechanical model was established. Based on force method equations and deformation compatibility relationships, an analytical approach, describing the contribution of the axial and shear forces acting at the intersection between the bolt and the joint plane to the stability of a rock slope, was developed. Influence of the inclination of the bolt to the joint plane was discussed. Laboratory tests were conducted with different inclinations of the bolt to the joint plane. Comparisons between the proposed approach, the experimental data and a code method were made. The calculation results are in good agreement with the test data. It is shown that transverse shear resistance plays a significant role to the bolting contribution and that the bigger the dip of the bolt to the joint plane, the more significant the dowel effect. It is also shown that the design method suggested in the code overestimates the resistance of the bolt. The proposed model considering dowel effect provides a more precise description on bolting properties of bedding rock slopes than the code method and will be helpful to improve bolting design methods.

  8. Response of rock-fissure seepage to snowmelt in Mount Taihang slope-catchment, North China.

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun


    The complex physiographic and hydrogeological systems of mountain terrains facilitate intense rock-fissure seepages and multi-functional ecological interactions. As mountain eco-hydrological terrains are the common water sources of river basins across the globe, it is critical to build sufficient understanding into the hydrological processes in this unique ecosystem. This study analyzes infiltration and soil/rock-fissure seepage processes from a 65 mm snowfall/melt in November 2009 in the typical granitic gneiss slope catchment in the Taihang Mountains. The snowfall, snowmelt and melt-water processes are monitored using soil-water time-domain reflectometry (TDR) probes and tipping bucket flowmeters. The results suggest that snowmelt infiltration significantly influences soil/rock water seepage in the 0-100 cm soil depth of the slope-catchment. It is not only air temperature that influences snowmelt, but also snowmelt infiltration and rock-fissure seepage. Diurnal variations in rock-fissure seepage are in close correlation with air temperature (R(2) > 0.7). Temperature also varies with soil/rock water viscosity, which element in turn influences soil/rock water flow. Invariably, water dynamics in the study area is not only a critical water supply element for domestic, industrial and agricultural uses, but also for food security and social stability.

  9. Primary Investigations on Yangtze River Bank Slope Stability in Wanzhou for the Three Gorges Reservoir Project

    Jian Wenxing; Yin Kunlong; Xu Yixian


    This paper investigates the main factors contributing to bank slope failures, such as the structure of rock and soil, water level change, bank slope gradient, vegetation, weathering and human activities. Based on these investigations, the bank slope failure models are analyzed. The stability of bank slopes in Wanzhou is investigated using geological surveying, 2D resistivity imaging surveying, excavated trenches and other methods. Finally, the disasters of bank slope failures in Wanzhou were investigated in detail. The results show that instability problems might occur in 60.38 km of bank slopes when the water level rises to 175 m. It is suggested that 37.8 km of unstable bank slopes should be stabilized, and 14.2 km of unstable banks should be moved or avoided after further geological surveying and reconnaissance. These results provide scientific basis and reliable data for the government to develop the third geodisaster prevention plan for the Three Gorges reservoir.

  10. Ambient vibrations of unstable rock slopes - insights from numerical modeling

    Burjanek, Jan; Kleinbrod, Ulrike; Fäh, Donat


    The recent events in Nepal (2015 M7.8 Gorkha) and New Zealand (2016 M7.8 Kaikoura) highlighted the importance of earthquake-induced landslides, which caused significant damages. Moreover, landslide created dams present a potential developing hazard. In order to reduce the costly consequences of such events it is important to detect and characterize earthquake susceptible rock slope instabilities before an event, and to take mitigation measures. For the characterisation of instable slopes, acquisition of ambient vibrations might be a new alternative to the already existing methods. We present both observations and 3D numerical simulations of the ambient vibrations of unstable slopes. In particular, models of representative real sites have been developed based on detailed terrain mapping and used for the comparison between synthetics and observations. A finite-difference code has been adopted for the seismic wave propagation in a 3D inhomogeneous visco-elastic media with irregular free surface. It utilizes a curvilinear grid for a precise modeling of curved topography and local mesh refinement to make computational mesh finer near the free surface. Topographic site effects, controlled merely by the shape of the topography, do not explain the observed seismic response. In contrast, steeply-dipping compliant fractures have been found to play a key role in fitting observations. Notably, the synthetized response is controlled by inertial mass of the unstable rock, and by stiffness, depth and network density of the fractures. The developed models fit observed extreme amplification levels (factors of 70!) and show directionality as well. This represents a possibility to characterize slope structure and infer depth or volume of the slope instability from the ambient noise recordings in the future.

  11. An Alternative Stability Equation For Rock Armoured Rubble Mound Breakwaters

    Hald, Tue; Burcharth, H. F.


    equations and model test results still exists. When turning toward prototype the situation is even worse. With the objective to reduce some of the variability an alternative approach based on force considerations is presented. The paper will describe a new stability equation for rock armoured slopes derived...

  12. 地震与水压力耦合作用下岩质边坡倾覆解析方法%Analytical Method for the Overturning Stability of a Rock Slope under the Coupling Action of Earthquakes and Water Pressure

    张彦君; 年廷凯; 郑路; 刘凯; 宋雷


    以往对平面破坏模式的岩质边坡稳定性评价,主要关注潜在滑坡体在自重、坡体内静水压力和地震荷载耦合作用下沿破坏面的抗滑稳定性,并未涉及各类外荷载作用线不通过潜在滑体重心而引起的绕坡趾倾覆稳定性。针对这一问题,提出地震与张裂缝水压耦合作用下的岩质边坡倾覆稳定性解析方法,基于力矩平衡原理推导出岩质边坡抗倾覆稳定性系数的一般表达式;通过深入的变动参数比较研究,探讨张裂缝水压和地震荷载对抗倾覆安全系数的影响,认为水压是控制岩质边坡倾覆破坏的决定性因素,而地震荷载处于次要因素,其在一定程度上增加或减小抗倾覆稳定性。在此基础上建立不同参数组合下的岩质边坡抗倾覆稳定图,为工程技术人员快速评估饱水岩质边坡地震倾覆稳定性提供直接依据。%The failure modes of rock slopes can be classified into five types:plane,wedge,circular, toppling,and buckling failures.These failure modes mainly depend on the lithological characteris-tics of the rock,properties of the discontinuities,and degree of weathering.Generally,rock slope stability analysis under the plane failure mode mainly focuses on the sliding stability of a potential sliding mass subjected to gravity,hydrostatic stress in the slope,and seismic loads.However,there exists the possibility of overturning failure around the toe of slopes because of the fact that all loadings do not act through the centroid of the sliding mass.This failure mode is completely dif-ferent from common topping failure,which involves the rotation of columns or blocks of rock about the fixed base,mainly occurring in anti-dipping layered rock mass slopes with steep dipping discontinuities.Thus,the existing methods for the stability assessment of the five common failure modes are no longer applicable,and a new method to determine the overturning failure is required

  13. Seismic Stability of Reinforced Soil Slopes

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.


    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the impact...... of the most significant parameters involved, such as the flexibility of the sliding system, the mechanical properties of the soil and of the geosynthetics material, the frequency content of the excitation and the interface shear strength....

  14. Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

    Kim, Jae Gon


    Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

  15. Methods to Analyze Flexural Buckling of the Consequent Slabbed Rock Slope under Top Loading

    Hongyan Liu


    Full Text Available The consequent slabbed rock slope is prone to flexural buckling failure under its self-weight and top loading. However, nearly none of the existing studies consider the effect of the top loading on the slope flexural critical buckling height (CBH. Therefore, on the basis of Euler’s Method and the flexural buckling failure mode of the consequent slabbed rock slope, the calculation method of the CBH of the vertical slabbed rock slope under the self-weight is firstly proposed, and then it is extended to that of the consequent slabbed rock slope. The effect of slope dip angle, friction angle, and cohesion between the neighboring rock slabs and rock elastic modulus on the slope CBH is discussed. Secondly, the calculation method of the CBH of the consequent slabbed rock slope under its self-weight and top loading is proposed according to the superposition principle. Finally, on the basis of the hypothesis that the rock mechanical behavior obeys the statistical damage model, the effect of the rock mechanical parameters n and ε0 on the slope CBH is studied. The results show that the rock strength has much effect on the slope CBH. If the rock is supposed to be a linear elastic body without failure in Euler’s Method, the result from it is the maximum of the slope CBH.

  16. Predicting Modes and Displacements of Seismic Rock Slope Failures

    Gibson, M. D.; Wartman, J.; Keefer, D. K.; Maclaughlin, M.; Arnold, L.; Applegate, K. N.; Smith, S.; Adams, S.


    Seismically induced rock slope failures have resulted in billions of dollars of economic damage and enormous loss of life throughout the world. Accurate prediction of the triggering and run out of these failures is elusive for a variety of reasons, including knowledge of the physical modes of failure. Our research explores the potential failure modes of an idealized rigid rock block and expands the modes typically considered to include not only sliding but also toppling (pure forward rotation) and slumping (combined backward rotation and translation). The yield acceleration (or minimum inertial acceleration to cause block movement) for slumping, similar to toppling, is found to be lower than for pure translational sliding. These yield accelerations indicate the initial modes of rock block failure; however, they do not always predict the ultimate failure mode. To predict the final failure modes, the results of discrete element numerical analyses were compared to pseudo static yield acceleration to develop a seismic failure mode decision-making chart based on block geometry and interface friction. With regard to seismic displacement predictions, current simplified models predicting ultimate displacement of a mass under seismic conditions are limited to purely translating, sliding blocks (i.e. Newmark's sliding block method). Our modeling introduces additional simplified analyses to predict ultimate displacement in toppling and slumping modes as well. Important findings from these new methods are that the magnitude of seismically-induced displacement is dependent on the size of the block (or failure mass) and that as the yield acceleration decreases the seismically induced displacements increase. We plan to map these tools into analyses that evaluate rock slope systems with complex geology and geotechnical characteristics. It is envisioned that the decision chart, which predicts the initial and ultimate modes of failure based on block geometry and interface friction

  17. Controlling and Evaluation on High Rock Slope Stability of Open-pit for Ash Storage%露天矿坑灰场岩质高边坡的稳定性评判与治理

    吕言新; 乔卫国; 魏烈昌; 孟庆彬


    Slopes of open-pit mine and ash storage are likely to result in the geological disasters of landslides, collapse, ground deformation and so on, due to its geological structure and mining activities, etc. Laizhou Power Plant is going to use the open-pit of Cangshang gold mine as ash storage field. Therefore, the long-term stability of the slope is of great significance. Through the geological investigation and analysis of open-pit mine slope of Cangshang Mine, the geological and tectonic conditions of ash slopes are summarized. On the basis of field monitoring,the stability of the slopes is analyzed in detail The estimated results can better reflect the actual stability of the open-pit slope. Feasible treatment scheme is put forward according to the engineering practice.%露天矿坑边坡及排土场边坡,由于地质构造、采矿活动等原因极易诱发滑坡、塌陷、地面变形等地质灾害.莱州电厂拟采用仓上金矿矿坑作为灰场,边坡的长期稳定性有着重要的意义.通过对仓上矿坑边坡的工程地质调查与分析,总结了灰场边坡的地质条件和构造情况.在现场监测的基础上,对矿坑边坡的稳定性进行了详细的分析,所得的结果能较理想地反映该矿坑边坡的实际稳定程度,并根据工程的实际情况提出了切实可行的治理方案.

  18. assessment of slope stability around gilgel gibe-ii hydroelectric

    preferred customer

    (1995) technique, whereas the slope having wedge mode of failure was analyzed by. 'SASW' computer .... Engineering properties of rocks ... were determined by using Schmidt hammer in ...... Engineering, 3rd ed., Institute of Mining and.

  19. A Genetic Algorithm for Locating the Multiscale Critical Slip Surface in Jointed Rock Mass Slopes

    Qiang Xu


    Full Text Available The joints have great influence on the strength of jointed rock mass and lead to the multiscale, nonhomogeneous, and anisotropic characteristics. In order to consider these effects, a new model based on a genetic algorithm is proposed for locating the critical slip surface (CSS in jointed rock mass slope (JRMS from its stress field. A finite element method (FEM was employed to analyze the stress field. A method of calculating the mechanical persistence ratio (MPR was used. The calculated multiscale and anisotropic characteristics of the MPR were used in the fitness function of genetic algorithm (GA to calculate the factor of safety. The GA was used to solve optimization problems of JRMS stability. Some numerical examples were given. The results show that the multiscale and anisotropic characteristics of the MPR played an important role in locating the CSS in JRMS. The proposed model calculated the CSS and the factor of safety of the slope with satisfactory precision.

  20. Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling

    Xing-ping Lai; Peng-fei Shan; Mei-feng Cai; Fen-hua Ren; Wen-hui Tan


    High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The phys-ico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally;specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acous-tic emission (AE) sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field pho-togrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model re-sults indicated a clear correlation between the model’s destabilization resulting from slope excavation and the collected monitoring informa-tion. During the model simulation, the overall angle of the slope increased by 1–6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.

  1. Coupling photogrammetric data with DFN-DEM model for rock slope hazard assessment

    Donze, Frederic; Scholtes, Luc; Bonilla-Sierra, Viviana; Elmouttie, Marc


    Structural and mechanical analyses of rock mass are key components for rock slope stability assessment. The complementary use of photogrammetric techniques [Poropat, 2001] and coupled DFN-DEM models [Harthong et al., 2012] provides a methodology that can be applied to complex 3D configurations. DFN-DEM formulation [Scholtès & Donzé, 2012a,b] has been chosen for modeling since it can explicitly take into account the fracture sets. Analyses conducted in 3D can produce very complex and unintuitive failure mechanisms. Therefore, a modeling strategy must be established in order to identify the key features which control the stability. For this purpose, a realistic case is presented to show the overall methodology from the photogrammetry acquisition to the mechanical modeling. By combining Sirovision and YADE Open DEM [Kozicki & Donzé, 2008, 2009], it can be shown that even for large camera to rock slope ranges (tested about one kilometer), the accuracy of the data are sufficient to assess the role of the structures on the stability of a jointed rock slope. In this case, on site stereo pairs of 2D images were taken to create 3D surface models. Then, digital identification of structural features on the unstable block zone was processed with Sirojoint software [Sirovision, 2010]. After acquiring the numerical topography, the 3D digitalized and meshed surface was imported into the YADE Open DEM platform to define the studied rock mass as a closed (manifold) volume to define the bounding volume for numerical modeling. The discontinuities were then imported as meshed planar elliptic surfaces into the model. The model was then submitted to gravity loading. During this step, high values of cohesion were assigned to the discontinuities in order to avoid failure or block displacements triggered by inertial effects. To assess the respective role of the pre-existing discontinuities in the block stability, different configurations have been tested as well as different degree of

  2. Slope stability monitoring from microseismic field using polarization methodology

    Yu. I. Kolesnikov


    Full Text Available Numerical simulation of seismoacoustic emission (SAE associated with fracturing in zones of shear stress concentration shows that SAE signals are polarized along the stress direction. The proposed polarization methodology for monitoring of slope stability makes use of three-component recording of the microseismic field on a slope in order to pick the signals of slope processes by filtering and polarization analysis. Slope activity is indicated by rather strong roughly horizontal polarization of the respective portion of the field in the direction of slope dip. The methodology was tested in microseismic observations on a landslide slope in the Northern Tien-Shan (Kyrgyzstan.


    RUIYongqin; JIANGZhiming; LIUJinghui


    Based on the model of slope engineering geology,the creep and its failure mechanism of tall and bedding slope are deeply analyzed in this paper .The creep laws of weak intercalations are also discussed.The analysis om the stability of creep slope and the age forecasting of sliding slope have been conducted through mumerical simulations using Finite Element Method (FEM)and Dintimct Element Method(DEM).

  4. A hazard and risk classification system for catastrophic rock slope failures in Norway

    Hermanns, R.; Oppikofer, T.; Anda, E.; Blikra, L. H.; Böhme, M.; Bunkholt, H.; Dahle, H.; Devoli, G.; Eikenæs, O.; Fischer, L.; Harbitz, C. B.; Jaboyedoff, M.; Loew, S.; Yugsi Molina, F. X.


    the susceptibility scores that can be divided into several classes, which are interpreted as susceptibility classes (very high, high, medium, low, and very low). Today the Norwegian Planning and Building Act uses hazard classes with annual probabilities of impact on buildings producing damages (1/100). The risk analysis focuses on the potential fatalities of a worst case rock slide scenario and its secondary effects only and is done in consequence classes with a decimal logarithmic scale. However we recommend for all high risk objects that municipalities carry out detailed risk analyses. Finally, the hazard and risk classification system will give recommendations where surveillance in form of continuous 24/7 monitoring systems coupled with early-warning systems (high risk class) or periodic monitoring (medium risk class) should be carried out. These measures are understood as to reduce the risk of life loss due to a rock slope failure close to 0 as population can be evacuated on time if a change of stability situation occurs. The final hazard and risk classification for all potentially unstable rock slopes in Norway, including all data used for its classification will be published within the national landslide database (available on

  5. Relating weak layer and slab properties to snow slope stability

    J. Schweizer


    Full Text Available Snow slope stability evaluation requires considering weak layer as well as slab properties – and in particular their interaction. We developed a stability index from snow micro-penetrometer measurements and compared it to 129 concurrent point observations with the compression test (CT. The index considers the SMP-derived micro-structural strength and the additional load which depends on the hardness of the surface layers. The new quantitative measure of stability discriminated well between point observations rated as either "poor" or "fair" (CT < 19 and those rated as "good" (CT ≥ 19. However, discrimination power within the intermediate range was low. We then applied the index to gridded snow micro-penetrometer measurements from 11 snow slopes to explore the spatial structure and possibly relate it to slope stability. Stability distributions on the 11 slopes reflected various possible strength and load (stress distributions that naturally can occur. Their relation to slope stability was poor possibly because the index does not consider crack propagation. Hence, the relation between spatial patterns of point stability and slope stability remains elusive. Whereas this is the first attempt of a truly quantitative measure of stability, future developments should consider a better reference of stability and incorporate a measure of crack propagation.

  6. Comprehensive analysis of slope stability and determination of stable slopes in the Chador-Malu iron ore mine using numerical and limit equilibrium methods



    One of the critical aspects in mine design is slope stability analysis and the determination of stable slopes. In the Chador Malu iron ore mine, one of the most important iron ore mines in central Iran, it was considered vital to perform a comprehensive slope stability analysis. At first, we divided the existing rock hosting pit into six zones and a geotechnical map was prepared. Then,the value of MRMR (Mining Rock Mass Rating) was determined for each zone. Owing to the fact that the Chador-Malu iron ore mine is located in a highly tectonic area and the rock mass completely crushed, the Hock-Brown failure criterion was found suitable to estimate geo-mechanical parameters. After that, the value of cohesion (c) and friction angle (e) were calculated for different geotechnical zones and relative graphs and equations were derived as a function of slope height. The stability analyses using numerical and limit equilibrium methods showed that some instability problems might occur by increasing the slope height.Therefore, stable slopes for each geotechnical zone and prepared sections were calculated and presented as a function of slope height.

  7. Numerical Study on Dynamic Response of a Horizontal Layered-Structure Rock Slope under a Normally Incident Sv Wave

    Zhifa Zhan


    Full Text Available Several post-earthquake investigations have indicated that the slope structure plays a leading role in the stability of rock slopes under dynamic loads. In this paper, the dynamic response of a horizontal layered-structure rock slope under harmonic Sv wave is studied by making use of the Fast Lagrangian Analysis of Continua method (FLAC. The suitability of FLAC for studying wave transmission across rock joints is validated through comparison with analytical solutions. After parametric studies on Sv wave transmission across the horizontal layered-structure rock slope, it is found that the acceleration amplification coefficient η, which is defined as the ratio of the acceleration at the monitoring point to the value at the toe, wavily increases with an increase of the height along the slope surface. Meanwhile, the fluctuation weakens with normalized joint stiffness K increasing and enhances with normalized joint spacing ξ increasing. The acceleration amplification coefficient of the slope crest ηcrest does not monotonously increase with the increase of ξ, but decreases with the increase of K. Additionally, ηcrest is more sensitive to ξ compared to K. From the contour figures, it can also be found that the contour figures of η take on rhythm, and the effects of ξ on the acceleration amplification coefficient are more obvious compared to the effects on K.

  8. New method for dynamic analysis of rock slope stability based on modal parameters%基于模态参量变化的边坡动态稳定分析新方法

    杜岩; 谢谟文; 吕夫侠; 王增福; 王桂杰; 刘秋强


    The slope stability analysis is a focal problem in the geotechnical engineering field. However, few dynamic stability analyses are made based on the ever-changing modal parameters. Therefore, the cohesion in key regions is taken as the dynamic parameter so as to realize the dynamic stability analysis of the slope. By using GIS (geographic information systems) 3D slope stability analysis models, the cohesion can be adjusted by real-time data of natural vibration frequencies in order to make the strength reduction method more real and effective. The establishment of the inherent relationship between the vibration frequency and the cohesion of landslide can effectively solve the difficulty of selection and adjustment of the parameter in numerical analysis. The experimental results show that the dynamic stability analysis based on the variation of modal parameters makes full use of the objective advantages of strength reduction and avoids the subjective disadvantages of the limit equilibrium method. Thus, the simulated results are more close to the actual conditions. Furthermore, this new method can take into full account the slope space features and allow an objective evaluation of the strength retrogression, so it is reliable for slope stability analysis.%边坡稳定问题一直是岩土工程领域研究的重要课题,但对于基于模态参量变化的动态稳定分析研究不多。因此,研究将坡体重点区域的黏聚力作为动态参量,实现边坡体动态稳定分析评价。基于 GIS 三维滑坡分析模块,结合实时固有振动频率对黏聚力参量进行调整,实现坡体更加客观的强度折减。固有振动频率与滑坡黏聚力关系的构建,可以有效解决数值分析中参数选取和调节的困难。通过试验和实际边坡的应用,基于模态参量变化的动态数值分析,避开了极限平衡法主观缺点,模拟结果更加符合客观实际。同时,分析结果更加客观、合理,

  9. From incipient slope instability through slope deformation to catastrophic failure - Different stages of failure development on the Ivasnasen and Vollan rock slopes (western Norway)

    Oppikofer, T.; Saintot, A.; Hermanns, R. L.; Böhme, M.; Scheiber, T.; Gosse, J.; Dreiås, G. M.


    The long-term evolution of rock slope failures involves different stages, from incipience of slope instability to catastrophic failure, through a more or less long-lasting slope deformation phase that also involves creeping or sliding. Topography, lithology, and structural inheritance are the main intrinsic factors that influence this evolution. Here, we investigate the role of these intrinsic factors on the rock slope failure development of the Ivasnasen and Vollan rock slopes (Sunndal Valley, western Norway) using a multitechnique approach that includes geomorphologic and structural field mapping, kinematic analysis, terrestrial cosmogenic nuclide exposure dating, topographic reconstruction, and deformation quantification. Ivasnasen is a rock slope failure complex with several past rock slope failures and a present unstable rock slope, located on a cataclinal NW-facing slope and developed in augen gneiss. Vollan on the opposite valley side is a deep-seated gravitational slope deformation (DSGSD) affecting the whole mountainside, developed in quartzite in the upper part and micaschist in the lower part. These different lithologies belong to different nappe complexes that were emplaced and folded into a series of syn- and anticlines during the Caledonian orogeny. These folds lead to different lithologies being exposed in different structural orientations on the opposite valley flanks, which in turn leads to different types and evolution of rock slope failures. At Ivasnasen the 45°-55° NW-dipping ductile foliation allowed for a fairly simple planar sliding mechanism for the 1.2 million m3 post-glacial rock slope failure. Failure occurred ca. 3.3 ka ago after a short period of prefailure deformation. For the present 2.2 million m3 unstable rock slope at Ivasnasen, a steepening of the foliation at the toe impedes such a mechanism and up to 10 m of displacement has not lead to a catastrophic failure yet. The Vollan DSGSD is characterized by a steep major back scarp

  10. Slope stability and erosion control: Ecotechnological solutions

    Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.


    This book is designed to assist the civil and geotechnical engineer, geomorphologist, forester, landscape architect or ecologist in choosing ecotechnological solutions for slopes that are prone to a variety of mass movements e.g. shallow failure or erosion. Within this book, the 'engineer' is used i

  11. Slope stability and erosion control: Ecotechnological solutions

    Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.


    This book is designed to assist the civil and geotechnical engineer, geomorphologist, forester, landscape architect or ecologist in choosing ecotechnological solutions for slopes that are prone to a variety of mass movements e.g. shallow failure or erosion. Within this book, the 'engineer' is used

  12. Slope stability and erosion control: Ecotechnological solutions

    Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.


    This book is designed to assist the civil and geotechnical engineer, geomorphologist, forester, landscape architect or ecologist in choosing ecotechnological solutions for slopes that are prone to a variety of mass movements e.g. shallow failure or erosion. Within this book, the 'engineer' is used i

  13. Parameterization experiments performed via synthetic mass movements prototypes generated by 3D slope stability simulator

    Colangelo, Antonio C.


    The central purpose of this work is to perform a reverse procedure in the mass movement conventional parameterization approach. The idea is to generate a number of synthetic mass movements by means of the "slope stability simulator" (Colangelo, 2007), and compeer their morphological and physical properties with "real" conditions of effective mass movements. This device is an integrated part of "relief unity emulator" (rue), that permits generate synthetic mass movements in a synthetic slope environment. The "rue" was build upon fundamental geomorphological concepts. These devices operate with an integrated set of mechanical, geomorphic and hydrological models. The "slope stability simulator" device (sss) permits to perform a detailed slope stability analysis in a theoretical three dimensional space, by means of evaluation the spatial behavior of critical depths, gradients and saturation levels in the "potential rupture surfaces" inferred along a set of slope profiles, that compounds a synthetic slope unity. It's a meta-stable 4-dimensional object generated by means of "rue", that represents a sequence evolution of a generator profile applied here, was adapted the infinite slope model for slope. Any slope profiles were sliced by means of finite element solution like in Bishop method. For the synthetic slope systems generated, we assume that the potential rupture surface occurs at soil-regolith or soil-rock boundary in slope material. Sixteen variables were included in the "rue-sss" device that operates in an integrated manner. For each cell, the factor of safety was calculated considering the value of shear strength (cohesion and friction) of material, soil-regolith boundary depth, soil moisture level content, potential rupture surface gradient, slope surface gradient, top of subsurface flow gradient, apparent soil bulk density and vegetation surcharge. The slope soil was considered as cohesive material. The 16 variables incorporated in the models were analyzed for

  14. Reliability Analysis of Slope Stability by Central Point Method

    Li, Chunge; WU Congliang


    Given uncertainty and variability of the slope stability analysis parameter, the paper proceed from the perspective of probability theory and statistics based on the reliability theory. Through the central point method of reliability analysis, performance function about the reliability of slope stability analysis is established. What’s more, the central point method and conventional limit equilibrium methods do comparative analysis by calculation example. The approach’s numerical ...

  15. Geosynthetic clay liners - slope stability field study

    Carson, D.A. [Environmental Protection Agency, Cincinnati, OH (United States); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States); Koerner, R.M. [Geosynthetic Research Institute, Philadelphia, PA (United States); Bonaparte, R. [GeoSyntec Consultants, Atlanta, GA (United States)


    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project.

  16. Kinematic Analyses of Rock Slope Failures Triggered by the Aysén 2007 Earthquake (Patagonia, Chile)

    Glüer, F.; Loew, S.


    Most studies related to earthquake triggering of rock slope failures are statistical investigations of the relationships between earthquake source properties to the spatial distribution of various landslide types, or strongly simplified dynamic stability analyses. Only very few investigators studied the detailed structural and kinematic properties of earthquake triggered rock slope failures. In this paper we present a detailed structural and kinematic analysis of ten rockslides with volumes ranging from 9,000 to 1,000,000 m3 triggered by the Aysén Fjord Mw 6.2 earthquake of April 2007 (Southern Chile). Detailed structural data from the release areas in the steep and only rarely accessible terrain were generated from ground-based photogrammetry, combined with geodetic surveying using a rangefinder binocular connected to a GPS through a GIS-interface. The orientations of discontinuities and release planes were measured in metric 3D images using the software ShapeMetriX3D. Kinematic analyses were applied using Markland methods with Hocking refinement to study possible failure mechanisms. Strength properties of fractures, rock and rock mass were assessed both from field work and laboratory tests on granodioritic and granitic samples. A detailed stability analysis of one selected rockslide was performed with simplified limit equilibrium methods and a two-dimensional numerical FE simulation using the code Phase2. Based on the structural inventory from all release areas a regional structural analysis was performed, showing four evident systematic discontinuity sets (215/75, 275/55, 110/60, 155/65) occurring in the entire study area, and exerting a major control on the location of slope failures. A generic kinematic analysis leads to the conclusion that the distribution of earthquake-triggered rock slope failures of April 2007 is mainly controlled by the slope aspect and slope angle in relationship to these fracture set orientations, with preferential planar failure on

  17. Dynamic Response and Dynamic Failure Mode of a Weak Intercalated Rock Slope Using a Shaking Table

    Fan, Gang; Zhang, Jianjing; Wu, Jinbiao; Yan, Kongming


    A large-scale shaking table test was performed to study the dynamic response of slopes parallel to geological bedding (bedding slopes) and slopes that cross-cut geological bedding (counter-bedding slopes). The test results show that the acceleration amplification coefficients increase with increasing elevation and, when the input earthquake amplitude is greater than 0.3 g, both bedding and counter-bedding slopes begin to show nonlinear dynamic response characteristics. With increasing elevation, the displacement of the bedding slope surface increases greatly. Conversely, the displacement of the counter-bedding slope surface increases first and then decreases; the slope develops a bulge at the relative elevation of 0.85. The displacement of the bedding slope surface is greater than that of the counter-bedding slope. The counter-bedding slope is more seismically stable compared with the bedding slope. Based on the Hilbert-Huang transform and marginal spectrum theories, the processes that develop dynamic damage of the bedding and counter-bedding slopes are identified. It is shown that the dynamic failure mode of the bedding slope is mainly represented by vertical tensile cracks at the rear of the slope, bedding slide of the strata along the weak intercalation, and rock collapse from the slope crest. However, the dynamic failure mode of the counter-bedding slope is mainly represented by staggered horizontal and vertical fissures, extrusion of the weak intercalation, and breakage at the slope crest.


    贺小黑; 逄思宇; 苏志军; 杜鹏; 王迎霜; 许多; 李英华


    通过对宜昌磷矿矿区内崩塌、滑坡、泥石流、地面塌陷、地裂缝等地质灾害等影响区内岩质边坡稳定性的因素的发育现状及现有防治的调查研究,并分析了地震、降雨、露天和地下开挖对边坡稳定性的影响.得出结论有:①崩塌及其隐患(危岩)是宜昌磷矿最主要的地质灾害,其次为地面塌陷和地裂缝,滑坡和泥石流较少.②地下采空区变形是引发地面塌陷和地裂缝的主要原因,也是引发崩塌危岩的重要原因;泥石流以沟谷型泥石流为主,采矿产生的固体废弃物可作为泥石流的物源,采空区回填、修建拦渣坝是预防其充当物源的主要措施.③影响岩质边坡稳定的因素包括地质因素、自然因素和人为因素等.④露天开挖时,在坡角不变时,稳定性系数随坡高的增大而减小;开挖高陡边坡所能形成的最大坡高约为460m.⑤当巷道位于边坡内部时,随着开挖范围的扩大,稳定性系数逐渐减小.%The occurrence situation as well as the present prevention and control measures of rock fall, landslide, debris flow, ground collapse and fracture at Yichang phosphate area is introduced. At the same time, the effect factors of rock slope stability with the effect of earthquake, rainfall, open-air and underground mining on slope stability are summarized. Some conclusion can be reached. Firstly, rock fall is the main geological hazard, secondly for ground collapse and fracture. Landslide and debris flow are less. Secondly, The mined-out area deformation is the important reason that rock fall, ground collapse and fracture are induced. The main type of debris flow is gully debris flow. Solid waste can become debris flow provenance, and backfilling mined-out area and building debris retaining dams are the main prevention measures. Thirdly, stability influence factors of rocky slope includes geological factor, natural factor and human factor. Fourthly, stability coefficient

  19. Toe Structure Stability of Sloping Breakwater

    吴中; 嵇才苏


    Based on physical model tests, the rubble mound toe structure stability under the action of both regular and irregular waves is studied. Test results show that wave height and water depth at the toe structure are the most important factors affecting the stability of toe berm stone, and that irregular waves cause greater damage to the toe structure than regular waves. Analyses prove that the Gerding formula agrees better with our test results than the Meer formula. Tests on two different types of main armors also indicate that the shape and composition of the main armor have effect on the stability of the toe structure.

  20. Large gravitational rock slope deformation in Romsdalen Valley (Western Norway

    Aline Saintot


    Full Text Available Large gravitational rock slope deformation affects Precambrian gneisses at four localities of the Romsdalen valley of Western Norway. At each locality, detailed studies have allowed to determine the mechanism of deformation and to assess the degree of susceptibility for failure. 1 Svarttinden is a 4.3 Mm³ translational rockslide. Its single basal detachment developed along a foliation-parallel cataclastic fault. Although a rockslide occurred along the same detachment and the deposits reached the edge of the plateau, no displacement of the current instability is detected. 2 At Flatmark distinct 2-25 Mm³ blocks detached from the edge of the plateau by an opening along the steep foliation. The collapse of the blocks is explained by a complex mechanism of sliding and toppling. No displacement is actually detected on the instabilities. 3 At Børa blocks located at the edge of the plateau deformed by the same mechanism as at Flatmark. They have a maximum volume of 0.5 Mm3 and displacement rates of 0.2-2 cm/year. The deformation at Børa has affected a large part of the plateau and the entire deformed volume would be of 50-200 Mm³ but it is currently inactive. 4 A wedge failure at the edge of Mannen plateau is inferred to allow the 4-5 cm/year downward displacement of a 2-3.5 Mm³ instability. The high susceptibility of failure led to a permanent monitoring of the site since 2009.

  1. Analysis of Tsunamigenic Coastal Rock Slope Failures Triggered by the 2007 Earthquake in the Chilean Fjordland

    Sepulveda, S. A.; Serey, A.; Hermanns, R. L.; Redfield, T. F.; Oppikofer, T.; Duhart, P.


    The fjordland of the Chilean Patagonia is subject to active tectonics, with large magnitude subduction earthquakes, such as the M 9.5 1960 earthquake, and shallow crustal earthquakes along the regional Liquiñe-Ofqui Fault Zone (LOFZ). One of the latter (M 6.2) struck the Aysen Fjord region (45.5 S) on the 21st of April 2007, triggering dozens of landslides in the epicentral area along the fjord coast and surroundings. The largest rock slides and rock avalanches induced a local tsunami that together with debris flows caused ten fatalities and severely damaged several salmon farms, the most important economic activity of the area. Multi-scale studies of the landslides triggered during the Aysen earthquake have been carried out, including landslide mapping and classification, slope stability back-analyses and structural and geomorphological mapping of the largest failures from field surveys and high-resolution digital surface models created from terrestrial laser scanning. The failures included rock slides, rock avalanches, rock-soil slides, soil slides and debris flows. The largest rock avalanche had a volume of over 20 million cubic metres. The landslides affected steep slopes of intrusive rocks of the North Patagonian batholith covered by a thin layer of volcanic soils, which supports a high forest. The results of geotechnical analyses suggest a site effect due to topographic amplification on the generation of the landslides, with peak ground accelerations that may have reached between about 1.0 and 2.0 g for rock avalanches and between 0.6 and 1.0 g for shallow rock-soil slides, depending on the amount of assumed vertical acceleration and the applied method (limit equilibrium and Newmark). Attenuation relationships for shallow crustal seismicity indicate accelerations below 0.5 g for earthquakes of a similar magnitude and epicentral distances. Detailed field structural analyses of the largest rock avalanche in Punta Cola indicate a key role in the failure


    Tymoteusz Adam Zydroń


    Full Text Available Determination of effect of the leaf area ratio on the results of slope stability calculation of one of the landslide's prone slope of in the Pogórze Wiśnickie was presented in the paper. The calculations were carried out in modules Vadose/W and SLOPE/W of package GeoStudio 2012. The calculations involved the integration of rainfall infiltration process and slope stability calculations. As a result, the calculations allow to determinate precipitation conditions (time and accumulated precipitation height causing slope failure (i.e. rainfall threshold. The calculation results showed significant impact of LAI on the results of modeling. It was revealed, that LAI values in range 1-3, corresponding to the grass vegetation, contribute in long-term to accumulation of precipitation within slope, which limits its retention ability when intense rainfalls occur. In turn, the leaf are index LAI = 5, corresponding to the coverage of trees, increase the retentive capacity of the soil, which resulting in delayed response of slope on rainfall with in comparison to an area covered with grass plants. It was also found significant impact of moisture content conditions on rainfall threshold. It was revealed that in case of analyzed slope threshold rainfall can be comprised from 90 mm to over 700 mm.

  3. Stability analysis for natural slope by kinematical approach

    孙志彬; 覃长兵


    The stability of natural slope was analyzed on the basis of limit analysis. The sliding model of a kind of natural slope was presented. A new kinematically admissible velocity field for the new sliding model was constructed. The stability factor formulation by the upper bound theorem leads to a classical nonlinear programming problem, when the external work rate and internal energy dissipation were solved, and the constraint condition of the programming problem was given. The upper bound optimization problem can be solved efficiently by applying a nonlinear SQP algorithm, and stability factor was obtained, which agrees well with previous achievements.

  4. Reliability analysis method for slope stability based on sample weight

    Zhi-gang YANG


    Full Text Available The single safety factor criteria for slope stability evaluation, derived from the rigid limit equilibrium method or finite element method (FEM, may not include some important information, especially for steep slopes with complex geological conditions. This paper presents a new reliability method that uses sample weight analysis. Based on the distribution characteristics of random variables, the minimal sample size of every random variable is extracted according to a small sample t-distribution under a certain expected value, and the weight coefficient of each extracted sample is considered to be its contribution to the random variables. Then, the weight coefficients of the random sample combinations are determined using the Bayes formula, and different sample combinations are taken as the input for slope stability analysis. According to one-to-one mapping between the input sample combination and the output safety coefficient, the reliability index of slope stability can be obtained with the multiplication principle. Slope stability analysis of the left bank of the Baihetan Project is used as an example, and the analysis results show that the present method is reasonable and practicable for the reliability analysis of steep slopes with complex geological conditions.

  5. 基于 GeoStudio 的某土石坝整治前后渗流及坝坡稳定分析%GeoStudio-based Analysis on Seepage Flow and Slope Stability of One Earth-Rock Fill Dam Before and After Treatment

    段炎冲; 安再展; 李光耀; 邵豫霞; 黄菊萍


    针对由于下游排水棱体失效而导致某土石坝坝体浸润线比较高、坝坡安全系数不能满足规范要求的情况,通过削坡和重建排水棱体对其进行整治,再利用GeoStudio2007软件对该土石坝的稳定渗流期进行有限元分析,对比分析整治前后的渗流场和坝坡抗滑稳定性,验证了整治措施对坝体渗流和稳定性的改善作用。%Slope cutting and drainage prism reconstruction of one earth-rock fill dam are executed as the phreatic line of the dam body is higher and the safety factor of dam slope cannot be satisfied, which are resulted from the failure of the drainage prism at downstream. Then,GeoStudio2007 is applied for analysis of the stable seepage-flow period in term of finite element.Through comparison and analysis of seepage field and stability of dam slope against sliding before and after the treatment, it is verified that the treatment measures contrib-ute to improve seepage flow and stability of dam body.

  6. Probabilistic approaches for geotechnical site characterization and slope stability analysis

    Cao, Zijun; Li, Dianqing


    This is the first book to revisit geotechnical site characterization from a probabilistic point of view and provide rational tools to probabilistically characterize geotechnical properties and underground stratigraphy using limited information obtained from a specific site. This book not only provides new probabilistic approaches for geotechnical site characterization and slope stability analysis, but also tackles the difficulties in practical implementation of these approaches. In addition, this book also develops efficient Monte Carlo simulation approaches for slope stability analysis and implements these approaches in a commonly available spreadsheet environment. These approaches and the software package are readily available to geotechnical practitioners and alleviate them from reliability computational algorithms. The readers will find useful information for a non-specialist to determine project-specific statistics of geotechnical properties and to perform probabilistic analysis of slope stability.

  7. Delay-slope-dependent stability results of recurrent neural networks.

    Li, Tao; Zheng, Wei Xing; Lin, Chong


    By using the fact that the neuron activation functions are sector bounded and nondecreasing, this brief presents a new method, named the delay-slope-dependent method, for stability analysis of a class of recurrent neural networks with time-varying delays. This method includes more information on the slope of neuron activation functions and fewer matrix variables in the constructed Lyapunov-Krasovskii functional. Then some improved delay-dependent stability criteria with less computational burden and conservatism are obtained. Numerical examples are given to illustrate the effectiveness and the benefits of the proposed method.

  8. Research on stability of the accumulated rock-soil body of reservoir bank under rainfall condition


    The shear strength parameters property of rock-soil aggregates in embankment slope of reservoir,that is,the relationship between cohesion and gravel content,between friction angle and gravel content,and the relationship between cohesion and water content,between friction angle and water content,is studied based on the direct shear test results,the shear strength change law of the rock-soil aggregates is given,and the unsaturated shear strength formulation of rock-soil aggregates that could consider suction and saturation degree influence is put forward in this paper,through which the sliding or failure physical mechanism of this type of slope under the condition of rainfall infiltration is studied. Also the 3D unsteady saturated-unsaturated seepage field and its FEM resolving mode are established based on the analysis of the slope rainfall infiltration process. Case study with this method indicates that the minimum safety factor of the accumulated rock-soil aggregates dose not arrive at the moment of rainfall cessation,but appears several hours after the rainfall cessation,this phenomenon is in accordance with the practical slope engineering’s failure process and could explain appropriately the slope failure caused by rainfall infiltration. Research results in this paper have an important reference value for the research on stability of the accumulated rock-soil aggregates in embankment slope of reservoir,and can enrich the stability analysis method and relevant theory of reservoir embankment slope.

  9. Beyond debuttressing: Mechanics of paraglacial rock slope damage during repeat glacial cycles

    Grämiger, Lorenz M.; Moore, Jeffrey R.; Gischig, Valentin S.; Ivy-Ochs, Susan; Loew, Simon


    Cycles of glaciation impose mechanical stresses on underlying bedrock as glaciers advance, erode, and retreat. Fracture initiation and propagation constitute rock mass damage and act as preparatory factors for slope failures; however, the mechanics of paraglacial rock slope damage remain poorly characterized. Using conceptual numerical models closely based on the Aletsch Glacier region of Switzerland, we explore how in situ stress changes associated with fluctuating ice thickness can drive progressive rock mass failure preparing future slope instabilities. Our simulations reveal that glacial cycles as purely mechanical loading and unloading phenomena produce relatively limited new damage. However, ice fluctuations can increase the criticality of fractures in adjacent slopes, which may in turn increase the efficacy of fatigue processes. Bedrock erosion during glaciation promotes significant new damage during first deglaciation. An already weakened rock slope is more susceptible to damage from glacier loading and unloading and may fail completely. We find that damage kinematics are controlled by discontinuity geometry and the relative position of the glacier; ice advance and retreat both generate damage. We correlate model results with mapped landslides around the Great Aletsch Glacier. Our result that most damage occurs during first deglaciation agrees with the relative age of the majority of identified landslides. The kinematics and dimensions of a slope failure produced in our models are also in good agreement with characteristics of instabilities observed in the field. Our results extend simplified assumptions of glacial debuttressing, demonstrating in detail how cycles of ice loading, erosion, and unloading drive paraglacial rock slope damage.

  10. 基于折线滑动面法的土石坝坝坡稳定分析%Stability Analysis for Earth-rock Dam Slope Based on Broken Line Method

    杨才; 丰土根


      采用折线滑动面法,利用visual basic程序语言编制计算程序求解危险工况下的最小稳定安全系数 Kc值。经计算,在三种工况下,水位在1/3坝高处、稳定渗流期设计洪水位以及正常蓄水位+地震, Kc值均满足要求。在此基础上,还讨论了上游水位变化对坝坡稳定的影响以及折坡折点位置变化对坝坡稳定的影响,并验证了与文献[8]中所述利用公式法计算得出的相关结论一致性,即坝内最小 Kcmin值的折面不会通过坝顶平面,只限于坝坡范围内。%Based on the broken line method ,the Visual Basic programming language is used to compile a program so as to get the value of minimum safety coefficient Kc under risk working conditions .Through calculation ,it is found that in three working cases ,the water level is in 1/3 of the dam height ,and the design flood level in steady seepage stage as well as and the normal storage level and earthquake ,and Kc value could meet the requirements of design .Based on this , the influence on the stability of dam slope due to the change of upstream water level and the turning point ’s position is discussed .At the same time ,the conclusion from Literature [8] is tested ,in which the formula is used for calculation , and the results are consistent ,that is ,the bending surface to the Kcmin value could not pass through the dam crest level and just be limited to the range of dam slope .

  11. Stability analysis of nonlinear systems with slope restricted nonlinearities.

    Liu, Xian; Du, Jiajia; Gao, Qing


    The problem of absolute stability of Lur'e systems with sector and slope restricted nonlinearities is revisited. Novel time-domain and frequency-domain criteria are established by using the Lyapunov method and the well-known Kalman-Yakubovich-Popov (KYP) lemma. The criteria strengthen some existing results. Simulations are given to illustrate the efficiency of the results.

  12. Stability Analysis of Nonlinear Systems with Slope Restricted Nonlinearities

    Xian Liu


    Full Text Available The problem of absolute stability of Lur’e systems with sector and slope restricted nonlinearities is revisited. Novel time-domain and frequency-domain criteria are established by using the Lyapunov method and the well-known Kalman-Yakubovich-Popov (KYP lemma. The criteria strengthen some existing results. Simulations are given to illustrate the efficiency of the results.

  13. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    Burcharth, Hans Falk; Lykke Andersen, Thomas


    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard...

  14. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    Burcharth, Hans Falk; Lykke Andersen, Thomas


    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard...

  15. Effect of graph generation on slope stability analysis based on graph theory

    Enpu Li; Xiaoying Zhuang; Wenbo Zheng; Yongchang Cai


    Limit equilibrium method (LEM) and strength reduction method (SRM) are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of bench-mark examples and a rock slope show good accuracy and efficiency of the presented method.

  16. HIRESSS: a physically based slope stability simulator for HPC applications

    G. Rossi


    Full Text Available HIRESSS (HIgh REsolution Slope Stability Simulator is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provides the pressure head as perturbation to the geotechnical stability model that computes the factor of safety (FS in probabilistic terms. The hydrological model is based on an analytical solution of an approximated form of the Richards equation under the wet condition hypothesis and it is introduced as a modeled form of hydraulic diffusivity to improve the hydrological response. The geotechnical stability model is based on an infinite slope model that takes into account the unsaturated soil condition. During the slope stability analysis the proposed model takes into account the increase in strength and cohesion due to matric suction in unsaturated soil, where the pressure head is negative. Moreover, the soil mass variation on partially saturated soil caused by water infiltration is modeled.

    The model is then inserted into a Monte Carlo simulation, to manage the typical uncertainty in the values of the input geotechnical and hydrological parameters, which is a common weak point of deterministic models. The Monte Carlo simulation manages a probability distribution of input parameters providing results in terms of slope failure probability. The developed software uses the computational power offered by multicore and multiprocessor hardware, from modern workstations to supercomputing facilities (HPC, to achieve the simulation in reasonable runtimes, compatible with civil protection real time monitoring.

    A first test of HIRESSS in three different areas is presented to evaluate the reliability of the results and the runtime performance on

  17. Infinite slope stability under steady unsaturated seepage conditions

    Lu, N.; Godt, J.


    [1] We present a generalized framework for the stability of infinite slopes under steady unsaturated seepage conditions. The analytical framework allows the water table to be located at any depth below the ground surface and variation of soil suction and moisture content above the water table under steady infiltration conditions. The framework also explicitly considers the effect of weathering and porosity increase near the ground surface on changes in the friction angle of the soil. The factor of safety is conceptualized as a function of the depth within the vadose zone and can be reduced to the classical analytical solution for subaerial infinite slopes in the saturated zone. Slope stability analyses with hypothetical sandy and silty soils are conducted to illustrate the effectiveness of the framework. These analyses indicate that for hillslopes of both sandy and silty soils, failure can occur above the water table under steady infiltration conditions, which is consistent with some field observations that cannot be predicted by the classical infinite slope theory. A case study of shallow slope failures of sandy colluvium on steep coastal hillslopes near Seattle, Washington, is presented to examine the predictive utility of the proposed framework. Copyright 2008 by the American Geophysical Union.

  18. Influence of filling-drawdown cycles of the Three Gorges reservoir on deformation and failure behaviors of anaclinal rock slopes in the Wu Gorge

    Huang, Da; Gu, Dong Ming


    The upper Wu Gorge on the Yangtze River has been the site of tens of reservoir-induced landslides since the filling of the Three Gorges reservoir in 2003. These landslides have been occurring in heavily fractured carbonate rock materials along the rim of the reservoir in the Wu Gorge. A detailed investigation was carried out to examine the influence of reservoir operations (filling and drawdown) on slope stabilities in the upper Wu Gorge. Field investigations reveal many collapses of various types occurred at the toe of the anaclinal rock slopes, owing to the long-term intensive river erosion caused by periodic fluctuation of the reservoir level. Analysis of data from deformation monitoring suggests that the temporal movement of the slopes shows seasonal fluctuations that correlate with reservoir levels and drawdown conditions, with induced slope acceleration peaking when reservoir levels are lowest. This may illustrate that the main mechanism is the reservoir drawdown, which induces an episodic seepage force in the highly permeable materials at the slope toes, and thus leads to the episodic rockslides. The coupled hydraulic-mechanical (HM) modeling of the G2 landslide, which occurred in 2008, shows that collapse initiated at the submerged slope toe, which then caused the upper slope to collapse in a rock topple-rock slide pattern. The results imply that preventing water erosion at the slope toe might be an effective way for landslide prevention in the study area.

  19. Seepage and slope stability modelling of rainfall-induced slope failures in topographic hollows

    Kiran Prasad Acharya


    Full Text Available This study focuses on topographic hollows, their flow direction and flow accumulation characteristics, and highlights discharge of hillslope seepage so as to understand porewater pressure development phenomena in relation with slope failure in topographic hollows. For this purpose, a small catchment in Niihama city of Shikoku Island in western Japan, with a record of seven slope failures triggered by typhoon-caused heavy rainfall on 19–20 October 2004, was selected. After extensive fieldwork and computation of hydro-mechanical parameters in unsaturated and saturated conditions through a series of laboratory experiments, seepage and slope stability modellings of these slope failures were done in GeoStudio environment using the precipitation data of 19–20 October 2004. The results of seepage modelling showed that the porewater pressure was rapid transient in silty sand, and the maximum porewater pressure measured in an area close to the base of topographic hollows was found to be higher with bigger topographic hollows. Furthermore, a threshold relationship between the topographic hollow area and maximum porewater pressure in this study indicates that a topographic hollow of 1000 sq. m area can develop maximum porewater pressure of 1.253 kPa. However, the porewater pressures required to initiate slope instability in the upper part of the topographic hollows is relatively smaller than those in the lower part of the topographic hollows.

  20. Parallel processing for efficient 3D slope stability modelling

    Marchesini, Ivan; Mergili, Martin; Alvioli, Massimiliano; Metz, Markus; Schneider-Muntau, Barbara; Rossi, Mauro; Guzzetti, Fausto


    We test the performance of the GIS-based, three-dimensional slope stability model r.slope.stability. The model was developed as a C- and python-based raster module of the GRASS GIS software. It considers the three-dimensional geometry of the sliding surface, adopting a modification of the model proposed by Hovland (1977), and revised and extended by Xie and co-workers (2006). Given a terrain elevation map and a set of relevant thematic layers, the model evaluates the stability of slopes for a large number of randomly selected potential slip surfaces, ellipsoidal or truncated in shape. Any single raster cell may be intersected by multiple sliding surfaces, each associated with a value of the factor of safety, FS. For each pixel, the minimum value of FS and the depth of the associated slip surface are stored. This information is used to obtain a spatial overview of the potentially unstable slopes in the study area. We test the model in the Collazzone area, Umbria, central Italy, an area known to be susceptible to landslides of different type and size. Availability of a comprehensive and detailed landslide inventory map allowed for a critical evaluation of the model results. The r.slope.stability code automatically splits the study area into a defined number of tiles, with proper overlap in order to provide the same statistical significance for the entire study area. The tiles are then processed in parallel by a given number of processors, exploiting a multi-purpose computing environment at CNR IRPI, Perugia. The map of the FS is obtained collecting the individual results, taking the minimum values on the overlapping cells. This procedure significantly reduces the processing time. We show how the gain in terms of processing time depends on the tile dimensions and on the number of cores.

  1. Post Earthquack Slope Stability Analysis of Rubble Mound Breakwater

    Amin Moradi


    Full Text Available Rubble mound breakwaters are structures built mainly of quarried rock. Generally armourstone or artificial concrete armour units are used for the outer armour layer,which should protect the structure againist wave attack. Armour stones and concrete armoure unites in this outer layer are usually placed with care to obtain effective interlocking and consequently better stability .

  2. Assessment of rock mass decay in artificial slopes : Beoordeling van de degradatie van gesteentemassa's in kunstmatige hellingen

    Huisman, M.


    This research investigates the decay of rock masses underlying slopes, and seeks to quantify the relations of such decay with time and geotechnical parameters of the slope and rock mass. Decay can greatly affect the geotechnical properties of rocks within engineering timescales, and may induce a

  3. Reconstruction of multistage massive rock slope failure: Polymethodical approach in Lake Oeschinen (CH)

    Knapp, Sibylle; Gilli, Adrian; Anselmetti, Flavio S.; Hajdas, Irka


    Lateglacial and Holocene rock-slope failures occur often as multistage failures where paraglacial adjustment and stress adaptation are hypothesised to control stages of detachment. However, we have only limited datasets to reconstruct detailed stages of large multistage rock-slope failures, and still aim at improving our models in terms of geohazard assessment. Here we use lake sediments, well-established for paleoclimate and paleoseismological reconstruction, with a focus on the reconstruction of rock-slope failures. We present a unique inventory from Lake Oeschinen (Bernese Alps, Switzerland) covering about 2.4 kyrs of rock-slope failure history. The lake sediments have been analysed using sediment-core analysis, radiocarbon dating and seismic-to-core and core-to-core correlations, and these were linked to historical and meteorological records. The results imply that the lake is significantly younger than the ~9 kyrs old Kandersteg rock avalanche (Tinner et al., 2005) and shows multiple rock-slope failures, two of which could be C14-dated. Several events detached from the same area potentially initiated by prehistoric earthquakes (Monecke et al., 2006) and later from stress relaxation processes. The data imply unexpected short recurrence rates that can be related to certain detachment scarps and also help to understand the generation of a historical lake-outburst flood. Here we show how polymethodical analysis of lake sediments can help to decipher massive multistage rock-slope failure. References Monecke, K., Anselmetti, F.S., Becker, A., Schnellmann, M., Sturm, M., Giardini, D., 2006. Earthquake-induced deformation structures in lake deposits: A Late Pleistocene to Holocene paleoseismic record for Central Switzerland. Eclogae Geologicae Helvetiae, 99(3), 343-362. Tinner, W., Kaltenrieder, P., Soom, M., Zwahlen, P., Schmidhalter, M., Boschetti, A., Schlüchter, C., 2005. Der nacheiszeitliche Bergsturz im Kandertal (Schweiz): Alter und Auswirkungen auf die

  4. On the seismic response of instable rock slopes based on ambient vibration recordings

    Kleinbrod, Ulrike; Burjánek, Jan; Fäh, Donat


    Rock slope failures can lead to huge human and economic loss depending on their size and exact location. Reasonable hazard mitigation requires thorough understanding of the underlying slope driving mechanisms and its rock mass properties. Measurements of seismic ambient vibrations could improve the characterization and detection of rock instabilities since there is a link between seismic response and internal structure of the unstable rock mass. An unstable slope near the village Gondo has been investigated. The unstable part shows strongly amplified ground motion with respect to the stable part of the rock slope. The amplification values reach maximum factors of 70. The seismic response on the instable part is highly directional and polarized. Re-measurements have been taken 1 year later showing exactly the same results as the original measurements. Neither the amplified frequencies nor the amplification values have changed. Therefore, ambient vibration measurements are repeatable and stay the same, if the rock mass has not undergone any significant change in structure or volume, respectively. Additionally, four new points have been measured during the re-measuring campaign in order to better map the border of the instability.[Figure not available: see fulltext.

  5. Rock-slope failure activity and geological crises in western Norway

    Hilger, Paula; Hermanns, Reginald L.; Myhra, Kristin S.; Gosse, John C.; Ivy-Ochs, Susan; Etzelmüller, Bernd


    In Norway a compilation of terrestrial cosmogenic nuclide (TCN) ages of rock-avalanche deposits suggests a close link of rock-slope failures related to deglaciation. Although ages spread over several thousand years at the end of the Late Pleistocene, 50% of all documented events occurred within 1000 years after deglaciation. It is therefore likely that debuttressing triggered most of the events. The same data set suggests that 25% of the events occurred during a period stretching until the Holocene thermal maximum (HTM). These events might be interpreted as possible reactions to additional factors such as the thawing of high-altitude permafrost. An example of a geological crisis following deglaciation and before the HTM are seven lobate rock-avalanche deposits mapped under the slope of the Vora mountain (1450 m asl.) in the Nordfjord area of western Norway. Three events of this rock-slope failure cluster date within a short time period of 2000 years, where modelling studies indicate that high-altitude permafrost was present. After the HTM rock-slope failures are distributed temporally and spatially rather evenly throughout the Holocene and western Norway. But there are two independent local clusters with frequent rock slides during a short time span. (1) At the active Mannen rock-slope instability several rock-avalanche and rockslide deposits were mapped on the valley bottom. Stratigraphic relations combined with TCN dating suggest that at least one event occurred when the valley bottom was below the marine limit. TCN ages of further four lobes cluster around 5.2 ka BP, which does not coincide with any other rock-avalanche occurrence in the region. The top of the north facing 1295 m high unstable slope concurs with the currently estimated permafrost boundary. Preliminary TCN ages of the sliding surface indicate that larger parts of the mountain did not become active until the climate maximum. It is likely that due to structural complexity not allowing for any easy

  6. Numerical simulation study of the influence on stability of slope by underground mining under opencast coal mine slope

    LIU Ting-ting; LU Guo-bin; TONG Li-ming


    In view of the study on mining transferred from open-pit to underground,the research on the problem of the stability of slope is less.This article combined the actual situation of the Gaohai Coal Mine in Fuxin City and set up a three-dimensional model of the part of Huizhou open-pit slope by the finite difference software.Through the three-dimensional numerical simulation study of the influence on the stability of slope by underground mining,the basic characteristics of the open-pit slope deformation and the situation of basic stability were discussed.The simulation results of the mining slope of the displacement and deformation analysis of the state for mining provide a reference to the slope stability research.

  7. Geomechanical parameters of intact rocks and rock masses from the Canary Islands: Implications on their flank stability

    Rodríguez-Losada, J. A.; Hernández-Gutiérrez, L. E.; Olalla, C.; Perucho, A.; Serrano, A.; Eff-Darwich, A.


    New data on the geomechanical properties of the highly cohesive volcanic rocks of the Canary Archipelago and their role in the flank stability on oceanic islands are provided in this work. On the basis of the textural and petrological features, a preliminary classification of rocks, grouped into lithotypes, was carried out. This classification includes vesicular and non vesicular basalts, trachybasalts, trachytes, phonolites, welded and non welded ignimbrites. Strength and strain-related features are summarized here for each distinctive lithotype. Taking into account the results of the uniaxial and triaxial compressive tests, the geological strength index of rock masses and their textural-structural features, an estimate of the rock mass parameters and Mohr-Coulomb fit has been carried out. A final discussion on the impact of those geomechanical parameters as factors governing the stability of steep slopes in volcanic islands is then made here as a contribution in volcanic risk.

  8. Integrated analysis of past, and potential future rock slope failures of various size from Rombakstøtta, Nordland

    Morken, Odd André


    Catastrophic failure of large rock slopes has led to fatalities in Norwegian settlements several times per century. The Geological Survey of Norway (NGU) currently carry out systematic geological mapping of potentially unstable rock slopes in Norway, on assignment from the Norwegian Water Resources and Energy Directorate (NVE). In this context, a hazard analysis and preliminary consequence assessment of the unstable rock slope at Rombakstøtta in Narvik kommune, Nordland fylke has been carried...

  9. Time-dependent evolution of rock slopes by a multi-modelling approach

    Bozzano, F.; Della Seta, M.; Martino, S.


    This paper presents a multi-modelling approach that incorporates contributions from morpho-evolutionary modelling, detailed engineering-geological modelling and time-dependent stress-strain numerical modelling to analyse the rheological evolution of a river valley slope over approximately 102 kyr. The slope is located in a transient, tectonically active landscape in southwestern Tyrrhenian Calabria (Italy), where gravitational processes drive failures in rock slopes. Constraints on the valley profile development were provided by a morpho-evolutionary model based on the correlation of marine and river strath terraces. Rock mass classes were identified through geomechanical parameters that were derived from engineering-geological surveys and outputs of a multi-sensor slope monitoring system. The rock mass classes were associated to lithotechnical units to obtain a high-resolution engineering-geological model along a cross section of the valley. Time-dependent stress-strain numerical modelling reproduced the main morpho-evolutionary stages of the valley slopes. The findings demonstrate that a complex combination of eustatism, uplift and Mass Rock Creep (MRC) deformations can lead to first-time failures of rock slopes when unstable conditions are encountered up to the generation of stress-controlled shear zones. The multi-modelling approach enabled us to determine that such complex combinations may have been sufficient for the first-time failure of the S. Giovanni slope at approximately 140 ka (MIS 7), even without invoking any trigger. Conversely, further reactivations of the landslide must be related to triggers such as earthquakes, rainfall and anthropogenic activities. This failure involved a portion of the slope where a plasticity zone resulted from mass rock creep that evolved with a maximum strain rate of 40% per thousand years, after the formation of a river strath terrace. This study demonstrates that the multi-modelling approach presented herein is a useful

  10. Force analysis of pile foundation in rock slope based on upper-bound theorem of limit

    ZHAO Ming-hua; LIU Jian-hua; LIU Dai-quan; WANG You


    Based on the characteristic that the potential sliding surfaces of rock slope are commonly in the shape of either line or fold line, analysis thought of conventional pile foundation in the flat ground under complex load condition was applied and the upper-bound theorem of limit analysis was used to compute thrust of rock layers with all possible distribution shapes. The interaction of slope and pile was considered design load in terms of slope thrust, and the finite difference method was derived to calculate inner-force and displacement of bridge pile foundation in rock slope under complex load condition. The result of example shows that the distribution model of slope thrust has certain impact on displacement and inner-force of bridge pile foundation. The maximum displacement growth rate reaches 54% and the maximum moment and shear growth rates reach only 15% and 20%, respectively, but the trends of inner-force and displacement of bridge pile foundation are basically the same as those of the conventional pile foundation in the flat ground. When the piles bear the same level lateral thrust, the distribution shapes of slope thrust have different influence on inner-force of pile foundation, especially the rectangle distribution, and the triangle thrust has the smallest displacement and inner-force of pile foundation.

  11. Assessment and mapping of slope stability based on slope units: A case study in Yan’an, China

    Jianqi Zhuang; Jianbing Peng; Yonglong Xu; Qiang Xu; Xinghua Zhu; Wei Li


    Precipitation frequently triggers shallow landslides in the Loess Plateau of Shaanxi, China, resulting in loss of life, damage to gas and oil routes, and destruction of transport infrastructure and farmland. To assess the possibility of shallow landslides at different precipitation levels, a method to draw slope units and steepest slope profiles based on ARCtools and a new method for calculating slope stability areproposed. The methods were implemented in a case study conducted in Yan’an, north-west China. High resolution DEM (Digital Elevation Model) images, soil parameters from in-situ laboratory measurements and maximum depths of precipitation infiltration were used as input parameters in the method. Next,DEM and reverse DEM were employed to map 2146 slope units in the study area, based on which the steepest profiles of the slope units were constructed. Combining analysis of the water content of loess, strength of the sliding surface, its response to precipitation and the infinite slope stability equation, a newequation to calculate infinite slope stability is proposed to assess shallow landslide stability. The slope unit stability was calculated using the equation at 10-, 20-, 50- and 100-year return periods of antecedent effective precipitation. The number of slope units experiencing failure increased in response to increasing effective antecedent rainfall. These results were validated based on the occurrence of landslides in recent decades. Finally, the applicability and limitations of the model are discussed.

  12. Stability investigation of road cut slope in basaltic rockmass, Mahabaleshwar, India

    Ashutosh Kainthola; P.K. Singh; T.N. Singh


    Slope failures along hill cut road slopes are the major nuisance for commuters and highway planners as they put the human lives at huge risk, coupled with immense monetary losses. Analysis of these vulnerable cut slopes entails the assessment and estimation of the suitable material strength input parameters to be used in the numerical models to accomplish a holistic stability examination. For the present study a 60 m high, basaltic and lateritic road cut hill slope in Mahabaleshwar, India, has been considered. A number of samples of both basalt and laterite, in their natural state were tested in the laboratory and the evaluated maximum, minimum and mean strength parameters were employed for the three cases in a distinct element numerical model. The Mohr-Coulomb failure criterion has been incorporated in the numerical model for the material as well as the joints. The numerical investigation offered the factor of safety and insights into the probable deformational mechanism for the three cases. Beside, several critical parameters have also been judged from the study viz., mode of failure, factor of safety, shear strain rate, displacement magnitudes etc. The result of this analysis shows that the studied section is prone to recurrent failures due to the capping of a substantially thick layer of weaker lateritic material above the high strength basaltic rock mass. External triggering mechanisms like heavy pre-cipitation and earthquake may also accelerate the slope failure in this area. The study also suggests employing instant preventive measures to avert the further risk of damage.

  13. Terrestrial LiDAR monitoring of rock slope-channel coupling

    Bell, R.; Blöthe, J. H.; Meyer, N. K.; Hoffmann, T.; Hoffert, H.; Kreiner, D.; Elverfeldt, K. V.


    In steep terrain, various types of landslides (e.g. rock falls, debris flows and slides) are important erosional processes which often have a major impact on fluvial systems. On the one hand, they may divert river channels to opposite slopes or even block entire river channels, leading to the formation of landslide-dammed lakes. On the other hand, rivers prepare or even trigger landslides by undercutting slopes, which again will have an impact on the river channel. Our focus is on two study areas. One of them, the Schlichem Valley, is located in the Swabian Alb (SW-Germany), a lower mountain range consisting of Jurassic sedimentary rocks forming a cuesta landscape. There, the focus is on a larger landslide complex which blocked the river Schlichem three times during the 18th century and which is still active. Recent activity, especially at the location where the landslide enters the fluvial system, is investigated using Terrestrial LiDAR monitoring. The second study area is located in the Gesaeuse National Park in the Austrian Alps. There, various geomorphic environments are investigated by Terrestrial LiDAR including a vertical rock face in Dachstein limestone, which talus slope is directly coupled to the river Enns. The talus slope is built up by rock fall deposits, eroded mainly through smaller debris flow events. Furthermore, the talus slope is undercut by flood events of the river Enns. In this study a concept and first results are presented. They suggest how rock slope processes and their interactions with river channels can be monitored.

  14. Comparison of slope stability in two Brazilian municipal landfills.

    Gharabaghi, B; Singh, M K; Inkratas, C; Fleming, I R; McBean, E


    The implementation of landfill gas to energy (LFGTE) projects has greatly assisted in reducing the greenhouse gases and air pollutants, leading to an improved local air quality and reduced health risks. The majority of cities in developing countries still dispose of their municipal waste in uncontrolled 'open dumps.' Municipal solid waste landfill construction practices and operating procedures in these countries pose a challenge to implementation of LFGTE projects because of concern about damage to the gas collection infrastructure (horizontal headers and vertical wells) caused by minor, relatively shallow slumps and slides within the waste mass. While major slope failures can and have occurred, such failures in most cases have been shown to involve contributory factors or triggers such as high pore pressures, weak foundation soil or failure along weak geosynthetic interfaces. Many researchers who have studied waste mechanics propose that the shear strength of municipal waste is sufficient such that major deep-seated catastrophic failures under most circumstances require such contributory factors. Obviously, evaluation of such potential major failures requires expert analysis by geotechnical specialists with detailed site-specific information regarding foundation soils, interface shearing resistances and pore pressures both within the waste and in clayey barrier layers or foundation soils. The objective of this paper is to evaluate the potential use of very simple stability analyses which can be used to study the potential for slumps and slides within the waste mass and which may represent a significant constraint on construction and development of the landfill, on reclamation and closure and on the feasibility of a LFGTE project. The stability analyses rely on site-specific but simple estimates of the unit weight of waste and the pore pressure conditions and use "generic" published shear strength envelopes for municipal waste. Application of the slope stability

  15. Evidence of rock slope breathing using ground-based InSAR

    Rouyet, Line; Kristensen, Lene; Derron, Marc-Henri; Michoud, Clément; Blikra, Lars Harald; Jaboyedoff, Michel; Lauknes, Tom Rune


    Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) campaigns were performed in summer 2011 and 2012 in the Romsdalen valley (Møre & Romsdal county, western Norway) in order to assess displacements on Mannen/Børa rock slope. Located 1 km northwest, a second GB-InSAR system continuously monitors the large Mannen rockslide. The availability of two GB-InSAR positions creates a wide coverage of the rock slope, including a slight dataset overlap valuable for validation. A phenomenon of rock slope breathing is detected in a remote and hard-to-access area in mid-slope. Millimetric upward displacements are recorded in August 2011. Analysis of 2012 GB-InSAR campaign, combined with the large dataset from the continuous station, shows that the slope is affected by inflation/deflation phenomenon between 5 and 10 mm along the line-of-sight. The pattern is not homogenous in time and inversions of movement have a seasonal recurrence. These seasonal changes are confirmed by satellite InSAR observations and can possibly be caused by hydrogeological variations. In addition, combination of GB-InSAR results, in situ measurements and satellite InSAR analyses contributes to a better overview of movement distribution over the whole area.

  16. Design of anti-slide piles for slope stabilization in Wanzhou city, Three Gorges Area, China

    Zhou, Chunmei; van Westen, Cees


    This study is related to the design of anti-slide piles for several landslides in Wanzhou city located in the Three Gorges area. Due to the construction of the Three Gorges Reservoir the hydro-geological conditions in this area have deteriorated significantly, leading to larger instability problems. China has invested a lot of money in slope stabilization measures for the treatment of landslides in the Three Gorges area. One of the methods for the stabilization of large landslides is the design of anti-sliding piles. This paper focuses on extensive slope stability analysis and modeling of the mechanical behavior of the landslide masses, and the parameters required for designing the number, size and dimensions of reinforced concrete stabilization piles. The study focuses on determining the rock parameters, anchor depth, and the pile and soil interaction coefficient. The study aims to provide guidelines for anti-slide pile stabilization works for landslides in the Wanzhou area. The research work contains a number of aspects. First a study is carried out on the distribution of pressures expected on the piles, using two different methods that take into account the expected pore water pressure and seismic acceleration. For the Ercengyan landslide , the Limit Equilibrium Method and Strength Reduction Method of FEM are compared through the results of the landslide pressure distributions on the piles and stress fields in the piles. The second component is the study of the required anchor depth of antislide piles, which is carried out using a statistical analysis with data from 20 landslides that have been controlled with anti-sliding piles. The rock characteristics of the anchor locations were obtained using laboratory tests, and a classification of rock mass quality is made for the anchors of antislide piles. The relationship between the critical anchor height and the angle of the landslide slip surface is determined. Two different methods are presented for the length

  17. Couple analysis on strength reduction theory and rheological mechanism for slope stability

    刘子振; 言志信; 段建


    Considering the rheological properties of rock and soil body,and exploiting the merit of strength reduction technique,a theory of couple analysis is brought forward on the basis of strength reduction theory and rheological properties.Then,the concept and the calculation procedure of the safety factor are established at different time.Making use of finite element software ANSYS,the most dangerous sliding surface of the slope can be obtained through the strength reduction technique.According to the dynamic safety factor based on rheological mechanism,a good forecasting could be presented to prevent and cure the landslide.The result shows that the couple analysis reveals the process of the slope failure with the time and the important influence on the long-term stability due to the rheological parameters.

  18. Bioengineering case studies sustainable stream bank and slope stabilization

    Goldsmith, Wendi; McCullah, John


    This unique volume describes and evaluates 30 projects from across the United States where bio-stabilization was employed to address a detrimental naturally occurring process or byproduct of the built environment. Bio-stabilization (or soil bioengineering) refers to the use of plant materials, primarily live cuttings, arranged in the ground in different arrays to reinforce soils and protect upland slopes and/or stream banks against surficial erosion and shallow slope failures. Examples included in the collection represent different regions of the country and their specific conditions and challenges. Each project is illustrated with a number of distinctive photographs to support the reader's understanding and showcase the wide scope of projects and techniques presented. This book also: ·         Presents a range of well-documented case studies on key techniques and best practices for bio-stabilization projects ·         Emphasizes evaluation and comparison of different techniques and challeng...

  19. Influence law of multipoint vibration load on slope stability in Xiaolongtan open pit mine in Yunnan, China

    韩流; 舒继森; N.R. HANIF; 席文佳; 李鑫; 靖洪文; 马力


    The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability. Based on the type and transmission way of vibration stress wave, the main stress in the horizontal and vertical directions was analyzed and the superposition effect of the stress wave was revealed. After the mechanical analysis of the sliding mass, the calculation formulas of the anti-sliding force and the sliding force were derived and the damage mechanism of blasting vibration to the structural plane was defined. In addition, according to the structure and lithologic parameter of the slope as well as the vibration monitoring data, the west slope stability of Xiaolongtan open pit mine was analyzed. The results show that the time-dependent stability factor is proportional to the vibration speed and the peak values appear at the same time. Vibration load promotes the breakage of the structural plane leading to the drop of the west slope stability factor by 0.23%. Under the multipoint simultaneous blasting, the fluctuating laws of the stability factors are consistent. The more the start-up points are, the higher the weakening degree to the slope stability is. Under the multipoint allochronic blasting, the stability factor depends on the synthetic waveform structure of all vibration waves. The greater the blasting time difference is, the lower the weakening degree to the slope stability is. Selecting the reasonable quantity of start-up points and time difference could fully reduce the adverse influence of vibration load to slope stability.

  20. Influence of strength parameters of soil on the slope stability

    Xu Bin Bin


    Full Text Available The stability analysis of uniform clay and sand slope is carried out using traditional limit equilibrium method and strength reduction method. In order to evaluate the influence of strength parameters including friction angle and cohesive strength, the errors among Fellenius’s method, Bishop’s method and strength reduction method are calculated in detail. The results are: 1 the safety factor obtained from Fellenius’s method is smaller than that obtained from Bishop’s method; 2 the error between Bishop’s method and strength reduction method usually firstly increases and then decrease as the friction angle/cohesive strength becomes larger.

  1. In-situ testing study on convection and temperature characteristics of a new crushed-rock slope embankment design in a permafrost region

    MingHao Liu; FuJun Niu; JianHong Fang; ZhanJu Lin; Jing Luo; GuoAn Yin



  2. Multi-factor sensitivity analysis of shallow unsaturated clay slope stability

    Zhuoying Tan; Meifeng Cai


    An unsaturated clay slope, with various sloping angles and a thickness of 14 m, consists of backfill, slope soil and residual soil. Slide interfaces were determined by geophysical approaches and the original slope was reconstructed. Sub-slope masses were classified based on the varieties of sloping angle. A force recursive principle was proposed to calculate the stability coefficient of the sub-slope masses. The influencing factors such as sloping angle, water content, hydrostatic pressure, seismic force as well as train load were analyzed. The range and correlation of the above-mentioned factors were discussed and coupled wave equations were established to reflect the relationships between unit weight, cohesion, internal frictional angle, and water content, as well as between internal frictional angle and cohesion. The sensitivity analysis of slope stability was carried out and susceptive factors were determined when the factors were taken as independent and dependent variables respectively. The results show that sloping angle, water content and earthquake are the principal susceptive factors influencing slope stability. The impact of hydrostatic pressure on slope stability is similar to the seismic force in quantity. Train load plays a small role in slope stability and its influencing only reaches the roadbed and its neighboring slope segment. If the factors are taken as independent variables, the influencing extent of water content and cohesion on slope stability can be weakened and train load can be magnified.

  3. Global analysis on slope stability and its engineering application


    In hydraulic engineering, sometimes it is necessary to consider the stability of sliding bodies with lateral frictional boundaries. Neither the existing three dimensional limit equilibrium methods nor the commercial software products are able to treat such situations. The three dimensional factor of safety is accordingly underestimated; while the shearing strength based on the three dimensional back analysis is overestimated. In this study, the lateral boundaries are regarded as the part of the slip surface. Based on the expression of the normal pressure on the slip surface and the patch interpolation, a rigorous solution for the three dimensional limit equilibrium analysis is realized. Meanwhile, the proposed procedure is applied to the stability analysis of the slope with a cable platform on the right bank in Da Gang Shan hydraulic project under construction.

  4. Dynamic and Static Combination Analysis Method of Slope Stability Analysis during Earthquake

    Liang Lu


    Full Text Available The results of laboratory model tests for simulating the slope failure due to vibration, including unreinforced slope and the slope reinforced by using geotextile, show that the slope failure occurs when a cumulative plastic displacement exceeds a certain critical value. To overcome the defects of conventional stability analysis, which evaluates the slope characteristics only by its strength parameters, a numerical procedure considering the stiffness and deformation of materials and geosynthetics is proposed to evaluate the seismic slope stability. In the proposed procedure, the failure of slope is defined when the cumulative plastic displacement calculated by a dynamic response analysis using actual seismic wave exceeds the critical value of displacement estimated by a static stability analysis considering seismic coefficient. The proposed procedure is applied to the laboratory model tests and an actual failure of slope in earthquake. The case study shows the possibility that the proposed procedure gives the realistic evaluation of seismic slope stability.

  5. Strategies for rock slope failure early warning using acoustic emission monitoring

    Codeglia, D.; Dixon, N.; Fowmes, G. J.; Marcato, G.


    Research over the last two decades has led to development of a system for soil slopes monitoring based on the concept of measuring Acoustic Emission (AE). A feature of the system is the use of waveguides installed within unstable soil slopes. It has been demonstrated that the AE measured through this technique are proportional to soil displacement rate. Attention has now been focused on the prospect of using the system within rock materials. The different nature of the slope material to be monitored and its setting means that different acoustic trends are measured, and development of new approaches for their interpretation are required. A total of six sensors have been installed in two pilot sites, firstly in Italy, for monitoring of a stratified limestone slope which can threaten a nationally important road, and secondly in Austria, for monitoring of a conglomerate slope that can endanger a section of the local railway. In this paper an outline of the two trial sites is given and AE data collected are compared with other physical measurements (i.e. rainfall and temperature) and traditional geotechnical instrumentation, to give an overview of recurring AE trends. These include clear AE signatures generated by stress changes linked to increased ground water levels and high energy events generated by freeze-thaw of the rock mass.


    Ivan Tomašić


    Full Text Available This paper presents an analysis of a complexity of interrelated structural, petrologic and climatic factors that considerably affect the instabilities in the open cast mine of Gradna, near Samobor. The instabilities provoke the slope failures such as slides and slumps of rock material. During the protracted periodical investigations, the relationship among the factors of regional geology, tectonics, structural geology, petrography, engineering geology, rock mechanics and the rock mining technology was observed in the area. The local control of hydrogeologic properties, as well as climatic fluctuations of temperature and precipitation on the slope stability, was also recognized. It turned out that the structural relationships, characteristic of the manifold cataclased dolomite, stimulated the development of local instabilities, particularly during the period of low temperatures affecting the process of ground-water accumulation. When the temperatures are worm, the ground-water circulation is slow, exerting only the small-scale influence on the local instabilities (the paper is published in Croatian.

  7. 库岸公路岩石边坡极限破坏角研究%On the critical angle deformation of reservoir bank highway rock slopes



    为了准确评价库岸公路岩石边坡的稳定性,合理指导工程施工,保证开挖边坡安全,考虑发生连续降雨、洪水等引起库水位抬高后,库岸公路岩石边坡滑动面处于饱水状态时的滑动面渗水压力,建立了渗压效应下岩石边坡的滑动简化模型.然后进行边坡上力的分析推导,得出边坡的坡高、坡角和极限破坏角之间的关系式,并对关系式进行求解,得出库岸公路岩石边坡极限破坏角公式.最后利用该公式对安康至陕川界高速公路沿线典型边坡计算并进行回归分析,得出沿线边坡坡高和坡角之间的关系式和极限破坏角公式.计算结果与实际相符.%This paper takes its main interest in the study of the critical angle deformation of reservoir bank highway rock slopes. As is known, a lot of methods and models are used for the time being to assess the stability of such deformation,for example, the limit equilibrium method and catastrophe theory. Statistically speaking,over 90% of the rock slope failure involves groundwater penetration or permeating, which implies that water is a key factor affecting the slope stability . However, it is rare for the researchers of rock slope to pay enough attention to studying the seepage pressure of sliding surface on the slope stability. Seeing the above said factors, the author of this paper is willing to turn the our direction to and take into full account such factors, as the continuous rainfall, flood discharge and so on, which may cause upraise of water level in the reservoir, in better assessing the stability of reservoir banks highway rock slope along with giving proper directions to water-conservation and highway-building engineering projects. In doing so, first of all, we have established a simplified model of sliding slope in condition of infiltration pressure, when gliding deformation of such rock slopes in case of water-saturated. And, then, the correlation equation can be derived

  8. Analysis of a Large Rock Slope Failure on the East Wall of the LAB Chrysotile Mine in Canada: LiDAR Monitoring and Displacement Analyses

    Caudal, Philippe; Grenon, Martin; Turmel, Dominique; Locat, Jacques


    A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main economic link between the region and the Northeast USA. This paper is part of a proposed integrated remote sensing-numerical modelling methodology to analyze mining rock slope stability. This paper presents the Light Detection and Ranging (LiDAR) monitoring of this slope failure. The main focus is the investigation of that rock slide using both terrestrial (TLS) and airborne (ALS) LiDAR scanning. Since 2010, four ALS and 14 TLS were performed to characterize and monitor the slide. First, laser scanning was used to investigate the geometry of the slide. The failure zone was 1100 m by 250 m in size with a mobilized volume of 25 hm3. Laser scanning was then used to investigate the rock slide's 3D displacement, thereby enabling a better understanding of the sliding kinematics. The results clearly demonstrate the ability of the proposed approach to monitor and quantify large-scale rock mass failure. The slope was monitored for a period of 5 years, and the total displacement was measured at every survey. The maximum cumulative total displacement reached was 145 m. This paper clearly shows the ability of LiDAR scanning to provide valuable quantitative information on large rock mass failures involving very large displacements.

  9. Linking slope stability and climate change: the Nordfjord region, western Norway, case study

    Vasskog, K.; Waldmann, N.; Ariztegui, D.; Simpson, G.; Støren, E.; Chapron, E.; Nesje, A.


    Valleys, lakes and fjords are spectacular features of the Norwegian landscape and their sedimentary record recall past climatic, environmental and glacio-isostatic changes since the late glacial. A high resolution multi-proxy study is being performed on three lakes in western Norway combining different geophysical methods and sediment coring with the aim of reconstructing paleoclimate and to investigate how the frequency of hazardous events in this area has changed through time. A very high resolution reflection seismic profiling revealed a series of mass-wasting deposits. These events, which have also been studied in radiocarbon-dated cores, suggest a changing impact of slope instability on lake sedimentation since the late glacial. A specially tailored physically-based mathematical model allowed a numerical simulation of one of these mass wasting events and related tsunami, which occurred during a devastating rock avalanche in 1936 killing 74 persons. The outcome has been further validated against historical, marine and terrestrial information, providing a model that can be applied to comparable basins at various temporal and geographical scales. Detailed sedimentological and geochemical studies of selected cores allows characterizing the sedimentary record and to disentangle each mass wasting event. This combination of seismic, sedimentary and geophysical data permits to extend the record of mass wasting events beyond historical times. The geophysical and coring data retrieved from these lakes is a unique trace of paleo-slope stability generated by isostatic rebound and climate change, thus providing a continuous archive of slope stability beyond the historical record. The results of this study provide valuable information about the impact of climate change on slope stability and source-to-sink processes.

  10. Vulnerabilities to Rock-Slope Failure Impacts from Christchurch, NZ Case History Analysis

    Grant, A.; Wartman, J.; Massey, C. I.; Olsen, M. J.; Motley, M. R.; Hanson, D.; Henderson, J.


    Rock-slope failures during the 2010/11 Canterbury (Christchurch), New Zealand Earthquake Sequence resulted in 5 fatalities and caused an estimated US$400 million of damage to buildings and infrastructure. Reducing losses from rock-slope failures requires consideration of both hazard (i.e. likelihood of occurrence) and risk (i.e. likelihood of losses given an occurrence). Risk assessment thus requires information on the vulnerability of structures to rock or boulder impacts. Here we present 32 case histories of structures impacted by boulders triggered during the 2010/11 Canterbury earthquake sequence, in the Port Hills region of Christchurch, New Zealand. The consequences of rock fall impacts on structures, taken as penetration distance into structures, are shown to follow a power-law distribution with impact energy. Detailed mapping of rock fall sources and paths from field mapping, aerial lidar digital elevation model (DEM) data, and high-resolution aerial imagery produced 32 well-constrained runout paths of boulders that impacted structures. Impact velocities used for structural analysis were developed using lumped mass 2-D rock fall runout models using 1-m resolution lidar elevation data. Model inputs were based on calibrated surface parameters from mapped runout paths of 198 additional boulder runouts. Terrestrial lidar scans and structure from motion (SfM) imagery generated 3-D point cloud data used to measure structural damage and impacting boulders. Combining velocity distributions from 2-D analysis and high-precision boulder dimensions, kinetic energy distributions were calculated for all impacts. Calculated impact energy versus penetration distance for all cases suggests a power-law relationship between damage and impact energy. These case histories and resulting fragility curve should serve as a foundation for future risk analysis of rock fall hazards by linking vulnerability data to the predicted energy distributions from the hazard analysis.

  11. Stability investigation of road cut slope in basaltic rockmass, Mahabaleshwar, India

    Ashutosh Kainthola


    Full Text Available Slope failures along hill cut road slopes are the major nuisance for commuters and highway planners as they put the human lives at huge risk, coupled with immense monetary losses. Analysis of these vulnerable cut slopes entails the assessment and estimation of the suitable material strength input parameters to be used in the numerical models to accomplish a holistic stability examination. For the present study a 60 m high, basaltic and lateritic road cut hill slope in Mahabaleshwar, India, has been considered. A number of samples of both basalt and laterite, in their natural state were tested in the laboratory and the evaluated maximum, minimum and mean strength parameters were employed for the three cases in a distinct element numerical model. The Mohr-Coulomb failure criterion has been incorporated in the numerical model for the material as well as the joints. The numerical investigation offered the factor of safety and insights into the probable deformational mechanism for the three cases. Beside, several critical parameters have also been judged from the study viz., mode of failure, factor of safety, shear strain rate, displacement magnitudes etc. The result of this analysis shows that the studied section is prone to recurrent failures due to the capping of a substantially thick layer of weaker lateritic material above the high strength basaltic rock mass. External triggering mechanisms like heavy precipitation and earthquake may also accelerate the slope failure in this area. The study also suggests employing instant preventive measures to avert the further risk of damage.


    M. Corsetti


    Full Text Available The methods for understanding rock instability mechanisms and for evaluating potential destructive scenarios are of great importance in risk assessment analysis dedicated to the establishment of appropriate prevention and mitigation actions. When the portion of the unstable rock mass is very large, effective actions to counteract the risks are complex and expensive. In these conditions, an optimal risk management cannot ignore procedures able to faster and accurately acquire i geometrical data for modeling the geometry of the rock walls and implementing reliable forecasting models and ii monitoring data able to describe the magnitude and the direction of deformation processes. These data contributes to the prediction of the behavior of a landslide if the measurements are acquired frequently and reliable numerical models can be implemented. Innovative geomatic techniques, based on GPS, Terrestrial Laser Scanning Surveying (TLS, automated total station and satellite and ground SAR Interferometry, have been recently applied to define the geometry and monitoring the displacements of unstable slopes. Among these, TLS is mainly adopted to generate detailed 3D models useful to reconstruct rock wall geometry by contributing to the estimation of geo-mechanical parameters, that is orientation, persistence and apparent spacing of rock discontinuities. Two examples of applications of TLS technique to the analysis of a large front in a quarry and of a rock shoulder of a dam are presented.

  13. Distribution, richness, quality, and thermal maturity of source rock units on the North Slope of Alaska

    Peters, K.E.; Bird, K.J.; Keller, M.A.; Lillis, P.G.; Magoon, L.B.


    Four source rock units on the North Slope were identified, characterized, and mapped to better understand the origin of petroleum in the area: Hue-gamma ray zone (Hue-GRZ), pebble shale unit, Kingak Shale, and Shublik Formation. Rock-Eval pyrolysis, total organic carbon analysis, and well logs were used to map the present-day thickness, organic quantity (TOC), quality (hydrogen index, HI), and thermal maturity (Tmax) of each unit. To map these units, we screened all available geochemical data for wells in the study area and assumed that the top and bottom of the oil window occur at Tmax of ~440° and 470°C, respectively. Based on several assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original organic richness prior to thermal maturation.

  14. Analytical solutions for recession analyses of sloping aquifers - applicability on relict rock glaciers in alpine catchments

    Pauritsch, Marcus; Birk, Steffen; Hergarten, Stefan; Kellerer-Pirklbauer, Andreas; Winkler, Gerfried


    Rock glaciers as aquifer systems in alpine catchments may strongly influence the hydrological characteristics of these catchments. Thus, they have a high impact on the ecosystem and potential natural hazards such as for example debris flow. Therefore, knowledge of the hydrodynamic processes, internal structure and properties of these aquifers is important for resource management and risk assessment. The investigation of such aquifers often turns out to be expensive and technically complicated because of their strongly limited accessibility. Analytical solutions of discharge recession provide a quick and easy way to estimate aquifer parameters. However, due to simplifying assumptions the validity of the interpretation is often questionable. In this study we compared results of an analytical solution of discharge recessions with results based on a numerical model. This was done in order to analyse the range of uncertainties and the applicability of the analytical method in alpine catchment areas. The research area is a 0.76 km² large catchment in the Seckauer Tauern Range, Austria. The dominant aquifer in this catchment is a rock glacier, namely the Schöneben Rock Glacier. This relict rock glacier (i.e. containing no permafrost at present) covers an area of 0.11 km² and is drained by one spring at the rock glacier front. The rock glacier consists predominantly of gneissic sediments (mainly coarse-grained, blocky at the surface) and extends from 1720 to 1905 m a.s.l.. Discharge of the rock glacier spring is automatically measured since 2002. Electric conductivity and water temperature is monitored since 2008. An automatic weather station was installed in 2011 in the central part of the catchment. Additionally data of geophysical surveys (refraction seismic and ground penetrating radar) have been used to analyse the base slope and inner structure of the rock glacier. The measured data are incorporated into a numerical model implemented in MODFLOW. The numerical

  15. North Slope, Alaska: Source rock distribution, richness, thermal maturity, and petroleum charge

    Peters, K.E.; Magoon, L.B.; Bird, K.J.; Valin, Z.C.; Keller, M.A.


    Four key marine petroleum source rock units were identified, characterized, and mapped in the subsurface to better understand the origin and distribution of petroleum on the North Slope of Alaska. These marine source rocks, from oldest to youngest, include four intervals: (1) Middle-Upper Triassic Shublik Formation, (2) basal condensed section in the Jurassic-Lower Cretaceous Kingak Shale, (3) Cretaceous pebble shale unit, and (4) Cretaceous Hue Shale. Well logs for more than 60 wells and total organic carbon (TOC) and Rock-Eval pyrolysis analyses for 1183 samples in 125 well penetrations of the source rocks were used to map the present-day thickness of each source rock and the quantity (TOC), quality (hydrogen index), and thermal maturity (Tmax) of the organic matter. Based on assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original TOC (TOCo) and the original hydrogen index (HIo) prior to thermal maturation. The quantity and quality of oil-prone organic matter in Shublik Formation source rock generally exceeded that of the other units prior to thermal maturation (commonly TOCo > 4 wt.% and HIo > 600 mg hydrocarbon/g TOC), although all are likely sources for at least some petroleum on the North Slope. We used Rock-Eval and hydrous pyrolysis methods to calculate expulsion factors and petroleum charge for each of the four source rocks in the study area. Without attempting to identify the correct methods, we conclude that calculations based on Rock-Eval pyrolysis overestimate expulsion factors and petroleum charge because low pressure and rapid removal of thermally cracked products by the carrier gas retards cross-linking and pyrobitumen formation that is otherwise favored by natural burial maturation. Expulsion factors and petroleum charge based on hydrous pyrolysis may also be high

  16. Characterization and monitoring of the Séchilienne rock slope using 3D imaging methods (Isère, France)

    Vulliez, Cindy; Guerin, Antoine; Abellán, Antonio; Derron, Marc-Henri; Jaboyedoff, Michel; Chanut, Marie-Aurélie; Dubois, Laurent; Duranthon, Jean-Paul


    The Séchilienne landslide located in the Romanche Valley (Isère, France) is a well instrumented mass movements of about 650 m high and 250 m wide, with a potential volume of about 3 million m3 in the most active part (Duranthon and Effendiantz, 2004 ; Kasperski et al., 2010). The slope, which is mainly composed of micaschist, is characterized by the presence of a NE-SW sub-vertical fracturing system involved in the destabilization of the area. The rock slope has been continuously moving since the eighties decade, with a growing acceleration during the period 2009-2013 followed by a progressive stabilization during the last years. The monitoring of the active part of the rock slide is currently carried out by an instrumentation system in order to prevent a large failure. In this work, we used different 3D techniques in order to monitor the whole rock slide displacements in three dimensions, as follows: (a) First of all, we used a Terrestrial Laser Scanning to obtain high resolution point clouds (8 cm point spacing) of the rock slope geometry. Nine different fieldwork campaigns were performed during the last six years, as follows: Aug. 2009, Jul. 2010, Nov. 2011, Nov. 2012, Jun. and Nov. 2013, Jul. and Oct. 2014, May 2015, which provided a set of 3D representations of the rock slope topography over time; (b) In addition, we used three Helicopter-based Laser Scanning campaigns carried out in Jan. 2011, Feb. 2012 and Mar. 2014 acquired by the Cerema (Chanut et al., 2014); (c) Finally, more than 600 photos were taken in Apr. 2015 in order to build a photogrammetric model of the area using Structure-from-Motion (SfM) workflow in Agisoft PhotoScan software. All types of data were complementary for the study of the movement and allowed us having a good spatial vision of the evolution of the most active part of the slope. A detailed structural analysis was performed from both LiDAR and SfM point clouds using Coltop3D (Jaboyedoff et al., 2007). Eight joint sets were

  17. Slope stability analysis for Valles Marineris, Mars: a numerical analysis of controlling conditions and failure types

    Crosta, G.; Castellanza, R.; De Blasio, F.; Utili, S.


    : Application to Martian landslides, J. Geophys. Res. - Planets, 116, E10001, DOI: 10.1144/1470-9236/05-042 Quantin, C., Allemand, P., Delacourt, C. (2004) Morphology and geometry of Valles Marineris landslides. Planetary and Space Science, 52, 11, 1011-1022 Neuffer, D.P., R.A. Schultz (2006) Mechanisms of slope failure in Valles Marineris, Mars. Quarterly Journal of Engineering Geology and Hydrogeology, 39,.3, 227-240 Schultz, R.A. (2002) Stability of rock slopes in Valles Marineris, Mars. Geophysical Research Letters, 29, 1932, doi:10.1029/2002GL015728

  18. Evaluation of Acid Producing Potential of Road-cut Rock Slopes

    Min, K.; Han, D.


    Acid rock drainage (ARD) developed as a result of road construction represents a number of technical, environmental, and social problems. Engineering impacts from ARD, the product of atmospheric oxidation of rock-forming sulfide minerals, including degradation of surface water quality, disintegration of construction materials, and structural damage of buildings, have been documented widely around the world. To characterize the ARD and to evaluate acid producing potential of road-cut rocks, samples of rocks and water were collected from two road-cut sites of shale to phyllite showing such visual indicators of ARD as orange iron precipitates along streambed and rocks. Acid Base Accounting (ABA) test, the most commonly applied static test to evaluate the potential acidity, and X-ray diffraction (XRD) analysis were performed for fifteen rock samples. In terms of NAPP (Net Acid Producing Potential) and NAGpH (pH of Net Acid Generation), seven, four, and four rock samples were classified into a PAF (potentially acid forming) group, a NAF (non-acid forming) group, and an uncertain group, respectively. Water samples with low pH of 4.4, low DO (dissolved oxygen), and high contents of heavy metals and sulfate ion showed the generation of ARD in the studied area, which confirmed the applicability of ABA test to prediction of ARD in road-cut rock slopes. Evaluation of acid producing potential of earth materials should be an essential step in the pre-design stage of construction works especially in the vicinity of mining areas.

  19. Abduction of Toe-excavation Induced Failure Process from LEM and FDM for a Dip Slope with Rock Anchorage in Taiwan

    Huang, W.-S.; Lin, M.-L.; Liu, H.-C.; Lin, H.-H.


    On April 25, 2010, without rainfall and earthquake triggering a massive landslide (200000 m3) covered a 200m stretch of Taiwan's National Freeway No. 3, killing 4 people, burying three cars and destroying a bridge. The failure mode appears to be a dip-slope type failure occurred on a rock anchorage cut slope. The strike of Tertiary sedimentary strata is northeast-southwest and dip 15˚ toward southeast. Based on the investigations of Taiwan Geotechnical Society, there are three possible factors contributing to the failure mechanism as follow:(1) By toe-excavation during construction in 1998, the daylight of the sliding layer had induced the strength reduction in the sliding layer. It also caused the loadings of anchors increased rapidly and approached to their ultimate capacity; (2) Although the excavated area had stabilized soon with rock anchors and backfills, the weathering and groundwater infiltration caused the strength reduction of overlying rock mass; (3) The possible corrosion and age of the ground anchors deteriorate the loading capacity of rock anchors. Considering the strength of sliding layer had reduced from peak to residual strength which was caused by the disturbance of excavation, the limit equilibrium method (LEM) analysis was utilized in the back analysis at first. The results showed the stability condition of slope approached the critical state (F.S.≈1). The efficiency reduction of rock anchors and strength reduction of overlying stratum (sandstone) had been considered in following analysis. The results showed the unstable condition (F.S. <1). This research also utilized the result of laboratory test, geological strength index(GSI) and finite difference method (FDM, FLAC 5.0) to discuss the failure process with the interaction of disturbance of toe-excavation, weathering of rock mass, groundwater infiltration and efficiency reduction of rock anchors on the stability of slope. The analysis indicated that the incremental load of anchors have

  20. Characterisation of tree root penetration in bedrock and its impact on slope stability

    Zhun, Mao; Selli, Lavinia; Guastini, Enrico; Preti, Federico


    The anchorage effect of tree root penetration in bedrock against shallow landslides has uniquely been discussed in conceptual models, but seldom been measured and characterised in fieldsite. Using both the ARBORADIX™ and the electrical resistivity tomography (ERT) techniques, we aims at (i) mapping the spatial distribution of tree roots penetrating in bedrock in situ, (ii) estimating their contributions to slope stabilization and (iii) comparing the two detection methods. The experimental site is located on Pomezzana (Lu), Tuscany Apennine, Italy, where a great shallow landslide occurred in 1996 following periods of intense precipitation events. On aslope of45°, the studied forest has a density of 1800 trees/ha, mainly composed of black alder Alnus glutinosa L. (95%). Root mapping was conducted in two plots close to each other: one within an intact zone with no landslide damage; the other within a restored zone since the landslide. In each plot, two repetitions were conducted in dense tree clusters and in gaps, respectively. Preliminary results showed that the density and spatial distribution of roots penetrating into bedrock were significantly associated to the site chronology (intact vs restored), stand density and tree positions. Thicker roots had much higher probability of penetrating into rocks. Each of detection methods showed it advantages and drawbacks. This study, highlighting the importance of the mechanical role of thick roots in slope stabilization, may significantly improve our understanding in the use of vegetation in ecological engineering.

  1. Vegetation as a driver of temporal variations in slope stability: The impact of hydrological processes

    Kim, John H.; Fourcaud, Thierry; Jourdan, Christophe; Maeght, Jean-Luc; Mao, Zhun; Metayer, James; Meylan, Louise; Pierret, Alain; Rapidel, Bruno; Roupsard, Olivier; de Rouw, Anneke; Sanchez, Mario Villatoro; Wang, Yan; Stokes, Alexia


    Although vegetation is increasingly used to mitigate landslide risks, how vegetation affects the temporal variability of slope stability is poorly understood, especially in earthquake-prone regions. We combined 3-year long soil moisture monitoring, measurements of soil physical properties and plant functional traits, and numerical modeling to compare slope stability under paired land uses with and without trees in tropical, subtropical, and temperate landslide- and earthquake-prone regions. Trees improved stability for 5-12 months per year from drawdown of soil moisture and resulted in less interannual variability in the duration of high-stability periods compared to slopes without trees. Our meta-analysis of published data also showed that slopes with woody vegetation were more stable and less sensitive to climate and soil factors than slopes with herbaceous vegetation. However, estimates of earthquake magnitude necessary to destabilize slopes at our sites suggest that large additional stabilization from trees is necessary for meaningful protection against external triggers.

  2. Geophysical anatomy of counter-slope scarps in sedimentary flysch rocks (Outer Western Carpathians)

    Tábořík, P.; Lenart, J.; Blecha, V.; Vilhelm, J.; Turský, O.


    A multidisciplinary geophysical survey, consisting of electrical resistivity tomography (ERT), ground penetrating radar (GPR), shallow seismic refraction (SSR) and gravity survey (GS), was used to investigate the counter-slope scarps, one of the typical manifestations of the relaxed zones of rock massifs, and the possible initial stages of deep-seated landslides (DSLs). Two upper parts of the extensive DSLs within the Moravskoslezské Beskydy Mountains (Outer Western Carpathians - OWC) built by the sedimentary flysch rock were chosen as the testing sites. A combined geophysical survey on the flysch rocks was performed on both localities to enhance our present findings. The survey revealed that the ERT is able to reliably detect underground discontinuities, which are manifested at the ground surface by one of the typical landforms (tension cracks, trenches, pseudokarst sinkholes, double-crested ridges and counter-slope scarps). Previous studies suggested that bedrock discontinuities should be depicted by high-resistivity features within ERT surveying. According to SSR and GS, expected zones of weakened rock massif were not confirmed directly underneath the superficial landforms, but they were shifted. Based on the SSR and GS measurements, the depicted high-contrast transitions between high- and low-resistivity domains within the ERT profiles were newly identified as possible manifestation of bedrock discontinuities. The results of GPR measurements give only limited information on the sedimentary flysch rocks, due to shallow penetrating depth and locally strong signal attenuation. The combined results of multidisciplinary geophysical surveying confirmed an importance of employing more than one geophysical technique for integrated interpretations of measured data. Integrated interpretations of the measured geophysical data provided a new insight into massif disintegration and the geomorphic origin of the landforms related to the DSL.

  3. Can we use ice calving on glacier fronts as a proxy for rock slope failures?

    Abellan, Antonio; Penna, Ivanna; Daicz, Sergio; Carrea, Dario; Derron, Marc-Henri; Jaboyedoff, Michel; Riquelme, Adrian; Tomas, Roberto


    Ice failures on glacier terminus show very similar fingerprints to rock-slope failure (RSF) processes, nevertheless, the investigation of gravity-driven instabilities that shape rock cliffs and glacier's fronts are currently dissociated research topics. Since both materials (ice and rocks) have very different rheological properties, the development of a progressive failure on mountain cliffs occurs at a much slower rate than that observed on glacier fronts, which leads the latter a good proxy for investigating RSF. We utilized a terrestrial Laser Scanner (Ilris-LR system from Optech) for acquiring successive 3D point clouds of one of the most impressive calving glacier fronts, the Perito Moreno glacier located in the Southern Patagonian Ice Fields (Argentina). We scanned the glacier terminus during five days (from 10th to 14th of March 2014) with very high accuracy (0.7cm standard deviation of the error at 100m) and a high density of information (200 points per square meter). Each data series was acquired at a mean interval of 20 minutes. The maximum attainable range for the utilized wavelength of the Ilris-LR system (1064 nm) was around 500 meters over massive ice (showing no-significant loss of information), being this distance considerably reduced on crystalline or wet ice short after the occurrence of calving events. As for the data treatment, we have adapted our innovative algorithms originally developed for the investigation of both precursory deformation and rockfalls to study calving events. By comparing successive three-dimensional datasets, we have investigated not only the magnitude and frequency of several ice failures at the glacier's terminus (ranging from one to thousands of cubic meters), but also the characteristic geometrical features of each failure. In addition, we were able to quantify a growing strain rate on several areas of the glacier's terminus shortly after their final collapse. For instance, we investigated the spatial extent of the

  4. Preliminary assessment of active rock slope instabilities in the high Himalaya of Bhutan

    Dini, Benedetta; Manconi, Andrea; Leith, Kerry; Loew, Simon


    The small kingdom of Bhutan, nested between India and Tibet (between 88° and 92° east and 26° and 28° north), is characterised by markedly different landscapes and climatic zones. V-shaped, forest-covered valleys in the south, affected by the monsoonal rains, give gradually way to steep, barren slopes of U-shaped valleys in the drier north, host of the highest peaks, a large number of glaciers and glacial lakes. A transition zone of vegetated, elevated plateaus collects the towns in which most of the population lives. Landslides in the high Himalaya of Bhutan have not been extensively studied despite the primary and secondary hazards related to them. The regulations and restrictions to travel to and within Bhutan imposed by the government, as well as the extremely rugged terrain hinder the accessibility to remote slopes and valleys, both of which have resulted in lack of data and investigations. In this work, we aim at producing an inventory of large rock slope instabilities (> 1 million m3) across the high Himalaya of Bhutan, identifying types of failure, assessing the activity and analysing the distribution of landslides in combination with predisposing and preparatory factors, such as lithology, tectonic structures, hypsometry, deglaciation, fluvial erosive power and climate. At this stage, we rely on the information retrieved through satellite remote sensing data, i.e. medium and high resolution DEMs, optical images and space borne Synthetic Aperture Radar (SAR) data. An initial inventory was compiled based on the identification of geomorphological features associated with slope instabilities using the available Google Earth images. Moreover, we assessed the SAR data coverage and the expected geometrical distortions by assuming different sensors (ERS, Envisat, and ALOS Palsar-1). As we are mainly interested in detecting the surface deformation related to large unstable slopes by applying Differential SAR, we also computed the percentage of potentially

  5. Rock Slope Monitoring from 4D Time-Lapse Structure from Motion Analysis

    Kromer, Ryan; Abellan, Antonio; Chyz, Alex; Hutchinson, Jean


    Structure from Motion (SfM) photogrammetry has become an important tool for studying earth surface processes because of its flexibility, ease of use, low cost and its capability of producing high quality 3-D surface models. A major benefit of SfM is that model accuracy is fit for purpose and surveys can be designed to meet a large range of spatial and temporal scales. In the Earth sciences, research in time-lapse SfM photogrammetry or videogrammetry is an area that is difficult to undertake due to complexities in acquiring, processing and managing large 4D datasets and represents an area with significant advancement potential (Eltner et al. 2016). In this study, we investigate the potential of 4D time-lapse SfM to monitor unstable rock slopes. We tested an array of statically mounted cameras collecting time-lapse photos of a limestone rock slope located along a highway in Canada. Our setup consisted of 8 DSLR cameras with 50 mm prime lenses spaced 2-3 m apart at a distance of 10 m from the slope. The portion of the rock slope monitored was 20 m wide and 6 m high. We collected data in four phases, each having 50 photographs taken simultaneously by each camera. The first phase of photographs was taken of the stable slope. In each successive phase, we gradually moved small, discrete blocks within the rock slope by 5-15 mm, simulating pre-failure deformation of rockfall. During the last phase we also removed discrete rock blocks, simulating rockfall. We used Agisoft Photoscan's 4D processing functionality and timeline tools to create 3D point clouds from the time-lapse photographs. These tools have the benefit of attaining better accuracy photo alignments as a greater number of photos are used. For change detection, we used the 4D filtering and calibration technique proposed by Kromer et al. (2015), which takes advantage of high degrees of spatial and temporal point redundancy to decrease measurement uncertainty. Preliminary results show that it is possible to attain

  6. Application of Three-Dimensional Laser Scanning and Surveying in Geological Investigation of High Rock Slope

    Huang Runqiu; Dong Xiujun


    The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.

  7. Effect of hydraulic hysteresis on the stability of infinite slopes under steady infiltration

    Chen, Pan; Mirus, Benjamin B.; Lu, Ning; Godt, Jonathan W.


    Hydraulic hysteresis, including capillary soil water retention (SWR), air entrapment SWR, and hydraulic conductivity, is a common phenomenon in unsaturated soils. However, the influence of hydraulic hysteresis on suction stress, and subsequently slope stability, is generally ignored. This paper examines the influence of each of these three types of hysteresis on slope stability using an infinite slope stability analysis under steady infiltration conditions. First, hypothetical slopes for representative silty and sandy soils are examined. Then a monitored hillslope in the San Francisco Bay Area, California is assessed, using observed rainfall conditions and measured hydraulic and geotechnical properties of the colluvial soil. Results show that profiles of suction stress and the corresponding factor of safety are generally strongly affected by hydraulic hysteresis. Results suggest that each of the three types of hydraulic hysteresis may play a major role in the occurrence of slope failure, indicating that ignoring hydraulic hysteresis will likely lead to underestimates of failure potential and hence to inaccurate slope stability analysis.

  8. Case-Based Reasoning for Slope Stability Evaluation and Its Application


    Slope is a non-linear and uncertain kinetic system affected by many factors. In view of the incompleteness and uncertainty of the information of slope stability evaluation, a new method of slope stability evaluation by using case-based reasoning is presented. Considering the sensitivity of attribute weights to the environment, the algorithm of attribute weights is set up on the basis of the concept of changeable weights. Calculating the similarity between target case of the slope and base case, the stability of target case is evaluated. It is shown from examples that the method is simple, visual, practical, and convenient for use.

  9. Toe rock stability for rubble mound breakwaters

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.


    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges.

  10. Deformation Mechanism and Stability of a Rocky Slope

    Huang Runqiu; Xiao Huabo; Ju Nengpan; Zhao Jianjun


    A high slope is located on the side of the spillway at a hydropower station in Southwest China, which has some weak inter-layers inclining outwards. Parts of the slope show heavy weathering and unloading. There appeared deformation and tensile crack either on the surface or on the afteredge of the slope during excavation, and under a platform (elev. 488 m), two levels of slopes collapsed on the downriver side. Based on the investigation in situ and the analysis of the geological structure, the conceptual model of deformation and failure mechanism was erected for this slope. Furthermore, the deformation characteristics were studied with FLAC3D numerical simulation. Comprehensive analysis shows that the whole deformation of the slope is unloading rebound in certain depth scope and the whole body does not slide along any weak interlayer. In addition, two parts with prominent local deformation in the shallow layer of the slope show the models of "creep sliding-tensile cracking" and "sliding-tensile cracking", respectively. Based on the above analysis, the corresponding project of support and reinforcement is proposed to make the slope more stable.

  11. Modeling the proportion of cut slopes rock on forest roads using artificial neural network and ordinal linear regression.

    Babapour, R; Naghdi, R; Ghajar, I; Ghodsi, R


    Rock proportion of subsoil directly influences the cost of embankment in forest road construction. Therefore, developing a reliable framework for rock ratio estimation prior to the road planning could lead to more light excavation and less cost operations. Prediction of rock proportion was subjected to statistical analyses using the application of Artificial Neural Network (ANN) in MATLAB and five link functions of ordinal logistic regression (OLR) according to the rock type and terrain slope properties. In addition to bed rock and slope maps, more than 100 sample data of rock proportion were collected, observed by geologists, from any available bed rock of every slope class. Four predictive models were developed for rock proportion, employing independent variables and applying both the selected probit link function of OLR and Layer Recurrent and Feed forward back propagation networks of Neural Networks. In ANN, different numbers of neurons are considered for the hidden layer(s). Goodness of the fit measures distinguished that ANN models produced better results than OLR with R (2) = 0.72 and Root Mean Square Error = 0.42. Furthermore, in order to show the applicability of the proposed approach, and to illustrate the variability of rock proportion resulted from the model application, the optimum models were applied to a mountainous forest in where forest road network had been constructed in the past.

  12. Linking hydrological, infinite slope stability and land-use change models through GIS for assessing the impact of deforestation on slope stability in high Andean watersheds

    Vanacker, Veerle; Vanderschaeghe, Michiel; Govers, Gerard; Willems, Edith; Poesen, Jean; Deckers, Jozef; De Bievre, Bert


    In the Ecuadorian Andes, episodic slope movements comprising shallow rotational and translational slides and rapid flows of debris and soil material are common. Consequently, not only considerable financial costs are experienced, but also major ecological and environmental problems arise in a larger geographical area. Sediment production by slope movement on hillslopes directly affects sediment transport and deposition in downstream rivers and dams and morphological changes in the stream channels. In developing countries world-wide, slope movement hazards are growing: increasing population pressure and economic development force more people to move to potentially hazardous areas, which are less suitable for agriculture and rangelands. This paper describes the methods used to determine the controlling factors of slope failure and to build upon the results of the statistical analysis a process-based slope stability model, which includes a dynamic soil wetness index using a simple subsurface flow model. The model provides a time-varying estimate of slope movement susceptibility, by linking land-use data with spatially varying hydrologic (soil conductivity, evapotranspiration, soil wetness) and soil strength properties. The slope stability model was applied to a high Andean watershed (Gordeleg Catchment, 250 ha, southern Ecuadorian Andes) and was validated by calculating the association coefficients between the slope movement susceptibility map of 2000 and the spatial pattern of active slope movements, as measured in the field with GPS. The proposed methodology allows assessment of the effects of past and future land-use change on slope stability. A realistic deforestation scenario was presented: past land-use change includes a gradual fragmentation and clear cut of the secondary forests, as observed over the last four decades (1963-2000), future land-use change is simulated based on a binary logistic deforestation model, whereby it was assumed that future land

  13. A three-dimensional slope stability model based on GRASS GIS and its application to the Collazzone area, Central Italy

    Mergili, M.; Marchesini, I.; Fellin, W.; Rossi, M.; Raia, S.; Guzzetti, F.


    Landslide risk depends on landslide hazard, i.e. the probability of occurrence of a slope failure of a given magnitude within a specified period and in a given area. The occurrence probability of slope failures in an area characterized by a set of geo-environmental parameters gives the landslide susceptibility. Statistical and deterministic methods are used to assess landslide susceptibility. Deterministic models based on limit equilibrium techniques are applied for the analysis of particular types of landslides (e.g., shallow soil slips, debris flows, rock falls), or to investigate the effects of specific triggers, i.e., an intense rainfall event or an earthquake. In particular, infinite slope stability models are used to calculate the spatial probability of shallow slope failures. In these models, the factor of safety is computed on a pixel basis, assuming a slope-parallel, infinite slip surface. Since shallow slope failures coexist locally with deep-seated landslides, infinite slope stability models fail to describe the complexity of the landslide phenomena. Limit equilibrium models with curved sliding surfaces are geometrically more complex, and their implementation with raster-based GIS is a challenging task. Only few attempts were made to develop GIS-based three-dimensional applications of such methods. We present a preliminary implementation of a GIS-based, three-dimensional slope stability model capable of dealing with deep-seated and shallow rotational slope failures. The model is implemented as a raster module (r.rotstab) in the Open Source GIS package GRASS GIS, and makes use of the three-dimensional sliding surface model proposed by Hovland (1977). Given a DEM and a set of thematic layers of geotechnical and hydraulic parameters, the model tests a large number of randomly determined potential ellipsoidal slip surfaces. In addition to ellipsoidal slip surfaces, truncated ellipsoids are tested, which can occur in the presence of weak layers or hard

  14. Stability analysis of slopes of expansive soils considering rainfall effect

    ZHU Fang-cai


    Typical failure types of slopes of expansive soils are divided to two kinds: slip in surface layer and slip in shallow layer. Based on total strength law of expansive soils, the relationship between its water content and shear strength inculding cohesion and friction angle, was studied in detail. Acoording to change of water content and depth effect during rainfall, distribution of shear strength in slopes of expansive soils was analyzed. Finally,with a slope of expansive soils in Nanning city of Guangxi Autonomous Region of China as a case, safety factor and slip surface was studied.

  15. The contribution of particle swarm optimization to three-dimensional slope stability analysis.

    Kalatehjari, Roohollah; Rashid, Ahmad Safuan A; Ali, Nazri; Hajihassani, Mohsen


    Over the last few years, particle swarm optimization (PSO) has been extensively applied in various geotechnical engineering including slope stability analysis. However, this contribution was limited to two-dimensional (2D) slope stability analysis. This paper applied PSO in three-dimensional (3D) slope stability problem to determine the critical slip surface (CSS) of soil slopes. A detailed description of adopted PSO was presented to provide a good basis for more contribution of this technique to the field of 3D slope stability problems. A general rotating ellipsoid shape was introduced as the specific particle for 3D slope stability analysis. A detailed sensitivity analysis was designed and performed to find the optimum values of parameters of PSO. Example problems were used to evaluate the applicability of PSO in determining the CSS of 3D slopes. The first example presented a comparison between the results of PSO and PLAXI-3D finite element software and the second example compared the ability of PSO to determine the CSS of 3D slopes with other optimization methods from the literature. The results demonstrated the efficiency and effectiveness of PSO in determining the CSS of 3D soil slopes.

  16. The Contribution of Particle Swarm Optimization to Three-Dimensional Slope Stability Analysis

    Roohollah Kalatehjari


    Full Text Available Over the last few years, particle swarm optimization (PSO has been extensively applied in various geotechnical engineering including slope stability analysis. However, this contribution was limited to two-dimensional (2D slope stability analysis. This paper applied PSO in three-dimensional (3D slope stability problem to determine the critical slip surface (CSS of soil slopes. A detailed description of adopted PSO was presented to provide a good basis for more contribution of this technique to the field of 3D slope stability problems. A general rotating ellipsoid shape was introduced as the specific particle for 3D slope stability analysis. A detailed sensitivity analysis was designed and performed to find the optimum values of parameters of PSO. Example problems were used to evaluate the applicability of PSO in determining the CSS of 3D slopes. The first example presented a comparison between the results of PSO and PLAXI-3D finite element software and the second example compared the ability of PSO to determine the CSS of 3D slopes with other optimization methods from the literature. The results demonstrated the efficiency and effectiveness of PSO in determining the CSS of 3D soil slopes.

  17. Slope stability improvement using low intensity field electrosmosis

    Armillotta, Pasquale


    The electrosmosis technique has been introduced in the past for slope stabilization. However, its application to real cases has been scarce due to several drawbacks mostly related to the high intensity electric field needed (1.0 V/cm or higher): the rapid degradation of the electrodes, the high system management cost, the heating and cracking of the soil and the reduction of its colloidal fraction. Thanks to the introduction of new materials, the technique is currently applied to decrease the consolidation time of saturated clay soils (forcing the elimination of water), consequently improving its mechanical strength. In clay soils, the volume variation is influenced by the presence of smectites. The clay compressibility decreases with the increasing of electrolytes concentration. Soil containing smectites that have interacted with calcium showed a reduction or the absence of swelling during hydration with distilled water and a positive increase of their shear strength. The different values of pH between the anode (acid) and the cathode (basic), induced by the electrosmosis create the conditions for the precipitation of CaCO3 near the cathode. The injection of solutions containing calcium in soils and their diffusion induced by the electrosmosis, lead to calcium precipitation and consequential increase of the shear strength. The material technological advances and the laboratory experiences described in this paper, demonstrate that the use low electric field (0.1 V/cm or lower) intensity electrosmosis (LEFE in acronym) can be effective for soil dewatering and shear strength increase while reducing its adverse effect. The LEFE can be used to: reduce the potential for swelling of active clay minerals through the introduction of ions and the precipitation of hardening substances; induce the "dewatering" in cohesive soils. Several Lab activities were carried out, using custom made electrosmosis equipment. These activities can be divided in two phases: Phase 1

  18. Stability analysis of sandy slope considering anisotropy effect in friction angle

    Hamed Farshbaf Aghajani; Hossein Salehzadeh; Habib Shahnazari


    This paper aims to investigate the effect of anisotropy of shear strength parameter on the stability of a sandy slope by performing the limit equilibrium analysis. Because of scarcity of mathematical equation for anisotropic friction angle of sand, at first, all results of principal stress rotation tests are processed by artificial neural network and a computational procedure is developed for determining sand friction angle subjected to various loading directions. By implementing this procedure, slope stability analysis is performed in both isotropic and anisotropic conditions. The results indicate that while isotropic slope stability overestimates the factor of safety between 5 and 25% which the deviation is more for flatter slope, the location of critical slip surface is coincident in both conditions. Also in specific slip surface, the parameters of face angle, geometry of slip surface and soil properties relating to anisotropy are the main factors governing the result of anisotropic slope stability.

  19. Numerical testing rock strata stability around mine workings

    Szmelter, J.; Walaszczyk, J.


    Methods are evaluated for stress analysis around mine roadways influenced by underground coal mining. Effects of underground mining on rock strata stability are analyzed. A discrete model of rock strata was developed using the finite element method. Effects of second-order strains on rock strata behavior were analyzed using the linear Hooke model. The fact that any deviation of rock strata from the state of equilibrium depended on transfer of energy from outside the system was used as a safety criterion. 2 refs.

  20. Fracture mapping in rock slope using geophysical instruments; Butsuri tansa ni yoru ganban shamennai no kiretsu bunpu hyoka

    Kurahashi, T.; Inazaki, T. [Public Works Research Institute, Tsukuba (Japan); Watanabe, S. [Geological Survey of Japan, Tsukuba (Japan)


    An attempt was made to visualize distribution of cracks in a rock slope by applying geophysical survey onto a rock slope. Geophysical logging and seismic survey using the reflection method were used as the methods for the geophysical survey. The rock slope subjected to the survey is located in a gorge along the Yoshino river in Yamashiro Town, Tokushima Prefecture. The slope has a width of 25 m and a height of 30 m. Its overhang in a nose form may has a possibility of causing collapse due to sliding. Cracks developed by horizontal schistosity were detected by performing geophysical logging on VSP, calipers, natural gamma-ray spectra, temperature and borehole in a borehole drilled vertically from the top of the slope. The seismic survey using the reflection method detected the cracks by emphasizing joints in the perpendicular direction. A possibility was shown to visualize the crack distribution with high resolution by using the above geophysical survey on the rock slope. In order to detect the crack distribution with still higher resolution, development into a three-dimensional exploration in the future is desired, not to speak of improvement in signal receivers, and discussions on geometry. 1 ref., 6 figs.

  1. Stress Intensity Factor Analysis and the Stability of Overhanging Rock

    Huang, R. Q.; Wu, L. Z.; He, Q.; Li, J. H.


    The collapse of overhanging rock is a common geological hazard in mountainous areas. The stability of overhanging rock is usually determined by the growth of a crack along a main structural plane. On the basis of linear fracture mechanics combined with the stress concentration coefficient, an analytical method to determine the stress intensity factor (SIF) of overhanging rock is developed to evaluate its stability. Experiments on pre-cracked sandstone were carried out to simulate failure of overhanging rock and verify the analytical solution to fracturing and failure of overhanging rocks. Additionally, numerical solutions using the finite element method are derived to compare with the experimental results. The J-integral and displacement extrapolation methods are used to determine stress changes at the crack tip in the overhanging rocks, and the results confirm that the analytical solutions are consistent with the results of the numerical solutions, including the displacement extrapolation used to analyze the SIF of the overhanging rock. The ratio of fracture toughness to effective SIF at the crack tip can be considered useful when examining the stability of overhanging rock.

  2. Regional variability of slope stability: Application to the Eel margin, California

    Lee, H.; Locat, J.; Dartnell, P.; Israel, K.; Florence, Wong


    Relative values of downslope driving forces and sediment resisting forces determine the locations of submarine slope failures. Both of these vary regionally, and their impact can be addressed when the data are organized in a Geographic Information System (GIS). The study area on the continental margin near the Eel River provides an excellent opportunity to apply GIS spatial analysis techniques for evaluation of slope stability. In this area, swath bathymetric mapping shows seafloor morphology and distribution of slope steepness in fine detail, and sediment analysis of over 70 box cores delineates the variability of sediment density near the seafloor surface. Based on the results of ten geotechnical studies of submarine study areas, we developed an algorithm that relates surface sediment density to the shear strength appropriate to the type of cyclic loading produced by an earthquake. Strength and stress normalization procedures provide results that are conceptually independent of subbottom depth. Results at depth are rigorously applicable if sediment lithology does not vary significantly and consolidation state can be estimated. Otherwise, the method applies only to shallow-seated slope failure. Regional density, slope, and level of anticipated seismic shaking information were combined in a GIS framework to yield a map that illustrates the relative stability of slopes in the face of seismically induced failure. When a measure of predicted relative slope stability is draped on an oblique view of swath bathymetry, a variation in this slope stability is observed on an otherwise smooth slope along the mid-slope region north of a plunging anticline. The section of slope containing diffuse, pockmarked gullies has a lower measure of stability than a separate section containing gullies that have sharper boundaries and somewhat steeper sides. Such an association suggests that our slope-stability analysis relates to the stability of the gully sides. The remainder of the

  3. Integrated satellite InSAR and slope stability modeling to support hazard assessment at the Safuna Alta glacial lake, Peru

    Cochachin, Alejo; Frey, Holger; Huggel, Christian; Strozzi, Tazio; Büechi, Emanuel; Cui, Fanpeng; Flores, Andrés; Saito, Carlos


    The Safuna glacial lakes (77˚ 37' W, 08˚ 50' S) are located in the headwater of the Tayapampa catchment, in the northernmost part of the Cordillera Blanca, Peru. The upper lake, Laguna Safuna Alta at 4354 m asl has formed in the 1960s behind a terminal moraine of the retreating Pucajirca Glacier, named after the peak south of the lakes. Safuna Alta currently has a volume of 15 x 106 m3. In 2002 a rock fall of several million m3 from the proximal left lateral moraine hit the Safuna Alta lake and triggered an impact wave which overtopped the moraine dam and passed into the lower lake, Laguna Safuna Baja, which absorbed most of the outburst flood from the upper lake, but nevertheless causing loss in cattle, degradation of agricultural land downstream and damages to a hydroelectric power station in Quitaracsa gorge. Event reconstructions showed that the impact wave in the Safuna Alta lake had a runup height of 100 m or more, and weakened the moraine dam of Safuna Alta. This fact, in combination with the large lake volumes and the continued possibility for landslides from the left proximal moraine pose a considerable risk for the downstream settlements as well as the recently completed Quitaracsa hydroelectric power plant. In the framework of a project funded by the European Space Agency (ESA), the hazard situation at the Safuna Alta lake is assessed by a combination of satellite radar data analysis, field investigations, and slope stability modeling. Interferometric analyses of the Synthetic Aperture Radar (InSAR) of ALOS-1 Palsar-1, ALOS-2 Palsar-2 and Sentinel-1 data from 2016 reveal terrain displacements of 2 cm y-1 in the detachment zone of the 2002 rock avalanche. More detailed insights into the characteristics of these terrain deformations are gained by repeat surveys with differential GPS (DGPS) and tachymetric measurements. A drone flight provides the information for the generation of a high-resolution digital elevation model (DEM), which is used for the

  4. Numerical Analysis of the Stability of Embankment Slope Reinforced with Piles

    CUI Wei; ZHANG Zhigeng; YAN Shuwang


    The effects of stabilizing piles on the stability of an embankment slope are analyzed by numerical simulation. The shear strength reduction method is used for the analysis, and the soil - pile interaction is simulated with zero-thickness elasto-plastic interface elements. Effects of pile spacing and pile position on the safety factor of slope and the behavior of piles under these conditions are given. The numerical analysis indicates that the positions of the pile have significant influence on the stability of the slope, and the pile needs to be installed in the middle of the slope for maximum safety factors. In the end, the soil arching effect closely associated with the space between stabilizing piles is analyzed. The results are helpful for design and construction of stabilizing piles.

  5. Morphodynamics and slope stability at Mergui Ridge, off western Thailand

    Schwab, J.; Gross, F.; Krastel, S.; Jintasaeranee, P.; Bunsomboonsakul, S.; Winkelmann, D.; Weinrebe, W.


    2D seismic data from the top and the western slope of the Mergui Ridge (200 km off the Thai west coast) have been acquired during MASS cruise III in January 2011 in water depths between 300 and 2200 m. The Mergui Ridge is a part of the outer shelf slope off the Thai-Malay Peninsula and forms the eastern boundary of the East Andaman Basin. Structural features in the working area include faulted older slope sediments at the transition from Mergui Ridge to East Andaman Basin that are onlapping on the (acoustic) basement of Mergui Ridge. At their top these sediments are bordered by a pronounced erosive unconformity. Younger sedimentary units on top include three E-W elongated carbonate platforms. Moreover, drift sediments are deposited on top of the ridge, comprising features such as large scale sediment waves and moats around the platforms indicating transport and reworking of the sediments. These sediments are thinning towards the edge of the ridge where a zone of non-sedimentation prevails. In the East Andaman Basin younger sediments comprise disturbed and partially faulted units that are overlain by plastered drifts with increasing thickness towards south, where pronounced sediment waves within the drifts may indicate slope normal sediment transport by bottom currents. At the basin ridge transition, within the drift sediments on top of Mergui Ridge, and at the edge of the ridge several smaller scale mass transport deposits were identified. These MTDs indicate a general instability of the slope. Instability and general morphology of the slope may result from long-term tectonic processes such as extension due to backarc basin formation in the Andaman Sea basin. Moreover, phases of uplift, erosion and subsidence may have contributed to faulting and deformation of older units in our working area. Ongoing tectonics might still cause deformation and instability. In addition, bottom currents may presently play an important role concerning morphodynamic development by

  6. Using Discrete Element Method to Simulate Influence of Vertical Joints and Upward Groundwater on The Stability of Dip Slope: A Case Study on Formosa Freeway

    Lu, An; Hsieh, Pei-Chen; Wu, Liang-Chun; Lin, Ming-Lang


    Earthquake and rainfall weakening potential sliding surface are common causes of dip slope failure. But in recent years, certain dip slopes failure, for example dip slope sliding without rain on the roadside of Formosa Freeway in northern Taiwan, are caused by uplift groundwater in vertical joints eventually weakening the potential sliding surface. The mechanism of sliding failure should be analyzed in more detail. Furthermore, prestress dissipating in anchors causing dip slope failure is also considered in this study. In this study, conceptual model is simplified from the case of Formosa Freeway in northern Taiwan and the main control factors including angle of slope, stratum, attitude of joints. In addition, drilling data, such as hydraulic conductivity, strength, friction angle and cohesion, are utilized to discuss mechanism and dominant factors of dip slope failure caused by uplift groundwater in vertical joints. UDEC(Universal Distinct Element Code) which is particularly well suited to problems involving jointed media and has been used extensively in stability analysis of jointed rock slopes is utilized in this study. The influence of external factors such as groundwater pressure on block sliding and deformation can also be simulated in UDEC. When the results from numerical simulation fit the condition of slope failure on the roadside of Formosa Freeway, the influence of prestress dissipating in anchors on slope stability is considered subsequently. Finally, simulation results by UDEC are compared with previous research results by FLAC, and discuss the difference between each other.

  7. Stability calculation method of slope reinforced by prestressed anchor in process of excavation.

    Li, Zhong; Wei, Jia; Yang, Jun


    This paper takes the effect of supporting structure and anchor on the slope stability of the excavation process into consideration; the stability calculation model is presented for the slope reinforced by prestressed anchor and grillage beam, and the dynamic search model of the critical slip surface also is put forward. The calculation model of the optimal stability solution of each anchor tension of the whole process is also given out, through which the real-time analysis and checking of slope stability in the process of excavation can be realized. The calculation examples indicate that the slope stability is changed with the dynamic change of the design parameters of anchor and grillage beam. So it is relatively more accurate and reasonable by using dynamic search model to determine the critical slip surface of the slope reinforced by prestressed anchor and grillage beam. Through the relationships of each anchor layout and the slope height of various stages of excavation, and the optimal stability solution of prestressed bolt tension design value in various excavation stages can be obtained. The arrangement of its prestressed anchor force reflects that the layout of the lower part of bolt and the calculation of slope reinforcement is in line with the actual. These indicate that the method is reasonable and practical.

  8. A simplified approach for slope stability analysis of uncontrolled waste dumps.

    Turer, Dilek; Turer, Ahmet


    Slope stability analysis of municipal solid waste has always been problematic because of the heterogeneous nature of the waste materials. The requirement for large testing equipment in order to obtain representative samples has identified the need for simplified approaches to obtain the unit weight and shear strength parameters of the waste. In the present study, two of the most recently published approaches for determining the unit weight and shear strength parameters of the waste have been incorporated into a slope stability analysis using the Bishop method to prepare slope stability charts. The slope stability charts were prepared for uncontrolled waste dumps having no liner and leachate collection systems with pore pressure ratios of 0, 0.1, 0.2, 0.3, 0.4 and 0.5, considering the most critical slip surface passing through the toe of the slope. As the proposed slope stability charts were prepared by considering the change in unit weight as a function of height, they reflect field conditions better than accepting a constant unit weight approach in the stability analysis. They also streamline the selection of slope or height as a function of the desired factor of safety.

  9. Prediction on rock stratum stability using numerical simulation

    刘少伟; 张永庆


    Numerical simulation, which is one of the important methods for tectonic simulation, can be successfully applied into the stability analysis of rock stratum in mining engineering. With numerical simulation, the characteristics of stress-deformation field of the area study can be well discovered, the stress concentration regions can be clearly located and the mechanism and effect of the stress concentration can be analyzed. The results of these studies offer fundamental data for evaluation of the rock stability and prediction of the tunnel wall stability in the working area.

  10. Application of FBG Sensing Technology in Stability Analysis of Geogrid-Reinforced Slope.

    Sun, Yijie; Xu, Hongzhong; Gu, Peng; Hu, Wenjie


    By installing FBG sensors on the geogrids, smart geogrids can both reinforce and monitor the stability for geogrid-reinforced slopes. In this paper, a geogrid-reinforced sand slope model test is conducted in the laboratory and fiber Bragg grating (FBG) sensing technology is used to measure the strain distribution of the geogrid. Based on the model test, the performance of the reinforced soil slope is simulated by finite element software Midas-GTS, and the stability of the reinforced soil slope is analyzed by strength reduction method. The relationship between the geogrid strain and the factor of safety is set up. The results indicate that the measured strain and calculated results agree very well. The geogrid strain measured by FBG sensor can be applied to evaluate the stability of geogrid-reinforced sand slopes.

  11. Application of FBG Sensing Technology in Stability Analysis of Geogrid-Reinforced Slope

    Sun, Yijie; Xu, Hongzhong; Gu, Peng; Hu, Wenjie


    By installing FBG sensors on the geogrids, smart geogrids can both reinforce and monitor the stability for geogrid-reinforced slopes. In this paper, a geogrid-reinforced sand slope model test is conducted in the laboratory and fiber Bragg grating (FBG) sensing technology is used to measure the strain distribution of the geogrid. Based on the model test, the performance of the reinforced soil slope is simulated by finite element software Midas-GTS, and the stability of the reinforced soil slope is analyzed by strength reduction method. The relationship between the geogrid strain and the factor of safety is set up. The results indicate that the measured strain and calculated results agree very well. The geogrid strain measured by FBG sensor can be applied to evaluate the stability of geogrid-reinforced sand slopes. PMID:28294995

  12. Stability Analysis of Tunnel-Slope Coupling Based on Genetic Algorithm

    Tao Luo


    Full Text Available Subjects in tunnels, being constrained by terrain and routes, entrances and exits to tunnels, usually stay in the terrain with slopes. Thus, it is necessary to carry out stability analysis by treating the tunnel slope as an entity. In this study, based on the Janbu slices method, a model for the calculation of the stability of the original slope-tunnel-bank slope is established. The genetic algorithm is used to implement calculation variables, safety coefficient expression and fitness function design. The stability of the original slope-tunnel-bank slope under different conditions is calculated, after utilizing the secondary development function of the mathematical tool MATLAB for programming. We found that the bearing capacity of the original slopes is reduced as the tunnels are excavated and the safety coefficient is gradually decreased as loads of the embankment construction increased. After the embankment was constructed, the safety coefficient was 1.38, which is larger than the 1.3 value specified by China’s standards. Thus, the original slope-tunnel-bank slope would remain in a stable state.

  13. How to Use COMSOL Multiphysics for coupled dual-permeability hydrological and slope stability modeling

    Shao, W.; Bogaard, T.A.; Bakker, M.


    Preferential flow paths, such as cracks, macropores, fissures, pipes etc. are common features of highly heterogeneous slopes. During intense rainstorms, preferential flow has a significant influence on subsurface flow and slope stability. Dual-permeability models are widely used to simulate

  14. How to Use COMSOL Multiphysics for coupled dual-permeability hydrological and slope stability modeling

    Shao, W.; Bogaard, T.A.; Bakker, M.


    Preferential flow paths, such as cracks, macropores, fissures, pipes etc. are common features of highly heterogeneous slopes. During intense rainstorms, preferential flow has a significant influence on subsurface flow and slope stability. Dual-permeability models are widely used to simulate preferen

  15. The effect of foreshore slope on breakwater stability

    Verhagen, H.J.


    In case of coasts with steep foreshores coastal structures suffer more from damage than normally could be expected from given boundary conditions at deep water. For that reason in many guidelines it is recommended to apply a heavier class of rock in those cases; manufacturers of single layer units (

  16. A continental slope stability evaluation in the Zhujiang River Mouth Basin in the South China Sea

    LIU Ke; WANG Jianhua


    In nature, a slope stability is determined by the ratio of a sliding resistance to a slide force. The slide force of a marine deep-water continental slope is mainly affected by sediment mechanics properties, a topography, and a marine seismic. However, the sliding resistance is mainly affected by sedimentary patterns and a sedi-mentary stress history. Both of these are different from case to case, and their impact can be addressed when the data are organized in a geographic information system (GIS). The study area on the continental slope in Zhujiang River Mouth Basin in South China Sea provides an excellent opportunity to apply GIS spatial analysis technology for the evaluation of the slope stability. In this area, a continental slope topography and a three-dimension (3-D) topography mapping show a sea-floor morphology and the distribution of a slope steepness in good detail, and the sediment analysis of seabed samples and an indoor appraisal reveals the variability of a sediment density near the sea-floor surface. On the basis of the results of nine geotechnical studies of submarine study areas, it has worked out that an equivalent cyclic shear stress ratio is roughly between 0.158 and 0.933, which is mainly depending on the initial water content of sediment. A regional density, slope and level of anticipated seismic shaking information are combined in a GIS framework to yield a map that illustrates a continental slope stability zoning under the influencing factors in Zhujiang River Mouth Basin in the South China Sea. The continental slope stability evaluation can contribute to north resources development in the South China Sea, the marine functional zoning, the marine engineering con-struction and adjust measures to local conditions, at the same time also can provide references for other deep-water slope stability analysis.

  17. E24 profile slope stability analysis in Haizhou Opencast Coal Mine of Fuxin

    Simplice F. BOBY; Jianping CHEN


    The E24 profile slope analyzed belongs to a series of excavated slopes of the Haizhou Opencast Coal Mine. It seems to be divided into Downslope Part and Upslope Part. Its profile comprises two noticeable coal seams, called the 8# and 9# weak layers, considered as the potential failure surfaces. In consideration of the actual configuration as in the perspective of any modification, assessing the stability of this slope with various profile forms under given conditions, and assessing the risk of instability and quantifying the influence of earthworks or other modifications to the stability of this slope, have constituted the primordial objectives carried out. From assumed potential failure surfaces, any specific profiles and specified slip surfaces are defined. A factor of safety (FoS) is computed for each specified slip surface; the smallest FoS found corresponds to the least favorable slip surface. The safety factor values obtained are compared to the suggested safety factor. Limit equilibrium methods of vertical slices implemented in Slope/W, computer program for slope stability analyses, have been adopted to perform the E24 slope stability analysis. The safety factor values computed with 9# weak layer are lower than for 8#; the factors of safety obtained with Sarma's method are the smallest; more, without groundwater (long term) overall values are greater than those determined under groundwater condition (short term). The lowest safety factor value is found for a profile depending on an adopted earthwork sequence. The E24 profile slope stability analysis shows the instability risk for the deepest weak layer, and also shows the short and long term stability of this slope for the envisaged earth movements. However it demonstrates the existence of instability risk for any earthwork firstly affecting the downslope part.

  18. The Stability Analysis Method of the Cohesive Granular Slope on the Basis of Graph Theory.

    Guan, Yanpeng; Liu, Xiaoli; Wang, Enzhi; Wang, Sijing


    This paper attempted to provide a method to calculate progressive failure of the cohesivefrictional granular geomaterial and the spatial distribution of the stability of the cohesive granular slope. The methodology can be divided into two parts: the characterization method of macro-contact and the analysis of the slope stability. Based on the graph theory, the vertexes, the edges and the edge sequences are abstracted out to characterize the voids, the particle contact and the macro-contact, respectively, bridging the gap between the mesoscopic and macro scales of granular materials. This paper adopts this characterization method to extract a graph from a granular slope and characterize the macro sliding surface, then the weighted graph is analyzed to calculate the slope safety factor. Each edge has three weights representing the sliding moment, the anti-sliding moment and the braking index of contact-bond, respectively, . The safety factor of the slope is calculated by presupposing a certain number of sliding routes and reducing Weight repeatedly and counting the mesoscopic failure of the edge. It is a kind of slope analysis method from mesoscopic perspective so it can present more detail of the mesoscopic property of the granular slope. In the respect of macro scale, the spatial distribution of the stability of the granular slope is in agreement with the theoretical solution.

  19. The Stability Analysis Method of the Cohesive Granular Slope on the Basis of Graph Theory

    Yanpeng Guan


    Full Text Available This paper attempted to provide a method to calculate progressive failure of the cohesivefrictional granular geomaterial and the spatial distribution of the stability of the cohesive granular slope. The methodology can be divided into two parts: the characterization method of macro-contact and the analysis of the slope stability. Based on the graph theory, the vertexes, the edges and the edge sequences are abstracted out to characterize the voids, the particle contact and the macro-contact, respectively, bridging the gap between the mesoscopic and macro scales of granular materials. This paper adopts this characterization method to extract a graph from a granular slope and characterize the macro sliding surface, then the weighted graph is analyzed to calculate the slope safety factor. Each edge has three weights representing the sliding moment, the anti-sliding moment and the braking index of contact-bond, respectively, . The safety factor of the slope is calculated by presupposing a certain number of sliding routes and reducing Weight repeatedly and counting the mesoscopic failure of the edge. It is a kind of slope analysis method from mesoscopic perspective so it can present more detail of the mesoscopic property of the granular slope. In the respect of macro scale, the spatial distribution of the stability of the granular slope is in agreement with the theoretical solution.

  20. Seismic slope stability of embankments: a comparative study on EC8 provisions

    Zania, Varvara; Tsompanakis, Y.; Psarropoulos, P.N.


    According to EC8 provisions, seismic stability assessment of natural slopes is currently performed based on simplified methods i.e. the pseudostatic and the Newmark’s sliding block method. The application of these methods requires the beforehand consideration of major assumptions necessary...... for the selection of either the seismic coefficient or the acceleration time history of the rigid block. Although both ULS and SLS are defined according to acceptable level of deformations at the slope, the assigned level of displacements is not clarified. In the current study the seismic slope stability...

  1. Is rock slope instability in high-mountain systems driven by topo-climatic, paraglacial or rock mechanical factors? - A question of scale!

    Messenzehl, Karoline; Dikau, Richard


    Due to the emergent and (often non-linear) complex nature of mountain systems the key small-scale system properties responsible for rock slope instability contrast to those being dominant at larger spatial scales. This geomorphic system behaviour has major epistemological consequences for the study of rockfalls and associated form-process-relationships. As each scale requires its own scientific explanation, we cannot simply upscale bedrock-scale findings and, in turn, we cannot downscale the valley-scale knowledge to smaller phenomena. Here, we present a multi-scale study from the Turtmann Valley (Swiss Alps), that addresses rock slope properties at three different geomorphic levels: (i) regional valley scale, (ii) the hillslope scale and (iii) the bedrock scale. Using this hierarchical approach, we aim to understand the key properties of high-mountain systems responsible for rockfall initiation with respect to the resulting form-process-relationship at each scale. (i) At the valley scale (110 km2) rock slope instability was evaluated using a GIS-based modelling approach. Topo-climatic parameters, i.e. the permafrost distribution and the time since deglaciation after LGM were found to be the key variables causative for the regional-scale bedrock erosion and the storage of 62.3 - 65.3 x 106 m3 rockfall sediments in the hanging valleys (Messenzehl et al. 2015). (ii) At the hillslope scale (0.03 km2) geotechnical scanline surveys of 16 rock slopes and one-year rock temperature data of 25 ibuttons reveal that the local rockfall activity and the resulting deposition of individual talus slope landforms is mainly controlled by the specific rock mass strength with respect to the slope aspect, than being a paraglacial reaction. Permafrost might be only of secondary importance for the present-day rock mechanical state as geophysical surveys disprove the existence of frozen bedrock below 2600 m asl. (Messenzehl & Draebing 2015). (iii) At the bedrock scale (0.01 mm - 10 m) the

  2. Stability of submarine slopes in the northern South China Sea: a numerical approach

    ZHANG Liang; LUAN Xiwu


    Submarine landslides occur frequently on most continental margins.They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations.In this paper,submarine slope stability is evaluated using a 2D limit equilibrium method.Considerations of slope,sediment,and triggering force on the factor of safety (FOS) were calculated in drained and undrained (φ=0) cases.Results show that submarine slopes are stable when the slope is <16° under static conditions and without a weak interlayer.With a weak interlayer,slopes are stable at <18° in the drained case and at <9° in the undrained case.Earthquake loading can drastically reduce the shear strength of sediment with increased pore water pressure.The slope became unstable at >13° with earthquake peak ground acceleration (PGA) of 0.5 g;whereas with a weak layer,a PGA of 0.2 g could trigger instability at slopes > 10°,and >3 ° for PGA of 0.5 g.The northern slope of the South China Sea is geomorphologically stable under static conditions.However,because of the possibility of high PGA at the eastern margin of the South China Sea,submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope.Therefore,submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake,the most important factor for triggering submarine slides on the northern slope of the South China Sea.Considering the distribution of PGA,we consider the northern slope of the South China Sea to be stable,excluding the Taiwan Bank slope,which is tectonically active.

  3. A Review On Dump Slope Stabilization By Revegetation With Reference To Indigenous Plant

    Vibhash Ranjan


    Full Text Available Abstract The waste sub-grade ROM and Fines dumps are characterized by high rock fragment contents low moisture retention capacity higher bulk density low nutrients lower pH and elevated metal concentrations. Use of suitable revegetation programme that require the selection of right type of plants to be used vis--vis the site condition and characteristics can enhance the long term stability both mechanical and ecological of dumps waste sub-grade ROM and fines through providing vegetative cover to control soil erosion amp gully formation consolidation of dump top amp side surfaces binding the loose particles through intricate roof system etc. This paper overviews the roles of Revegetation programme that can be used where vegetation is considered to be the long term answer to slope protection and erosion control. Various revegetation processes like Coir matting Lemmon Grass Vetiver Grass and Indigenous plant etc. may find a wide range of usage in Iron ore mines for dump stabilization.Miyawaki method of plantation is more effective than the conventional method of plantation. This will lead to co-existence of plants and as a matter of fact each plant draws from the other vital nutrients and they grow to become strong and healthy. The Miyawaki Plantation technique aim at Survival at fittest the area undergone such plantation have an ecology of their own. The Indigenous Plant has good binding capacity and helps to control soil erosion as well as improve the dump stability. Indigenous plant species like as Shorea robusta Sal CROTON ROXBURGHII Dal-bergia Sisoo SHISHAM KARANJ Azadirachta NEEM etc. The growth of indigenous plants is depending upon the soil quality as well as the organic matter of the dump material. The leaf debris plays important role for improving the organic matter of dump material for successfully implementation of revegetation programme.

  4. Impact of Rain Water Infiltration on the Stability of Earth Slopes

    Muhammad Farooq Ahmed


    Full Text Available Slope failure occurs very often in natural and man-made slopes which are subjected to frequent changes in ground water level, rapid drawdown, rainfall and earthquakes. The current study discusses the significance of water infiltration, pore water pressure and degree of saturation that affect the stability of earth slopes. Rainwater infiltration not only mechanically reduces the shear strength of a slope material, but also chemically alters the mineral composition of the soil matrix. It results in the alteration of macro structures which in turn decreases the factor of safety. A few case studies are discussed in this paper to quantitatively observe the variation in factor of safety (FOS of various earth slopes by changing the degree of saturation. The results showed that most of the earth slopes get failed or become critical when the degree of saturation approaches to 50 % or more.

  5. Parametric study on the effect of rainfall pattern to slope stability

    Hakim Sagitaningrum Fathiyah


    Full Text Available Landslide in Indonesia usually occurs during the rainy seasons. Previous studies showed that rainfall infiltration has a great effect on the factor of safety (FS of slopes. This research focused on the effect of rainfall pattern on the FS of unsaturated slope with different slope angle i.e.: 30°, 45°, and 60°. Three different rainfall patterns, which are normal, advanced, and delayed were considered in the analysis. The effects of low or high hydraulic conductivity of the soil are also observed. The analyses were conducted with SEEP/W for the seepage and SLOPE/W for the slope stability. It is found that the lowest FS for gentle slope is reached under the application of advanced rainfall pattern and the lowest FS for steep slope is reached under the application of delayed rainfall pattern. Reduction of FS is known to be the largest for gentle slope rather than steep slope due to negative pore water pressure reduction and the rising of ground water level. The largest FS reduction caused by rainfall was achieved for gentle slope under advanced rainfall pattern.

  6. Stability estimation of factory area slope of Dalian Marine Valve factory%大连船用阀门厂厂区边坡稳定性评价

    张强; 张立晶; 张敏


    拟扩建新厂区边坡岩体类型为Ⅳ,边坡工程安全等级为二级,该岩体可见共有六组节理发育。外倾节理一组,产状为280°~300°∠42°~75°与边坡坡向277°几乎一致,经计算边坡稳定性系数均小于1.30,为不稳定边坡。经分析拟建边坡小于40°时趋于稳定,大于40°时为不稳定边坡。%Slope rock type of the new plant expansion isⅣ, slope safety grade two level, the rock body has six sets joints. A set of extraverted joint, the occurrence 280 °~300 °,∠42 °~75 ° almost same to slope 277 °. By calculating the slope stability coefifcient is less than 1.30, is the unstable slope. Through the analysis, the slope less than 40 ° tends to be stable, more than 40 °is unstable slope.

  7. Stability analysis of new safety cleaning bank in steep slope mining

    吴爱祥; 姜立春; 鲍勇峰; 李建锋


    Based on the study of the slope with gently granular structure in Xingqiao open mine, a new safety cleaning bank mode for steep slope mining was developed, including setting up dint cut, and forming natural retai ning wall based on the character of gentle incline slope. It can effectively eliminate the impact of sliding body on the bottom working place and slope body, reduce the dilution of ore, keep rainwater from upper steps away, decrease influence of the weak intermediate layer, and cut cost of disposal waste rock. The safety and reliability of the mode were analyzed and verified from 3 aspects: static load calculation, ANSYS simulation of dynamic loading and spot experiment. The result of static loading calculation shows that the retaining wall can support accumulation and ex trusion of granular body, and the glide or overturn disaster will not take place. The simulations of dynamic loading show that the retaining wall remains stable until sliding body collapses from 360 m (10 sublevels). Only one new safety cleaning bank in each 1 - 5 sublevels can fully meet the need of engineering. The new mode sustains steep slope mining, increases the angle of ultimate slope, and reduces invalid overburden amount of rock by 3 %-5 %. The result of spot experiment has verified the exactness of the above calculations and simulations.

  8. Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

    Mohammad Hossein Taherynia


    Full Text Available Assessment of the stability of natural and artificial rock slopes is an important topic in the rock mechanics sciences. One of the most widely used methods for this purpose is the classification of the slope rock mass. In the recent decades, several rock slope classification systems are presented by many researchers. Each one of these rock mass classification systems uses different parameters and rating systems. These differences are due to the diversity of affecting parameters and the degree of influence on the rock slope stability. Another important point in rock slope stability is appraisal hazard and risk analysis. In the risk analysis, the degree of danger of rock slope instability is determined. The Lashotor pass is located in the Shiraz-Isfahan highway in Iran. Field surveys indicate that there are high potentialities of instability in the road cut slopes of the Lashotor pass. In the current paper, the stability of the rock slopes in the Lashotor pass is studied comprehensively with different classification methods. For risk analyses, we estimated dangerous area by use of the RocFall software. Furthermore, the dangers of falling rocks for the vehicles passing the Lashotor pass are estimated according to rockfall hazard rating system.

  9. Fracture and slope stability monitoring at Puigcercós landslide (Catalonia, Spain)

    Khazaradze, Giorgi; Vasquez, Sebastian; López, Robert; Guinau, Guinau; Calvet, Jaume; Vilaplana, Joan Manuel; Blanch, Xabier; Tapia, Mar; Roig, Pere; Suriñach, Emma


    The village of Puigcercós ( 50 inhabitants) is located in the region of Pallars Jussà (Lleida) in Catalonia, several km south of the town of Tremp. In 1881 the entire village had to be moved from its historical location on top of the hill to its current location. This was caused by a series of landslides caused by continuing rainfall. The most important landslide occurred on January 13th 1881, which displaced more than 5 million cubic meters of sediments and rocks and created an impressive rock scar of approximately 25 m height and 150 m width. The area where the sediments were accumulated is extensive, reaching 8 hectares. During the last years, our group has chosen the site of Puigcercós to conduct pilot studies of landslides and rockfalls using multidisciplinary approach, involving Terrestrial Laser Scanner, Total Station, DGPS, seismic monitoring and geophysical techniques. The geophysical surveys of the zone of the sediment accumulation, can help determine the internal structure of the displaced sediments. The work presented here mainly concerns the deformation monitoring at the site using geodetic techniques. In July 2015, a network of 11 new geodetic points has been established and measured with GPS. The location of these points was chosen with the purpose of answering two important questions in the studies of the stability and geomorphological activity of the Puigcercós landslide: 1) As a result of combined analysis of the tape-meter, total station and GPS measurements, we hope to obtain absolute values of deformation in the upper part of the escarpment, controlling the stability of the escarpment front and the associated fractures near the coronation. For this purpose, two geodetic control points have been established at the hilltop, some 5 meters away from the escarpment itself. 2) Determine the slope stability of the depositional area, where we established nine geodetic points. As of today, these points have been measured twice, in 2015 and 2016

  10. Formation Mechanism and Stability Assessment of the Colluvial Deposit Slope in Zuoyituo

    Jian Wenxing; Zhang Yihu; Yin Hongmei


    The basic features of the colluvial deposit slope in Zuoyituo such as geological conditions, dimensions, slip surfaces and groundwater conditions are described concisely in this paper. The formation mechanism of the slope is discussed. It is considered that the formation of the colluvial deposit slope in Zuoyituo has undergone accumulation, slip, load, deformation and failure. The effects of rainfall on slope stability are categorized systematically based on existing methodology, and ways to determine the effects quantitatively are presented. The remained slip force method is improved by the addition of quantitative relations to the existing formulae and programs. The parameters of the colluvial deposit slope are determined through experimentation and the method of back-analysis. The safety factors of the slope are calculated with the improved remained slip force method and the Sarma method. The results show that rainfall and water level in the Yangtze River have a significant effect on the stability of the colluvial deposit slope in Zuoyituo. The hazards caused by the instability of the slope are assessed, and prevention methods are put forward.

  11. Rock mechanics stability at Olkiluoto, Haestholmen, Kivetty and Romuvaara

    Johansson, E.; Rautakorpi, J. [Saanio and Riekkola Oy, Helsinki (Finland)


    Posiva Oy is studying the suitability of the Finnish bedrock for the geological disposal of spent nuclear fuel at four sites, Olkiluoto in Eurajoki, Haestholmen in Loviisa, Kivetty in Aeaenekoski and Romuvaara in Kuhmo. To enable the rock properties to be specified in great detail, the site-selection research programme has included rock mechanics investigations such as the measurement of in-situ rock stress and laboratory tests on rock samples. This report presents the results of the rock mechanics analyses performed on the main rock types at the Olkiluoto, Romuvaara, Kivetty and Haestholmen sites. The objective of this study was to assess the near-field stability of the final disposal tunnels and deposition holes at each of the investigation sites. Two empirical methods and a numerical method based on three-dimensional element code (3DEC) were used the analysis tools. A statistical approach was used to select the necessary input data and to specify the cases being analysed. The stability of the KBS-3 and MLH (Medium Long Hole) repository concepts during the pre-closure and post-closure phases was analysed. The repository depths investigated lay between 300 m and 700 m. The empirical methods are based on the study of the ratios between rock strength and the in-situ stress which could result in possible fracturing of the rock mass. Interpretation of the numerical analyses is based on the assumption of an elastic distribution of stress around the disposal tunnel and the deposition hole and the brittle rock strength criterion. The results obtained in this study indicate that in general, the rock mechanics conditions during the pre-closure and post-closure phases at each of the investigated sites remain good and stable between the studied depth levels, especially when the deposition rooms are oriented in a direction parallel to the major in-situ stress. If the disposal tunnels are orientated in a direction perpendicular to the major in-situ stress, the resultant

  12. Aspect-Driven Changes in Slope Stability Due to Ecohydrologic Feedbacks

    Poulos, M. J.; Pierce, J. L.; Flores, A. N.; Benner, S. G.; Smith, T. J.; McNamara, J. P.


    southwestern batholith, are most sensitive to aspect, with average northern slope angles of 29°, and southern slope angles of 21°. Initial assessment of ecohydrologic factors in Dry Creek finds that annual precipitation for the watershed ranges from 20-35 inches, forestation ranges from ~15% forested on south-facing slopes, to ~80% forested on north-facing slopes, and annual insolation on north-facing slopes is roughly three-fifths that for south-facing slopes. Furthermore, preliminary analysis of soil textures finds soils to contain 29-41% silt on north-facing slopes, and ~12% silt on south-facing slopes. Slope distributions from the Lochsa River basin in the northern Idaho Batholith had little contrast between slope angles; this basin, however, receives 30-70 inches of precipitation and has nearly-homogenous forest cover for all aspects. Ongoing study seeks to 1) use large-scale spatial analysis to correlate the influence of aspect on slope angles to changes in ecohydrologic conditions and 2) understand the spatial distribution and relative influence of processes that affect the weathering of slope materials, erosive processes that reduce slope angles, and cohesive forces that stabilize slopes (e.g. root strength, soil texture, and soil moisture).

  13. The Influence of Shales on Slope Instability

    Stead, Doug


    Shales play a major role in the stability of slopes, both natural and engineered. This paper attempts to provide a review of the state-of-the-art in shale slope stability. The complexities of shale terminology and classification are first reviewed followed by a brief discussion of the important physical and mechanical properties of relevance to shale slope stability. The varied mechanisms of shale slope stability are outlined and their importance highlighted by reference to international shale slope failures. Stability analysis and modelling of anisotropic rock slope masses are briefly discussed and the potential role of brittle rock fracture and damage highlighted. A short review of shale slopes in open pits is presented.

  14. Study of Wave and Tide Influence on Slope Stability of the Navigation Channel of Tianjin Port


    The Tianjin Port is the largest man-made port in China. Since the navigation channel of the Tianjin Port is constructed by dredging, a very important problem, as many people concerned, is the submarine slope stability. As the environment on land is different from that in submarine, it is necessary to evaluate the influence of the environmental loading, such as wave and tide, on the stability of navigation channel slope. In the present study, based on the observed results, the characteristics of the navigation channel slope are summarized, and the causes of creating the special slope shape are analyzed. The roles of waves and tides are evaluated, and failure mechanics are discussed to helq us predict what will happen in the future.

  15. Coupled Numerical Analysis of the Stability Behaviour of Unsaturated Soil Slopes Under Rainfall Conditions

    WANG Cheng-hua(王成华); THOMAS H R


    The stability behaviour of unsaturated soil slopes under rainfall conditions is investigated via a parametric finite element analysis, which is a fully coupled flow and deformation approach linked to a dynamic programming technique for determining the minimum factor of safety as well as its corresponding critical slip surface based on the stress fields from the numerical computation. The effects of rainfall features, soil strength parameters and permeability properties on slope stability are studied. The analyses revealed that the soil matric suction decreased during rainfall, especially in slopes with high permeability and/or with high suction angles of unsaturated soils. The influence of rainfall conditions on such slopes is quite obvious, and soil suction drops rapidly, which leads to a consequent quick reduction in the factor of safety.

  16. The stability analysis of expansive slope in Jing-Yi Expressway

    ZUO Chang-qun; CHEN Jian-ping


    This paper firstly introduces the distribution of weathered layers, and then presents the relationship between water content and expansive force and the working model of expansive forces in expansive soil slopes. Taking the expansive soil slope of Jing-Yi Expressway as example and applying the Slices Method, this paper puts forward the stability calculation method considering the effect of expansive forces, and also proposes the treatments.

  17. Overtopping and Rear Slope Stability of Reshaping & Non-reshaping Berm Breakwaters

    Andersen, Thomas Lykke; Burcharth, H. F.


    Overtopping and rear slope stability of reshaping and non-reshaping berm breakwaters have been studied in a wave flume. A total of 695 tests have been performed to cover the influence of crest freeboard, crest width, berm width, berm elevation, stone size and sea state. Formula for average...... overtopping discharge that includes these parameters has been derived. The measurements show good correlation between average overtopping discharge and rear slope damage....

  18. Rapid evolution of the paraglacial Moosfluh rock slope instability (Swiss Alps) captured by Sentinel-1

    Manconi, Andrea; Glueer, Franziska; Loew, Simon


    The Great Aletsch Region (GAR, Swiss Alps) has undergone to several cycles of glacial advancement and retreat, which have deeply affected the evolution of the surrounding landscape. Currently, this region is one of the places where the effects of climate change can be strikingly observed, as the Aletsch glacier is experiencing a remarkable retreat with rates in the order of 50 meters every year. In particular, a deep-seated slope instability located in the area called "Moosfluh" has shown during the past 20 years evidences of a slow but progressive increase of surface displacement. The moving mass associated to the Moosfluh rockslide affects an area of about 2 km2 and entails a volume estimated in the order of 150-200 Mm3. In the late summer 2016, an unusual acceleration of the Moosfluh rockslide was observed. Compared to previous years, when ground deformations were in the order of few centimeters, in the period September-October 2016 maximum velocities have reached locally 1 m/day. Such a critical evolution resulted in an increased number of local rock failures and caused the generation of several deep tensile cracks, hindering the access to hiking paths visited by tourists. Moreover, surface deformations have also affected the Moosfluh cable car station, located near the crest of the unstable slope. In this critical framework, the information available on ground was not enough to disentangle the spatial extent of the most active region. To investigate that, we have processed a number of Sentinel-1 SAR images acquired over the GAR. We paired images with maximum temporal baseline spanning 12 and 24 days, in order to preserve the highest possible interferometric coherence over the target area. Secondly, by stacking surface displacements obtained from the differential interferograms, we have increased the signal-to-noise ratio to produce velocity maps of the Moosfluh landslide over the period of interest. This approach has allowed us to constrain the lateral borders


    李典庆; 蒋水华; 张利民; 周创兵


    .A method for estimating the time-variant system reliability of rock slopes based on Monte Carlo simulation is presented.Consequently,an example of anchored rock slope with a single slip surface is presented to demonstrate the validity and capability of the proposed methods.The results indicate that the corrosion model proposed by K.A.T.Vu and M.G Stewart is suitable for rock bolts subjected to environmental conditions of humidity and drying/wetting cycles.The rock bolt corrosion at free section has a more significant influence on the stability of rock slopes at the early stage,whereas the effect of rock bolt corrosion at anchored section becomes more obvious at the later stage.Moreover,the variations in the anchored force of each rock bolt and the system probability of slope failure at the later stage are more significant than those at the early stage.The system probability of slope failure decreases with the increasing thickness of the rock bolt cover,while increases with the increasing water-to-cement ratio of the grout.However,the system probability of slope failure does not significantly increase with time,when the thickness of the rock bolt cover and water-to-cement ratio of the grout reach certain values,respectively.

  20. Effects of nonlinear strength parameters on stability of 3D soil slopes

    高玉峰; 吴迪; 张飞; 秦红玉; 朱德胜


    Actual slope stability problems have three-dimensional (3D) characteristics and the soils of slopes have curved failure envelopes. This incorporates a power-law nonlinear failure criterion into the kinematic approach of limit analysis to conduct the evaluation of the stability of 3D slopes. A tangential technique is adopted to simplify the nonlinear failure criterion in the form of equivalent Mohr-Coulomb strength parameters. A class of 3D admissible rotational failure mechanisms is selected for soil slopes including three types of failure mechanisms: face failure, base failure, and toe failure. The upper-bound solutions and corresponding critical slip surfaces can be obtained by an efficient optimization method. The results indicate that the nonlinear parameters have significant influences on the assessment of slope stability, especially on the type of failure mechanism. The effects of nonlinear parameters appear to be pronounced for gentle slopes constrained to a narrow width. Compared with the solutions derived from plane-strain analysis, the 3D solutions are more sensitive to the values of nonlinear parameters.

  1. Effects of Rainfall Characteristics on the Stability of Tropical Residual Soil Slope

    Rahardjo Harianto


    Full Text Available Global climate change has a significant impact on rainfall characteristics, sea water level and groundwater table. Changes in rainfall characteristics may affect stability of slopes and have severe impacts on sustainable urban living. Information on the intensity, frequency and duration of rainfall is often required by geotechnical engineers for performing slope stability analyses. Many seepage analyses are commonly performed using the most extreme rainfall possible which is uneconomical in designing a slope repair or slope failure preventive measure. In this study, the historical rainfall data were analyzed and investigated to understand the characteristics of rainfall in Singapore. The frequency distribution method was used to estimate future rainfall characteristics in Singapore. New intensity-duration-frequency (IDF curves for rainfall in Singapore were developed for six different durations (10, 20, 30 min and 1, 2 and 24 h and six frequencies (2, 5, 10, 25, 50 and 100 years. The new IDF curves were used in the seepage and slope stability analyses to determine the variation of factor of safety of residual soil slopes under different rainfall intensities in Singapore.

  2. Dynamic stability of quadruped robot walking on slope with trot gait



    The dynamic stability of a quadruped robot trotting on slope was analyzed.Compared with crawl gait, trot gait can improve walking speed of quadruped robots.When a quadruped robot trots, each leg is in the alternate state of swing phase or supporting phase, and two legs in the diagonal line are in the same phase.The feet in the supporting phase form a supporting region on the ground.When a quadruped robot walks on slope, the vertical distance from zero moment point ( ZMP) to the sup-porting diagonal line is defined as ZMP offset distance.Whether this distance is less than the maxi-mum offset distance or not, the stability of robot trotting on slope can be judged.The foot trajectory was planned with the sinusoidal function.Based on the kinematic analysis, the ZMP offset distance of quadruped robot under different slope angles, step length and step height was calculated, then the reasonable slope angle, step length and step height for quadruped robot trotting on slope to keep dy-namic stability can be determined.On the other hand, the posture angle of quadruped robot should be controlled within the desired range.Computer simulations were executed to verify the theoretical analysis.The study will provide reference for determining reasonable step parameters of the quadru-ped robot.

  3. Slope stability FEM analysis and retaining wall design: a case study of clinker in Benxi of Liaoning

    Aref M. O. AL-JABALI; Lei NIE; Jianlei LIU; Huangping DING; Nengjuan ZHOU; Mohammed HAZAEA


    Stability is always the most important problem after high slope was excavated. The study analyzed the stress and strain inside the slope by Finite Element Method (FEM) and carried through stress distribution and failure zone, then analyzed the stability of the slope using three different methods and came to the conclusion that it is in unstable condition, so the designed retaining wall was put forward which makes the slope stable.

  4. Slope Stability Analysis of Earth-Rockfill Dams Using MGA and UST

    Li Nansheng


    Full Text Available The nonlinear Unified Strength Theory (UST, which takes into account the effect of intermediate stress and nonlinear behavior on geotechnical strength, is applied in slope stability analysis of earth-rockfill dams (ERD in this paper. The biggest drawback for general determination of slip surface is that it must presuppose the shape of slip surface and is unable to identify the critical noncircular slip surface more accurately. This paper proposes an optimal analytic model of slope stability analysis of ERD and employs modified genetic algorithm (MGA to search for the slip surface on the basis of shear failure criteria of the nonlinear UST without prior assumption of the shape of slip surface. The application of MGA dependent on Matlab toolbox to the slope stability analysis of ERD shows that MGA can consequently overcome the weakness of easily falling into local optimal solutions brought by general optimal algorithms.

  5. An Investigation of the Acid Rock Drainage Generation from the Road Cut Slope in the Middle Part of South Korea

    Ji, S.; Cheong, Y.; Yim, G.


    To examine the Acid Rock Drainage (ARD) generation from the road cut slope, a prediction study including Acid-Base Accounting (ABA) test and Net Acid Generation (NAG) test was performed for road cut rock samples (20 samples) at the new construction site of a highway in the middle part of South Korea. This slope is composed of slate and phyllite. It was a pit wall which was operated as a quarry which produced materials for roofing. pH1:2 and EC1:2 measurements were performed to evaluate free hydrogen ion contents and salts in samples. ABA test was performed to estimate the balance of the acid generating minerals (mainly pyrite) and the acid neutralizing minerals (mainly carbonates) in rock samples. Total sulfur was analyzed by sulfur analyzer, and then the maximum potential acidity (MPA, kg H2SO4/t) was calculated. X-ray diffraction (XRD) analysis was performed to identify the mineral composition of rock samples. Acid neutralizing capacity (ANC) test, after the Sobek et al. (1978), was performed to estimate the amount of acid originated from the oxidation of sulfide minerals. NAPP (Net Acid Producing Potential) was calculated by total sulfur (MPA) and ANC. NAG test was performed with grounded samples and 15 % hydrogen peroxide, and then NAG was analyzed by measuring pH (NAGpH) of the mixed solution. pH1:2 and EC1:2 ranged from 2.95 to 7.23 and 17.1 to 3070.0 ¥ìS/cm, respectively. MPA of samples was ranged from 0.0 to 79.9 kg H2SO4/t. From the XRD analysis pyrite was found at the most samples. In the sample from highly weathered dike, goethite was found. Results of the ANC tests indicated that the value of ANC reached up to 59.36 kg H2SO4/t. Rock samples could be classified as Potential Acid Forming rock (PAF) and Non- Acid Forming rock (NAF) by plotting NAPP versus NAGpH. In this study 17 samples were classified as PAF rock. It means that this slope would generate ARD when they reacted with rain. Two samples were grouped as NAF. By application this ARD prediction


    P. Nalina


    Full Text Available The stability of slopes is always under severe threats in many parts of Western Ghats, especially in Kallar-Coonoor hill road stretch, causing disruption, loss of human life and economy. To minimize the instability of soil slope in between Kallar-Coonoor, a critical evaluation of roads is required. The stability of slopes depends on the soil shear strength parameters such as Cohesion, Angle of internal friction, Unit weight of soil and Slope geometry. The stability of a slope is measured by its factor of safety using geometric and shear strength parameter based on infinite slopes. In this present study, investigation was carried out at 32 locations in the above said hill road stretch to estimate the factor of safety of the slope determined by Mohr-Coulomb theory based on shear strength parameter calculated from direct shear test which is a conventional procedure for this study. Back Propagation Artificial Neural Network (BP-ANN Model is used to predict the factor of safety. The input parameters for the (BP-ANN are chosen as Cohesion, Angle of internal friction, Density and Slope angle and the factor of safety as output. Out of the parameters of 32 locations, the study of BP-ANN is trained with parameters of first 25 locations. Factor of safety was calculated for the remaining 7 locations. The results obtained in BP-ANN method were compared with that of conventional method and observed a good agreement between these two methods. The results obtained from these two methods were also compared with the details of actual field Landslide occurred and indicates 71.4% of conventional method locations matching with the physical occurrences and 85.7% of BP-ANN predicted vulnerable locations match with the physically observed landslide locations.

  7. Geology and Slope Stability Analysis using Markland Method on Road Segment of Piyungan – Patuk, Sleman and Gunungkidul Regencies, Yogyakarta Special Region, Indonesia

    B. N. Kresna Citrabhuwana


    Full Text Available Road segment of Piyungan - Patuk is a part of Yogyakarta - Wonosari highway, fairly dense traversed by vehicles, from bicycles to buses and trucks. This road crosses hilly topography, causing its sides bounded by quite steep slopes or cliffs. Steep slopes and cliffs are potential to create mass movement. Geologic condition of the surrounding area is built of various volcanic lithology such as breccia, siltstone, sandstone and tuff. There are also geologic structures of joints and faults that affect the stability of the slopes around this road. Slope stability analysis for road segment of Piyungan – Patuk was conducted by applying Markland method. Laboratory testings were done to determine the mechanical and physical properties of rocks that influence the slope strength. Results of the testings show that cohesion and friction angle of volcanic breccia are c = 20.0441 kg/cm2 and  = 56.38˚; cohesion and friction angle of sandstone are cr = 0.6862 kg/cm2, cp = 4.6037 kg/cm2, r = 26.37˚, and p = 32.79˚; cohesion and friction angle of tuff is cr = 1.677 kg/cm2, cp = 7.5553 kg/cm2, r = 17.85˚, and p = 24.19˚. Based on the analysis, some slopes in the study area are potential to move. The movements can be classified into rock fall, debris fall, and rock slides with the sliding plane categorized as planar and wedge. On the other hand, landslide prone zones in the study area can be divided into: Areas with high vulnerability, Areas with moderate vulnerability, and Areas with low vulnerability. Areas prone to landslide should be managed by a series of measures, among others understand natural phenomena, recognizing symptoms of avalanche, attempting to reduce the risk, and land use regulation. The management activities should involve all stakeholders in an integrated manner of implementation.

  8. Wangxia Slope Stability Analysis Based on Slope's Geomorphic Evolution%望霞大斜坡地质灾害链形成过程分析

    陈小婷; 黄波林


    望霞大斜坡位于重庆市巫山县巫峡北岸横石溪背斜核部.由于软硬相间的地质结构,望霞大斜坡发育危岩体、滑坡多处.根据地质灾害历史和崩滑体的空间分布,该区域存在崩塌-滑坡链式地质灾害.从望霞大斜坡地貌演化过程来看,其变形改造一方面与河流下切密切相关,另一方面与自身的地质结构相关,而后者在第四纪以后起着主导作用.现今受采矿及水库蓄水的影响地貌改造进程会加速.通过坡形对比,望霞大斜坡存在的直接地质灾害间题是危岩体崩塌,间接地质灾害问题是因崩塌而产生的滑坡.通过调查,该大斜坡长期稳定性差.目前桐心村危岩体变形剧烈,一旦失稳造成的后果较为严重.基于这些认识,建议该区域进行生态移民,对桐心村危岩体进行工程治理,并加强向家湾滑坡后缘陡崖危岩的监测.%Wangxia slope is located in the core of Hengshixi Anticline in the north side of Changjiang River in Wushan County, Chongqing City. Because of its soft-hard interbed structure, there developes many dangerous rockmass and landslides. According to local geohazard history and geohazard spacial distributing, there presences rockfall-landslide chain geohazard in this region. From the geomorphic evolutionary process of Wangxia slope, Wangxia Slope's deformation rebuilding is related with stream trenching. On the other side,it is related with its geological structure, the latter may be the principal factor after Quatenary. Nowaday,mining and reservior impounding accelerates slope geomorhpic evolution. Compared with slope form, the direct geohazard is rock falling, the indirect geohazard is landslide, the slope long-time stability is bad. In short time, Tongxintun Dangerous rockmass deforms seriously, its stability is bad, which will results seriously consequence. Based on these ackownledge, this paper suggests the local move to somewhere safety,and some engineering measurement

  9. Use of terrestrial laser scanning for engineering geological applications on volcanic rock slopes - an example from Madeira island (Portugal)

    Nguyen, H. T.; Fernandez-Steeger, T. M.; Wiatr, T.; Rodrigues, D.; Azzam, R.


    This study focuses on the adoption of a modern, widely-used Terrestrial Laser Scanner (TLS) application to investigate volcanic rock slopes in Ribeira de João Gomes valley (Funchal, Madeira island). The TLS data acquisition in May and December 2008 provided information for a characterization of the volcanic environment, detailed structural analysis and detection of potentially unstable rock masses on a slope. Using this information, it was possible to determine specific parameters for numerical rockfall simulations such as average block size, shape or potential sources. By including additional data, such as surface roughness, the results from numerical rockfall simulations allowed us to classify different hazardous areas based on run-out distances, frequency of impacts and related kinetic energy. Afterwards, a monitoring of hazardous areas can be performed in order to establish a rockfall inventory.

  10. Slope Stability Estimation of the Kościuszko Mound in Cracow

    Wrana Bogumił


    Full Text Available In the paper, the slope stability problem of the Kościuszko Mound in Cracow, Poland is considered. The slope stability analysis was performed using Plaxis FEM program. The outer surface of the mound has complex geometry. The slope of the cone is not uniform in all directions, on the surface of the cone are pedestrian paths. Due to its complicated geometry it was impossible to do computing by Plaxis input pre-procesor. The initial element mesh was generated using Autodesk Autocad 3D and next it was updated by Plaxis program. The soil parameters were adopted in accordance with the detailed geological soil testing performed in 2012. Calculating model includes geogrids. The upper part was covered by MacMat geogrid, while the lower part of the Mound was reinforced using Terramesh Matt geogrid. The slope analysis was performed by successives reduction of φ /c parameters. The total multiplayer ΣMsf is used to define the value of the soil strength parameters. The article presents the results of slope stability before and after the rainfall during 33 days of precipitation in flood of 2010.

  11. Stability assessment and feature analysis of slope in Nanfen Open Pit Iron Mine

    Yang Jun; Tao Zhigang; Li Baoliang; Gui Yang; Li Haifeng


    Under the combined influences of special topography and the long term mining in Nanfen Open Pit Iron Mine,many large scale landslide masses appeared in heading side of stope,and tens of millions of iron mine is buried underside,making great economic losses.In order to guide the safety mining and increase the supply quantity,this paper through the use of MSARMA-method and the "MSARMA evaluation and analytical system for slope stability analysis" based on this method,which aimed at the quantitative evaluating of the slope stability before and after the actual mining below the slip mass,and the sensitivity analysis for the main influencing factor,providing scientific proof for the parameter optimization of open mine surface slope,the security and sustainable exploitation.

  12. Mechanics of weathered clay-marl rock masses along the rupture surface in homogeneous dry slopes

    Kostić Srđan


    Full Text Available Authors analyze stress-strain distribution within slope using the shear stress reduction technique based on finite element method, which was previously confirmed to provide approximately the same results as the Janbu's corrected limit equilibrium method. Results obtained indicate that the largest vertical displacements occur at the slope base and crest, while central part of the slope is exposed to the largest horizontal displacements. Normal and shear stress show maximum values in the middle part of the slope. It was also determined that separate stress-strain relations could be derived for the exact upper and lower part of the rupture surface. [Projekat Ministarstva nauke Republike Srbije, br. 37005

  13. Overtopping and Rear Slope Stability of Reshaping & Non-reshaping Berm Breakwaters

    Andersen, Thomas Lykke; Burcharth, H. F.


    Overtopping and rear slope stability of reshaping and non-reshaping berm breakwaters have been studied in a wave flume. A total of 695 tests have been performed to cover the influence of crest freeboard, crest width, berm width, berm elevation, stone size and sea state. Formula for average overto...

  14. Mathematical modelling of stability of closing slopes in large-scale surface coal mines

    Kloss, K. (Stavebni Geologie, Prague (Czechoslovakia))


    Describes methods of modelling stability of slopes of the Krusne Hory mountains in North Bohemian brown coal mines using the finite element method and a large IBM computer, with output on a Digigraph plotter. Briefly discusses results for the Merkur, Jansky and Jiretin mines, illustrating their geological profiles with diagrams of finite element networks. 4 refs.

  15. A steady-state analytical slope stability model for complex hillslopes

    Talebi, A.; Troch, P.A.; Uijlenhoet, R.


    This paper presents a steady-state analytical hillslope stability model to study the role of topography on rain-induced shallow landslides. We combine a bivariate continuous function of the topographic surface, a steady-state hydrological model of hillslope saturated storage, and the infinite slope

  16. A steady-state analytical slope stability model for complex hillslopes

    Talebi, A.; Troch, P.A.; Uijlenhoet, R.


    This paper presents a steady-state analytical hillslope stability model to study the role of topography on rain-induced shallow landslides. We combine a bivariate continuous function of the topographic surface, a steady-state hydrological model of hillslope saturated storage, and the infinite slope

  17. Design and operation of a comprehensive and permanent rock slope deformation monitoring system at the Great Aletsch Glacier (Switzerland)

    Glueer, Franziska; Loew, Simon; Seifert, Reto; Frukacz, Mariusz; Wieser, Andreas


    Most geodetic monitoring systems of rock slope instabilities include a series of stable reference points. However, detailed studies of Alpine rock slopes with long term Global Navigation Satellite Systems (GNSS), high-resolution tilt meters and Total Stations (TPS) have shown unequivocally, that truly stable points are very rare. The underlying causes of such natural movements are long- and short-periodic reversible deformations of stable slopes caused by annual and daily changes of pore pressure and temperature in fractured rock masses. These movements impact TPS measurements and cause inconsistencies in the reference frame which, if not accounted for, will introduce systematic errors in the calculated deformation pattern and time series. This complex situation can be found in many mountain slopes. However, detailed measurements and analyses of the superposition of reversible slope deformations and gravitational mass movements of active instabilities are not existing. At the terminus of the Great Aletsch Glacier a comprehensive permanent deformation and displacement monitoring system has been installed, which allows to investigate large scale reversible deformations as well as active rock slope instabilities (Moosfluh and Driest) in response to rapid glacier retreat. The system includes 2 high-precision TPS stations with automated reflector recognition, 58 reflectors, 4 GNSS stations, climate sensors, and 2 high-resolution tilt meters and provides a fully automated survey with high accuracies over distances up to 2 km. The self-sustaining monitoring systems at Aletsch are installed at two high-alpine locations, remotely operated and automatically collect data on a set time schedule mainly at night. Deformation artefacts from thermal and wind disturbances of total stations' pillars and climatic refraction are studied with separate monitoring programs. We describe various aspects of the design, construction, testing and practical operation of this unique monitoring

  18. The principle of stability control of surrounding rock-bearing struc-tures in high stress soft rock roadways

    WANG Wei-jun; ZHU Yong-jian; LI Shu-qing; ZHANG Peng


    Through the description of the deformational features of the surrounding rock around high stress engineering soft rock roadways,the coupling stabilization principle of inner and outer structures in surrounding rock was put forward.The supporting principles of high stress engineering soft rock roadway (high resistance and yielding support,timely support,high strength and high stiffness supports) were proposed,which were applied in engineering practices,and obtained better achievements.

  19. The principle of stability control of surrounding rock-bearing structures in high stress soft rock roadways

    Wei-jun Wang; Yong-jian Zhu; Shu-qing Li; Peng Zhang [Hunan Key Laboratory of Safe Mining Techniques of Coal Mines, Xiangtan (China)


    Through the description of the deformational features of the surrounding rock around high stress engineering soft rock roadways, the coupling stabilization principle of inner and outer structures in surrounding rock was put forward. The supporting principles of high stress engineering soft rock roadway (high resistance and yielding support, timely support, high strength and high stiffness supports) were proposed, which were applied in engineering practices in Shuijingtou colliery, and obtained better achievements. 5 refs., 4 figs.

  20. GIS-based modelling of deep-seated slope stability in complex geology

    Mergili, Martin; Marchesini, Ivan; Schneider-Muntau, Barbara; Cardinali, Mauro; Fiorucci, Federica; Valigi, Daniela; Santangelo, Michele; Bucci, Francesco; Guzzetti, Fausto


    We use the model r.slope.stability to explore the chances and challenges of physically-based modelling of deep-seated slope stability in complex geology over broad areas and not on individual slopes. The model is developed as a C and python-based raster module within the GRASS GIS software. It makes use of a modification of the three-dimensional sliding surface model proposed by Hovland (1977) and revised and extended by Xie and co-workers (2006). Given a digital elevation model and a set of thematic layers (lithological classes and related geotechnical parameters), the model evaluates the slope stability for a large number of randomly selected potential slip surfaces, ellipsoidal in shape. The bottoms of soil or bedrock layers can also be considered as potential slip surfaces by truncating the ellipsoids. Any single raster cell may be intersected by multiple sliding surfaces, each associated with a computed safety factor. For each pixel, the lowest value of the safety factor and the depth of the associated slip surface are stored. This information can be used to obtain a spatial overview of the potentially unstable regions in the study area. The r.slope.stability model can be executed both in a soil class-based mode, where the input data are mainly structured according to horizontally defined soil classes, and in a layer-based mode, where the data are structured according to a potentially large number of layers. Here, we test the model for the layer-based mode, allowing for the analysis of relatively complex geologic structures. We test the model in the Collazzone area, Umbria, central Italy, which is susceptible to landslides of different types. According to field observations in this area, morpho-structural settings (i.e., the orientation and dip of the geological layers) play a crucial role for the distribution of the deep-seated landslides. We have prepared a lithological model based on aerial photointerpretation, field survey and surface information on the

  1. Probabilistic stability evaluation and seismic triggering scenarios of submerged slopes in Lake Zurich (Switzerland)

    Strupler, M.; Hilbe, M.; Anselmetti, F. S.; Kopf, A. J.; Fleischmann, T.; Strasser, M.


    Subaqueous landslides and their consequences, such as tsunamis, can cause serious damage to offshore infrastructure and coastal communities. Stability analyses of submerged slopes are therefore crucial, yet complex steps for hazard assessment, as many geotechnical and morphological factors need to be considered. Typically, deterministic models with data from a few sampling locations are used for the evaluation of slope stabilities, as high efforts are required to ensure high spatial data coverage. This study presents a simple but flexible approach for the probabilistic stability assessment of subaqueous slopes that takes into account the spatial variability of geotechnical data. The study area ( 2 km2) in Lake Zurich (northern Switzerland) shows three distinct subaquatic landslides with well-defined headscarps, translation areas (i.e. the zone where translational sliding occurred) and mass transport deposits. The ages of the landslides are known ( 2,210 and 640 cal. yr BP, and 1918 AD), and their triggers have been assigned to different mechanisms by previous studies. A combination of geophysical, geotechnical, and sedimentological methods served to analyse the subaquatic slope in great spatial detail: 3.5 kHz pinger seismic reflection data and a 300 kHz multibeam bathymetric dataset (1 m grid) were used for the detection of landslide features and for the layout of a coring and an in situ cone penetration testing campaign. The assignment of geotechnical data to lithological units enabled the construction of a sediment-mechanical stratigraphy that consists of four units, each with characteristic profiles of bulk density and shear strength. The thickness of each mechanical unit can be flexibly adapted to the local lithological unit thicknesses identified from sediment cores and seismic reflection profiles correlated to sediment cores. The sediment-mechanical stratigraphy was used as input for a Monte Carlo simulated limit-equilibrium model on an infinite slope for

  2. Probabilistic stability evaluation and seismic triggering scenarios of submerged slopes in Lake Zurich (Switzerland)

    Strupler, M.; Hilbe, M.; Anselmetti, F. S.; Kopf, A. J.; Fleischmann, T.; Strasser, M.


    Subaqueous landslides and their consequences, such as tsunamis, can cause serious damage to offshore infrastructure and coastal communities. Stability analyses of submerged slopes are therefore crucial, yet complex steps for hazard assessment, as many geotechnical and morphological factors need to be considered. Typically, deterministic models with data from a few sampling locations are used for the evaluation of slope stabilities, as high efforts are required to ensure high spatial data coverage. This study presents a simple but flexible approach for the probabilistic stability assessment of subaqueous slopes that takes into account the spatial variability of geotechnical data. The study area ( 2 km2) in Lake Zurich (northern Switzerland) shows three distinct subaquatic landslides with well-defined headscarps, translation areas (i.e. the zone where translational sliding occurred) and mass transport deposits. The ages of the landslides are known ( 2,210 and 640 cal. yr BP, and 1918 AD), and their triggers have been assigned to different mechanisms by previous studies. A combination of geophysical, geotechnical, and sedimentological methods served to analyse the subaquatic slope in great spatial detail: 3.5 kHz pinger seismic reflection data and a 300 kHz multibeam bathymetric dataset (1 m grid) were used for the detection of landslide features and for the layout of a coring and an in situ cone penetration testing campaign. The assignment of geotechnical data to lithological units enabled the construction of a sediment-mechanical stratigraphy that consists of four units, each with characteristic profiles of bulk density and shear strength. The thickness of each mechanical unit can be flexibly adapted to the local lithological unit thicknesses identified from sediment cores and seismic reflection profiles correlated to sediment cores. The sediment-mechanical stratigraphy was used as input for a Monte Carlo simulated limit-equilibrium model on an infinite slope for

  3. Relationships between slope erosion processes and aggregate stability of Ultisols from subtropical China during rainstorms

    Liu, Gang; Xiao, Hai; Liu, Puling


    Soil aggregates, being a key soil structural unit, influence several soil physical properties such as water infiltration, runoff and erosion. The relationship between soil aggregate stability and interrill and rill erodibility is unclear but critical to process-based erosion prediction models. One obvious reason is that it is hard to distinguish between interrill and rill-eroded sediment during the erosion process. This study was designed to partition interrill and rill erosion rates and relates them to the aggregate stability of Ultisols in subtropical China. Six kinds of rare earth element (REE) were applied as tracers mixed with two cultivated soils derived from the Quaternary red clay soil and the shale soil at six slope positions. Soil aggregate stability was determined by the Le Bissonnais (LB)-method. Simulated rainfall with three intensities (60, 90 and 120 mm/h) were applied to a soil plot (2.25 m long, 0.5 m wide, 0.2 m deep) at three slope gradients (10°, 20° and 30°) with duration of 30 min after runoff initiation. The results indicated that interrill and rill erosion increased with increasing rainfall intensity and slope gradient for both types of soil. Rill and interrill erosion rates of the shale soil were much higher than those of the Quaternary red clay soil. Rill erosion contribution enhanced with increasing rainfall intensity and slope gradient for both soils. Percentage of the downslope area erosion to total erosion was the largest, followed by the mid-slope area and then upslope area. Equations using an aggregate stability index As to replace the erodibility factor of interrill and rill erosion in the Water Erosion Prediction Project (WEPP) model were constructed after analyzing the relationships between estimated and measured rill and interrill erosion data. It was shown that these equations based on the stability index, As, have the potential to improve methods for assessing interrill and rill erosion erodibility synchronously for the

  4. Analysis of sea cliff slope stability integrating traditional geomechanical surveys and remote sensing

    S. Martino


    Full Text Available An integrated approach to the geomechanical characterization of coastal sea cliffs was demonstrated at Mt. Pucci (Gargano promontory, Southern Italy by performing direct traditional geomechanical and remote geostructural investigations via Terrestrial Laser Scanner (TLS. The consistency of the integrated techniques allowed us to achieve a comprehensive and affordable characterization of the main joint sets on the sea cliff slope. The observed joint sets were observed to evaluate the susceptibility of the slope to rock falls by attributing safety factors (SFs to the topple- and wedge-prone rock blocks under three triggering conditions: (a filling with static water, (b seismic action, and (c weathering of joint surfaces. The results of the susceptibility analysis for the topple-prone blocks show that the critical height of water filling of the joint is up to 50 cm and that the critical pseudo-static acceleration values vary in the range of 0.16–0.3 g depending on the block geometry and slope face orientation. For the wedge blocks, the critical height of water filling of the joint is generally up to several centimeters, and the critical pseudo-static acceleration values vary in the range of 0.05–0.8 g depending on the block geometry and slope face orientation. Moreover, the unstable conditions of the blocks due to weathering generally represent 60% of the joint degradation of the intact rock. The combined action of weathering and static water fill was also considered, resulting in a significant decrease of the SFs. Specifically, unstable conditions are associated with water levels lower than 47% of the water levels observed in intact joints, even if less than 60% of the weathering is attributed to the joints. Furthermore, remote survey analyses via Thermal InfraRed Camera and Terrestrial SAR Interferometry (TInSAR were performed to evaluate the role of the surveyed joint sets in inducing instabilities in the Mt. Pucci sea cliff. The results of

  5. Vane Shear Strength Based Stability Analysis of Slopes in Unconsolidated Soft Clay

    刘润; 闫澍旺; 张连福


    In-situ vane shear test is frequently performed to determine shear strength for slope stability analysis in Tianjin New Harbor.However,the soil shear strength varies with the shear plane orientation.A possible means to reduce the effect of directional dependency of shear strength is to convert the in-situ vane shear strength into undrained shear strength parameters.A method of converting in-situ vane shear strength into undrained shear strength parameters is presented.The shear strength parameters determined for all of the in-situ vane shear strengths are subjected to statistical regression analysis to take into consideration the possible effect of non-homogeneity in the soft clay deposit.Using the regressed shear strength parameters,slope stability analyses are performed for five existing soil slopes.The results of stability analyses indicate that the safety factors obtained from the converted parameters reflect the state of the slopes analyzed much better than those obtained from in-situ vane shear strength and laboratory consolidated-undrained and unconsolidated-undrained strength parameters.It is concluded that the presented methsod of determining undrained shear strength parameters for in-situ vane shear strength is effective.

  6. Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

    Song Qing, E-mail: [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada); Yanful, Ernest K., E-mail: [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada)


    Research Highlights: > A channelled cover with preferential flow can still mitigate ARD to some extent. > Oxygen ingress was more sensitive to the location of the channel than to K{sub s}. > The channel in the barrier layer was a major passage for O{sub 2} ingress. > Actual flushing was an important factor when estimating O{sub 2} decay coefficient. - Abstract: An ideal engineered soil cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O{sub 2} ingress into an underlying waste rock pile. However, the barrier layer in the soil cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O{sub 2} transport in the soil cover and decrease performance in the long run. The present study employed a 10-cm-wide sand-filled channel installed in a soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the cover. The soil cover had a slope of 20%. Oxygen transport through the soil cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without soil cover). Moreover, gaseous O{sub 2} transport in the soil cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the soil cover with channel had a lower oxidation rate than the waste rock without cover because of reduced O{sub 2} ingress and water flushing in the soil cover with channel, which meant a partial soil cover might still be effective to some extent in reducing ARD generation. Gaseous O{sub 2} ingress into the covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy

  7. Experimental test of theory for the stability of partially saturated vertical cut slopes

    Morse, Michael M.; Lu, N.; Wayllace, Alexandra; Godt, Jonathan W.; Take, W.A.


    This paper extends Culmann's vertical-cut analysis to unsaturated soils. To test the extended theory, unsaturated sand was compacted to a uniform porosity and moisture content in a laboratory apparatus. A sliding door that extended the height of the free face of the slope was lowered until the vertical cut failed. Digital images of the slope cross section and upper surface were acquired concurrently. A recently developed particle image velocimetry (PIV) tool was used to quantify soil displacement. The PIV analysis showed strain localization at varying distances from the sliding door prior to failure. The areas of localized strain were coincident with the location of the slope crest after failure. Shear-strength and soil-water-characteristic parameters of the sand were independently tested for use in extended analyses of the vertical-cut stability and of the failure plane angle. Experimental failure heights were within 22.3% of the heights predicted using the extended theory.

  8. Maximum-Entropy Method for Evaluating the Slope Stability of Earth Dams

    Shuai Wang


    Full Text Available The slope stability is a very important problem in geotechnical engineering. This paper presents an approach for slope reliability analysis based on the maximum-entropy method. The key idea is to implement the maximum entropy principle in estimating the probability density function. The performance function is formulated by the Simplified Bishop’s method to estimate the slope failure probability. The maximum-entropy method is used to estimate the probability density function (PDF of the performance function subject to the moment constraints. A numerical example is calculated and compared to the Monte Carlo simulation (MCS and the Advanced First Order Second Moment Method (AFOSM. The results show the accuracy and efficiency of the proposed method. The proposed method should be valuable for performing probabilistic analyses.

  9. Denudational slope processes on weathered basalt in northern California: 130 ka history of soil development, periods of slope stability and colluviation, and climate change

    McDonald, Eric; Harrison, Bruce; Baldwin, John; Page, William; Rood, Dylan


    The geomorphic history of hillslope evolution is controlled by multiple types of denudational processes. Detailed analysis of hillslope soil-stratigraphy provides a means to identify the timing of periods of slope stability and non-stability, evidence of the types of denudational processes, and possible links to climatic drivers. Moreover, the degree of soil formation and the presence of buried or truncated soils provide evidence of the relative age of alternating periods of colluviation and stability. We use evaluation of soil stratigraphy, for a small forested hillslope (slope length) located in the Cascades of northern California, to elucidate both the timing and processes controlling 130 ka of hillslope evolution. The soils and slope colluvium are derived from highly weathered basalt. Stratigraphic interpretation is reinforced with soil profile development index (PDI) derived age estimates, tephrochronology, luminescence ages on colluvium, and He3 nuclide exposure dates. Soils formed along hilltop ridges are well developed and reflect deep (>2-3 m) in-situ weathering of the basalt bedrock. PDI age estimates and He3 exposure dates indicate that these hilltop soils had been in place for 100-130 ka, implying a long period of relative surface stability. At about 40-30 ka, soil stratigraphy indicates the onset of 3 distinct cycles of denudation of the hilltop and slopes. Evidence for changes in stability and onset of soil erosion is the presence of several buried soils formed in colluvium downslope of the hilltop. These buried soils have formed in sediment derived from erosion of the hilltop soils (i.e. soil parent material of previously weathered soil matrix and basalt cobbles). The oldest buried soil indicates that slope stability was re-established between 32-23 ka, with stability and soil formation lasting to about 10 ka. Soil-stratigraphy indicates that two additional intervals of downslope transport of sediment between 6-10 ka, and 2-5 ka. Soil properties

  10. Reliability analysis of tunnel surrounding rock stability by Monte-Carlo method

    XI Jia-mi; YANG Geng-she


    Discussed advantages of improved Monte-Carlo method and feasibility aboutproposed approach applying in reliability analysis for tunnel surrounding rock stability. Onthe basis of deterministic parsing for tunnel surrounding rock, reliability computing methodof surrounding rock stability was derived from improved Monte-Carlo method. The com-puting method considered random of related parameters, and therefore satisfies relativityamong parameters. The proposed method can reasonably determine reliability of sur-rounding rock stability. Calculation results show that this method is a scientific method indiscriminating and checking surrounding rock stability.

  11. Long-term stability analysis of the left bank abutment slope at Jinping I hydropower station

    Long Zhang; Qiang Yang; Yaoru Liu


    The time-dependent behavior of the left bank abutment slope at Jinping I hydropower station has a major influence on the normal operation and long-term safety of the hydropower station. To solve this problem, a geomechanical model containing various faults and weak structural planes is established, and numerical simulation is conducted under normal water load condition using FLAC3D, incorporating creep model proposed based on thermodynamics with internal state variables theory. The creep deformations of the left bank abutment slope are obtained, and the changes of principal stresses and deformations of the dam body are analyzed. The long-term stability of the left bank abutment slope is evaluated ac-cording to the integral curves of energy dissipation rate in domain and its derivative with respect to time, and the non-equilibrium evolution rules and the characteristic time can also be determined using these curves. Numerical results show that the left bank abutment slope tends to be stable in a global sense, and the stress concentration is released. It is also indicated that more attention should be paid to some weak regions within the slope in the long-term deformation process.

  12. Long-term stability analysis of the left bank abutment slope at Jinping I hydropower station

    Long Zhang


    Full Text Available The time-dependent behavior of the left bank abutment slope at Jinping I hydropower station has a major influence on the normal operation and long-term safety of the hydropower station. To solve this problem, a geomechanical model containing various faults and weak structural planes is established, and numerical simulation is conducted under normal water load condition using FLAC3D, incorporating creep model proposed based on thermodynamics with internal state variables theory. The creep deformations of the left bank abutment slope are obtained, and the changes of principal stresses and deformations of the dam body are analyzed. The long-term stability of the left bank abutment slope is evaluated according to the integral curves of energy dissipation rate in domain and its derivative with respect to time, and the non-equilibrium evolution rules and the characteristic time can also be determined using these curves. Numerical results show that the left bank abutment slope tends to be stable in a global sense, and the stress concentration is released. It is also indicated that more attention should be paid to some weak regions within the slope in the long-term deformation process.

  13. Stability Analysis of Anchored Soil Slope Based on Finite Element Limit Equilibrium Method

    Rui Zhang


    Full Text Available Under the condition of the plane strain, finite element limit equilibrium method is used to study some key problems of stability analysis for anchored slope. The definition of safe factor in slices method is generalized into FEM. The “true” stress field in the whole structure can be obtained by elastic-plastic finite element analysis. Then, the optimal search for the most dangerous sliding surface with Hooke-Jeeves optimized searching method is introduced. Three cases of stability analysis of natural slope, anchored slope with seepage, and excavation anchored slope are conducted. The differences in safety factor quantity, shape and location of slip surface, anchoring effect among slices method, finite element strength reduction method (SRM, and finite element limit equilibrium method are comparatively analyzed. The results show that the safety factor given by the FEM is greater and the unfavorable slip surface is deeper than that by the slice method. The finite element limit equilibrium method has high calculation accuracy, and to some extent the slice method underestimates the effect of anchor, and the effect of anchor is overrated in the SRM.

  14. Probabilistic analysis of slope stability towards the slip by the kinematic method

    dadouche, F. Zeroual Née; lazhar, Belabed; Zennir, A.

    The analysis of slope stability or a slope is a complex problem that requires careful reflection and common sense. In effect because of the diversity of sites and especially their heterogeneity, each case is unique, the stability check is done by studying the general failure along the slip surface that is superficial, shallow, deep or very deep by conventional methods found in the literature such as the Bishop method, Jumbu, Fellenius etc. ... based on the determination of global minimum factor of safety. In this paper, we propose a mechanical model for calculating the failure along the sliding surface based on the kinematic method of rigid solids (Limit analysis). The statistical-probabilistic concept of safety is a very useful tool for comparison because it reflects the dispersion of random parameters (geometry, intrinsic characteristics of the soil load, etc. ...) will be applied to this model, the reliability of the system will expressed using the reliability index. The introduction of the concept of reliability index Geotechnical is a valuable tool capable of giving the engineer a greater objectivity in the design of slopes. We determine the critical slopes and the corresponding costs from the state equation R-S = 0 limit of the present mechanism. Finally recommendations will be given for modeling the failure along the sliding surface [10].

  15. Nonlinear analysis on purely mechanical stabilization of a wheeled inverted pendulum on a slope

    Yoshida, Katsutoshi; Hosomi, Kenta


    This paper investigates the potential for stabilizing an inverted pendulum without electric devices, using gravitational potential energy. We propose a wheeled mechanism on a slope, specifically, a wheeled double pendulum, whose second pendulum transforms gravity force into braking force that acts on the wheel. In this paper, we derive steady-state equations of this system and conduct nonlinear analysis to obtain parameter conditions under which the standing position of the first pendulum becomes asymptotically stable. In this asymptotically stable condition, the proposed mechanism descends the slope in a stable standing position, while dissipating gravitational potential energy via the brake mechanism. By numerically continuing the stability limits in the parameter space, we find that the stable parameter region is simply connected. This implies that the proposed mechanism can be robust against errors in parameter setting.

  16. 3-dimensional slope stability analyses using non-associative stress-strain relationships

    CHEN ZuYu; SUN Ping; WANG YuJie; ZHANG HongTao


    The research work presented in this paper refers to a new slope stability analysis method used for landslide risk evaluations. It is an extension of the 3-dimensional upper-bound slope stability analysis method proposed by Chen et sl. in 2001, which employs the Mohr-Coulomb's associative flow rule. It has been found that in a 3-dimensional area, a prism may not be able to move at friction angles to all its surrounding interfaces, as required by this associative rule, and convergence problems may occa-sionally arise. The new method establishes two velocity fields: (i) The plastic one that represents a non-associative and the best representative dilation behavior, and (ii) the virtual one that permits the solution for factor of safety in the work and energy balance equation. The new method can then allow any input value of dilation angle and thus solve the convergence problem. A practical application to a concrete dam foundation is illustrated.

  17. Algorithm and Software for Landslide Slopes Stability Estimation with Online Very Low Frequency Monitoring

    Gordeev, V. F.; Kabanov, M. M.; Kapustin, S. N.


    In addition to preliminary surveying, landslide slopes stability estimation problems require online real-time monitoring alerting about potential emergencies. Very low frequency monitoring data provided by geodynamic processes automated control system provides a solution to that problem. Authors describe the software and algorithms implemented for that system, make conclusions on the efficiency of applied solutions and propose options for the further development of online very low frequency monitoring system.

  18. Stability Thresholds and Performance Standards for Flexible Lining Materials in Channel and Slope Restoration Applications


    stabilization Select industry term Vegetated reinforced soil slope VRSS A bioengineered system of geotextile -wrapped, vegetated soil lifts USACE...5.1-cm) samples intended for the geotextile fabric industry. When considering results for an application, designers should refer to the minimum...beneath TRM. 4 Non-woven geotextile fabric is recommended beneath ARVS for continuous flow applications and for unvegetated conditions or applications (0

  19. Root reinforcement and slope bioengineering stabilization by Spanish Broom (Spartium junceum L.

    F. Giadrossich


    Full Text Available The present paper deals with the root system's characteristics of Spanish Broom (Spartium junceum L., a species whose capacity for adaptating and resisting to drought is worth investigating. In particular, the aims of the study were 1 to investigate the plant's bio-mechanical aspects and 2 to verify whether root reinforcement and the field rooting ability of stem cuttings enhance its potential for use in slope stabilization and soil bio-engineering techniques, particularly in the Mediterranean areas. Single root specimens were sampled and tested for tensile strength, obtaining classic tensile strength-diameter relationships. Analysis were performed on the root systems in order to assess root density distribution. The Root Area Ratio (RAR was analyzed by taking both direct and indirect measurements, the latter relying on image processing. The data obtained were used to analyze the stability of an artificial slope (landfill and the root reinforcement. The measurement and calculation of mean root number, mean root diameter, RAR, root cohesion and Factor of safety are presented in order to distinguish the effect of plant origin and propagation. Furthermore, tests were performed to assess the possibility of agamic propagation (survival rate of root-ball endowed plants, rooting from stem cuttings. These tests confirmed that agamic propagation is difficult, even though roots were produced from some buried stems, and for practical purposes it has been ruled out. Our results show that Spanish Broom has good bio-mechanical characteristics with regard to slope stabilization, even in critical pedoclimatic conditions and where inclinations are quite steep, and it is effective on soil depths up to about 50 cm, in agreement with other studies on Mediterranean species. It is effective in slope stabilization, but less suitable for soil bio-engineering or for triggering natural plant succession.

  20. Coal Mine Roadway Stability in Soft Rock: A Case Study

    Shen, Baotang


    Roadway instability has always been a major concern in deep underground coal mines where the surrounding rock strata and coal seams are weak and the in situ stresses are high. Under the high overburden and tectonic stresses, roadways could collapse or experience excessive deformation, which not only endangers mining personnel but could also reduce the functionality of the roadway and halt production. This paper describes a case study on the stability of roadways in an underground coal mine in Shanxi Province, China. The mine was using a longwall method to extract coal at a depth of approximately 350 m. Both the coal seam and surrounding rock strata were extremely weak and vulnerable to weathering. Large roadway deformation and severe roadway instabilities had been experienced in the past, hence, an investigation of the roadway failure mechanism and new support designs were needed. This study started with an in situ stress measurement programme to determine the stress orientation and magnitude in the mine. It was found that the major horizontal stress was more than twice the vertical stress in the East-West direction, perpendicular to the gateroads of the longwall panel. The high horizontal stresses and low strength of coal and surrounding rock strata were the main causes of roadway instabilities. Detailed numerical modeling was conducted to evaluate the roadway stability and deformation under different roof support scenarios. Based on the modeling results, a new roadway support design was proposed, which included an optimal cable/bolt arrangement, full length grouting, and high pre-tensioning of bolts and cables. It was expected the new design could reduce the roadway deformation by 50 %. A field experiment using the new support design was carried out by the mine in a 100 m long roadway section. Detailed extensometry and stress monitorings were conducted in the experimental roadway section as well as sections using the old support design. The experimental section

  1. Geochemistry of petroleum systems in the Niuzhuang South Slope of Bohai Bay basin - pt. 1: source rock characterization

    Sumei Li [Petroleum University, Beijing (China). Chinese Ministry of Education; Geological Survey of Canada, Alberta (Canada); Xionqi Pang; Zhijun Jin [Petroleum University, Beijing (China). Chinese Ministry of Education; Maowen Li [Geological Survey of Canada, Alberta (Canada)


    Detailed mapping of the Tertiary strata of the Dongying Depression, Bohai Bay Basin reveals that oil shales and dark mudstones in the Es{sub 4} and Es{sub 3} members of the Eocene-Oligocene Shahejie Formation have excellent potential as petroleum source rocks. Regional distributions of total organic carbon content, kerogen type and thermal maturation indicate that abundant mature source rocks are present in the Niuzhuang Sag, whereas source rocks along the Niuzhuang South Slope are currently immature or marginally mature for the generation of conventional oils. This study examined the molecular characteristics for a number of biomarker compound classes, and related these to either source facies change or different burial and thermal maturation. An important observation made during this study is the significant variation in the relative distributions and absolute concentrations of a wide range of aliphatic and aromatic hydrocarbon markers in the rock extracts as a function of burial depth. This variation may potentially explain the uncertainty associated with the maturity assessment and genetic modeling for so-called ''immature oils'' that are usually defined on the basis of alkane biomarker isomerization ratios and the presence of biomarkers with ''biological'' configurations. (author)

  2. A multidisciplinary methodological approach for slope stability assessment of an area prone to shallow landslides

    Bordoni, Massimiliano; Meisina, Claudia; Valentino, Roberto; Bittelli, Marco; Battista Bischetti, Gian; Vercesi, Alberto; Chersich, Silvia; Giuseppina Persichillo, Maria


    Rainfall-induced shallow landslides are widespread slope instabilities phenomena in several hilly and mountainous contexts all over the world. Due to their high density of diffusion also in small areas, they can provoke important damages to terrains, infrastructures, buildings, and, sometimes, loss of human lives. Shallow landslides affect superficial soils of limited thickness (generally lower than 2 m), located above weathered or not bedrock levels. Their triggering mechanism is strictly linked to the hydrological response of the soils to rainfall events. Thus, it becomes fundamental a comprehensive analysis of the soil properties which can influence the susceptibility of a slope to shallow landslides. In this study, a multidisciplinary approach was followed for the characterization of the soils and the individuation of the triggering conditions in an area particularly prone to shallow failures, for slope stability assessment. This area corresponded to the hilly sector of North-Eastern Oltrepò Pavese (Lombardy Region, Northern Italy), where the density of shallow landslides is really high, reaching more than 36 landslides per km2. The soils of the study area were analyzed through a multidisciplinary characterization, which took into account for the main geotechnical, mechanical and mineralogical parameters and also for the main pedological features of the materials. This approach allowed for identifying the main features and the horizons which could influence the soil behavior in relation to the conditions that are preparatory to shallow landslides development. In a test-site slope, representative of the main geomorphological, geological and landslides distribution characteristics typical of the study area, a continuous in time monitoring of meteorological (rainfall amount, air temperature, air humidity, atmospheric pressure, net solar radiation, wind speed and direction) and hydrological (soil water content, pore water pressure) parameters was implemented. In

  3. Slope stability and bearing capacity of landfills and simple on-site test methods.

    Yamawaki, Atsushi; Doi, Yoichi; Omine, Kiyoshi


    This study discusses strength characteristics (slope stability, bearing capacity, etc.) of waste landfills through on-site tests that were carried out at 29 locations in 19 sites in Japan and three other countries, and proposes simple methods to test and assess the mechanical strength of landfills on site. Also, the possibility of using a landfill site was investigated by a full-scale eccentric loading test. As a result of this, landfills containing more than about 10 cm long plastics or other fibrous materials were found to be resilient and hard to yield. An on-site full scale test proved that no differential settlement occurs. The repose angle test proposed as a simple on-site test method has been confirmed to be a good indicator for slope stability assessment. The repose angle test suggested that landfills which have high, near-saturation water content have considerably poorer slope stability. The results of our repose angle test and the impact acceleration test were related to the internal friction angle and the cohesion, respectively. In addition to this, it was found that the air pore volume ratio measured by an on-site air pore volume ratio test is likely to be related to various strength parameters.


    Dănuţ Tanislav


    Full Text Available Landslides distribution is differentiated function of various causal factors or conditions (litology, declivity, land use,precipitations. For each factor, it can be depicted some homogeneous areas, with numerical coefficients, in a incresingsuccession (1 – very high; … 5 – very low, using the GIS. The complex arrangement involves the analysis and diagnosisof watershed planning, establishing its vulnerability to the action of natural and anthropogenic factors. New technologiesfor earth reinforcement with other engineering works to stabilize the slopes, are durable works because the chemicalproperties of high density polyethylene, which does not react with any other environmental component (ex. earth geogridreinforcement. New technologies for earth reinforcement executed in complex with other engineering works to stabilizethe slopes, are durable works because the chemical properties of high density polyethylene, which does not react withany other environmental component. Using special technology to stabilize determined substantial time and cost savingscompared to traditional solutions. The landscape of slopes reinforced with geogrids, due to external quality topsoil isclearly superior to the classical solutions of stabilization.

  5. Research on the Application of Fluid-Structure Interaction in Soil Rock Mixture Slope

    Wang Yongcun


    Full Text Available traditional seepage theory has defects, and the fluid-structure interaction research has developed. Through the analysis of the fluid-structure interaction problems in engineering, this paper expounds the characteristics of fluid-structure interaction, research methods and research status quo, mathematical model of the slope is put forward.

  6. Permeability test and slope stability analysis of municipal solid waste in Jiangcungou Landfill, Shaanxi, China.

    Yang, Rong; Xu, Zengguang; Chai, Junrui; Qin, Yuan; Li, Yanlong


    With the rapid increase of city waste, landfills have become a major method to deals with municipal solid waste. Thus, the safety of landfills has become a valuable research topic. In this paper, Jiangcungou Landfill, located in Shaanxi, China, was investigated and its slope stability was analyzed. Laboratory tests were used to obtain permeability coefficients of municipal solid waste. Based on the results, the distribution of leachate and stability in the landfill was computed and analyzed. These results showed: the range of permeability coefficient was from 1.0 × 10(-7) cm sec(-1) to 6.0 × 10(-3) cm sec(-1) on basis of laboratory test and some parameters of similar landfills. Owing to the existence of intermediate cover layers in the landfill, the perched water level appeared in the landfill with heavy rain. Moreover, the waste was filled with leachate in the top layer, and the range of leachate level was from 2 m to 5 m in depth under the waste surface in other layers. The closer it gets to the surface of landfill, the higher the perched water level of leachate. It is indicated that the minimum safety factors were 1.516 and 0.958 for winter and summer, respectively. Additionally, the slope failure may occur in summer. The research of seepage and stability in landfills may provide a less costly way to reduce accidents. Landslides often occur in the Jiangcungou Landfill because of the high leachate level. Some measures should be implemented to reduce the leachate level. This paper investigated seepage and slope stability of landfills by numerical methods. These results may provide the basis for increasing stability of landfills.

  7. Sensitivity analysis and calibration of a dynamic physically based slope stability model

    Zieher, Thomas; Rutzinger, Martin; Schneider-Muntau, Barbara; Perzl, Frank; Leidinger, David; Formayer, Herbert; Geitner, Clemens


    Physically based modelling of slope stability on a catchment scale is still a challenging task. When applying a physically based model on such a scale (1 : 10 000 to 1 : 50 000), parameters with a high impact on the model result should be calibrated to account for (i) the spatial variability of parameter values, (ii) shortcomings of the selected model, (iii) uncertainties of laboratory tests and field measurements or (iv) parameters that cannot be derived experimentally or measured in the field (e.g. calibration constants). While systematic parameter calibration is a common task in hydrological modelling, this is rarely done using physically based slope stability models. In the present study a dynamic, physically based, coupled hydrological-geomechanical slope stability model is calibrated based on a limited number of laboratory tests and a detailed multitemporal shallow landslide inventory covering two landslide-triggering rainfall events in the Laternser valley, Vorarlberg (Austria). Sensitive parameters are identified based on a local one-at-a-time sensitivity analysis. These parameters (hydraulic conductivity, specific storage, angle of internal friction for effective stress, cohesion for effective stress) are systematically sampled and calibrated for a landslide-triggering rainfall event in August 2005. The identified model ensemble, including 25 behavioural model runs with the highest portion of correctly predicted landslides and non-landslides, is then validated with another landslide-triggering rainfall event in May 1999. The identified model ensemble correctly predicts the location and the supposed triggering timing of 73.0 % of the observed landslides triggered in August 2005 and 91.5 % of the observed landslides triggered in May 1999. Results of the model ensemble driven with raised precipitation input reveal a slight increase in areas potentially affected by slope failure. At the same time, the peak run-off increases more markedly, suggesting that

  8. Experimental study on pore pressure in rock-soil slope during reservoir water level fluctuation

    LIU; Yuewu; CHEN; Huixin; LIU; Qingquan; GONG; Xin; ZHANG


    A test system was developed for measuring the pore pressure in porous media, and a new model was devised for the pore pressure testing in both saturated and unsaturated rock-soil. Laboratory experiments were carried out to determine the pore pressure during water level fluctuation. The variations of transient pore pressure vs. time at different locations of the simulated rock-soil system were acquired and processed, and meanwhile the deformation and failure of the model are observed. The experiment results show that whether the porous media are saturated or not, the transient pore pressure is mainly dependent on the water level fluctuation, and coupled with the variation of the stress field.

  9. The effect of chestnut coppice forests abandon on slope stability: a case study

    Vergani, Chiara; Bassanelli, Chiara; Rossi, Lorenzo; Chiaradia, Enrico Antonio; Battista Bischetti, Gian


    Sweet chestnut has been fundamental for Italian mountainous economies for many centuries. This kind of forest was traditionally managed by coppicing in shortly rotation (15-20 years) to rapidly produce wood biomass until half of XX century. In the last decades these forests were in large part abandoned due to change in economy which made coppiced forest management unprofitable, especially in steeper slopes and where forest viability is scarce. As a consequence most of them are over aged and very dense, leading to an observed increasing in localized slope instability, primary because of the uprooting of stools (Vogt et al., 2006). In this work the effect of the abandon of chestnut coppice on slope stability was analyzed, focusing on shallow landslides triggering. The mechanical contribution to soil shear strength of differently managed chestnut stand was estimated and compared in terms of additional root cohesion. The study area is located in the Valcuvia Valley (Lombardy Prealps - Northern Italy) at an elevation about 600 m a.s.l., where two different stands, one managed and the other abandoned (over 40 year aged), were chosen. The two sampling stands are on cohesionless slopes (quaternary moraine deposits) and are homogeneous with regard to the substrate, exposure and elevation. Slope steepness influences heavily forestry practices and steeper stands are more frequently abandoned than stands on gentler terrain: in fact in the abandoned coppice the slope was higher (35 degrees against 13 in the managed stand) and no stands completely homogeneous can be found. In each site the main characteristics of the stand were surveyed and a trench in each stand was excavated to analyze root diameter and number distribution with depth; root specimens were also collected for the tensile force determination through laboratory tensile tests. Root distribution and force were then used to estimate root cohesion values through a Fiber Boundle Model (Pollen and Simon, 2005). Results

  10. Methods for assessing the stability of slopes during earthquakes-A retrospective

    Jibson, R.W.


    During the twentieth century, several methods to assess the stability of slopes during earthquakes were developed. Pseudostatic analysis was the earliest method; it involved simply adding a permanent body force representing the earthquake shaking to a static limit-equilibrium analysis. Stress-deformation analysis, a later development, involved much more complex modeling of slopes using a mesh in which the internal stresses and strains within elements are computed based on the applied external loads, including gravity and seismic loads. Stress-deformation analysis provided the most realistic model of slope behavior, but it is very complex and requires a high density of high-quality soil-property data as well as an accurate model of soil behavior. In 1965, Newmark developed a method that effectively bridges the gap between these two types of analysis. His sliding-block model is easy to apply and provides a useful index of co-seismic slope performance. Subsequent modifications to sliding-block analysis have made it applicable to a wider range of landslide types. Sliding-block analysis provides perhaps the greatest utility of all the types of analysis. It is far easier to apply than stress-deformation analysis, and it yields much more useful information than does pseudostatic analysis. ?? 2010.

  11. Application of Vegetation Geosynthetic Technique to Slope Stability in the Three Gorges Reservoir

    Yu Fei; Wang Yuanhan


    The vegetation geosynthetic reinforced slope is one of the new composite structures in civil engineering. It has a series of characteristics, such as low cost, convenient construction, optimal land utilization and flexible structure, and it has been widely used in hydraulic engineering, road, railway and harbor construction. The Three Gorges reservoir bank protection system is a challenging work. As the background, the interaction mechanism of soil and reinforced material has been studied. The test engineering is simulated by the numerical methods. The failure mechanism of the reinforced slope in the process is studied through analyzing the variation of the displacement, stress, plastic failure fields and factor of safety in the changing process of the water level. The reasonable evaluation of the protecting effect and bank slope stability is carried out. The research results could be used in the protective design and construction in the high slope in the Three Gorges reservoir region, and it also could provide reference to other protective engineerings in the littoral area.

  12. Utilization of advanced calibration techniques in stochastic rock fall analysis of quarry slopes

    Preh, Alexander; Ahmadabadi, Morteza; Kolenprat, Bernd


    In order to study rock fall dynamics, a research project was conducted by the Vienna University of Technology and the Austrian Central Labour Inspectorate (Federal Ministry of Labour, Social Affairs and Consumer Protection). A part of this project included 277 full-scale drop tests at three different quarries in Austria and recording key parameters of the rock fall trajectories. The tests involved a total of 277 boulders ranging from 0.18 to 1.8 m in diameter and from 0.009 to 8.1 Mg in mass. The geology of these sites included strong rock belonging to igneous, metamorphic and volcanic types. In this paper the results of the tests are used for calibration and validation a new stochastic computer model. It is demonstrated that the error of the model (i.e. the difference between observed and simulated results) has a lognormal distribution. Selecting two parameters, advanced calibration techniques including Markov Chain Monte Carlo Technique, Maximum Likelihood and Root Mean Square Error (RMSE) are utilized to minimize the error. Validation of the model based on the cross validation technique reveals that in general, reasonable stochastic approximations of the rock fall trajectories are obtained in all dimensions, including runout, bounce heights and velocities. The approximations are compared to the measured data in terms of median, 95% and maximum values. The results of the comparisons indicate that approximate first-order predictions, using a single set of input parameters, are possible and can be used to aid practical hazard and risk assessment.

  13. A Test Model of Water Pressures within a Fault in Rock Slope


    This paper introduces model test results of water pressure in a fault, which is located in a slope and 16 different conditions. The results show that the water pressures in fault can be expressed by a linear function, which is similar to the theoretical model suggested by Hoek. Factors affecting water pressures are water level in tension crack, dip angle of fault, the height of filling materials and thickness of fault zone in sequence.

  14. Feature of resistivity response of slope from steady to unsteady

    谢忠球; 张玉池; 温佩琳; 段靓靓


    Using resistivity as index and referring to the law about effect of slope to resistivity,the apparent resistivities of geophysical model concerned with unsteady rock type slope failure were calculated systematically by using the boundary integral equation method.After studying the feature of resistivity response of slope failure,the variety of resistivity during evolution of slope from steady to unsteady was found and the characteristics of resistivity response about slope failure was concluded.These make electrical exploring method for detecting the slip plane or structural plane of slope failure,evaluating the stability of the slope,and forecasting slope failure become true.

  15. Quantification of the influence of preferential flow on slope stability using a numerical modeling approach

    W. Shao


    Full Text Available The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is used to compute the spatial and temporal water pressure response to rainfall. Preferential flow is simulated with a dual-permeability continuum model consisting of a matrix domain coupled to a preferential flow domain. The second part is a~soil mechanics model and is used to compute the spatial and temporal distribution of the local factor of safety based on the water pressure distribution computed with the subsurface flow model. Two types of rainfall events were considered: long duration, low-intensity rainfall, and short duration, high-intensity rainfall. The effect of preferential flow on slope stability is assessed through comparison of the failure area when subsurface flow is simulated with the dual-permeability model as compared to a single-permeability model (no preferential flow. For the low-intensity rainfall case, preferential flow has a positive effect on the slope stability as it drains the water from the matrix domain resulting in a smaller failure area. For the high-intensity rainfall case, preferential flow has a negative effect on the slope stability as the majority of rainfall infiltrates into the preferential flow domain when rainfall intensity exceeds the infiltration capacity of the matrix domain, resulting in larger water pressure and a larger failure area.

  16. Integrating GIS-based geologic mapping, LiDAR-based lineament analysis and site specific rock slope data to delineate a zone of existing and potential rock slope instability located along the grandfather mountain window-Linville Falls shear zone contact, Southern Appalachian Mountains, Watauga County, North Carolina

    Gillon, K.A.; Wooten, R.M.; Latham, R.L.; Witt, A.W.; Douglas, T.J.; Bauer, J.B.; Fuemmeler, S.J.


    Landslide hazard maps of Watauga County identify >2200 landslides, model debris flow susceptibility, and evaluate a 14km x 0.5km zone of existing and potential rock slope instability (ZEPRSI) near the Town of Boone. The ZEPRSI encompasses west-northwest trending (WNWT) topographic ridges where 14 active/past-active rock/weathered rock slides occur mainly in rocks of the Grandfather Mountain Window (GMW). The north side of this ridgeline is the GMW / Linville Falls Fault (LFF) contact. Sheared rocks of the Linville Falls Shear Zone (LFSZ) occur along the ridge and locally in the valley north of the contact. The valley is underlain principally by layered granitic gneiss comprising the Linville Falls/Beech Mountain/Stone Mountain Thrust Sheet. The integration of ArcGIS??? - format digital geologic and lineament mapping on a 6m LiDAR (Light Detecting and Ranging) digital elevation model (DEM) base, and kinematic analyses of site specific rock slope data (e.g., presence and degree of ductile and brittle deformation fabrics, rock type, rock weathering state) indicate: WNWT lineaments are expressions of a regionally extensive zone of fractures and faults; and ZEPRSI rock slope failures concentrate along excavated, north-facing LFF/LFSZ slopes where brittle fabrics overprint older metamorphic foliations, and other fractures create side and back release surfaces. Copyright 2009 ARMA, American Rock Mechanics Association.

  17. Large rock-slope failures impacting on lakes - Reconstruction of events and deciphering mobility processes at Lake Oeschinen (CH) and Lake Eibsee (D)

    Knapp, Sibylle; Anselmetti, Flavio; Gilli, Adrian; Krautblatter, Michael; Hajdas, Irka


    Among single event landslide disasters large rock-slope failures account for 75% of disasters with more than 1000 casualties. The precise determination of recurrence rates and failure volumes combined with an improved understanding of mobility processes are essential to better constrain runout models and establish early warning systems. Here we present the data sets from the two alpine regions Lake Oeschinen (CH) and Lake Eibsee (D) to show how lake studies can help to decipher the multistage character of rock-slope failures and to improve the understanding of the processes related to rock avalanche runout dynamics. We focus on such that impacted on a (paleo-) lake for two main reasons. First, the lake background sedimentation acts as a natural chronometer, which enables the stratigraphic positioning of events and helps to reconstruct the event history. This way it becomes possible to (i) decipher the multistage character of the failure of a certain rock slope and maybe detect progressive failure, (ii) determine the recurrence rates of failures at that certain rock slope, and (iii) consider energies based on estimated failure volumes, fall heights and deposition patterns. Hence, the interactions between a rock-slope failure, the water reservoir and the altered rock-slope are better understood. Second, picturing a rock avalanche running through and beyond a lake, we assume the entrainment of water and slurry to be crucial for the subsequent flow dynamics. The entrainment consumes a large share of the total energy, and orchestrates the mobility leading to fluidization, a much higher flow velocity and a longer runout-path length than expected. At Lake Oeschinen (CH) we used lake sediment cores and reflection seismic profiles in order to reconstruct the 2.5 kyrs spanning rock-slope failure history including 10 events, six of which detached from the same mountain flank, and correlated them with (pre-) historical data. The Lake Eibsee records provide insights into the

  18. Soil aggregation and slope stability related to soil density, root length, and mycorrhiza

    Graf, Frank; Frei, Martin


    Eco-engineering measures combine the use of living plants and inert mechanical constructions to protect slopes against erosion and shallow mass movement. Whereas in geotechnical engineering several performance standards and guidelines for structural safety and serviceability of construction exist, there is a lack of comparable tools in the field of ecological restoration. Various indicators have been proposed, including the fractal dimension of soil particle size distribution, microbiological parameters, and soil aggregate stability. We present results of an soil aggregate stability investigation and compare them with literature data of the angle of internal friction ?' which is conventionally used in slope stability analysis and soil failure calculation. Aggregate stability tests were performed with samples of differently treated moraine, including soil at low (~15.5 kN/m³) and high (~19.0 kN/m³) dry unit weight, soil planted with Alnus incana (White Alder) as well as the combination of soil planted with alder and inoculated with the mycorrhizal fungus Melanogaster variegatus s.l. After a 20 weeks growth period in a greenhouse, a total of 100 samples was tested and evaluated. Positive correlations were found between the soil aggregate stability and the three variables dry unit weight, root length per soil volume, and degree of mycorrhization. Based on robust statistics it turned out that dry unit weight and mycorrhization degree were strongest correlated with soil aggregate stability. Compared to the non-inoculated control plants, mycorrhized White Alder produced significantly more roots and higher soil aggregate stability. Furthermore, the combined biological effect of plant roots and mycorrhizal mycelia on aggregate stability on soil with low density (~15.5 kN/m³) was comparable to the compaction effect of the pure soil from 15.5 to ~19.0 kN/m³. Literature data on the effect of vegetation on the angle of internal friction ?' of the same moraine showed

  19. Multi-scale characterization of rock mass discontinuities and rock slope geometry using terrestrial remote sensing techniques

    Sturzenegger, Matthieu

    Terrestrial remote sensing techniques including both digital photogrammetry and laser scanning, represent useful complements to conventional field mapping and rock mass discontinuity characterization. Several studies have highlighted practical advantages at close-range (design projects has grown substantially over recent years. As these techniques are increasingly applied by geologists and geological engineers, it is important that their use be properly evaluated. Furthermore, guidelines to optimize their application are required in a similar manner to standardization of conventional discontinuity mapping techniques. An important thesis objective is to develop recommendations for optimal applications of terrestrial remote sensing techniques for discontinuity characterization, based on a quantitative evaluation of various registration approaches, sampling bias and extended manual mapping of 3D digital models. It is shown that simple registration networks can provide adequate measurement of discontinuity geometry for engineering purposes. The bias associated with remote sensing mapping is described. The advantages of these techniques over conventional mapping are demonstrated, including reliable discontinuity orientation measurements. Persistence can be precisely quantified instead of approximately estimated, resulting in a new class for extremely persistent discontinuities being suggested. Secondary roughness and curvature can also be considered at larger scales. The techniques are suitable for the definition of discontinuity sets, and the estimation of both trace intensity and block size/shape, if sampling bias is correctly accounted for. A new type of sampling window, suitable for the incorporation of remote sensing data into discrete fracture network models is presented. Another significant thesis objective is the extension of terrestrial digital photogrammetric methods to greater distances (> 1 km), using f = 200-400 mm lenses. This has required a careful

  20. Analysis of slope stability in unsaturated weathered soil dependent on rainfall infiltration velocity

    Chae, Byung-Gon; Park, Hyuck-Jin; Choi, Jung-Hae; Jang, Bo-An


    In this study the unsaturated soil column tests were carried out for weathered granite and weathered mudstone soils to find out the relationship between rainfall intensity and rainfall infiltration velocity on the basis of different unit weight conditions for the soils. For this purpose, the volumetric water content and pore water pressure were measured using TDR sensors and tensiometers at constant time interval. For the column tests, three different unit weights such as in-situ, loose and dense condition were applied, and two different rainfall intensities (20mm/h and 50mm/h) were selected for the analysis. The test results showed that the higher rainfall intensity and the lower unit weight of soil, the faster average infiltration velocity. In addition, the weathered granite soils had faster rainfall infiltration velocities than those of the weathered mudstone soils. It is because weathered mudstone soils contain more clay minerals than weathered granite soils. The infinite slope stability was analyzed to find out the relationship between the slope stability and rainfall infiltration velocity considering saturation depth ratio of rainfall based on column test results. The analysis showed that the faster average infiltration velocity and the higher unit weight of soil, the faster reducing the factor of safety. Finally, landslide susceptibility of a study area was analyzed using the calculation results of the factor of safety and GIS techniques. For the analysis, slope angle and soil depth were obtained from digital topographic data, and cohesion, unit weight and internal friction angle for slope materials were obtained from the laboratory tests and field investigation. In addition, landslide locations were identified using the aerial photos and landslide inventory map.




    After 1970 Transuranic (TRU) and suspect TRU waste was buried in the ground with the intention that at some later date the waste would be retrieved and processed into a configuration for long term storage. To retrieve this waste the soil must be removed (excavated). Sloping the bank of the excavation is the method used to keep the excavation from collapsing and to provide protection for workers retrieving the waste. The purpose of this paper is to document the minimum distance (setback) that equipment must stay from the edge of the excavation to maintain a stable slope. This evaluation examines the equipment setback distance by dividing the equipment into two categories, (1) equipment used for excavation and (2) equipment used for retrieval. The section on excavation equipment will also discuss techniques used for excavation including the process of benching. Calculations 122633-C-004, 'Slope Stability Analysis' (Attachment A), and 300013-C-001, 'Crane Stability Analysis' (Attachment B), have been prepared to support this evaluation. As shown in the calculations the soil has the following properties: Unit weight 110 pounds per cubic foot; and Friction Angle (natural angle of repose) 38{sup o} or 1.28 horizontal to 1 vertical. Setback distances are measured from the top edge of the slope to the wheels/tracks of the vehicles and heavy equipment being utilized. The computer program utilized in the calculation uses the center of the wheel or track load for the analysis and this difference is accounted for in this evaluation.

  2. Partial reactivation of a huge deep-seated ancient rock slide: recognition, formation mechanism, and stability

    Tang, Minggao; Xu, Qiang; Li, Yusheng; Huang, Runqiu; Rengers, Niek; Zhu, Xing


    About 18 years ago, a large-scale discontinuous layer in properties and colour was found in the new Fengjie town at the shore of the Three Gorges Reservoir area in China. There are many resettled residents and buildings on the sloping area, the safety of which is potentially affected by this layer, so it has become the focus of attention. Before this study started there were two viewpoints regarding the origin of this layer. One was that is was from a huge ancient slide and the other was that is was from a fault graben. In order to find out how it was formed and to be able to carry out a stability analysis of the slope the authors have carried out a research program, including geological field investigations and mapping, a deep drilling hole, a geotechnical centrifuge model test, and a simulation analysis. The results of the research led to the conclusion that the layer is the sliding plane of a huge deep-seated ancient rock slide, which we called the Sanmashan landslide. An important argument for the conclusion is the recognition of a regional compressive tectonic stress field in this area, which cannot lead to the formation of a fault graben because it needs a tensional tectonic stress field. Moreover, numerous unique geological features, sliding marks, and other relics of the ancient slide have been discovered in the field. The formation process of the ancient slide could be repeated in a large geotechnical centrifuge model test. The test shows that a deformation and failure process of "creep-crack-cut" has occurred. The type of the ancient slide can be classified as a "successive rotational rock slide". Finally, the role of seepage in the stability of the Sanmashan landslide has been analysed. Our final conclusions are that, during rainfall and filling-drawdown cycles in the Three Gorges Reservoir, the Sanmashan landslide as a whole is dormant and stable and the secondary landslides in the toe area of the slope are presently stable but can be reactivated. This

  3. Damage to Buildings in Large Slope Rock Instabilities Monitored with the PSInSAR™ Technique

    Paolo Frattini


    Full Text Available The slow movement of active deep-seated slope gravitational deformations (DSGSDs and deep-seated rockslides can cause damage to structures and infrastructures. We use Permanent Scatterers Synthetic Aperture Radar Interferometry (PSInSAR™ displacement rate data for the analysis of DSGSD/rockslide activity and kinematics and for the analysis of damage to buildings. We surveyed the degree of damage to buildings directly in the field, and we tried to correlate it with the superficial displacement rate obtained by the PSInSAR™ technique at seven sites. Overall, we observe that the degree of damage increases with increasing displacement rate, but this trend shows a large dispersion that can be due to different causes, including: the uncertainty in the attribution of the degree of damage for buildings presenting wall coatings; the complexity of the deformation for large phenomena with different materials and subjected to differential behavior within the displaced mass; the absence of differential superficial movements in buildings, due to the large size of the investigated phenomena; and the different types of buildings and their position along the slope or relative to landslide portions.

  4. 露天矿土-岩复合逆倾边坡空间形态优化%Space Shape Optimization of the Soil-rock Composite Reverse Dip Slope in Open-pit Mine

    曹兰柱; 李广贺; 王东


    In view of the shape design of the boundary slope of the soil-rock composite reverse dip slope in the open-pit mine,the landslide model and stability of soil rock composite reverse dip slope in Dalianhe Open-pit Coal Mine is studied by a-dopting the method of rigid body limit equilibrium and three-dimensional numerical simulation. The study is based on the engi-neering practice of the compound reverse dip slope of the north slope of outer dump and the top slope of the stope in Dalianhe open-pit coal mine,by which the safety of the mining of coal resources of the north to boundary slope is guaranteed. The study results show that for the compound reverse dip slope of the north slope of outer dump and the top slope of the stope in Dalianhe open-pit coal mine,the landslide model is circular sliding;in order to meet the safety requirements, the mining slope angle should be up to 33°;the failure form of rock mass is the composition of tension and shear. At the foot of slope,local rock mass destruction should be done due to the stress concentration caused by the rock mass weight and it is the inducing factor of the whole slope failure.%针对露天矿土-岩复合逆倾边坡到界边坡形态设计问题,结合达连河露天煤矿外排土场北帮—采场顶帮复合逆倾边坡的工程实际,基于刚体极限平衡与三维数值模拟的手段,研究了露天矿土-岩复合逆倾边坡的滑坡模式及稳定性规律,设计了最终边坡形态,确保北帮到界过程中煤炭资源回采的安全。研究结果表明:达连河露天煤外排土场北帮—采场顶帮复合逆倾边坡的滑坡模式为圆弧滑动;使外排土场北帮—采场顶帮复合逆倾边坡满足安全要求的采场边坡角为33°;露天矿土-岩复合逆倾边坡岩体的破坏形式为拉张-剪切复合型,岩体自重作用下的坡脚处应力集中造成的局部岩体破坏是整体边坡失稳的诱发因素。

  5. Availability of phosphorus in defluorinated rock phosphate and bone meal for broiler chickens as assessed by a slope ratio assay

    P.P Ketaren


    Full Text Available An experiment was conducted to determine the availability of P in defluorinated rock phosphate (DRP and bone meal (TT using a slope ratio assay (SRA technique . Ten different diets were fed to 300 day-old broiler chicks for three weeks. Basal diet (RB was formulated to contain 0.38% total P. DRP, TT and dicalcium phosphate (DCP diets were each containing three different levels of total P: 0.45, 0.52 and 0.59%: At the end of the experiment, tibia bones were collected for ash determination. The availability of P was determined by SRA using tibia bone ash as the main parameter. The result indicated that the availability ofP in the DRP and TT were 83 .6 and 91 .3%, respectively .

  6. The role of post-failure brittleness of soft rocks in the assessment of stability of intact masses: FDEM technique applications to ideal problems

    Lollino, Piernicola; Andriani, Gioacchino Francesco; Fazio, Nunzio Luciano; Perrotti, Michele


    Strain-softening under low confinement stress, i.e. the drop of strength that occurs in the post-failure stage, represents a key factor of the stress-strain behavior of rocks. However, this feature of the rock behavior is generally underestimated or even neglected in the assessment of boundary value problems of intact soft rock masses. This is typically the case when the stability of intact rock masses is treated by means of limit equilibrium or finite element analyses, for which rigid-plastic or elastic perfectly-plastic constitutive models, generally implementing peak strength conditions of the rock, are respectively used. In fact, the aforementioned numerical techniques are characterized by intrinsic limitations that do not allow to account for material brittleness, either for the method assumptions or due to numerical stability problems, as for the case of the finite element method, unless sophisticated regularization techniques are implemented. However, for those problems that concern the stability of intact soft rock masses at low stress levels, as for example the stability of shallow underground caves or that of rock slopes, the brittle stress-strain response of rock in the post-failure stage cannot be disregarded due to the risk of overestimation of the stability factor. This work is aimed at highlighting the role of post-peak brittleness of soft rocks in the analysis of specific ideal problems by means of the use of a hybrid finite-discrete element technique (FDEM) that allows for the simulation of the rock stress-strain brittle behavior in a proper way. In particular, the stability of two ideal cases, represented by a shallow underground rectangular cave and a vertical cliff, has been analyzed by implementing a post-peak brittle behavior of the rock and the comparison with a non-brittle response of the rock mass is also explored. To this purpose, the mechanical behavior of a soft calcarenite belonging to the Calcarenite di Gravina formation, extensively

  7. Field observation on the behavior of falling rock. 1st report. Study on the rock fall along a slope; Firudo ni okeru rakuseki no rakka kyodo. 1. Ganban shamen no rakuseki ni kansuru kenkyu

    Ujihira, M. [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Hosoya, S.; Ogawa, K.; Takagai, N. [Hokkaido Univ., Sapporo (Japan). Graduate School


    A tendency of gradual extinction of disasters caused by the breaking of loose stones and falling rocks in limestone mines and quarries is brought by the improvement of safety control against slope accidents in these years. In this study, in order to examine the accumulation of data contributing to the countermeasure against falling rock in strip mines, the movement of rocks in an open-shooting quarry were shot by video cameras and analysed to clarify the behaviors of falling rock. The following results are obtained. It is found by observing falling rocks from a slope side that the value of falling velocity is getting smaller in an order of block-shaped, tabular and stick-shaped rocks. In the case of tabular rock, there is a tendency that the velocity distribution has two peaks. Not only the falling velocity but also the rolling velocity of block-shaped rock is smaller than those of block-shaped and tabular rock. Further, values near the supremum of actually measured values can be given by a rolling velocity equation wherein the shape of falling rock is assumed as orbicular. If setting it forth as a premise, said equation is possible to be used for estimating rolling velocity. 24 refs., 20 figs., 2 tabs.

  8. Hydrologically complemented deterministic slope stability analysis in part of Indian Lesser Himalaya

    John Mathew


    Full Text Available This study uses a deterministic approach to evaluate the factor of safety (FS of the terrain for different hydrological conditions, in part of Indian Lesser Himalaya. The results indicate sudden increase in the percentage unstable area from 7.5% to 13.8% for rainfall intensity variation from 50 to 100 mm/day. For the rainfall intensity of 15 August 2007 which caused many landslides in the study area, 18.5% of the total area was unstable and it increases to 21.7%, 23.5% and 24.7%, respectively, for rainfall intensities corresponding to 10, 25 and 50 year return periods. This increment stagnates at about 260 mm/day, making about 25% of the area unstable. Higher rainfall intensities make progressively gentler slopes unstable, but limited to 25 degrees of slope in this area. The area underlain by granitic gneiss showed 23.1% of area as unstable for 135 mm/day of rainfall intensity, and was followed by those areas underlain by amphibolite (16%, limestone (13.7% and quartzite (10.4%. Receiver operating characteristic (ROC curve analysis has given 84.2% accuracy for the model. Conversion of FS to failure probability through Z scores enables identification unstable or marginally unstable areas, for planning selective slope stabilization measures.




    The suitability of current nuclear safety guides to high slope antiseismic stability assessment of nuclear power plant is studied;and the analysis method and domestic research status of high slope stability are reviewed. Taking the typical high slope at a certain nuclear power station for example,qualitative analysis methods are combined with quantitative methods to comprehensively analyze the stability and failure mode of nuclear power plant high slopes. Firstly,red flat projection method and Chinese slope mass rating(CSMR) are applied to half quantitatively forecaste the landslide and define the design ratio of slope. Then,on the basis of typical two-dimensional calculation profile,rigid limit equilibrium method,strength reduction method and limit equilibrium finite element method based on stress field are used to calculate the slope antiseismic stability. Finally,three-dimensional(3D) fracture network model is established. 3D discrete element method is used to simulate the highly nonlinear and large deformation of jointed rock masses and qualitatively analyze failure mode and failure zone of slope. The collapse material migration process is reproduced;and its maximal migration distance is calculated under the action of earthquake. In addition,slope treatment ideas and common reinforcement method are summarized. The present research enriches the theory of high slope stability with nuclear safety grade and can provide technical support for stability analysis,assessment and engineering design of nuclear power plant slopes.%分析当前核安全规范和导则对核电厂高边坡抗震稳定验算方法和适用性,综述国内核电厂高边坡案例的研究进展。以某三代核电厂级高边坡为例,探讨应用多种定性和定量方法综合分析核电厂高边坡稳定性和破坏模式的分析思路。首先,采用赤平投影法和CSMR分类法半定量地评价边坡的稳定性,给出边坡设计坡比建议;然后,基于典型二维

  10. Instrumental record of debris flow initiation during natural rainfall: Implications for modeling slope stability

    Montgomery, D.R.; Schmidt, K.M.; Dietrich, W.E.; McKean, J.


    The middle of a hillslope hollow in the Oregon Coast Range failed and mobilized as a debris flow during heavy rainfall in November 1996. Automated pressure transducers recorded high spatial variability of pore water pressure within the area that mobilized as a debris flow, which initiated where local upward flow from bedrock developed into overlying colluvium. Postfailure observations of the bedrock surface exposed in the debris flow scar reveal a strong spatial correspondence between elevated piezometric response and water discharging from bedrock fractures. Measurements of apparent root cohesion on the basal (Cb) and lateral (Cl) scarp demonstrate substantial local variability, with areally weighted values of Cb = 0.1 and Cl = 4.6 kPa. Using measured soil properties and basal root strength, the widely used infinite slope model, employed assuming slope parallel groundwater flow, provides a poor prediction of hydrologie conditions at failure. In contrast, a model including lateral root strength (but neglecting lateral frictional strength) gave a predicted critical value of relative soil saturation that fell within the range defined by the arithmetic and geometric mean values at the time of failure. The 3-D slope stability model CLARA-W, used with locally observed pore water pressure, predicted small areas with lower factors of safety within the overall slide mass at sites consistent with field observations of where the failure initiated. This highly variable and localized nature of small areas of high pore pressure that can trigger slope failure means, however, that substantial uncertainty appears inevitable for estimating hydrologie conditions within incipient debris flows under natural conditions. Copyright 2009 by the American Geophysical Union.

  11. Large Rock-Slope Failures Impacting on Lakes - Event Reconstruction and Interaction Analysis in Two Alpine Regions Using Sedimentology and Geophysics

    Knapp, S.; Anselmetti, F.; Gilli, A.; Krautblatter, M.; Hajdas, I.


    Massive rock-slope failures are responsible for more than 60% of all catastrophic landslides disasters. Lateglacial and Holocene rock-slope failures often occur as multistage failures, but we have only limited datasets to reconstruct detailed stages and still aim at improving our knowledge of mobility processes. In this context, studying lakes will become more and more important for two main reasons. On the one hand, the lake background sedimentation acts as a natural chronometer, which enables the stratigraphic positioning of events and helps to reconstruct the event history. This way we will be able to improve our knowledge on multistage massive rock-slope failures. On the other hand, climate warming forces us to face an increase of lakes forming due to glacial melting, leading to new hazardous landscape settings. We will be confronted with complex reaction chains and feedback loops related to rock-slope instability, stress adaptation, multistage rock-slope failures, lake tsunamis, entrainment of water and fines, and finally lubrication. As a result, in future we will have to deal more and more with failed rock material impacting on lakes with much longer runout-paths than expected, and which we have not been able to reconstruct in our models so far. Here we want to present the key findings of two of our studies on lake sediments related to large rock-slope failures: We used reflection seismic profiles and sediment cores for the reconstruction of the rockfall history in the landslide-dammed Lake Oeschinen in the Bernese Oberland, Switzerland, where we detected and dated ten events and correlated them to (pre)historical data. As a second project, we have been working on the mobility processes of the uppermost sediments deposited during the late event stadium of the Eibsee rock avalanche at Mount Zugspitze in the Bavarian Alps, Germany. In the reflection seismic profiles we detected sedimentary structures that show high levels of fluidization and thus would hint at

  12. 3-dimensional slope stability analyses using non-associative stress-strain relationships


    The research work presented in this paper refers to a new slope stability analysis method used for landslide risk evaluations. It is an extension of the 3-dimensional upper-bound slope stability analysis method proposed by Chen et al. in 2001,which employs the Mohr-Coulomb’s associative flow rule. It has been found that in a 3-dimensional area,a prism may not be able to move at friction angles to all its surrounding interfaces,as required by this associative rule,and convergence problems may occasionally arise. The new method establishes two velocity fields:(i) The plastic one that represents a non-associative and the best representative dilation behavior,and (ii) the virtual one that permits the solution for factor of safety in the work and energy balance equation. The new method can then allow any input value of dilation angle and thus solve the convergence problem. A practical application to a concrete dam foundation is illustrated.

  13. Rock slope response to fluvial incision in the central Swiss Alps

    Leith, Kerry; Fox, Matthew; Moore, Jeffrey R.


    The longitudinal profile of rivers intersecting the Rhone Valley in the central Swiss Alps suggests the development of topography throughout much of this region has been dominated by interglacial fluvial incision and ongoing tectonic uplift with only minimal glacial erosion since the mid-Pleistocene transition. Evidence indicates bedrock river incision during this period reflects a base level fall of between 500 m and 800 m (depending on the degree of overdeepening following an early period of enhanced glacial incision). This observation raises important questions regarding the preservation, or development of hillslope morphologies through multiple glacial-interglacial cycles. Since the pioneering works of Richter (1900) and Penck and Brückner (1909), Alpine geomorphologists have commented on a sequence of between three and five moderately dipping matched terraces that converge toward inferred paleo-river channels up to 800 m above the axis of many valleys. Here, we use a combination of integral analysis, forward streampower models, and a new method of topographic analysis based on high resolution LiDAR DEMs in order to test the correspondence of valley morphologies in this formerly glaciated landscape, with hillslope processes initiated by fluvial incision up to 700,000 years ago. Results indicate topography adjacent to reaches subjected to transient fluvial incision is characterized by a coherent region of consistently steep slopes, while narrow gorges correspond to rapid incision close to the Rhone valley since MIS 5. A majority of hillslopes converge to our initial fluvial valley floor, or the location of propagating knickpoints. The correspondence between intermediate-level terraces and modeled stages of river incision is, however, currently unclear. These results offer a unique insight into the long-term response of bedrock slopes to varying rates of base level fall, and the cumulative impact of glacial erosion on Alpine valley walls since MIS 11. Penck, A

  14. Catastrophic rock slope failures and late Quaternary developments in the Nanga Parbat-Haramosh Massif, Upper Indus basin, northern Pakistan

    Hewitt, Kenneth


    The Nanga Parbat-Haramosh Massif has some of the greatest relief on Earth and highest measured rates of uplift, denudation, and river incision in bedrock. Many studies have sought to understand how its morphology relates to geotectonic evolution and glaciations. However, few catastrophic rock slope failures had been recognised and many of their impacts had been attributed to other processes. Recently more than 150 of these landslides have been found within a 100-km radius of Nanga Parbat (8125 m). New discoveries are reported east, north and west of Nanga Parbat along the Indus streams. Most generated long-run-out rock avalanches that dammed the Indus or its tributaries, some impounding large lakes. They initiated episodes of intermontane sedimentation followed by trenching and removal of sediment. Valley-floor features record a complex interplay of impoundment and sedimentation episodes, superimposition of streams in pre-landslide valley floors, and exhumation of buried features. These findings depart from existing reconstructions of Quaternary events. A number of the rock-avalanche deposits were previously misinterpreted as tills or moraine and their associated lacustrine deposits attributed to glacial lakes. Features up to 1000 m above the Indus, formerly seen as tectonically raised terraces, are depositional features emplaced by landslides, or erosion terraces recording the trenching of valley fill in landslide-interrupted river reaches. Unquestionably, tectonics and glaciation have been important but decisive and misread formative events of the Holocene involve a post-glacial, landslide-fragmented fluvial system. The latter has kept valley developments in a chronic state of disequilibrium with respect to climatic and geotectonic controls. Accepted glacial chronologies are put in doubt, particularly the extent and timing of the last major glaciation. The pace and role processes in the Holocene have been seriously underestimated.

  15. Mechanical interaction between roots and soil mass in slope vegetation


    The most basic function of slope vegetation is to strengthen rock and soil mass through plant roots which increase the shear strength of the slope markedly and thereby increase the stability of the slope. However, the calculation of the reinforcement ability of slope vegetation still remains at the stage of judging by experience, because it is rather difficult due to the intricacy and volatility of the force condition of plant roots in rock and soil medium. Although some scholars have tried to study the interaction between plant roots and soil mass, the systemic analysis of the mechanical reinforcement mechanism and the contribution of plant roots to strengthening the rock and soil mass on the surface of the slope is untapped. In this paper, by analyzing the mechanism of slope vegetation and the corresponding reinforcement effect, the effects that slope vegetation generates on the shear strength of slope soil mass are studied, thereby a theoretical basis for plant protection designing is provided.

  16. Slope stability assessment of weathered clay by using field data and computer modelling: a case study from Budapest

    P. Görög


    Full Text Available A future development site of a housing estate, an abandoned-brick yard with clayey slopes was studied in details to assess slope stability and to calculate the factor of safety. The Oligocene clay, the former raw material, is divided into two different geotechnical units in the clay pit. The lower one consists of grey impermeable clays while the upper unit is characterised by yellowish weathered clay having a limited permeability. At some localities the topmost weathered clay layers are covered by loess, and slope debris. Parts of the former pit were also used as a landfill site. The slope stability analyses were performed based on borehole information and laboratory analyses in order to provide necessary engineering geological data for further site development and urban planning. Two geotechnical codes Plaxis and Geo4 were used to model the slope failures and assess the slope stability. The aim of using two different approaches was to compare them since Plaxis uses finite elements modelling while Geo4 uses conventional calculation methods to obtain circular and polygonal slip surfaces. According to model calculations and field data, the main trigger mechanisms of landslides seem to be high pore pressure due to rainwater and small slope debris covered springs. The slip surface is located at the boundary zone of yellow weathered and grey unaltered clay. Two computer models gave very similar results; although Plaxis provides combined safety factor which is slightly more pessimistic when compared to the safety factor obtained by using Geo4.

  17. Elucidating the mechanical effects of pore water pressure increase on the stability of unsaturated soil slopes

    Buscarnera, G.


    The increase of the pore water pressure due to rain infiltration can be a dominant component in the activation of slope failures. This paper shows an application of the theory of material stability to the triggering analysis of this important class of natural hazards. The goal is to identify the mechanisms through which the process of suction removal promotes the initiation of mechanical instabilities. The interplay between increase in pore water pressure, and failure mechanisms is investigated at material point level. In order to account for multiple failure mechanisms, the second-order work criterion is used and different stability indices are devised. The paper shows that the theory of material stability can assess the risk of shear failure and static liquefaction in both saturated and unsaturated contexts. It is shown that the combined use of an enhanced definition of second-order work for unsaturated porous media and a hydro-mechanical constitutive framework enables to retrieve bifurcation conditions for water-infiltration processes in unsaturated deposits. This finding discloses the importance of the coupling terms that incorporate the interaction between the solid skeleton and the pore fluids. As a consequence, these theoretical results suggest that some material properties that are not directly associated with the shearing resistance (e.g., the potential for wetting compaction) can play an important role in the initiation of slope failures. According to the proposed interpretation, the process of pore pressure increase can be understood as a trigger of uncontrolled strains, which at material point level are reflected by the onset of bifurcation conditions.

  18. Three-dimensional critical slip surface locating and slope stability assessment for lava lobe of Unzen volcano


    Even Unzen volcano has been declared to be in a state of relative dormancy,the latest formed lava lobe No.11 now represents a potential slope failure mass based on the latest research.This paper concentrates on the stability of the lava lobe No.11 and its possible critical sliding mass.It proposes geographic information systems (GIS) based three-dimensional (3D) slope stability analysis models.It uses a 3D locating approach to identify the 3D critical slip surface and to analyze the 3D stability of the lava...

  19. Assessment of Slope Stability and Interference of Structures Considering Seismity in Complex Engineering-Geological Conditions Using the Method of Finite Elements

    Menabdishvili, Papuna; Eremadze, Nelly


    There is elaborated the calculation model of slope deformation mode stability and the methodic of calculation considering the interference of structures to be built on it using the method of finite elements. There is examined the task of slope stability using the soil physically nonlinear finite element considering the seismicity 8. The deformation mode and field of coefficients of stability are obtained and slope supposed sliding curve is determined. The elaborated calculation methodic allows to determine the slope deformation mode, stability and select the optimum version of structure foundation at any slant and composition of slope layers.

  20. Scoops3D: software to analyze 3D slope stability throughout a digital landscape

    Reid, Mark E.; Christian, Sarah B.; Brien, Dianne L.; Henderson, Scott T.


    The computer program, Scoops3D, evaluates slope stability throughout a digital landscape represented by a digital elevation model (DEM). The program uses a three-dimensional (3D) method of columns approach to assess the stability of many (typically millions) potential landslides within a user-defined size range. For each potential landslide (or failure), Scoops3D assesses the stability of a rotational, spherical slip surface encompassing many DEM cells using a 3D version of either Bishop’s simplified method or the Ordinary (Fellenius) method of limit-equilibrium analysis. Scoops3D has several options for the user to systematically and efficiently search throughout an entire DEM, thereby incorporating the effects of complex surface topography. In a thorough search, each DEM cell is included in multiple potential failures, and Scoops3D records the lowest stability (factor of safety) for each DEM cell, as well as the size (volume or area) associated with each of these potential landslides. It also determines the least-stable potential failure for the entire DEM. The user has a variety of options for building a 3D domain, including layers or full 3D distributions of strength and pore-water pressures, simplistic earthquake loading, and unsaturated suction conditions. Results from Scoops3D can be readily incorporated into a geographic information system (GIS) or other visualization software. This manual includes information on the theoretical basis for the slope-stability analysis, requirements for constructing and searching a 3D domain, a detailed operational guide (including step-by-step instructions for using the graphical user interface [GUI] software, Scoops3D-i) and input/output file specifications, practical considerations for conducting an analysis, results of verification tests, and multiple examples illustrating the capabilities of Scoops3D. Easy-to-use software installation packages are available for the Windows or Macintosh operating systems; these packages

  1. Scoops3D: software to analyze 3D slope stability throughout a digital landscape

    Reid, Mark E.; Christian, Sarah B.; Brien, Dianne L.; Henderson, Scott T.


    The computer program, Scoops3D, evaluates slope stability throughout a digital landscape represented by a digital elevation model (DEM). The program uses a three-dimensional (3D) method of columns approach to assess the stability of many (typically millions) potential landslides within a user-defined size range. For each potential landslide (or failure), Scoops3D assesses the stability of a rotational, spherical slip surface encompassing many DEM cells using a 3D version of either Bishop’s simplified method or the Ordinary (Fellenius) method of limit-equilibrium analysis. Scoops3D has several options for the user to systematically and efficiently search throughout an entire DEM, thereby incorporating the effects of complex surface topography. In a thorough search, each DEM cell is included in multiple potential failures, and Scoops3D records the lowest stability (factor of safety) for each DEM cell, as well as the size (volume or area) associated with each of these potential landslides. It also determines the least-stable potential failure for the entire DEM. The user has a variety of options for building a 3D domain, including layers or full 3D distributions of strength and pore-water pressures, simplistic earthquake loading, and unsaturated suction conditions. Results from Scoops3D can be readily incorporated into a geographic information system (GIS) or other visualization software. This manual includes information on the theoretical basis for the slope-stability analysis, requirements for constructing and searching a 3D domain, a detailed operational guide (including step-by-step instructions for using the graphical user interface [GUI] software, Scoops3D-i) and input/output file specifications, practical considerations for conducting an analysis, results of verification tests, and multiple examples illustrating the capabilities of Scoops3D. Easy-to-use software installation packages are available for the Windows or Macintosh operating systems; these packages

  2. Slope Stability Assessment of the Sarcheshmeh Landslide, Northeast Iran, Investigated Using InSAR and GPS Observations

    Mahdi Motagh


    Full Text Available The detection and monitoring of mass movement of susceptible slopes plays a key role in mitigating hazards and potential damage associated with creeping slopes and landslides. In this paper, we use observations from both Interferometric Synthetic Aperture Radar (InSAR and Global Positioning System (GPS to assess the slope stability of the Sarcheshmeh ancient landslide in the North Khorasan province of northeast Iran. InSAR observations were obtained by the time-series analysis of Envisat SAR images covering 2004–2006, whereas repeated GPS observations were conducted by campaign measurements during 2010–2012. Surface displacement maps of the Sarcheshmeh landslide obtained from InSAR and GPS are both indicative of slope stability. Hydrogeological analysis suggests that the multi-year drought and lower than average precipitation levels over the last decade might have contributed to the current dormancy of the Sarcheshmeh landslide.

  3. Numerical analysis of the stability of inhomogeneous slopes considering partially saturated conditions

    Pichler Patrick P.


    Full Text Available It is well accepted that rainfall could play a significant role in instability of slopes. The main objective of the presented study is to quantify the influence of varying characteristics of water flow, its associated changes of pore-water pressures and shear strength on the stability of simplified, but inhomogeneous, slope geometries. The commonly used van Genuchten model was used to describe the Soil Water Characteristic Curve (SWCC mathematically. In the context of this study, the influence of different hydraulic behaviour of soil layers, i.e. different SWCC, on the factor of safety (FoS is evaluated by means of fully coupled flow-deformation analyses employing the finite element method. To quantify the slopes’ factor of safety during rainfall events after specified times of infiltration or evaporation, the strength reduction method was applied. In addition to various combinations of soil layers, the influence of a water bearing high permeable soil layer between two less permeable soil layers, a situation which is often encountered in practice, on the factor of safety has been investigated.

  4. A shallow landslide analysis method consisting of contour line based method and slope stability model with critical slip surface

    Tsutsumi, D.


    To mitigate sediment related disaster triggered by rainfall event, it is necessary to predict a landslide occurrence and subsequent debris flow behavior. Many landslide analysis method have been developed and proposed by numerous researchers for several decades. Among them, distributed slope stability models simulating temporal and spatial instability of local slopes are more essential for early warning or evacuation in area of lower part of hill-slopes. In the present study, a distributed, physically based landslide analysis method consisting of contour line-based method that subdivide a watershed area into stream tubes, and a slope stability analysis in which critical slip surface is searched to identify location and shape of the most instable slip surface in each stream tube, is developed. A target watershed area is divided into stream tubes using GIS technique, grand water flow for each stream tubes during a rainfall event is analyzed by a kinematic wave model, and slope stability for each stream tube is calculated by a simplified Janbu method searching for a critical slip surface using a dynamic programming method. Comparing to previous methods that assume infinite slope for slope stability analysis, the proposed method has advantage simulating landslides more accurately in spatially and temporally, and estimating amount of collapsed slope mass, that can be delivered to a debris flow simulation model as a input data. We applied this method to a small watershed in the Izu Oshima, Tokyo, Japan, where shallow and wide landslides triggered by heavy rainfall and subsequent debris flows attacked Oshima Town, in 2013. Figure shows the temporal and spatial change of simulated grand water level and landslides distribution. The simulated landslides are correspond to the uppermost part of actual landslide area, and the timing of the occurrence of landslides agree well with the actual landslides.

  5. Steady as a rock: Biogeomorphic influence of nurse rocks and slope processes on kūpaoa (Dubautia menziesii) shrubs in Haleakalā Crater (Maui, Hawai'i)

    Pérez, Francisco L.


    This study examines biogeomorphic interactions between nurse rocks, slope processes, and 300 kūpaoa (Dubautia menziesii) shrubs in Haleakalā Crater (Maui, Hawai'i). Research objectives were to: assess the association of kūpaoa with substrates upslope and downslope of plants, and proximity to the closest rock uphill; contrast shrub/substrate relationships with site frequency of sediment types; measure surface soil shear-strength and compressibility on 50 paired locations near boulders; and investigate the aggregation characteristics and spatial patterns of kūpaoa in relation to rock and substrate variation. Data analyzed came from three 100-plant surveys at 3 sites: a plant census at 2720-2975 m altitude, and wandering-quarter transects (WQTs) across two areas (2610-2710 m); ground sediment cover was estimated along four phototransects on these sites. Data for the three 100-plant surveys included substrate type-outcrops, blocks, cobbles, pebbles, exposed soil, organic litter-upslope from each plant, and distance to the largest rock upslope. The two surveys examined along WQTs included substrate type found downslope from kūpaoa, plant height, plant diameters across and along the slope, and distance between successively censused plants. Most plants grew downslope of nurse rocks; > 74% were adjacent to blocks or outcrops, and > 17% near cobbles. Plants showed avoidance for finer substrates; only 5.3% and 2.7% grew on/near bare soils and pebbles, respectively. About 92% of kūpaoa were ≤ 10 cm downslope of rocks; > 89% grew ≤ 2 cm away, and 83% in direct contact with a rock. Some seedlings also grew on pukiawe (Leptecophylla tameiameiae) nurse plants. Several stable rock microsites protected plants from disturbance by slope processes causing debris shift. Site sediments were significantly finer than substrates near plants; shrubs grew preferentially adjacent to boulders > 20 cm wide, which were more common near plants than across sites. Soils downslope of 50

  6. Deformation mechanisms and petrophysical properties of chert and limestone fault rocks within slope-to-basin succession (Gargano Promontory, Southern Italy)

    Korneva, Irina; Tondi, Emanuele; Balsamo, Fabrizio; Agosta, Fabrizio


    In this work, we examine faults that crosscut limestone and chert rocks pertaining to a slope-to-basin succession of the eastern Gargano Promontory (southern Italy). Based on field data, microstructural observations, and quantitative analysis of cataclastic fabric, two stages of faulting are recognized. The first one, the pre-lithification faulting stage, took place within partially lithified sediments prior to their complete lithification. Differently, the second one, the post-lithification faulting stage, occurred within cohesive, well-lithified rocks. The structural properties of pre-lithification faults were likely controlled by the competence contrast between limestone and chert sediments. In fact, due to their different lithification stages, faulting occurred when chert was still not completely lithified, and hence was dragged along the fault planes. As a consequence, the pre-lithification fault cores are mainly composed of chert clasts. On the contrary, post-lithification fault cores are mostly made up of limestone clasts. The results of both microstructural and image analyses show that the carbonate fault rock includes a higher percentage of bigger clasts with lower values of angularity than the chert fault rock. Mercury-intrusion porosimetry indicates that the chert fault rock is characterized by larger pore throats and a lower amount of total porosity with respect to the limestone fault rock. The permeability values obtained for the limestone fault rock are lower than those for the chert fault rock, probably because of the lower amount of pore connectivity within the former fault rock. Results of this multidisciplinary work highlight the role played by cherty layers present within well-layered, slope-to-basin carbonate successions on both microtextural and petrophysical fault rock properties. Furthermore, these results increase our ability to predict how lithological heterogeneities and amount of lithification influence the deformation mechanisms, hence

  7. Study of root tensile strength of softwood and hardwood tree species: Implications for slope stability

    Esmaiili, Marzieh; Abdi, Ehsan; Jafary, Mohammad; Majnounian, Baris


    Landslides are known as one of the major natural hazards and often incurring economics and human life losses. The role of tree roots in slope stability is very important, especially when human lives and infrastructure are at risk. The anchorage of roots and improvement of slope stability mainly depend on specific properties of root network systems, such as tensile strength. These properties of the roots which govern the degree of reinforcement are different among tree species. Although, many studies have been conducted about plant biotechnical properties of species, yet there is lack of knowledge on comparing root systems of softwood and hardwood tree species for similar site conditions. Therefore this study was conducted to assess the tensile strength of the root system of Picea abies (softwood species) and Fraxinus excelsior (hardwood species) planted on two forested hillslopes. To this aim, single root specimens were sampled for each species and their tensile strength were then measured in laboratory using a computer controlled Instron Universal Testing Machine. According to the results root tensile strength tends to decrease with diameter according to a power law for both species. Based on analysis of covariance (ANCOVA), a significant difference has been observed in the tensile strength between the two studied species. Also the results showed that the value of mean root tensile strength for Picea abies (19.31 ± 2.64 MPa) was much more than that of Fraxinus excelsior (16.98 ± 1.01 MPa) within all root diameter classes. The data presented in this study may expand the knowledge of biotechnical properties of Picea abies and Fraxinus excelsior, as biomaterial for soil bioengineering.

  8. Manganese reduction and its stabilization in the rock record

    Johnson, J. E.; Savalia, P.; Kocar, B. D.; Webb, S. M.; Nealson, K. H.; Fischer, W. W.


    . However, when phosphate is excluded, either complete or incomplete reduction may ensue. When incomplete reduction occurs, the dominant solid phase at the end of experimentation is a Mn(III)-bearing oxide, but in experiments with complete Mn(VI) reduction, we observe either the formation of Mn carbonate(s), or complete dissolution (no secondary precipitates) depending on the presence of organic ligands and carbonate chemistry of the media. Accordingly, we will discuss (bio)geochemical mechanisms which may explain Mn stabilization within sediments as Mn(II)-carbonate and Mn(III)-dominated minerals, and relate them to observations of Mn within the rock record.

  9. The Devdorak ice-rock avalanche and consequent debris flow from the slope of Mt. Kazbek (Caucasus, Georgia) in 2014

    Chernomorets, Sergey; Savernyuk, Elena; Petrakov, Dmitry; Dokukin, Mikhail; Gotsiridze, George; Gavardashvili, Givi; Drobyshev, Valery; Tutubalina, Olga; Zaporozhchenko, Eduard; Kamenev, Nikolay; Kamenev, Vladimir; Kääb, Andreas; Kargel, Jeffrey; Huggel, Christian


    the middle and lower course of the valley below 3000 m a.s.l. was about 2 million cubic metres, while the ice content in the deposits reached 25-30%. It is planned to assess the volume of the trigger mass in the initiation zone later. The flow went along the valley with characteristic superelevations and run-ups, as it moved from one valley side to the other. We identified six superelevaions in fresh deposits, with differences of up to 45 m in flow height on the left and right valley banks. Instrumental measurements of superelevations and subsequent calculations yield the flow velocities of over 200 km/hour. These results lead to a reassessment of similar events which occurred in this valley in 18-19th centuries. Previously the trigger of these events was supposed to be the ice accumulation during surges of Devdorak glacier with subsequent temporary damming of the Amilishka River valley. The analysis of the 2014 event demonstrates that a similar trigger was possible in the past: an ice-rock avalanche onto Devdorak glacier tongue from significantly higher locations. Following the field data analysis, we issued a warning through mass media on 12 August 2014, forecasting a high risk of a new glacial disaster in this site and a new blockage of the Terek River valley and of Military Georgian Road. This forecast came true on 20 August 2014: a glacial debris flow reached the Terek River valley, and partially buried the Dariali hydropower station (under construction), the customs and border control buildings. Three people have been killed. We studied the deposits of this debris flow and morphology of the gully. The deposits entrained by the flow were previously deposited by the ice-rock avalanche of 17 May 2014. The debris flow started after shower rains. The debris flow-gully has a box-like crossection. At the confluence of Amilishka and Chach rivers it reached 30-32 m in width, and eroded the deposits of 17 May 2014 by 7 m. The channel slope at this location was about 7

  10. Experimental study on stability control technology of surrounding rock of deep roadways in coal mine

    Luo Yong; Yuan Liang; Yang Yang


    In order to solve effectively the problems of deep mining with safety and high efficiency,the multi-ple factors influencing the stability of deep rock roadway and technical problems are analyzed in the light of the severe situation of effective mining for deep coal resource,and the stability control methods for deep rock road-way are provided,which are based on the idea of combined support with separated steps and integral control of surrounding rock of deep rock roadway. The suggested methods were applied to a deep rock roadway with-648 m depth in Gubei coal mine of Huainan area. The field test was carried out and the in-situ monitoring was imple-mented,and the support scheme was optimized and adjusted to improve the stability of the surrounding rock of the roadway based on the feedback analysis. The results showed that the stability can be improved greatly by the provided control methods for deep roadway. The present methods for stability control of deep rock roadway can be used to other deep rock roadways with the similar conditions.

  11. Bi-cruciate stabilized total knee arthroplasty can reduce the risk of knee instability associated with posterior tibial slope.

    Hada, Masaru; Mizu-Uchi, Hideki; Okazaki, Ken; Kaneko, Takao; Murakami, Koji; Ma, Yuan; Hamai, Satoshi; Nakashima, Yasuharu


    The purpose of this study was to evaluate the relationship between posterior tibial slope and knee kinematics in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA), which has not been previously reported. This computer simulation study evaluated Journey 2 BCS components (Smith & Nephew, Inc., Memphis, TN, USA) implanted in a female patient to simulate weight-bearing stair climbing. Knee kinematics, patellofemoral contact forces, and quadriceps forces during stair climbing (from 86° to 6° of flexion) were computed in the simulation. Six different posterior tibial slope angles (0°-10°) were simulated to evaluate the effect of posterior tibial slope on knee kinematics and forces. At 65° of knee flexion, no anterior sliding of the tibial component occurred if the posterior tibial slope was less than 10°. Anterior contact between the anterior aspect of the tibial post- and the femoral component was observed if the posterior tibial slope was 6° or more. An increase of 10° in posterior tibial slope (relative to 0°) led to a 4.8% decrease in maximum patellofemoral contact force and a 1.2% decrease in maximum quadriceps force. BCS TKA has a wide acceptable range of posterior tibial slope for avoiding knee instability if the posterior tibial slope is less than 10°. Surgeons should prioritize avoiding adverse effects over trying to achieve positive effects such as decreasing patellofemoral contact force and quadriceps force by increasing posterior tibial slope. Our study helps surgeons determine the optimal posterior tibial slope during surgery with BCS TKA; posterior tibial slope should not exceed 10° in routine clinical practice.

  12. High Performance Computing for probabilistic distributed slope stability analysis, an early example

    Rossi, Guglielmo; Catani, Filippo


    The term shallow landslides is widely used in literature to describe a slope movement of limited size that mainly develops in soils up to a maximum of a few meters thick. Shallow landslides are usually triggered by heavy rainfall because, as the water starts to infiltrate into the soil, the pore-water pressure increases so that the shear strength of the soil is reduced leading to slope failure. We have developed a distributed hydrological-geotechnical model for forecasting the temporal and spatial distribution of shallow landslides to be used as a real time warning system for civil protection purposes. The stability simulator is developed to use High Performance Computing (HPC) resources and in this way can manage large areas, with high spatial and temporal resolution, at useful computational time for a warning system . The output of the model is a probabilistic value of slope instability. In its current stage the model applied for predicting the expected location of shallow landslides involves several stand-alone components. The base solution suggested by Iverson for the Richards equation is adapted to be used in a real time simulator to estimate the probabilistic distribution of the transient groundwater pressure head according to radar detected rainfall intensity. The use of radar detected rainfall intensity as the input for the hydrological simulation of the infiltration allows a more accurate computation of the redistribution of the groundwater pressure associated with transient infiltration of rain. A soil depth prediction scheme and a limit-equilibrium infinite slope stability algorithm are used to calculate the distributed factor of safety (FS) at different depths and to record the probability distribution of slope instability in the final output file. The additional ancillary data required have been collected during fieldwork and with laboratory standard tests. The model deals with both saturated and unsaturated conditions taking into account the effect of

  13. Stability classification model of mine-lane surrounding rock based on distance discriminant analysis method

    ZHANG Wei; LI Xi-bing; GONG Feng-qiang


    Based on the principle of Mahalanobis distance discriminant analysis (DDA) theory, a stability classification model for mine-lane surrounding rock was established, including six indexes of discriminant factors that reflect the engineering quality of surrounding rock: lane depth below surface, span of lane, ratio of directly top layer thickness to coal thickness, uniaxial comprehensive strength of surrounding rock, development degree coefficient of surrounding rock joint and range of broken surrounding rock zone. A DDA model was obtained through training 15 practical measuring samples. The re-substitution method was introduced to verify the stability of DDA model and the ratio of mis-discrimination is zero. The DDA model was used to discriminate3 new samples and the results are identical with actual rock kind. Compared with the artificial neural network method and support vector mechanic method, the results show that this model has high prediction accuracy and can be used in practical engineering.

  14. Evaluation of human response to blasting vibration from excavation of a large scale rock slope: A case study

    Yan, Peng; Lu, Wenbo; Zhang, Jing; Zou, Yujun; Chen, Ming


    Ground vibration, as the most critical public hazard of blasting, has received much attention from the community. Many countries established national standards to suppress vibration impact on structures, but a world-accepted blasting vibration criterion on human safety is still missing. In order to evaluate human response to the vibration from blasting excavation of a large-scale rock slope in China, this study aims to suggest a revised criterion. The vibration frequency was introduced to improve the existing single-factor (peak particle velocity) standard recommended by the United States Bureau of Mines (USBM). The feasibility of the new criterion was checked based on field vibration monitoring and investigation of human reactions. Moreover, the air overpressure or blast effects on human beings have also been discussed. The result indicates that the entire zone of influence can be divided into three subzones: severe-annoyance, light-annoyance and perception zone according to the revised safety standard. Both the construction company and local residents have provided positive comments on this influence degree assessment, which indicates that the presented criterion is suitable for evaluating human response to nearby blasts. Nevertheless, this specific criterion needs more field tests and verifications before it can be

  15. The horizontal transport of pollutants from a slope wind layer into the valley core as a function of atmospheric stability

    Leukauf, Daniel; Gohm, Alexander; Rotach, Mathias W.; Posch, Christian


    Slope winds provide a mechanism for the vertical exchange of air between the valley and the free atmosphere aloft. By this means, heat, moisture and pollutants are exported or imported. However, it the static stability of the valley atmosphere is strong, one part of the up-slope flow is redirected towards the valley center and pollutants are recirculated within the valley. This may limit the venting potential of slope winds severely. The main objective of this study is to quantify the horizontal transport of pollutants from the slope wind layer into the stable valley core and to determine the dependency of this flux as a function of the initial stability of the atmosphere. For this purpose, we conducted large eddy simulations with the Weather Research and Forecasting (WRF) model for a quasi-two-dimensional valley. The valley geometry consists of two slopes with constant slope angle rising to a crest height of 1500 m and a 4 km wide flat valley floor in between. The valley is 20 km long and homogeneous in along-valley direction. Hence, only slope winds but no valley winds can evolve. The surface sensible heat flux is prescribed by a sine function with an amplitude of 125 W m-2. The initial sounding characterized by an atmosphere at rest and by a constant Brunt-Väisälä frequency which is varied between 0.006 s-1 and 0.02 s-1. A passive tracer is released with an arbitrary but constant rate at the valley floor. As expected, the atmospheric stability has a strong impact on the vertical and horizontal transport of tracer mass. A horizontal intrusion forms at the top of the mixed layer due to outflow from the slope wind layer. Tracer mass is transported from the slope towards the center of the valley. The efficiency of this mechanism increases with increasing stability N. For the lowest value of N, about 70% of the tracer mass released at the valley bottom is exported out of the valley. This value drops to about 12% in the case of the strongest stability. Hence, most

  16. Application of dynamic programming to evaluate the slope stability of a vertical extension to a balefill.

    Kremen, Arie; Tsompanakis, Yiannis


    The slope-stability of a proposed vertical extension of a balefill was investigated in the present study, in an attempt to determine a geotechnically conservative design, compliant with New Jersey Department of Environmental Protection regulations, to maximize the utilization of unclaimed disposal capacity. Conventional geotechnical analytical methods are generally limited to well-defined failure modes, which may not occur in landfills or balefills due to the presence of preferential slip surfaces. In addition, these models assume an a priori stress distribution to solve essentially indeterminate problems. In this work, a different approach has been applied, which avoids several of the drawbacks of conventional methods. Specifically, the analysis was performed in a two-stage process: (a) calculation of stress distribution, and (b) application of an optimization technique to identify the most probable failure surface. The stress analysis was performed using a finite element formulation and the location of the failure surface was located by dynamic programming optimization method. A sensitivity analysis was performed to evaluate the effect of the various waste strength parameters of the underlying mathematical model on the results, namely the factor of safety of the landfill. Although this study focuses on the stability investigation of an expanded balefill, the methodology presented can easily be applied to general geotechnical investigations.

  17. Observing slope stability changes on the basis of tilt and hydrologic measurements

    Mentes, Gy.


    In Hungary, the high loess bank of the River Danube in Dunaszekcső has been moving with varying rate since 2007. On the high bank a geodetic monitoring network was established in September 2007. At the same time two borehole tiltmeters and later two ground water level sensors were also installed. The high-sensitive tiltmeters made it possible to study the relationships between the small tilts of the high bank and the ground water levels and the water level of the River Danube. Results of the multiple regression analysis between tilt components and water levels showed that the temporal variation of the regression coefficients is in close connection with the stability of the high bank. The investigations also showed that the movements are in very strong connection with the variation of the ground water level and less depend on the variation of the water level of the River Danube. The characteristic tilt processes, 3-4 weeks before large movements, and the slope stability changes inferred from the relationships between tilts and water level variations can be useful for early warning of landslides.

  18. Probabilistic analysis of embankment slope stability in frozen ground regions based on random finite element method

    Xi Chen; JianKun Liu; Nan Xie; HuiJing Sun


    Prediction on the coupled thermal-hydraulic fields of embankment and cutting slopes is essential to the assessment on evolution of melting zone and natural permafrost table, which is usually a key factor for permafrost embankment design in frozen ground regions. The prediction may be further complicated due to the inherent uncertainties of material properties. Hence, stochastic analyses should be conducted. Firstly, Karhunen-Loeve expansion is applied to attain the random fields for hydraulic and thermal conductions. Next, the mixed-form modified Richards equation for mass transfer (i.e., mass equation) and the heat transport equation for heat transient flow in a variably saturated frozen soil are combined into one equation with temperature unknown. Furthermore, the finite element formulation for the coupled thermal-hydraulic fields is derived. Based on the random fields, the stochastic finite element analyses on stability of embankment are carried out. Numerical results show that stochastic analyses of embankment stability may provide a more rational picture for the distribution of factors of safety (FOS), which is definitely useful for embankment design in frozen ground regions.

  19. Rock2 stabilizes β-catenin to promote tumor invasion and metastasis in colorectal cancer.

    Qiu, Yumin; Yuan, Rongfa; Zhang, Shouhua; Chen, Leifeng; Huang, Da; Hao, Haibin; Shao, Jianghua


    Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is an effector for the small GTPase Rho and plays an important role in tumor progression and metastasis. However, the effect of Rock2 in colorectal cancer (CRC) still remains unclear. In this study, we found that Rock2 expression was markedly increased in clinical CRC tissues compared with adjacent non-cancerous tissues. High expression of Rock2 was correlated with tumor metastasis and poor prognosis in CRC. In addition, the knockdown of Rock2 suppressed the invasion and metastasis of CRC cells both in vitro and in vivo. Furthermore, we found that the β-catenin/TCF4 pathway contributed to the effects of Rock2 in CRC cells, and Rock2 stabilized β-catenin by preventing its ubiquitination and degradation. Taken together, this novel pathway for β-catenin control plays a biologically relevant role in CRC metastasis.

  20. Seismic response and stability of underground rock caverns: a case study of Baihetan underground cavern complex

    Cui, Zhen; Sheng, Qian; Leng, Xianlun; Chen, Jian


    The seismic stability of the underground cavern complex, which houses the Baihetan hydropower plant in Yunnan Province, China, currently the world's 2nd largest underground rock cavern group, is studied in this article...

  1. Hydrologically complemented deterministic slope stability analysis in part of Indian Lesser Himalaya

    Mathew, John; Kundu, S; Kumar, K. Vinod; Pant, Charu C


    .... This increment stagnates at about 260 mm/day, making about 25% of the area unstable. Higher rainfall intensities make progressively gentler slopes unstable, but limited to 25 degrees of slope in this area...

  2. A distributed model for slope stability analysis using radar detected rainfall intensity

    Leoni, L.; Rossi, G.; Catani, F.


    The term shallow landslides is widely used in literature to describe a slope movement of limited size that mainly develops in soils up to a maximum of a few meters. Shallow landslides are usually triggered by heavy rainfall because, as the water starts to infiltrate in the soil, the pore-water pressure increases so that the shear strength of the soil is reduced leading to slope failure. We have developed a distributed hydrological-geotechnical model for the forecasting of the temporal and spatial distribution of shallow landslides to be used as a warning system for civil protection purpose. The model uses radar detected rainfall intensity as the input for the hydrological simulation of the infiltration. Using the rainfall pattern detected by the radar is in fact possible to dynamically control the redistribution of groundwater pressure associated with transient infiltration of rain so as to infer the slope stability of the studied area. The model deals with both saturated and unsaturated conditions taking into account the effect of soil suction when the soil is not completely saturated. Two pilot sites have been chosen to develop and test this model: the Armea basin (Liguria, Italy) and the Ischia Island (Campania, Italy). In recent years several severe rainstorms have occurred in both these areas. In at least two cases these have triggered numerous shallow landslides that have caused victims and damaged roads, buildings and agricultural activities. In its current stage, the basic basin-scale model applied for predicting the probable location of shallow landslides involves several stand-alone components. The solution suggested by Iverson for the Richards equation is used to estimate the transient groundwater pressure head distribution according to radar detected rainfall intensity. A soil depth prediction scheme and a limit-equilibrium infinite slope stability algorithm are used to calculate the distributed factor of safety (FS) at different depths and to record

  3. Stabilization of ground movement with yield rock bolts using spatial effect

    Naprasnikov, S.V.; Alexandrov, S.N.; Sazhnev, V.P.; Nazimko, V.V. [Donetsk State Technical University, Donetsk (Ukraine)


    New rock bolting technology has been developed for stabilization of roofs and floor closures in underground openings. Yield rock bolts should be inclined 5-40{degree} to the relative direction of expected roof deflection and oriented in the plane under an angle of 5-90{degree} relative to the orthogonal cross-section of the roadway. Such an orientation increases the pullout force by 2% and enhances stability of a roadway. 3 refs., 2 figs., 1 tab.

  4. A new improved multicopter chassis structure tested on slope stability monitoring

    Rossi, Guglielmo; Tanteri, Luca; Salvatici, Teresa; Scaduto, Gabriele; Tacconi Stefanelli, Carlo; Casagli, Nicola; Moretti, Sandro


    The multicopter has an increasing role in remote sensing and aerial photography. The piloting ease and the mechanical simplicity are the main reasons for drone diffusion as a hobby and for professional use. Usually multicopters have a "spider" structure with a central body and many radial arms that support the propulsion device. To improve the structure of the existing multicopter, the Department of Earth Sciences of Florence (DST) has developed and patented a new type of chassis structure that allows us to overcome some critical issues for scientific and heavy payload or long flight applications. The drone has an innovative perimetric chassis that fully supports flight dynamics. The new structure allows us to obtain high flight performance combined with low vibration transmission to the carried instruments. The new patented structure is implemented in two new prototypes of high performance drones completely developed by the Department of Earth Sciences of Florence: Saturn 2 and Saturn mini X-21. Saturn 2 is a high performance multi-role drone capable of carrying up to 14 kg of scientific instruments. Saturn Mini X-21 is a high performance drone, entirely 3D printed and specialized for digital and 3D rapid mapping. The Saturn mini X-21 was especially developed to obtain for the first time, by a drone, a 3D high resolution digital model for slope monitoring purposes of the Stromboli Sciara del Fuoco, a large inaccessible area that presents harsh flight conditions such as high persistent wind, rotors, volcanic ash and saltiness. The Saturn drones are mainly developed and tested, all around software and hardware, on slope stability monitoring. Four test cases are proposed, which were performed during the development and testing phase: a large area 3D survey (Scillato - Sicily), a harsh condition 3D survey (Stromboli -Sicily), a multitemporal 3D survey (Ricasoli - Tuscany) and the testing phase of measurement performed by onboard radar equipment.

  5. Analysis about the Influence of Clay Core Wall Structure towards the Slope Stability of High Embankment Dam

    Li Bin


    Full Text Available As the main part of the anti-seepage system, core wall is a key point in the design of high em-bankment dam. The dam slope stability is a major factor for the type of core wall. But it is still unclear what effects the core wall structure might have on the slope stability. Based on practical projects of high embankment dam in Nuozhadu, Lianghekou and Shuangjiangkou, this paper analyzes safety factors and dangerous slip sur-faces of dam slopes of high embankment dams in both straight and slanting core wall structures and compares the influences of different core wall structures on the slope stability of high embankment dam through numerical calculations. The safety margin of the embankment dam of straight core wall is larger than that of slanting core wall in the operating condition of the reservoir water level’s drawdown. Compared with that of the straight core wall scheme, the position of the dangerous slip surface of the downstream dam slope is closer to the dam crest in the slanting core wall scheme.

  6. Linkages between precipitation cycle and slope stability: A case study in the Caijiapo landslide among Weihe River Basin

    Zhu, Y. L.; Qi, G. P.


    It is of great importance to forecast landslide in future certain time interval. Hence, this study proposed a method combination precipitation period with variety of slope stability factor based on macro scale. This study designed 5 grades of rainfall strength simulation and corresponding 5 grades of slope state using Markoff prediction technique analysis change of slope factor K in the short time. Results indicated that: (1) the rainfall in Baoji area has three periods of 5a, 13a and 25a, in which 5a is the primary period; (2) the slope safety factor K has a similar fluctuation trend compared to precipitation state, thus division slope factor K of 5 grade as safety state, basically safety state, stable state, partial risk state and risk state, respectively; (3) in the previous year if slope in the safety, basically safe and stable state, in the next year slope factor K above 1.15 has 60%, 75% and 72% probability, respectively; (4) when the previous year at partial risk or risk situation, there is high probability that value of the K is always more than 1.15, it is means to a great extent the landslide have already occurred, thus defined a concept which between “the safety state after destruction” and “safety state have no destruction”.

  7. Slope Stability Analysis and Mitigation Measures in the Area of the Sighişoara Medieval Citadel

    George-Cătălin Silvaş


    Full Text Available The Sighişoara Medieval Citadel has a very big importance to the cultural, architectural and historical heritage of Romania. The citadel is situated on the Fortress Hill and it is the only inhabited fortress in Romania. But underneath the beauty of the Citadel lies some problems that only the inhabitants and the authorities know. These problems consist in the presence of the slope instability phenomenon. Throughout the years the slopes of the Fortress Hill, because of a series of factors, became instable. Thus landslides occurred that affected the Citadel fortress walls. There are still some areas of the walls that have never been reconstructed yet. So a slope stability analysis shall show if the slope instability phenomenon is still active and the mitigation measures recommended will stop the activity of this phenomenon.

  8. Friction rock stabilizer and method of installing same in an earth structure

    Lindeboom, H.


    The stabilizer comprises a generally tubular, metal body, the leading end of which has been hardened to rock-cutting strength in order that the stabilizer, according to the method of invention, can be impacted with a high frequency, low-blow actuator to cause the stabilizer to bore its own hole in the earth structure, this to eliminate a pre-boring, stabilizer installation step.

  9. Integrating the effects of forest cover on slope stability in a deterministic landslide susceptibility model (TRIGRS 2.0)

    Zieher, T.; Rutzinger, M.; Bremer, M.; Meissl, G.; Geitner, C.


    The potentially stabilizing effects of forest cover in respect of slope stability have been the subject of many studies in the recent past. Hence, the effects of trees are also considered in many deterministic landslide susceptibility models. TRIGRS 2.0 (Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability; USGS) is a dynamic, physically-based model designed to estimate shallow landslide susceptibility in space and time. In the original version the effects of forest cover are not considered. As for further studies in Vorarlberg (Austria) TRIGRS 2.0 is intended to be applied in selected catchments that are densely forested, the effects of trees on slope stability were implemented in the model. Besides hydrological impacts such as interception or transpiration by tree canopies and stems, root cohesion directly influences the stability of slopes especially in case of shallow landslides while the additional weight superimposed by trees is of minor relevance. Detailed data on tree positions and further attributes such as tree height and diameter at breast height were derived throughout the study area (52 km²) from high-resolution airborne laser scanning data. Different scenarios were computed for spruce (Picea abies) in the study area. Root cohesion was estimated area-wide based on published correlations between root reinforcement and distance to tree stems depending on the stem diameter at breast height. In order to account for decreasing root cohesion with depth an exponential distribution was assumed and implemented in the model. Preliminary modelling results show that forest cover can have positive effects on slope stability yet strongly depending on tree age and stand structure. This work has been conducted within C3S-ISLS, which is funded by the Austrian Climate and Energy Fund, 5th ACRP Program.

  10. Research on inspection of stability of subsiding area in composite rock-mass roadway



    The research concentrates mainly on the development of failure process in composite rock-mass through acoustic emission, convergence inspection, stress measurement, subside area measurement, level measurement in the process of stability and safety monitoring as well as inspecting of subside area in composite hard rock. In terms of the modern signal analysis technology, various aspects are discussed. The monitoring result and the stability of rock mass can be synthetically evaluated and inferred, and the location of acoustic origin according to the acoustic emission regularity can be successfully detected. Finally the key factors of the deformation can be inferred from in subside area.

  11. Probabilistic Rock Slope Engineering.


    sample data should be guided by subject-matter knowledge, experience, and judgment (see Whitten 1966). Exanp les of Iapp in "’eclhnijues 21. Many ...equal values. However, a nugget practically always occurs in variograms of geologic data and may indicate highly erratic sample values spaced at close...reverse Fourier transformed to provide a simulated series of fracture data values that have the desired spatial covariance. 125. The first step in

  12. The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

    Gomes, Guilherme J.C.; Vrugt, Jasper A.; Vargas, Eurípedes A.; Camargo, Julia T.; Velloso, Raquel Q.; van Genuchten, Martinus Th


    We investigate the uncertainty in bedrock depth and soil hydraulic parameters on the stability of a variably-saturated slope in Rio de Janeiro, Brazil. We couple Monte Carlo simulation of a three-dimensional flow model with numerical limit analysis to calculate confidence intervals of the safety fac

  13. 75 FR 65366 - Recovery Policy RP9524.2, Landslides and Slope Stability Related to Public Facilities


    ... SECURITY Federal Emergency Management Agency Recovery Policy RP9524.2, Landslides and Slope Stability Related to Public Facilities AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice of availability. SUMMARY: This document provides notice of the final Recovery Policy RP9524.2, Landslides and...

  14. Comparison of Homogenous and Multi-layered Berm Breakwaters with Respect to Overtopping and Front Slope Stability

    Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.


    A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...

  15. Slope stability analysis and optimum design in Dading open-pit iron mine%大顶铁矿露天采场边坡稳定性分析与优化设计

    蔡美峰; 朱青山; 乔兰; 李长洪; 王金安; 谭文辉


    The slope of Dading open-pit iron mine in south China has the characteristic of low rock strength and bad stability. Its basic information on engineering-geological conditions, hydro-geological conditions and rock mass structures together with physical and mechanical properties of rock mass was derived from systematical field and laboratory investigations, experiments and tests. Stability analysis and optimum design were done for the slope by using a combined method of numerical modeling and limit equilibrium analysis. The slope angle increases more than 3° compared with the original design.%针对大顶铁矿露天采场边坡岩体强度低、稳定性差的特点,在系统的现场工程地质、水文地质、岩体结构与岩性分布调查和岩石物理力学性质试验基础上,采用符合现代岩石力学原理的数值模拟和极限平衡相结合的方法,进行边坡稳定性和设计优化研究,并推荐了该矿的边坡设计方案.总体边坡角比原设计平均提高3°以上.

  16. Identification of active release planes using ground-based differential InSAR at the Randa rock slope instability, Switzerland

    V. Gischig


    Full Text Available Five ground-based differential interferometric synthetic aperture radar (GB-DInSAR surveys were conducted between 2005 and 2007 at the rock slope instability at Randa, Switzerland. Resultant displacement maps revealed, for the first time, the presence of an active basal rupture zone and a lateral release surface daylighting on the exposed 1991 failure scarp. Structures correlated with the boundaries of interferometric displacement domains were confirmed using a helicopter-based LiDAR DTM and oblique aerial photography. Former investigations at the site failed to conclusively detect these active release surfaces essential for kinematic and hazard analysis of the instability, although their existence had been hypothesized. The determination of the basal and lateral release planes also allowed a more accurate estimate of the currently unstable volume of 5.7±1.5 million m3. The displacement patterns reveal that two different kinematic behaviors dominate the instability, i.e. toppling above 2200 m and translational failure below. In the toppling part of the instability the areas with the highest GB-DInSAR displacements correspond to areas of enhanced micro-seismic activity. The observation of only few strongly active discontinuities daylighting on the 1991 failure surface points to a rather uniform movement in the lower portion of the instability, while most of the slip occurs along the basal rupture plane. Comparison of GB-DInSAR displacements with mapped discontinuities revealed correlations between displacement patterns and active structures, although spatial offsets occur as a result of the effective resolution of GB-DInSAR. Similarly, comparisons with measurements from total station surveys generally showed good agreement. Discrepancies arose in several cases due to local movement of blocks, the size of which could not be resolved using GB-DInSAR.

  17. Assessing slope stability by ground based and remote techniques - a case study of 2015 Tbilisi disaster

    Akhalaia, G.; Cakir, Z.; Tsiskarishvili, L.; Otinashvili, M.; Sukhishvili, L.; Merebashvili, G.; Tserodze, M.; Akubardia, D.; Managadze, M.


    At the night of 13th of June 2015 complex-type landslide was triggered by heavy rainfall in the river Vere basin, 10 km to the west of Georgian capital Tbilisi. Flashflood flow transported the landslide body to the center of Tbilisi. As a result 20 people are dead and 2 still missing, direct infrastructure damage is about 50 mln USD. The landslide is located at Mtatsminda anticline, its length is 3600 meters and sliding surface area estimates 315 000 km2. Bedrock dips varies 20-800 and surface inclination is almost the same. Our group used geodetic, geophysical and UAV survey approaches to estimate total volume of landslide body. As a result of the investigation we calculated that 1 300 000 m3 was transported but about 25% of total amount is still on sliding surface. As the whole area is prone to landslide, different approaches were applied to assess slope stability and indentifing ongoing deformation areas. Two most challenging factors were steep terrain and forest cover, so we used InSAR techniques, optical remote sensing, RTK measurements and geophysical methods. The detection and assessment pre and post-failure deformation, represent important task to understand the failure mechanism and geometry of the landslide, an ultimately purpose is to evaluate its stability. Interferometric Synthetic Aperture Radar data from ENVISAT sensor was utilized in the analysis of the pre-/ post-event deformation. Also, Network of GNSS (Continuously Operating Reference Stations) was used for RTK, to provide centimeter precise measurements. After comparing results derived from these different approaches, proper methods were selected to identify the most unstable areas within the landslide zone.

  18. Coir geotextile for slope stabilization and cultivation - A case study in a highland region of Kerala, South India

    Vishnudas, Subha; Savenije, Hubert H. G.; Van der Zaag, Pieter; Anil, K. R.

    A sloping field is not only vulnerable to soil erosion it may also suffer from soil moisture deficiency. Farmers that cultivate on slopes everywhere face similar problems. Conservation technologies may reduce soil and nutrient losses, and thus enhance water holding capacity and soil fertility. But although these technologies promote sustainable crop production on steep slopes, the construction of physical structure such as bench terraces are often labour intensive and expensive to the farmers, since construction and maintenance require high investments. Here we studied the efficiency of coir geotextile with and without crop cultivation in reducing soil moisture deficiency on marginal slopes in Kerala, India. From the results it is evident that the slopes treated with geotextile and crops have the highest moisture retention capacity followed by geotextiles alone, and that the control plot has the lowest moisture retention capacity. As the poor and marginal farmers occupy the highland region, this method provides an economically viable option for income generation and food security along with slope stabilization.

  19. Inclinometer monitoring system for stability analysis: the western slope of the Bełchatów field case study

    Cała Marek


    Full Text Available The geological structure of the Bełchatów area is very complicated as a result of tectonic and sedimentation processes. The long-term exploitation of the Bełchatów field influenced the development of horizontal displacements. The variety of factors that have impact on the Bełchatów western slope stability conditions, forced the necessity of complex geotechnical monitoring. The geotechnical monitoring of the western slope was carried out with the use of slope inclinometers. From 2005 to 2013 fourteen slope inclinometers were installed, however, currently seven of them are in operation. The present analysis depicts inclinometers situated in the north part of the western slope, for which the largest deformations were registered. The results revealed that the horizontal displacements and formation of slip surfaces are related to complicated geological structure and intensive tectonic deformations in the area. Therefore, the influence of exploitation marked by changes in slope geometry was also noticeable.

  20. An extension of 2D Janbu's generalized procedure of slices for 3D slope stability analysis Ⅰ- Basic theory

    ZHANG; Junfeng; QI; Tao; LI; Zhengguo


    Based on 2D Janbu's generalized procedure of slices (GPS), a new three-dimensional slope stability analysis method has been developed, in which all forces acting on the discretized blocks in static equilibrium are taken into account in all three directions. In this method, the potential sliding mass is divided into rigid blocks and each block is analyzed separately by using both geometric relations and static equilibrium formulations. By introducing force boundary conditions, the stability problem is determined statically. The proposed method can be applied to analyze the stability of slopes with various types of potential sliding surfaces, complicated geological boundaries and stratifications, water pressure, and earthquake loading. This method can also be helpful in determining individual factor of safety and local potential sliding direction for each block. As an extension of 2D Janbu's method, the present method has both the advantages and disadvantages of Janbu's generalized procedure of slices.

  1. Snowpack spatial variability: Towards understanding its effect on remote sensing measurements and snow slope stability

    Marshall, Hans-Peter

    on a slope. The ability to accurately characterize snowpack properties at much higher resolutions and spatial extent than previously possible will hopefully help lead to a more complete understanding of spatial variability, its effect on remote sensing measurements and snow slope stability, and result in improvements in avalanche prediction and accuracy of SWE estimates from space.

  2. Preliminary blasting as a means of constructing the final slopes

    Lopez Jimeno, E.; Lopez Jimeno, C. (Lignitos de Meirama, La Coruna (Spain))


    In order to undertake construction of a new belt at the Meirama opencast lignite workings in the Province of Coruna it has been necessary partially to re-site the slope of the general haulage drift. Preliminary blasting was thought to be the most suitable method of blasting in order to maintain slope stability of the rock mass. (17 refs.)

  3. Assessing deep-seated landslide susceptibility using 3-D groundwater and slope-stability analyses, southwestern Seattle, Washington

    Brien, Dianne L.; Reid, Mark E.


    In Seattle, Washington, deep-seated landslides on bluffs along Puget Sound have historically caused extensive damage to land and structures. These large failures are controlled by three-dimensional (3-D) variations in strength and pore-water pressures. We assess the slope stability of part of southwestern Seattle using a 3-D limit-equilibrium analysis coupled with a 3-D groundwater flow model. Our analyses use a high-resolution digital elevation model (DEM) combined with assignment of strength and hydraulic properties based on geologic units. The hydrogeology of the Seattle area consists of a layer of permeable glacial outwash sand that overlies less permeable glacial lacustrine silty clay. Using a 3-D groundwater model, MODFLOW-2000, we simulate a water table above the less permeable units and calibrate the model to observed conditions. The simulated pore-pressure distribution is then used in a 3-D slope-stability analysis, SCOOPS, to quantify the stability of the coastal bluffs. For wet winter conditions, our analyses predict that the least stable areas are steep hillslopes above Puget Sound, where pore pressures are elevated in the outwash sand. Groundwater flow converges in coastal reentrants, resulting in elevated pore pressures and destabilization of slopes. Regions predicted to be least stable include the areas in or adjacent to three mapped historically active deep-seated landslides. The results of our 3-D analyses differ significantly from a slope map or results from one-dimensional (1-D) analyses.

  4. Guide for calculating the stability of mine berms and spoil bank slopes in the Maritsa-Iztok coal basin

    Georgiev, G.; Todorova, M.; Doneva, V.; Novachkov, N.; Nedyalkov, N.; Mitev, A.; Rachev, R.


    Major landslides are described which occurred in the basin between 1963 and 1970 during overburden removal and formation of spoil banks. Guidelines for the prevention of landslides were developed on the basis of large scale studies of geomechanics, geostatic calculations and geodetic observations of slope behavior; no further landslide has occurred since 1970. Cohesion coefficients, angle of internal friction and shear properties were determined for each material occurring in the clayey and sandy overburden and for the coal (ash content 15-55%). Slope stability of working benches and spoil banks at the Troyanovo mines was then calculated. 8 references.

  5. Stability Of Rubble Mound Breakwaters Using High Density Rock

    Burcharth, H. F.; Beck, J. B.


    The present paper discusses the effect of mass density on stability of rubble mound breakwaters. A short literature review of existing knowledge is give to establish a background for the ongoing research. Furthermore, several model tests are described in which the stability of rubble mound breakw...

  6. Slope Stability Analysis for Shallow Landslides using TRIGRS: A Case Study for Sta. Cruz, Zambales, Philippines

    Mendoza, J. P. A.


    The Philippines, being located in the circum-Pacific, bounded by multiple subduction zones, open seas and ocean, is one of the most hazard-prone countries in the world (Benson, 1997). This widespread recurrence of natural hazards in the country requires much attention for disaster management (Aurelio, 2006). On the average, 21 typhoons enter the Philippine area of responsibility annually with 6-9 making a landfall. Several rainfall-induced landslide events are reported annually particularly during and after the inundation of major typhoons which imposes hazards to communities and causes destruction of properties due to the moving mass and possible flash floods it may induce. Shallow landslides are the most commonly observed failure involving soil-mantled slopes and are considered major geohazards, often causing property damage and other economic loss. Hence numerous studies on landslide susceptibility including numerical models based on infinite slope equation are used in order to identify slopes prone to occurrences of shallow landslides. The study aims to determine the relationships between the slope and elevation to the factor of safety for laterite-mantled topography by incorporating precipitation values in the determination of landslide susceptibility. Using a DEM, flow direction map and slope map of the Sta Cruz (Zambales, Philippines), the FORTRAN based program TRIGRS, was used to generate the values for the factors of safety in the study area. Overlays with a generated slope map and elevation map were used to determine relationships of the mentioned factors and the factors of safety. A slope in a topography mantled with lateritic soil will fail at a slope angle higher than 20 degrees. Generally, the factor of safety decreases as the slope angle increases; this increases the probability and risk of slope failure. Elevation has no bearing on the computation for the factor of safety. The factor of safety is heavily dependent on the slope angle. The value of

  7. Terrestrial Radar Interferometry: The current state-of-the-art demonstrated by real-world slope stability case studies

    Wooster, Michael; Thomas, Adam; Holley, Rachel


    Risk associated with natural terrain is typically mapped and monitored using established geodetic, geotechnical and remote sensing (satellite and airborne) techniques; however such techniques can pose challenges related to health and safety, cost and the density and frequency of measurements. Terrestrial Radar Interferometry (TRI) systems offer users new capabilities in the mapping and monitoring of ground displacements, and more specifically, slope stability. Use of portable radar systems that facilitate quick deployment and data acquisition, rapid and long distance scanning, and the ability to function and operate in most weather conditions, are revolutionising the terrestrial survey industry. This work presents a summary of the capabilities, limitations and applications of a state-of-the-art TRI system. The system is quick to deploy, allowing data acquisition within tens of minutes of arrival on site and requiring little or no permanent site infrastructure. Imaging scans are typically completed in less than 1 minute for a field of view of up to 360°, with repeat scans possible at up to 1-2 minute intervals. The system gives an azimuth resolution of around 8 m at distances of 1 km, with the capability to image slopes at distances of between 50 m and 10 km from the sensor with a deformation accuracy of less than 1 mm. These capabilities represent a significant advance over more traditional stability monitoring methods. The benefits of the TRI technology will be demonstrated through various natural and artificial slope stability case studies. Measurements on artificial slopes in environments such as quarries and open-cast mines allow benchmarking of capabilities across a variety of surface characteristics and failure mechanisms. These results allow an informed consideration of the applicability in various natural slope stability applications, and enable discussion on how TRI can meet the additional challenges encountered in natural environments.

  8. Stability of Large Parallel Tunnels Excavated in Weak Rocks: A Case Study

    Ding, Xiuli; Weng, Yonghong; Zhang, Yuting; Xu, Tangjin; Wang, Tuanle; Rao, Zhiwen; Qi, Zufang


    Diversion tunnels are important structures for hydropower projects but are always placed in locations with less favorable geological conditions than those in which other structures are placed. Because diversion tunnels are usually large and closely spaced, the rock pillar between adjacent tunnels in weak rocks is affected on both sides, and conventional support measures may not be adequate to achieve the required stability. Thus, appropriate reinforcement support measures are needed, and the design philosophy regarding large parallel tunnels in weak rocks should be updated. This paper reports a recent case in which two large parallel diversion tunnels are excavated. The rock masses are thin- to ultra-thin-layered strata coated with phyllitic films, which significantly decrease the soundness and strength of the strata and weaken the rocks. The behaviors of the surrounding rock masses under original (and conventional) support measures are detailed in terms of rock mass deformation, anchor bolt stress, and the extent of the excavation disturbed zone (EDZ), as obtained from safety monitoring and field testing. In situ observed phenomena and their interpretation are also included. The sidewall deformations exhibit significant time-dependent characteristics, and large magnitudes are recorded. The stresses in the anchor bolts are small, but the extents of the EDZs are large. The stability condition under the original support measures is evaluated as poor. To enhance rock mass stability, attempts are made to reinforce support design and improve safety monitoring programs. The main feature of these attempts is the use of prestressed cables that run through the rock pillar between the parallel tunnels. The efficacy of reinforcement support measures is verified by further safety monitoring data and field test results. Numerical analysis is constantly performed during the construction process to provide a useful reference for decision making. The calculated deformations are in

  9. Characteristics and stability of slope movement response to underground mining of shallow coal seams away from gullies

    Zhang Dongsheng; Fan Gangwei; Wang Xufeng


    Underground pressure is abnormal during mining of shallow coal seams under gullies.We studied gully slope movements,subject to underground mining,with physical simulation and theoretical analysis.The rules disclose that the slope rock slides horizontally in response to mining in the direction of gullies and rotates reversely with the appearance of a polygon block in mining away from gullies.We focused our attention on the case of mining away from a gully.We built a mechanical model in terms of a polygon block hinged structure and investigated the variation of horizontal thrust and shear force at the hinged point in relation to the rotation angle under different fragmentations.The Sliding-Rotation instability conditions of the polygon block hinged structure are presented based on the analyses of sliding instability and rotation instability.These results can serve as a theoretical guide for roof control during mining away from gullies in a coalfield defined by gullies.

  10. 北京千灵山生态修复边坡稳定性研究%Analysis on stability of ecologically-restored slope in Qianlingshan,Beijing

    张辉旭; 王小烈; 王红才; 郭彬彬; 朱立新; 赵卫华; 李阿伟; 孙东生; 马越


    开采形成的矿山岩质高陡边坡,造成山体缺损、水土流失、生态破坏,容易产生边坡失稳、崩塌滑落等地质灾害,急需进行生态修复治理。本文以北京市西郊千灵山生态修复岩质高陡边坡为例,根据地质雷达实测剖面分析及室内试验得到的岩体内部结构信息和岩石力学参数,建立了生态边坡的地质力学模型,并用有限元强度折减法对千灵山岩质高陡边坡生态修复前后的稳定性进行了模拟计算。结果表明,非降雨、降雨(饱水)条件下自然岩石边坡和生态修复后的边坡其安全系数分别为17、12.5、5、2;边坡变形以坡脚和生态带区域的中下部位最大,边坡潜在滑动面主要沿坡脚45°方向上扩展。因此,岩石边坡坡脚和生态带区域的中下部位应是重点加固区,需通过锚杆加固和有效排水对之进行处理。%The analysis on high-steep rocky slope stability is a research focus for a long time,because it is considered as the reason why geological disasters occurres,such as slope instability and landslide.Ecological restoration of slope is an urgent issue that can improve environment but may reduce the stability of the whole slope system in some extent.The stability of the ecological slope in Qianlingshan,west suburb of Beijing is analyzed with nonlinear FEM strength reduction method.The interpretation of geological penetrating radar surveying refers to that the rock slope consists of isotropic limestone without obvious fault.The numerical modeling is based on the parameters by rock mechanical experiment,combined with the internal structure of rock mass measured by geological penetrating radar.The safety factors and plastic area distribution and de-formation contours are obtained under different load conditions.The result shows that the safety factors are 17 and 12.5 and 5 and 2 respectively on dry natural slope,dry ecologically-restored slope and saturated natu

  11. Evaluating a slope-stability model for shallow rain-induced landslides using gage and satellite data

    Yatheendradas, S.; Kirschbaum, D.; Baum, Rex L.; Godt, Jonathan W.


    Improving prediction of landslide early warning systems requires accurate estimation of the conditions that trigger slope failures. This study tested a slope-stability model for shallow rainfall-induced landslides by utilizing rainfall information from gauge and satellite records. We used the TRIGRS model (Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis) for simulating the evolution of the factor of safety due to rainfall infiltration. Using a spatial subset of a well-characterized digital landscape from an earlier study, we considered shallow failure on a slope adjoining an urban transportation roadway near the Seattle area in Washington, USA.We ran the TRIGRS model using high-quality rain gage and satellite-based rainfall data from the Tropical Rainfall Measuring Mission (TRMM). Preliminary results with parameterized soil depth values suggest that the steeper slope values in this spatial domain have factor of safety values that are extremely close to the failure limit within an extremely narrow range of values, providing multiple false alarms. When the soil depths were constrained using a back analysis procedure to ensure that slopes were stable under initial condtions, the model accurately predicted the timing and location of the landslide observation without false alarms over time for gage rain data. The TRMM satellite rainfall data did not show adequately retreived rainfall peak magnitudes and accumulation over the study period, and as a result failed to predict the landslide event. These preliminary results indicate that more accurate and higher-resolution rain data (e.g., the upcoming Global Precipitation Measurement (GPM) mission) are required to provide accurate and reliable landslide predictions in ungaged basins.

  12. On slope stability evaluation of underground trough and bunker in mountainous areas%山区地下槽仓边坡稳定性评价



    针对平朔东露天煤矿产品煤槽仓岩土特征,利用极限平衡法对开挖后的边坡按天然、降雨、地震以及地震和降雨同时作用的四种工况进行了模拟,并进行稳定性评价,从而为槽仓边坡的治理及合理监测方案的制定提供了依据。%According to the rock features of the product coal troughs and bunkers of Ping-Shou Eastern Open-pit Coal Mine, the paper under- takes the simulation for the four situations of the slopes affected by natural influence, the rainfall, the earthquake and the common influence of the earthquake and rainfall by adopting the limit equilibrium method, and has the stability evaluation, so as to provide the reference for the treat- ment of slopes with the trough and bunker and the reasonable establishment of the supervision schemes.

  13. SLOPE/W在某露天煤矿采掘场边坡稳定性分析中的应用%Application of SLOPEP/W in Slope Stability Analysis of an Open Pit Mining Field

    赵星宇; 王卫; 戴雄辉; 毕芬芬


    某煤矿采掘场非工作帮边坡为软岩高边坡,为分析边坡是否存在潜在安全隐患而影响施工进度及施工安全,进行了非工作帮边坡的稳定性分析.采用Geo-studio软件中的Slope/W模块建立了边坡的计算模型,并用Bishop法和Morgenstern-price法对暴雨工况和暴雨叠加地震工况进行计算,得出边坡的稳定性系数.推测的滑面计算结果与边坡稳定性评价的标准进行对比,发现计算结果与现场勘察后预测结论基本一致.该边坡整体稳定性为基本稳定.%The nonworking slope of a coal mining field is a high soft rocky slope. In order to analyze the slope whether there is a potential security risk to affect the construction schedule and construction safety, the stability of the nonworking slope is analyzed. The computational model of the slope is established with the Slope/W module in Geo-studio software, the rainstorm working condition and heavy rain superposition seism condition are calculated with Bishop and Morgenstem-price method, and the stability factor of the slope is obtained. Finally, compared the calculation results of the speculated sliding surface with the slope stability assessment standards, it is found that the calculation results and site survey forecasting conclusions are basically the same. The whole stability of the slope is basically stable.

  14. Study of dynamic sensitivity of rock slope under excitation function role of force increase mutation%力幅突变激扰作用的岩石边坡动力敏感性研究

    王建国; 王振伟


    动载荷作用引起岩石边坡失稳破坏,尤其力幅突变激扰作用对边坡稳定影响很大.对动、静载荷作用下岩石力学性质进行了分析,建立了岩石边坡非线性运动方程,分析了岩石边坡动力变形模型及非线性动力响应,得出当扰动频率增加到一定程度,滑体振幅突然增加,产生向上突跳并随力幅的增加继续增加:反之,当力幅较大并逐渐减小时,滑体振幅也随之减小,当扰动的振幅减小至一定程度,滑体振幅突然降低,产生向下突跳减小.对初始条件和力幅突变激扰对岩石力学非线性振动系统的影响进行了分析,得到初始条件的微小变化可引起系统响应的巨大差异,当振幅A极小时,线性系统的振荡很弱,它对非线性系统的作用也很弱,整个系统的运动便可看作两运动的独立叠加.当振幅A再加大到使其幅值超过非线性系统三奇点之间的间隔时,系统可以在这些奇点之间来回跃迁振荡,从而运动复杂化,随振幅A的增加,系统从倍周期运动向混运动变化,研究结果可为岩石边坡的动力稳定提供指导.%The dynamic loading leads to instability and failure of rock slope.Especially,the role of force increase mutation has a great influence on slope stability.The rock mechanical properties are analyzed under static and dynamic loadings.And then,the nonlinear equation of rock slope is established.The dynamic deformation model of rock slope and the nonlinear dynamic response are studied.The amplitude of the sliding body suddenly increase,resulting in the sudden jump up and continue to increasing with the increase of the force,when the disturbance frequency to a certain extent.Conversely,the amplitude of the landslide suddenly reduces,resulting in the sudden decreases when the perturbation amplitude reduces to a certain extent.Tiny changes in initial conditions can cause a huge difference of the system response.The movement of the entire system can

  15. Comparison of Homogenous and Multi-layered Berm Breakwaters with Respect to Overtopping and Front Slope Stability

    Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.


    A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...... previously been used in the Icelandic type of berm breakwater because it seems that the number of stone classes in the berm can be reduced from five to two without significantly influencing overtopping and stability performance. Moreover, the new results are compared to the design formulae established...

  16. A hybrid method for quasi-three-dimensional slope stability analysis in a municipal solid waste landfill.

    Yu, L; Batlle, F


    Limited space for accommodating the ever increasing mounds of municipal solid waste (MSW) demands the capacity of MSW landfill be maximized by building landfills to greater heights with steeper slopes. This situation has raised concerns regarding the stability of high MSW landfills. A hybrid method for quasi-three-dimensional slope stability analysis based on the finite element stress analysis was applied in a case study at a MSW landfill in north-east Spain. Potential slides can be assumed to be located within the waste mass due to the lack of weak foundation soils and geosynthetic membranes at the landfill base. The only triggering factor of deep-seated slope failure is the higher leachate level and the relatively high and steep slope in the front. The valley-shaped geometry and layered construction procedure at the site make three-dimensional slope stability analyses necessary for this landfill. In the finite element stress analysis, variations of leachate level during construction and continuous settlement of the landfill were taken into account. The "equivalent" three-dimensional factor of safety (FoS) was computed from the individual result of the two-dimensional analysis for a series of evenly spaced cross sections within the potential sliding body. Results indicate that the hybrid method for quasi-three-dimensional slope stability analysis adopted in this paper is capable of locating roughly the spatial position of the potential sliding mass. This easy to manipulate method can serve as an engineering tool in the preliminary estimate of the FoS as well as the approximate position and extent of the potential sliding mass. The result that FoS obtained from three-dimensional analysis increases as much as 50% compared to that from two-dimensional analysis implies the significance of the three-dimensional effect for this study-case. Influences of shear parameters, time elapse after landfill closure, leachate level as well as unit weight of waste on FoS were also

  17. Geomorphologic mapping in the Ny Ålesund area (Svalbard Island, Norway) for the analysis of geomorphologic effects on rock slopes induced by glacier retreat in climate sensitive High Arctic regions

    Miccadei, Enrico; Piacentini, Tommaso; Casacchia, Ruggero; Sparapani, Roberto


    The geomorphological effects of glacial retreat, rapidly changing Arctic environments and consequent local temporary permafrost melting are several types of glacial and periglacial landforms (pingos, solifluction, drumlins, etc.) but also debris and rock falls, alluvial fan and glacial outwash development and scarp/slopes retreat and evolution. In this work we have realized a geomorphologic map of rockfalls, landslides, alluvial fans and the slopes and scarps of steep mountainsides in the Ny Ålesund area (Svalbard Island, Norway) focused on the analysis of rock falls as geomorphological effects of glacier retreat, permafrost degradation and higher temperatures on slope processes. The investigation is based on geological and geomorphological field survey, and remote sensing and aerial photo interpretation, The Ny Ålesund area landscape is characterized by rugged non-vegetated mountains only partially covered by glaciers, with steep flanks and rock scarps; the scarps are formed by different types of rocks (intrusive and effusive igneous rocks, marine sedimentary rocks); this landscape is highly affected by debris and rock falls (from scarps and slopes) forming wide talus slopes and by alluvial fan and fluvial outwash (from glaciers), which make the surface sedimentary cover of the island together with rock glaciers and moraine deposits and locally fluvial deposits. The work is focused on the comprehension of the role of different factors in inducing rock falls, alluvial fans, slope/scarps evolution in high geomorphological sensitivity environments (i.e. glacial, periglacial or mountain) including: orography, lithology, rock fracturation, morphostructural setting, meteorological context. The conclusions focus on the possible geomorphological hazards affecting the Ny Ålesund area.

  18. Analysis of a Large Rock Slope Failure on the East Wall of the LAB Chrysotile Mine in Canada: Back Analysis, Impact of Water Infilling and Mining Activity

    Grenon, Martin; Caudal, Philippe; Amoushahi, Sina; Turmel, Dominique; Locat, Jacques


    A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main commercial link between the region and the Northeast USA. LiDAR scanning and subsequent analyses were performed and enabled quantifying the geometry and kinematics of the failure area. Using this information, this paper presents the back analysis of the July 2012 failure. The analyses are performed using deterministic and probabilistic limit equilibrium analysis and finite-element shear strength reduction analysis modelling. The impact of pit water infilling on the slope stability is investigated. The impact of the mining activity in 2011 in the lower part of the slope is also investigated through a parametric analysis.

  19. Study on engineering geological stability of rock mass at Shanmen silver deposit

    Ming FENG; Li LIU; Yu ZHANG; Xigang REN; Chengke XU


    The natural balance conditions will be disturbed and produce a series of problems when mineral deposit has mined. This paper has researched the engineering rock masses have been researched in this study, structural planes, the distribution characteristics of tectonic geological factors and the stability of engineering structures according to the theory and research methods of rock mechanics, it will provide the engineering geological evidence for mining area exploited, meanwhile pledge the safety production. Shanmen silver deposit is a large epithermal deposit,it is controlled by NE to NNE strike faults. The stability of rock mass is acted on the tectonic movement and hot metalliferous brine in long-term. Especially,strength of rock mass becomes softened, muddy and loosed under the action of water,so the lower stability of rock mass is,the easier it can take place for harm of disaster threatening production safe of mining. For this reason,it is very important that drawing up a plan to lower harm for mine and protect.

  20. Uncertainty of the Soil–Water Characteristic Curve and Its Effects on Slope Seepage and Stability Analysis under Conditions of Rainfall Using the Markov Chain Monte Carlo Method

    Weiping Liu


    Full Text Available It is important to determine the soil–water characteristic curve (SWCC for analyzing slope seepage and stability under the conditions of rainfall. However, SWCCs exhibit high uncertainty because of complex influencing factors, which has not been previously considered in slope seepage and stability analysis under conditions of rainfall. This study aimed to evaluate the uncertainty of the SWCC and its effects on the seepage and stability analysis of an unsaturated soil slope under conditions of rainfall. The SWCC model parameters were treated as random variables. An uncertainty evaluation of the parameters was conducted based on the Bayesian approach and the Markov chain Monte Carlo (MCMC method. Observed data from granite residual soil were used to test the uncertainty of the SWCC. Then, different confidence intervals for the model parameters of the SWCC were constructed. The slope seepage and stability analysis under conditions of rainfall with the SWCC of different confidence intervals was investigated using finite element software (SEEP/W and SLOPE/W. The results demonstrated that SWCC uncertainty had significant effects on slope seepage and stability. In general, the larger the percentile value, the greater the reduction of negative pore-water pressure in the soil layer and the lower the safety factor of the slope. Uncertainties in the model parameters of the SWCC can lead to obvious errors in predicted pore-water pressure profiles and the estimated safety factor of the slope under conditions of rainfall.


    E. Michnevich


    Full Text Available Hydrologic conditions that cause the Goryn river floods have been described in the paper. The paper considers engineering solutions pertaining to prevention of catastrophic floodings by bifurcation of maximum river flow while constructing a watershed dike and creating a non-flood polder in the flood plain. The formulas have been developed for calculation of dike slope fixing by dumped riprap when the slopes are subjected to stream impact. The paper provides an analysis of existing dependences for calculation of riprap material size in order to protect slopes against waves. The possible ways for lower cost of fixation while using  waste tyres and also while constructing  small wave-suppressing dikes reinforced by dumped riprap and shrub vegetation along the main dike have been revealed in the paper.

  2. Research on the stability analysis and design of soil tunnel surrounding rock

    Zheng Yingren; Qiu Chenyu; Xiao Qiang


    The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel and the size of the plastic zone of surrounding rock as the criterion of stability.So the writers put forward the idea that the safety factor of surrounding rock calculated through strength reduction FEM(finit element method)should be regarded as the criterion of stability,which has strict mechanical basis and unified standard and would not be influenced by other factors.The paper also studies the safety factors of tunnel surrounding rock(safety factors of shear and tension failure)and lining and some methods of designing and calculating tunnels.At last,the writers take the loess tunnel for instance and show the design and calculation results of two-lane railway tunnel.

  3. A Novel Model of Set Pair Analysis Coupled with Extenics for Evaluation of Surrounding Rock Stability

    Mingwu Wang


    Full Text Available The evaluation of surrounding rock stability is a complex problem involving numerous uncertainty factors. Here, based on set pair analysis (SPA coupled with extenics, a novel model, considering incompatibility, certainty, and uncertainty of evaluation indicators, was presented to analyze the surrounding rock stability. In this model, extension set was first utilized to describe the actual problem of surrounding rock stability. Then, the connectional membership degree of the set pair was introduced to compare the measured values with classification standards from three aspects embracing identity, discrepancy, and contrary. Also, according to identity-discrepancy-contrary (IDC analysis in the universe of the extension set, the connection numbers were proposed to specify the connectional membership degree of an evaluation indicator to each class. Combined with the weights of evaluation indicators, integrated connectional membership degrees were calculated to determine their classes of rock stability. Finally, a case study and comparison with variable fuzzy set method, triangular fuzzy number method, and basic quality (BQ grading method were performed to confirm the validity and reliability of the proposed model. The results show that this model can effectively and quantitatively express the differences within a group, transformation of different groups, and uncertainty of complex indicators as a whole.

  4. Estimate of rock mass stability in surface–borehole mining of high-grade iron ore

    Sammal, AS; Antsiferov, SV; Deev, PV; Sergeev, SV


    Under consideration is the estimate of rock mass stability around underground openings generated as a result of hydraulic borehole mining of iron ore. The authors use analytical solutions of two plane elasticity problems on stress state of infinite media with the zone of weakening in the form of one or two circular holes, given initial stresses are set in the study domains.

  5. The stability of locus equation slopes across stop consonant voicing/aspiration

    Sussman, Harvey M.; Modarresi, Golnaz


    The consistency of locus equation slopes as phonetic descriptors of stop place in CV sequences across voiced and voiceless aspirated stops was explored in the speech of five male speakers of American English and two male speakers of Persian. Using traditional locus equation measurement sites for F2 onsets, voiceless labial and coronal stops had significantly lower locus equation slopes relative to their voiced counterparts, whereas velars failed to show voicing differences. When locus equations were derived using F2 onsets for voiced stops that were measured closer to the stop release burst, comparable to the protocol for measuring voiceless aspirated stops, no significant effects of voicing/aspiration on locus equation slopes were observed. This methodological factor, rather than an underlying phonetic-based explanation, provides a reasonable account for the observed flatter locus equation slopes of voiceless labial and coronal stops relative to voiced cognates reported in previous studies [Molis et al., J. Acoust. Soc. Am. 95, 2925 (1994); O. Engstrand and B. Lindblom, PHONUM 4, 101-104]. [Work supported by NIH.

  6. Root reinforcement and its contribution to slope stability in the Western Ghats of Kerala, India

    Lukose Kuriakose, Sekhar; van Beek, L. P. H.


    The Western Ghats of Kerala, India is prone to shallow landslides and consequent debris flows. An earlier study (Kuriakose et al., DOI:10.1002/esp.1794) with limited data had already demonstrated the possible effects of vegetation on slope hydrology and stability. Spatially distributed root cohesion is one of the most important data necessary to assess the effects of anthropogenic disturbances on the probability of shallow landslide initiation, results of which are reported in sessions GM6.1 and HS13.13/NH3.16. Thus it is necessary to the know the upper limits of reinforcement that the roots are able to provide and its spatial and vertical distribution in such an anthropogenically intervened terrain. Root tensile strength and root pull out tests were conducted on nine species of plants that are commonly found in the region. They are 1) Rubber (Hevea Brasiliensis), 2) Coconut Palm (Cocos nucifera), 3) Jackfruit trees (Artocarpus heterophyllus), 4) Teak (Tectona grandis), 5) Mango trees (Mangifera indica), 6) Lemon grass (Cymbopogon citratus), 7) Gambooge (Garcinia gummi-gutta), 8) Coffee (Coffea Arabica) and 9) Tea (Camellia sinensis). About 1500 samples were collected of which only 380 could be tested (in the laboratory) due to breakage of roots during the tests. In the successful tests roots failed in tension. Roots having diameters between 2 mm and 12 mm were tested. Each sample tested had a length of 15 cm. Root pull out tests were conducted in the field. Root tensile strength vs root diameter, root pull out strength vs diameter, root diameter vs root depth and root count vs root depth relationships were derived. Root cohesion was computed for nine most dominant plants in the region using the perpendicular root model of Wu et al. (1979) modified by Schimidt et al. (2001). A soil depth map was derived using regression kriging as suggested by Kuriakose et al., (doi:10.1016/j.catena.2009.05.005) and used along with the land use map of 2008 to distribute the

  7. The effects of the mineral phase on C stabilization mechanisms and the microbial community along an eroding slope transect

    Doetterl, S.; Opfergelt, S.; Cornelis, J.; Boeckx, P. F.; van oost, K.; Six, J.


    An increasing number of studies show the importance of including soil redistribution processes in understanding carbon (C) dynamics in eroding landscapes. The quality and quantity of soil organic carbon in sloping cropland differs with topographic position. These differences are commonly more visible in the subsoil, while the size and composition of topsoil C pools are similar along the hillslope. The type (plant- or microbial-derived) and quality (level of degradation) of C found in a specific soil fraction depends on the interplay between the temporal dynamic of the specific mechanism and it's strength to protect C from decomposition. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths and slope positions and how they affect the microbial community and the degradation of C. For this we analyzed soil samples from different soil depths along a slope transect applying (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, (ii) a semi-quantitative and qualitative analysis of the clay mineralogy, (iii) an analysis of the microbial community using amino sugars and (iv) an analysis of the level of degradation of C in different soil fractions focusing on the soil Lignin signature. The results show that the pattern of minerals and their relative importance in stabilizing C varies greatly along the transect. In the investigated soils, pyrophosphate extractable Manganese, and not Iron or Aluminum as often observed, is strongly correlated to C in the bulk soil and in the non-aggregated silt and clay fractions. This suggests a certain role of Manganese for C stabilization where physical protection is absent. In contrast, pyrophosphate extractable Iron and Aluminum components are largely abundant in water-stable soil aggregates but not correlated to C, suggesting importance of these extracts to stabilize aggregates and

  8. 平直与水平凹形边坡力学结构及稳定性对比研究%Comparative study on stability and mechanical structure of straight slope and horizontal concave slope

    马力; 李克民; 韩流; 舒继森; 孟庆武


    In order to study the internal mechanism causing the differences of stability between straight slopes and horizontal concave slopes, the mechanical models of simply supported beam for straight slope and two hinged arch structure for horizontal concave slope were established, basis parameters formulas of axial force, shearing force and bending moment were deduced, and the effect of entirety mechanical structure difference on stability were revealed. The effect of straight slope and horizontal concave slope on stability was studied within a three-dimensional analysis model. The results have shown that:1) The stability of horizontal concave slope is greater than that of straight slope, because the curved arch structure of horizontal concave slope can alleviate shear stress concentration distribution effectively and reduce slope failure risk; 2) End-slope stability can also be enhanced effectively if bot-tom width is lowered by increasing advancing speed of inner-dump working face; 3) Straight and hori-zontal concave slope stabilities decrease progressively in a linear gradient with slope angle increasing; 4) And with slope height increasing, the rising amplitude of the stability coefficient of horizontal concave slope decreases gradually compared to that of straight slope.%为了研究平直和水平凹形边坡稳定性差异的内部机理,以简支梁结构和两铰拱结构为基础模型,建立了平直和水平凹形边坡的整体力学模型,推导出端帮结构中的轴力、剪力和弯矩等基本力学参数计算公式,揭示了整体力学结构差异对稳定性的影响关系。通过建立边坡分析的三维模型,研究了平直与水平凹形边坡对稳定性的影响,结果表明:水平凹形边坡的曲面拱形结构能够有效缓解剪应力的集中分布,降低边坡失稳的风险,其稳定性优于平直边坡;内排跟进缩小坑底宽度能够有效提高端帮边坡稳定性;平直和水平凹形边坡稳定

  9. Slope Stability Analysis and Support Design of Zhuzi dam Quarry of Guandi Hydropower Station%官地水电站竹子坝料场边坡滑坡分析及支护设计



    针对竹子坝料场岩体结构面极为发育,边坡存在局部平面滑动、圆弧滑动、溃屈破坏、楔形体滑动等破坏模式,结合南东段边坡滑坡现场勘查结果,采用刚体极限平衡法对拟定的半开挖、全开挖、全支护方案不同工况下的边坡稳定性进行分析。结果表明:南东坡发育的fx2与fx5断层,对边坡稳定影响很大,边坡需整体放缓,推荐采用全开挖进行边坡治理。%In view of the structure faces extremely development about Zhuziba quarry rock quarry which has various failure modes such as local plane sliding,circular sliding,buckling failure and wedge sliding.Combin-ing the investigation results of southeastern slope landslide site ,the high side-slope stability has been calcu-lated under different excavating conditions based on the rigid body limit equilibrium.The analytic result show that the fx2 and fx5 development fault in southeast slope has great influence for the slope stability ,the slope need to be overall slowed down,and whole excavation scheme as the recommend slope treatment has been rec-ommend.

  10. Tibial slope correction combined with second revision ACL produces good knee stability and prevents graft rupture.

    Dejour, David; Saffarini, Mo; Demey, Guillaume; Baverel, Laurent


    Revision ACL reconstruction requires careful analysis of failure causes particularly in cases of two previous graft ruptures. Intrinsic factors as excessive tibial slope or narrow femoral notch increase failure risks but are rarely addressed in revision surgery. The authors report outcomes, at minimum follow-up of 2 years, for second revision ACL reconstructions combined with tibial deflexion osteotomy for correction of excessive slope (>12°). Nine patients that underwent second revision ACL reconstruction combined with tibial deflexion osteotomy were retrospectively studied. The mean age was 30.3 ± 4.4 years (median 28; range 26-37), and mean follow-up was 4.0 ± 2.0 years (median 3.6; range 2.0-7.6). Autografts were harvested from the quadriceps tendon (n = 8) or hamstrings (n = 1), and tibial osteotomy was done by anterior closing wedge, without detachment of the patellar tendon, to obtain a slope of 3° to 5°. All patients had fused osteotomies, stable knees, and there were no intraoperative or postoperative complications. The mean posterior tibial slope decreased from 13.2° ± 2.6° (median 13°; range 12°-18°) preoperatively to 4.4° ± 2.3° (median 4°; range 2°-8°) postoperatively. The mean Lysholm score was 73.8 ± 5.8 (median 74; range 65-82), and the IKDC-SKF was 71.6 ± 6.1 (median 72.8; range 62.2-78.5). The satisfactory results of second revision ACL reconstruction combined with tibial deflexion osteotomy at minimum follow-up of 2 years suggest that tibia slope correction protects reconstructed ACL from fatigue failure in this study. The authors stress the importance of careful analysis failure causes prior to revision ACL reconstruction, and recommend correction of tibial slope if it exceeds 12°, to reduce the risks of graft retear. III.

  11. Geology, glacier retreat and permafrost degradation as controlling factors of slope instabilities in a high-mountain rock wall: the Monte Rosa east face

    L. Fischer


    Full Text Available The Monte Rosa east face, Italian Alps, is one of the highest flanks in the Alps (2200–4500 m a.s.l.. Steep hanging glaciers and permafrost cover large parts of the wall. Since the end of the Little Ice Age (about 1850, the hanging glaciers and firn fields have retreated continuously. During recent decades, the ice cover of the Monte Rosa east face experienced an accelerated and drastic loss in extent. Some glaciers have completely disappeared. New slope instabilities and detachment zones of gravitational mass movements developed and enhanced rock fall and debris flow activity was observed. This study is based on multidisciplinary investigations and shows that most of the detachment zones of rock fall and debris flows are located in areas, where the surface ice disappeared only recently. Furthermore, most of these detachment zones are located in permafrost zones, for the most part close to the modelled and estimated lower boundary of the regional permafrost distribution. In the view of ongoing or even enhanced atmospheric warming and associated changes it is therefore very likely that the slope instabilities in the Monte Rosa east face will continue to represent a critical hazard source.

  12. Effect of discontinuities characteristics on coal mine stability and sustainability:A rock fall prediction approach

    Oraee Kazem; Oraee Nikzad; Goodarzi Arash; Khajehpour Parham


    Rock fall related accidents continue to occur in coal mines, although artificial support mechanisms have been used extensively. Roof stability is primarily determined in many underground mines by a limited number of methods that often resort to subjective criteria. It is argued in this paper that stability condi-tions of mine roof strata, as a key factor in sustainability in coal mines, must be determined by a survey which proactively investigates fundamental aspects of said mine. Failure of rock around the opening hap-pens as a result of both high rock stress conditions and the presence of structural discontinuities. The properties of such discontinuities affect the engineering behavior of rock masses causing wedges or blocks to fall from the roof or sliding out of the walls. A practical rule-based approach to assess the risk of a roof fall is proposed in the paper. The method is based on the analysis of structural data and the geometry and stability of wedges in underground coal mines. In this regard, an accident causing a huge collapse in a coal mine leading to 4 fatalities is illustrated by way of a case study. Horizontal and vertical profiles are prepared by geophysical methods to define the falling zone and its boundaries. The collapse is then modeled by the use of sophisticated computer programs in order to identify the causes of the accident.

  13. Contribution of the root system of vetiver grass towards slope stabilization of the São Francisco River

    Lorena Machado


    Full Text Available The control of soil erosion along the banks of the São Francisco River requires the use of efficient and economically viable strategies. Soil bioengineering techniques may be an alternative to the conventional methods as they provide good soil stabilization by mechanical reinforcement promoted by the roots. The objective of this study was to evaluate the contribution of the root cohesion of vetiver grass (Chrysopogon zizanioides (L. Roberty on slope stabilization in erosion control along the right margin of the São Francisco river. Seedlings of vetiver grass were planted in the riverbank of the Lower São Francisco located in Sergipe State, northeast Brazil, and plants were sampled after two years of growth to evaluate the effect of grass on the shear strength of the soil. The monolith and cylinder method was used to collect roots for the evaluation of Root Density (RL, Root Length Density (RLD, Root Area Ratio (RAR, Root Tensile Strength (TR, and Root Cohesion (CR. Data were submitted to analysis of variance (p < 0.05, with polynomial regression analysis. The results show that for RL, RLD, and RAR, the layers of soil at depths of 0-0.10 m had the highest values of 4.84 kg m-3, 12.45 km m-3, 1.66%, respectively. The mean TR was 83 MPa and CR was 528 kPa. Vetiver increases shear strength of the soil and slope stabilization.

  14. Determination of the Stable Slope Configuration of Oval-Shaped Furrow Pits

    ZHU Nai-long; ZHANG Shi-xiong


    The space effects of oval-shaped furrow pit slopes were analyzed by the elastic mechanics principle. The interaction of limit equilibrium slope angle, friction coefficient, cohesion and horizontal radius of oval-shaped furrow pits has been derived. The oval trumpet-like rock mass is homogeneous and elastic while only loadedby its dead weight. The interaction indicates that the deeper an oval-shaped furrow pit is excavated, the greater thelimit equilibrium slope angle. Both the theory base for reducing stripping waste rock in an oval- shaped furrow pitand the basic way to determine the configuration of a stable slope were developed from the mentioned interaction.The theory includes the preceding principles of stability analysis of slopes. Compared with the configuration deter-mined by traditional theory of slope stability, a great quantity of stripping waste rock can be reduced by that deter-mined in this paper under stable conditions.

  15. Geological Aspect of Slope Failure and Mitigation Approach in Bireun - Takengon Main Road, Aceh Province, Indonesia

    Ibnu Rusydy


    Full Text Available A soil and rock slope assessment survey was conducted along Bireun – Takengon main road in Aceh Province, Indonesia. The slope assessment survey was carried out to determine the geological condition, verify and identify the potential areas of slope failure and to study what type of slope stability and protection method could be applied to the road. Several research methodologies were conducted in the field such as rock and soil identification, and slope assessment. The survey was conducted in four selected areas along Bireun – Takengon main road. In study area I, soil creep occurred because of a presence of montmorillonite clay. The mitigation methods to reduce soil creeping in this area are building a retaining wall and pile. The shotcrete, wire mesh, net rock bolting, and rock removal method is suitable to apply in study area II. The shotcrete and soil nails were used because the type of rocks in those areas is sedimentary rock such as shale, sandstone, siltstone, and a boulder of a volcanic rock. The same approach shall be applied in study area IV. study area III was the best spot to learn about the mitigation approach for slope stability and provides many lessons learned. Aceh Province experience active tectonic movement, high intensity of rain, geological structures, a high degree of weathering, and high intensity of earthquake,as primary factors which trigger landslides. The techonology of slope stabilizing and protection methods can be applied to mitigate landslides.

  16. Stability Analysis on Deep-Cutting Loess Slope and Rational Design on Slope Shape%黄土深路堑边坡稳定性分析及边坡坡型的合理设计



    边坡的稳定状况直接关系着工程的施工安全、运营安全和建设成本等.如何合理设计边坡,一直是工程设计中的一个重要环节,也是工程设计的一个难点.以某工程为例,利用有限元方法计算分析了不同高度不同坡率下黄土边坡的受力特性.研究表明:路堑开挖过程中,在边坡高度不变的情况下,边坡坡率越缓,坡脚的应力越小,但是随着坡率的逐渐变缓,应力变化趋于缓和.笔者通过比较各种边坡形式,综合评价了黄土深路堑边坡的稳定状况,为边坡的坡型设计和施工提供了可靠的依据.%The stability of a slope has direct effects on the construction safety, operation safety, construction costs etc. How to rationally design the slope is a important part of engineering design, also is a difficult point all the time. In the thesis, a project was taken as an example, so that the mechanical characteristics of loess slope with different heights and different slope ratios could be calculated and analyzed by using FEM. The research shows: in the process of slope excavating with the same slope height, the slower the slope ratio is, the smaller the stress at the slope toe becomes. However, with the slope ratio slows gradually, the change of the stresses tends to moderate. Furthermore, through comparing various slope shapes, the author carried out a comprehensive evaluation on the stability of the loess slope of deep cutting, which will provide reliable basis for the slope shape design and the slope construction.

  17. 基于Hoek-Brown准则的无限岩坡稳定性概率可靠度分析研究%Study of Probabilistic Infinite Rock Slope Analysis Based on the Hoek-Brown Criterion

    韩孝峰; 孙树林; 阮晓波; 程亚男; 陈晓磊


    Infinite rock slope stability analysis is highly amenable to probabilistic treatment. To assecess the probability distribution of the safety factor of the infinite rock slope using the jointly distributed random variables method based on the equivalent parameters derived from the Hoek-Brown criterion, the program on the basis of the MATLAB is provided, and the results verifies the feasibility of this method and shows the safety factor approximately obeys the normal distribution. The sensitivity analysis to the 4 parameters shows that the most effective parameters are σci and γ.%无限岩坡稳定性分析问题是一个概率问题.结合由Hoek-Brown准则衍生的等效Mohr-Coulomb参数,采用概率密度函数联合分布方法确定无限岩坡最终安全系数的概率分布,借助Matlab数学软件对该方法实现程序表达,并对安全系数的4个影响因素进行敏感性分析.结果表明:联合分布法可以用作对无限岩坡稳定性分析的评价;安全系数的最终概率分布曲线呈现正态分布;GSI、σci、mi和γ均值的减小对安全系数的影响程度存在差异,其中σci和y的影响作用特别显著.

  18. Revegetation/rock cover for stabilization of inactive uranium mill tailings disposal sites

    Beedlow, P.A.; McShane, M.C.; Cadwell, L.L.


    Pacific Northwest Laboratory is developing design and performance guidelines for surface stabilization of inactive uranium mill tailings. In this work, vegetation and rock covers are being evaluated for maintaining long-term integrity of impoundment systems. Methods are being developed to estimate erosion rates associated with rock and/or vegetation covers, and to determine the effects of surface treatments on soil moisture. Interactions between surface treatments and barriers (radon and biological) are being studied as well. The product will be a set of guidelines to aid in designing surface covers. This report presents the status of this program and a discussion of considerations pertinent to the application of surface covers to tailings. Test plots located in Grand Junction, Colorado and Waterflow, New Mexico are being used to study: (1) the interactions between vegetation and radon and biological barriers, (2) the effects of surface covers on soil moisture, and (3) the effects of rock covers on vegetation.

  19. Thermal conditions of rock slopes below unstable infrastructure in Alpine permafrost area: the cases of the Cosmiques hut and the Grands Montets cable-car station (Mont Blanc massif)

    Duvillard, Pierre-Allain; Magnin, Florence; Mörtl, Christian; Ravanel, Ludovic; Deline, Philip


    Thermal state of steep permafrost-affected rock faces is crucial to assess the safety and reliability of mountain infrastructure as current permafrost degradation affects the rock slope stability. In the Mont-Blanc massif, 23 infrastructures are built on such a rock face with 13 of them that are characterized by a high risk of destabilization (Duvillard et al., 2015), including the upper station of the Grands Montets cable car (3325 m a.s.l.) as well as the Cosmiques hut (3613 m a.s.l.) on which we will focus. These two buildings have already been affected by different geomorphological processes. A rockfall event (600 m3) occurred for example on the SE face on the Arête inférieure des Cosmiques on the 21st of August 1998 (Ravanel et al., 2013) and the Grands Montets case shows a slow subsidence of the stairway over the last decade. In order to better assess the role of the permafrost in these processes and to gain insight on possible future geomorphic activity, we characterized the current permafrost conditions and simulated its changes up to the end of the 21st century using two complementary approaches: (i) the result of ERT (Electrical Resistivity Tomography) surveys carried out in October 2016 on the northern and southern faces right below the Cosmiques hut (at the level of the foundations) and at the Aiguilles des Grands Montets; (ii) the modeling of mean annual rock surface temperature for 2016 and at the end of the 21st century (Magnin et al., in rev.). Duvillard P.-A., Ravanel L., Deline P. (2015). Risk assessment of infrastructure destabilisation due to global warming in the high French Alps. Journal of Alpine Research, 103 (2). Magnin F., Josnin J.-Y., Ravanel L., Pergaud J., Pohl B., Deline P. (in rev.). Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21st century. The Cryosphere Discuss., doi:10.5194/tc-2016-132. Ravanel L., Deline P., Lambiel C. and Vincent C. (2013). Instability of a high alpine

  20. Hazard assessment of vegetated slopes

    Norris, J.E.; Greenwood, J.R.; Achim, A.; Gardiner, B.A.; Nicoll, B.C.; Cammeraat, E.; Mickovski, S.B.; Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.


    The hazard assessment of vegetated slopes are reviewed and discussed in terms of the stability of the slope both with and without vegetation, soil erosion and the stability of the vegetated slope from windthrow and snow loading. Slope stability can be determined by using either limit equilibrium or

  1. Hazard assessment of vegetated slopes

    J.E. Norris; J.R. Greenwood; A. Achim; B.A. Gardiner; B.C. Nicoll; E. Cammeraat; S.B. Mickovski


    The hazard assessment of vegetated slopes are reviewed and discussed in terms of the stability of the slope both with and without vegetation, soil erosion and the stability of the vegetated slope from windthrow and snow loading. Slope stability can be determined by using either limit equilibrium or

  2. Analysis of Yielding Steel Arch Support with Rock Bolts in Mine Roadways Stability Aspect

    Majcherczyk, Tadeusz; Niedbalski, Zbigniew; Małkowski, Piotr; Bednarek, łukasz


    The result of the search for new technological solutions in the field of support for roadways in coal mines has in recent years been the widespread use of steel arch with rockbolt support systems. The efficiency of these systems is affected among other things by the option of installing rock bolts after the actual driving the mine roadway, the increased load capacity that these systems can support, and their resistance to dynamic weight. Large variation in the way that these steel arch support can be connected using different types of rock bolts necessitates mining research revealing the effectiveness of such solutions. Although the steel arch with rockbolt support system is used in the majority of European coal mines, it is still not possible to apply templates of schemes due to the diversity of geological and mining conditions. Therefore, throughout a period of several years, the authors of this article conducted research in situ under conditions of different schemes related to connecting arched support frames with rock bolts, with only selected results being presented in the article. The measurements of convergence, load supported by the system frame, load supported by the rock bolts, and the stratification of roof rocks were analyzed, carried out in two roadways with yielding steel arch support in which strand bolts were applied. The article also proposes the index for working maintenance nuw, used in preliminarily assessing the stability of a given working with a limited number of data concerning geomechanical conditions. Additionally considered are empirical methods used in Poland for designing steel arch with rock bolt support systems. The results of mine research indicate that strengthening yielding steel support with strand bolts through steel beams maintains the stability of a roadway, even when exposed to the exploitation stress. Aside from the impact of exploitation, deformations of the support system are negligible, despite the fact that the tensile

  3. 均质边坡稳定性极限曲线法%Limit curve method of homogeneous slope stability

    方宏伟; 李长洪; 李波


    基于滑移线场理论,按边坡坡面变形量评价其稳定性,提出均质边坡极限曲线法。该法是求有重边坡极限荷载的逆过程,也是强度折减法的对偶过程。以特征线法差分方程组(SCM)和试验方程近似公式(CCM)求得的极限坡面曲线与坡面线相交为变形破坏准则,定义了安全度(DOS)和破坏度(DOF)2个评价指标。该方法不必假设和搜索临界滑动面。经典考题和典型算例的验算表明,随着节点的增加 SCM 法计算精度增加,边界步长不变时,3次样条插值求得的变形破坏准则判断值不变,说明 SCM 算法稳定。典型算例的计算数据和图例表明,边坡角变大时边坡稳定性降低,极限坡面曲线与坡面由无交点变为有交点,证明了变形破坏准则的正确性。由2个例题计算结果对比可知,安全系数较大时,SCM 法、CCM法计算结果与其具有可比性,相对于原边界条件增加了外荷载;安全系数变小时,SCM 法、CCM 法偏于保守。34个样本计算正确率为安全系数法67.7%,应力状态法73.5%,CCM 法79.4%,SCM 法70.6%,表明 SCM 法和 CCM 法正确率较高,计算结果可靠,SCM 法、CCM 法因素敏感性分析结论与安全系数法完全一致。在露天矿边坡稳定性和最终边坡角的分析与计算中,SCM 法、CCM 法结论与原报告相同,当参数变小时 CCM 法更有利于实践,具有一定的工程应用价值。%Based on the theory of slip line field, this paper proposes a limit curve method of slope stability according to the deformation situation; the method is the inverse process for computing a heavy slope ultimate load and the dual process of strength reduction method. Defines two evaluation indexes: the degree of safety(DOS) and the degree of failure(DOF) according to the deformation failure criterion of the limit stable slope curve and the slope surface intersection computed by

  4. Stability Evaluation on Surrounding Rocks of Underground Powerhouse Based on Microseismic Monitoring

    Feng Dai


    Full Text Available To study the stability of underground powerhouse at Houziyan hydropower station during excavation, a microseismic monitoring system is adopted. Based on the space-time distribution characteristics of microseismic events during excavation of the main powerhouse, the correlation between microseismic events and blasting construction is established; and the microseismic clustering areas of the underground powerhouse are identified and delineated. The FLAC3D code is used to simulate the deformation of main powerhouse. The simulated deformation characteristics are consistent with that recorded by microseismic monitoring. Finally, the correlation between the macroscopic deformation of surrounding rock mass and microseismic activities is also revealed. The results show that multiple faults between 1# and 3# bus tunnels are activated during excavation of floors V and VI of the main powerhouse. The comprehensive method combining microseismic monitoring with numerical simulation as well as routine monitoring can provide an effective way to evaluate the surrounding rock mass stability of underground caverns.

  5. Sensitivity Analysis of Mechanical Parameters of Different Rock Layers to the Stability of Coal Roadway in Soft Rock Strata

    Zeng-hui Zhao


    Full Text Available According to the geological characteristics of Xinjiang Ili mine in western area of China, a physical model of interstratified strata composed of soft rock and hard coal seam was established. Selecting the tunnel position, deformation modulus, and strength parameters of each layer as influencing factors, the sensitivity coefficient of roadway deformation to each parameter was firstly analyzed based on a Mohr-Columb strain softening model and nonlinear elastic-plastic finite element analysis. Then the effect laws of influencing factors which showed high sensitivity were further discussed. Finally, a regression model for the relationship between roadway displacements and multifactors was obtained by equivalent linear regression under multiple factors. The results show that the roadway deformation is highly sensitive to the depth of coal seam under the floor which should be considered in the layout of coal roadway; deformation modulus and strength of coal seam and floor have a great influence on the global stability of tunnel; on the contrary, roadway deformation is not sensitive to the mechanical parameters of soft roof; roadway deformation under random combinations of multi-factors can be deduced by the regression model. These conclusions provide theoretical significance to the arrangement and stability maintenance of coal roadway.

  6. Sensitivity analysis of mechanical parameters of different rock layers to the stability of coal roadway in soft rock strata.

    Zhao, Zeng-hui; Wang, Wei-ming; Gao, Xin; Yan, Ji-xing


    According to the geological characteristics of Xinjiang Ili mine in western area of China, a physical model of interstratified strata composed of soft rock and hard coal seam was established. Selecting the tunnel position, deformation modulus, and strength parameters of each layer as influencing factors, the sensitivity coefficient of roadway deformation to each parameter was firstly analyzed based on a Mohr-Columb strain softening model and nonlinear elastic-plastic finite element analysis. Then the effect laws of influencing factors which showed high sensitivity were further discussed. Finally, a regression model for the relationship between roadway displacements and multifactors was obtained by equivalent linear regression under multiple factors. The results show that the roadway deformation is highly sensitive to the depth of coal seam under the floor which should be considered in the layout of coal roadway; deformation modulus and strength of coal seam and floor have a great influence on the global stability of tunnel; on the contrary, roadway deformation is not sensitive to the mechanical parameters of soft roof; roadway deformation under random combinations of multi-factors can be deduced by the regression model. These conclusions provide theoretical significance to the arrangement and stability maintenance of coal roadway.

  7. Stress and Sliding Stability Analysis of Songlin Rock-Filled Concrete Gravity Dam

    Sundström, Max; Ivedal, Max


    The construction of Songlin rock-filled concrete gravity dam, located in the Yunnan province, China began in the end of 2015. In this master thesis the finite element method (FEM) based software Abaqus has been used to perform a computational analysis on tension stresses, compression stresses and sliding stability for static conditions. One overflow section and one non-overflow section of the dam have been analysed. The results of the analysis have been evaluated by comparing with Chinese sta...

  8. Effect Blasting Excavation of Yujiapeng Tunnel on Stability of Nearby Giant Dangerous Rock Masses (DRM)


    On the basis of the interpretation of engineering geology of the tunnel and of its adjacent dangerous rock masses (DRM), this paper presents the energy and vibration parameters of the explosion that propagates in different blasting modes according to the experimental formulas now usually employed. Then the stability checking computation of T8-T12 area, the most dangerous area of DRM, is conducted under the limited blasting condition and with the limited equilibrium method. The result shows that the effect on the stability is only 5.5 % and that this area also contains certain safety reserves.

  9. Use of an Integrated Discrete Fracture Network Code for Stochastic Stability Analyses of Fractured Rock Masses

    Merrien-Soukatchoff, V.; Korini, T.; Thoraval, A.


    The paper presents the Discrete Fracture Network code RESOBLOK, which couples geometrical block system construction and a quick iterative stability analysis in the same package. The deterministic or stochastic geometry of a fractured rock mass can be represented and interactively displayed in 3D using two different fracture generators: one mainly used for hydraulic purposes and another designed to allow block stability evaluation. RESOBLOK has downstream modules that can quickly compute stability (based on limit equilibrium or energy-based analysis), display geometric information and create links to other discrete software. The advantage of the code is that it couples stochastic geometrical representation and a quick iterative stability analysis to allow risk-analysis with or without reinforcement and, for the worst cases, more accurate analysis using stress-strain analysis computer codes. These different aspects are detailed for embankment and underground works.

  10. An Index for Estimating the Stability of Brittle Surrounding Rock Mass: FAI and its Engineering Application

    Zhang, C. Q.; Zhou, H.; Feng, X. T.


    Based on the geometric analysis of the relationship between the stress state at a point and the yield surface defined in the principal stress space, a coefficient ω is set up as an estimation index to describe the stress-induced yield risk. After yield, the equivalent plastic shear strains is usually used to characterize the failure degree (FD) of the material and adopted here as an index of the damage degree for the surrounding rock masses. Then, a unified variable combining ω and FD, named failure approaching index (FAI), is constructed to estimate the stability of rock mass which may be at different deformation stages. The formulas of FAI are derived for some popular yield criteria in geomechanics. Details for such development are addressed in the paper. Its rationality is verified by numerical simulation and comparative analysis of the conventional triaxial compression tests and typical tunnel projects. In addition, the method for applying FAI to the stability estimation of surrounding rock mass is proposed. As examples, the stability of the underground powerhouse, access tunnels and headrace tunnels at the Jinping II hydropower station are estimated by making use of the method we presented. The results indicate that not only is the index rational in mechanics, but the theory also has good expansibility, and the estimation methods are simple and practical as well. It is easier for field engineers to analyze and understand the numerical results.

  11. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado: Remedial Action Selection Report. Preliminary final


    This proposed remedial action plan incorporates the results of detailed investigation of geologic, geomorphic, and seismic conditions at the proposed disposal site. The proposed remedial action will consist of relocating the uranium mill tailings, contaminated vicinity property materials, demolition debris, and windblown/waterborne materials to a permanent repository at the proposed Burro Canyon disposal cell. The proposed disposal site will be geomorphically stable. Seismic design parameters were developed for the geotechnical analyses of the proposed cell. Cell stability was analyzed to ensure long-term performance of the disposal cell in meeting design standards, including slope stability, settlement, and liquefaction potential. The proposed cell cover and erosion protection features were also analyzed and designed to protect the RRM (residual radioactive materials) against surface water and wind erosion. The location of the proposed cell precludes the need for permanent drainage or interceptor ditches. Rock to be used on the cell top-, side-, and toeslopes was sized to withstand probable maximum precipitation events.

  12. Slope stability analysis of landslide in Wayang Windu Geothermal Field, Pangalengan, West Java Province, Indonesia

    Yuhendar, A. H.; Wusqa, U.; Kartiko, R. D.; Raya, N. R.; Misbahudin


    Large-scale landslide occurred in Margamukti village, Pangalengan, Bandung Regency, West Java Province, Indonesia. The landslide damaged geothermal gas pipeline along 300 m in Wayang Windu Geothermal Field. Based on field observation, landslide occured in rotational sliding movement. Laboratory analysis were conducted to obtain the characteristics of the soil. Based on the condition of the landslide in this area, the Factor of Safety can be simulated by the soil mechanics approach. Factor of safety analysis based on soil cohesion and internal friction angle was conducted using manual sensitivity analysis for back analysis. The analysis resulted soil cohesion in critical condition (FS<1) is 6.01 kPa. This value is smaller than cohesion of undisturbed slope soil sample. Water from rainfall is the most important instability factors in research area. Because it decreases cohesion in soils and increases weight and pore water pressure in granular media.

  13. Stability assessment of rock surrounding an I-beam supported retreating roadway

    严红; 张吉雄; 李林玥; 冯锐敏


    The installation of a back-wall guard-board is the key to successfully supporting underground retreating roadways in coal mines. Based on the coordinate support principle, and using an I-shaped steel support for the surrounding rock, a mechanical model was developed for the stability of the roadway support and surrounding rock. Analysis of the bearing capacity of the roof back-wall guard-board and modelling of the equations for the maximum deflection and the maximum compressive stress of the top and side beams of the I-shaped steel support were undertaken. Simultaneously, the model was used to calculate and analyse the stability of the top and side beams of the I-shaped steel support structure and analyse the criteria for their stability. The results provide a reliable theoretical basis for the judgment of the stability of the surrounding rock and support structure. The theoretical evaluation results are consistent with field data. Finally, the key support parameters of the top and side beams of the I-shaped steel support structure and the variation of the maximum deflection and the maximum compressive stress as affected by the influence of the guard-board length were investigated. It is concluded that, as the back-board length increases, the maximum compressive stress in the top beam of the I-shaped steel support increases while the compressive stress in the side beam decreases. The results show that the accuracy of judgment of the stability of a supported retreating roadway is improved, providing guidance for the design of such typical I-shaped steel support and back-board structures.

  14. Quantification of the influence of preferential flow on slope stability using a numerical modeling approach (discussions)

    Shao, W.; Bogaard, T.A.; Bakker, M.; Greco, R.


    The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is use

  15. The Influence of Plant Root Systems on Subsurface Flow: Implications for Slope Stability

    Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological m...

  16. Distribution of Rock Fragment Content on Slopes in the Small Watershed of Diediegou of Liupan Mountains%六盘山叠叠沟小流域的土壤石砾含量坡面分布特征

    杜阿朋; 王彦辉; 管伟; 何常清; 于澎涛; 刘建立


    The content of rock fragment in slope soil of mountainous regions is often very high. This can not be neglected during analyzing the eco-hydrological functions of forest soil and ecosystems. In order to understand the spatial distribution of rock fragment content in the Liupan mountains, the variation of rock fragment content with slope aspect, slope position and soil depth was investigated in the small watershed of Diediegou. The results shows that the averaged volume content of rock fragment in soil (taking the top layer of 0-20 cm as example) between different slope aspects was in the order of sunny slope (3. 07%) > shady slope (2. 89%) > half-shady slope (1. 99%), and varied with slope position as down slope (3. 46%) > middle-up slope (3. 05%) > slope top (2. 46%) > middle slope (2. 20%) > up-slope (2. 08%). The soil depth distribution of rock fragment content was affected by both the soil erosion and the distance to bedrock. Firstly, the soil erosion led a relative enrichment of rock fragment in the surface soil layer; and secondly, the rock fragment content increased with soil depth. Based on this analysis, a model describing the variation of rock fragment content with soil depth under different slope aspects and slope positions was developed, and it a-greed with observed data comparatively well.%山区土壤石砾含量经常很高,这对土壤水文功能具有不可忽视的作用.为了解六盘山区土壤石砾含量的空间分布特征.在叠叠沟小流域调查研究了土壤石砾含量随坡向、坡位和土层深度的变化规律.结果表明,土壤(以表层0-20 cm为例)石砾体积含量的坡向顺序为阳坡(3.07%)>阴坡(2.89%)>半阴半阳坡(1.99%),坡位顺序为下部(3.46%)>中上部(3.05%)>坡顶(2.46%)>中部(2.20%)>上部(2.08%).在受侵蚀影响导致表层土壤石砾富集的同时,石砾含量主要受离开母岩距离的影响,因而表现为随土壤加深而增加的趋势,基于此提出了不同坡向坡位时石砾

  17. Complementing geotechnical slope stability and land movement analysis using satellite DInSAR

    Tripolitsiotis, Achilleas; Steiakakis, Chrysanthos; Papadaki, Eirini; Agioutantis, Zacharias; Mertikas, Stelios; Partsinevelos, Panagiotis


    This paper explores the potential of using satellite radar inteferometry to monitor time-varying land movement prior to any visible tension crack signs. The idea was developed during dedicated geotechnical studies at a large open-pit lignite mine, where large slope movements (10-20 mm/day) were monitored and large fissures were observed in the immediate area outside the current pit limits. In this work, differential interferometry (DInSAR), using Synthetic Aperture Radar (SAR) ALOS images, was applied to monitor the progression of land movement that could potentially thwart mine operations. Early signs of land movements were captured by this technique well before their visual observation. Moreover, a qualitative comparison of DInSAR and ground geodetic measurements indicates that the technique can be used for the identification of high risk areas and, subsequently, for the optimization of the spatial distribution of the available ground monitoring equipment. Finally, quantitative land movement results from DInSAR are shown to be in accordance with simultaneous measurements obtained by ground means.

  18. Shear Strength of Partially Bonded Concrete-Rock Interfaces for Application in Dam Stability Analyses

    Krounis, Alexandra; Johansson, Fredrik; Larsson, Stefan


    The shear strength of the concrete-rock interface has a substantial influence on the sliding stability of concrete gravity dams founded on rock. While several studies have been done on concrete-rock contacts, there remains uncertainty regarding the peak shear strength of partially bonded interfaces. There exists, in particular, an uncertainty regarding the contribution from surface roughness of the unbonded parts to the peak shear strength of the interface due to the dependency of mobilized strength on shear displacement. In this study, a series of 24 direct shear tests are performed under CNL conditions on concrete-rock samples with different bonding conditions. Tests on samples with fully bonded and unbonded interfaces are conducted to study the strain compatibility of the different contacts, while the results of samples with partially bonded interfaces are evaluated in the context of linking the joint roughness of the unbonded parts to the peak shear strength of the interface. The results indicate that a significant part of the surface roughness of the unbonded parts is mobilized prior to degradation of bond strength, in particular for interfaces with low bonding percentages. It is recommended that further research should be conducted to understand how the contribution from roughness change with an increase in scale and degree of matedness.

  19. Stability of ice/rock mixtures with application to a partially differentiated Titan

    O'Rourke, Joseph G.; Stevenson, David J.


    Titan's moment of inertia, calculated assuming hydrostatic equilibrium from gravity field data obtained during the Cassini-Huygens mission, implies an internal mass distribution that may be incompatible with complete differentiation. This suggests that Titan may have a mixed ice/rock core, possibly consistent with slow accretion in a gas-starved disk, which may initially spare Titan from widespread ice melting and subsequent differentiation. A partially differentiated Titan, however, must still efficiently remove radiogenic heat over geologic time. We argue that compositional heterogeneity in the major saturnian satellites indicates that Titan formed from planetesimals with disparate densities. The resulting compositional anomalies would quickly redistribute to form a vertical density gradient that would oppose thermal convection. We use elements of the theory of double-diffusive convection to create a parameterized model for the thermal evolution of ice/rock mixtures with a stabilizing compositional gradient. To account for large uncertainties in material properties and accretionary processes, we perform simulations for a wide range of initial conditions. Ultimately, for realistic density gradients, double-diffusive convection in the ice/rock interior can delay, but not prevent, ice melting and differentiation, even if a substantial fraction of potassium is leached from the rock component. Consequently, Titan is not partially differentiated.

  20. Hard-Rock Stability Analysis for Span Design in Entry-Type Excavations with Learning Classifiers.

    García-Gonzalo, Esperanza; Fernández-Muñiz, Zulima; García Nieto, Paulino José; Bernardo Sánchez, Antonio; Menéndez Fernández, Marta


    The mining industry relies heavily on empirical analysis for design and prediction. An empirical design method, called the critical span graph, was developed specifically for rock stability analysis in entry-type excavations, based on an extensive case-history database of cut and fill mining in Canada. This empirical span design chart plots the critical span against rock mass rating for the observed case histories and has been accepted by many mining operations for the initial span design of cut and fill stopes. Different types of analysis have been used to classify the observed cases into stable, potentially unstable and unstable groups. The main purpose of this paper is to present a new method for defining rock stability areas of the critical span graph, which applies machine learning classifiers (support vector machine and extreme learning machine). The results show a reasonable correlation with previous guidelines. These machine learning methods are good tools for developing empirical methods, since they make no assumptions about the regression function. With this software, it is easy to add new field observations to a previous database, improving prediction output with the addition of data that consider the local conditions for each mine.

  1. Stability Assessment of Natural Caves Using Empirical Approaches and Rock Mass Classifications

    Jordá-Bordehore, L.


    The stability of underground voids such as caves can be assessed, in an initial approximation, by geomechanical classifications such as the Barton Q index. From a geomechanical viewpoint, the stability of 137 large span natural caves was analyzed herein. The caves were graphically represented based on existing tunnel and underground graphs, according to width and rock quality index Q. Many natural caves analyzed by a tunnel-type engineering approach could result as apparently unstable when represented in empirical existing graphics and would require reinforcements incompatible with speleothems and large chamber heights. A new graph and equation are proposed herein for the maximum span, for the exclusive case of caves, resulting in a reliable representation of large stable natural caves. The main contribution is a new stability chart for natural caves, consisting of two zones: a zone where stable caves are represented and a zone where unstable caves and collapsed caves are located.

  2. Study of Triaxial Creep Tests of Soil from Fracture Zone between the Slope Layer in Toppling Rock Slope%倾倒变形边坡层间破碎带土体三轴蠕变试验研究

    张浴阳; 巨能攀; 周新


    倾倒变形是工程边坡变形中常见的一种形式。发生倾倒变形的影响因素很多,其中,层间破碎带的发育极大的促进了边坡倾倒变形的发生。从澜沧江某水电站的倾倒变形边坡中取样来进行三轴蠕变试验。首先,分析层间破碎带土体的蠕变特性;其次,优选出适合蠕变特征曲线的本构模型,该模型为Burgers模型,并确定该模型参数;最后,以实验的成果为依托确定了层间破碎带土体的长期强度为瞬时强度的0.47~0.58倍。这对评价倾倒变形边坡的长期稳定性有着重要的现实意义,同时也为以后类似工程提供借鉴。%Toppling deformation is a common form of slope deformation in hydraulic engineering , this phenome-non may be induced by many factors , in which the interlayer fracture zone greatly contributed to the development of slope toppling deformation .The samples to do the triaxial creep test were from toppling slope of Lancang River Hy-dropower Station .It has analyzed the creep properties of soil from interlayer fracture zone , selected the appropriate Burgers creep model and determined model parameters .Finally, based on the results of experiments , the value of the long-term strength of the interlayer fracture zone is 0.47~0.58 times that of the instantaneous intensity , which not only has important practical significance to evaluate the long-term stability of the toppling slope , but also has provided reference experience for future similar projects .

  3. A Tensile Strength of Bermuda Grass and Vetiver Grass in Terms of Root Reinforcement Ability Toward Soil Slope Stabilization

    Noorasyikin, M. N.; Zainab, M.


    An examination on root characteristics and root properties has been implemented in this study. Two types of bioengineering were chose which are Vetiver grass and Bermuda grass as these grasses were widely applied for slope stabilization. The root samples were taken to the laboratory to investigate its classification, characteristics and strength. The root of both grasses was found grow with fibrous root matrix system. In terms of root anchorage, the root matrix system of Vetiver grass was exhibits more strengthen than the Bermuda grass. However, observation on root image from Scanning Electron Microscope test reveals that the root of Vetiver grass becomes non-porous as the moisture content reduced. Meanwhile, the root tensile strength of Bermuda grass was obtained acquired low value with higher percentage of moisture content, root morphology and bonding strength. The results indicated that the root tensile strength is mainly influence by percentage of moisture content and root morphology.

  4. 基于GeoStudio边坡稳定性分析%Slope Stability Analysis Based on GeoStudio

    胡海; 陈玉明; 玉尖地


    本文主要通过GeoStudio软件分析A排土场边坡稳定性,为该排土场在生产上提供理论上的技术基础,通过技术分析研究了该排土场的安全性,降低了安全事故发生的概率。%This article mainly analyzes the slope stability of A refuse dump through GeoStudio, so as to provide theoretical basis for the production of the dump. Through technical analysis, the safety of the dump is analyzed and the probability of safety accidents is reduced.

  5. Impact of meteorological conditions on stability of selected slopes in the Wiśnicz Foothills

    Demczuk Piotr


    Full Text Available Wpływ warunków meteorologicznych na kształtowanie się warunków stateczności wybranych zboczy Pogórza Wiśnickiego. Jednym z najważniejszych procesów wpływających na kształtowanie stoków górskich zbudowanych z fl iszu karpackiego są ruchy masowe. Tylko na nielicznych obiektach prowadzono kompleksowe, pogłębione badania mechanizmów inicjacji ruchów osuwiskowych. Badania takowe są czasochłonne, a zadowalające i wiarygodne wyniki osiąga się po co najmniej kilkuletnim okresie pomiarów i analiz. Większość programów badań ogranicza się do krótkich, jednorazowych obserwacji i pomiarów powierzchniowych. Uwaga uczestników tych projektów skupia się na dużych osuwiskach strukturalnych obejmujących swoim zasięgiem głęboko zalegające skały trzeciorzędowe, pomijając płytkie osuwiska zachodzące na granicy zwietrzeliny i skał litych oraz w zasięgu samej zwietrzeliny. Celem pracy było określenie przebiegu zmian warunków stateczności wybranych zboczy związanych ze warunkami meteorologicznych występujących w latach 2008-2013 na obszarze Pogórza Wiśnickiego. Dla potrzeb pracy wykorzystano dane meteorologiczne, tj. temperatura powietrza, wilgotność gleby, prędkość wiatru, sumy opadów i liczba dni z deszczem, pochodzące ze Stacji Naukowej IGiGP UJ w Łazach koło Bochni (Pogórze Wiśnickie. Przeprowadzono terenowe i laboratoryjne badania parametrów geotechnicznych gruntów stanowiących pokrywy stokowe wybranych zboczy osuwiskowych we wsiach Królówka i Łychówo. Wcześniej wspomiane dane meteorologiczne, a także dane dotyczące temperatury, wilgotności względnej powietrza wykorzystano w dalszej części pracy do określenia zmian stanu naprężeń dla dwóch zboczy osuwiskowych. W tym celu zastosowano moduły Slope/W, Vados/W oraz Seep/W stanowiące część pakietu GeoSlope. Wyniki analiz potwierdziły, że stabilność zbocza jest silnie związana z opadami atmosferycznymi, ale wykazały r

  6. The effect of proximal tibial slope on dynamic stability testing of the posterior cruciate ligament- and posterolateral corner-deficient knee.

    Petrigliano, Frank A; Suero, Eduardo M; Voos, James E; Pearle, Andrew D; Allen, Answorth A


    Proximal tibial slope has been shown to influence anteroposterior translation and tibial resting point in the posterior cruciate ligament (PCL)-deficient knee. The effect of proximal tibial slope on rotational stability of the knee is unknown. Change in proximal tibial slope produced via osteotomy can influence both static translation and dynamic rotational kinematics in the PCL/posterolateral corner (PLC)-deficient knee. Controlled laboratory study. Posterior drawer, dial, and mechanized reverse pivot-shift (RPS) tests were performed on hip-to-toe specimens and translation of the lateral and medial compartments measured utilizing navigation (n = 10). The PCL and structures of the PLC were then sectioned. Stability testing was repeated, and compartmental translation was recorded. A proximal tibial osteotomy in the sagittal plane was then performed achieving either +5° or -5° of tibial slope variation, after which stability testing was repeated (n = 10). Analysis was performed using 1-way analysis of variance (ANOVA; α = .05). Combined sectioning of the PCL and PLC structures resulted in a 10.5-mm increase in the posterior drawer, 15.5-mm increase in the dial test at 30°, 14.5-mm increase in the dial test at 90°, and 17.9-mm increase in the RPS (vs intact; P slope (high tibial osteotomy [HTO] +5°) in the PCL/PLC-deficient knee reduced medial compartment translation by 3.3 mm during posterior drawer (vs deficient; P slope (HTO -5°) caused a 4.8-mm increase in medial compartment translation (vs deficient state; P slope diminished static posterior instability of the PCL/PLC-deficient knee as measured by the posterior drawer test but had little effect on rotational or dynamic multiplanar stability as assessed by the dial and RPS tests, respectively. Conversely, decreasing posterior slope resulted in increased posterior instability and a significant increase in the magnitude of the RPS. These results suggest that increasing posterior tibial slope may improve

  7. 一种边坡稳定分析的新方法%New method for slope stability analysis

    秦忠国; 张向阳


    结合有限单元法和极限平衡法,提出了一种边坡稳定计算的新方法,介绍了该方法的基本理论和公式推导。与边坡稳定经典计算方法的不同在于,不需要对条间力等条件进行人为简化和假定,且严格满足所有的平衡条件。数值算例分析表明了该方法的正确性和有效性,适用范围广,且计算公式相对简单,易于编程,收敛速度快。%A new method is proposed for the calculation of slope stability, and the basic theories and formula derivations of the method are introduced. The method is based on the idea of both the finite element method and the limit equilibrium method. In contrast with that of the classical limit equilibrium methods for the calculation of slope stability, the advantage of the new method is that it can strictly satisfy all the equilibrium conditions without factitious simplification and assumptions to the inter-slice forces, and only needs to specify a slip surface with any shape. The analyses of numerical examples indicate the validity and effectiveness of the proposed method, that is, it is practical to use for many applications and has advantages of relatively simple calculation formulas, easy programming and fast convergence in iterations.

  8. Simulation of long-term debris flow sediment transport based on a slope stability and a debris flow routing model

    Müller, T.; Hoffmann, T.


    Debris flows play a crucial role in the coupling of hillslope-sediment sources and channels in mountain environments. In most landscape evolution models (LEMs), the sediment transport by debris flows is (if at all) often represented by simple empirical rules. This generally results from the mismatch of the coarse resolution of the LEMs and the small scale impacts of debris flow processes. To extend the accuracy and predictive power of LEMs, either a higher resolution of LEMs in combination with process-based debris flow models or a better parametrisation of subpixel scale debris flow processes is necessary. Furthermore, the simulation of sediment transport by debris flows is complicated by their episodic nature and unknown factors controlling the frequency and magnitude of events. Here, we present first results using a slope stability model (SINMAP) and an event-based debris flow routing model (SCIDDICA-S4c) to simulate the effects of debris flows in LEMs. The model was implemented in the XULU modelling platform developed by the Department of Computer Science at the University of Bonn. The combination of the slope stability model and the event-based routing and mass balance model enables us to simulate the triggering and routing of debris flow material through the iteration of single events over several thousand years. Although a detailed calibration and validation remains to be done, the resulting debris flow-affected areas in a test elevation model correspond well with data gained from a geomorphological mapping of the corresponding area, justifying our approach. The increased computation speed allows to run high resolution LEM in convenient short time at relatively low cost. This should encourage the development of more detailed LEMs, in which process-based models should be incorporated.

  9. Failure mechanism and stability control technology of rock surrounding a roadway in complex stress conditions

    Yu Yang; Bai Jianbiao; Chen Ke; Wang Xiangyu; Xiao Tongqiang; Chen Yong


    To solve the problem of supporting three downhill coal structures in the Yongan Coal Mine of Shanxi Jincheng,we studied the regular development of stress and plastic zones and characteristics of deformation of rock surrounding roadway groups after a period of roadway driving,mining one side as well as mining both sides,we used FLAC3D for our numerical and theoretical analyses.Field test were carried out,where we revealed the deformation mechanism of roadways and its coal pillars in complex stress conditions.We proposed a roadway stability control technology using backwall grouting with high-water rapid hardening material and combined support with bolt and cable anchoring after mining both sides.Our field practices showed that deformation of rock surrounding roadways can be controlled with this technology.

  10. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Hui Zhou


    Full Text Available Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  11. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Hui Zhou; Chuanqing Zhang; Zhen Li; Dawei Hu; Jing Hou


    Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  12. Stability of Ice/Rock Mixtures with Application to a Partially Differentiated Titan

    O'Rourke, Joseph G


    Titan's moment of inertia, calculated assuming hydrostatic equilibrium from gravity field data obtained during the Cassini-Huygens mission, implies an internal mass distribution that may be incompatible with complete differentiation. This suggests that Titan may have a mixed ice/rock core, possibly consistent with slow accretion in a gas-starved disk, which may initially spare Titan from widespread ice melting and subsequent differentiation. A partially differentiated Titan, however, must still efficiently remove radiogenic heat over geologic time. We argue that compositional heterogeneity in the major Saturnian satellites indicates that Titan formed from planetesimals with disparate densities. The resulting compositional anomalies would quickly redistribute to form a vertical density gradient that would oppose thermal convection. We use elements of the theory of double-diffusive convection to create a parameterized model for the thermal evolution of ice/rock mixtures with a stabilizing compositional gradient...

  13. 节理岩体等效流变损伤模型及其在卸载边坡中的应用%Equivalent rheological damage model of jointed rock and its application to unloading slope

    马春驰; 李天斌; 孟陆波; 陈国庆; 陈子全


    . In order to reflect the instantaneous plastic deformation in the unloading-rebound stage of slope as well as the viscoplastic deformation in the time-evolution stage of slope, loading-plastic and viscoplastic components are applied to the rheology model; thus a composite visco-elastoplastic model (elastic-viscous-viscoelastic-viscoplastic-plastic) is established. Results of compression(unloading) creep test proves the rationality of this model;and rheological parameters are recognized. On this basis, damage tensor describes the characteristics of joint geometry, and damage evolution equation based on the viscoplastic partial strain is established; eventually, a new type of equivalent rheological damage model of jointed rock is established. Applying this model to a soft-hard interbedded slope under the cutting(unloading) condition, the results show that instantaneous plastic damage in unloading-rebound stage and viscoplastic damage in time-evolution stage, of the damageable parts (soft rock section, buried section of soft rock, hard rock section of soft-hard handover), gradually accumulate;the unloading damage areas gradually appear;creep rates of every part gradually increase in varying degrees of growth with the damage accumulating. The reasonable analysis results can reflect the dynamic stability in the process of slope cutting, and guide the intervention time of supporting measures.

  14. Slope stability of proposed ski facilities at the southeast side of Snodgrass Mountain, Gunnison County, Colorado

    Baum, Rex L.


    Part of the proposed expansion of ski facilities at Crested Butte Mountain Resort, Gunnison County, Colorado, is in an area underlain by landslide deposits that are on the southeast side of Snodgrass Mountain. Except for localized movement, the landslides do not appear to be moving at present or to have moved in the past several decades. Shallow sliding and debris flows have occurred in similar materials nearby and are likely to occur in the landslide deposits during the 50-100 year life of the proposed facilities. Hazards related to debris flow, shallow slumping, and expansive soils in the deposits can be reduced by appropriate engineering and remedial measures but maintenance for the proposed facility may become costly. Snow making is likely to aggravate the hazards of shallow slumping, deep-seated sliding, and debris flow. Reactivation and deep-seated movement of a 1.6-million-m3 slide at the east side of the deposits would damage or destroy a proposed gondola, ski lift N-3, and related facilities. Moving the gondola and lift off the slide and prohibiting snow making on the slide will protect the gondola and lift and reduce the chances of debris-flow damage to a proposed development near the toe of the slide. Insufficient data are available to assess the current or future stability of the landslides or to evaluate possible mitigation strategies; detailed stability analyses are needed before developing any facilities on the landslide deposits.

  15. Massive Rock Detachments from the Continental slope of the Balsas River Submarine Delta that occur due to Instability of Sediments which Produce Turbidity Currents and Tsunamis

    Sandoval-Ochoa, J.; Aguayo-Camargo, J.


    During the NOAA oceanographic delivery cruise of the US R/V "Roger Revelle" to the Scripps Institution of Oceanography at the University of California in San Diego, California USA, in July 1996; a well calibrated bathymetric equipment, the SeaBeam* 2012, was tested. Good resolutions in data allowed bathymetric mapping to visualize the sea floor relief. Detailed colorful chartographic images showed a portion of the continental slope between the Balsas River Delta and the Middle America Trench and between the Balsas Canyon and La Necesidad Canyon. The surveyed area covered more than 3 000 square kilometers. After the delivery cruise, one of the goals was to measure and analyze the Morphobathymetry of the uneven lower portion of the Balsas River Submarine Delta. So far some of the findings with the morphometric analyses consist of several isolated slump scars that each comprise more than 12 cubic kilometers in volume and a multiple slump scar with an evident steep hollow about 200 cubic kilometers absent of rock. These volumes of rock apparently underwent a remobilization from the slope during the Late Quaternary. The rock detachments occured in relatively small portions but in instantaneous massive displacements because of their instability as well as other identified factors in the region. Over time more and more authors have accepted that coastal cuts or submarine slump scars have been left by sudden movements of rock and fluids. The phenomena that occur in the region in general, are accompanied on one side by potential and kinetic energies like falling bodies, flows and gravity waves, and on the other side, by mass transfer of rock and fluid mobilization like turbidity currents, accumulations, sea wave surges or tsunamis. In some cases the phenomena is produced by another natural triggering forces or by an earthquake. We propose that events like these, i.e. massive detachments and their products such as accumulations, turbidity currents and depositional debrites

  16. Soil formation on hard rock with and without cover of Pleistocene periglacial slope deposits in humid-temperate climate of Europe

    Sauer, Daniela; Schülli-Maurer, Isabelle


    Until the 1960s pedologists in Germany assumed that soils on hard rock in the mountainous regions of Germany developed directly from the underlying hard rock. Then, especially Schilling and Wiefel (1962) in eastern Germany and Semmel (1964, 1968) in western Germany developed, independently from each other, the concept of Pleistocene periglacial slope deposits (PPSD). However, it took several decades until this concept became largely accepted and was also introduced in textbooks and in the German soil and substrate taxonomy. This paper compares soil development on hard rock covered by PPSD in the eastern Rhenish Massif (Germany) to soil development that took place indeed directly on hard rock, in southern Norway, where glaciers removed all loose, weathered material from the rock during the last glacial period. Eight soil profiles developed in PPSD on quartzite and 12 soil profiles developed in PPSD on diabase are compared to four profiles in the Oslofjord region developed from hard rock. Soils were described in the field and analysed with regard to particle size analysis, pH in water, total element composition, Fed, Feo, CEC and base saturation. 1) Podzol developed from medium-grained granite This soil has an age of ca. 10,000 years. An 18 cm thick organic surface layer has accumulated on top of the mineral soil consisting of an E (14 cm) and BCs (14 cm) horizon. Vegetation at the site consists mainly of pine, birch, fir, and blueberry, heather and mosses. 2) Podzol developed from coarse-grained granite This soil has an age of above 11,000 years. The organic surface layer has a thickness of 7 cm; the mineral soil comprises an E (7 cm) and Bs (7 cm) horizon. Vegetation consists mainly of pine, fir, birch, and blueberry, heather, ferns and mosses. 3) Cambic Leptosol developed from Latite This soil has an age of ca. 10,000 years. The thickness of the organic surface layer is 5 cm; the mineral soil comprises an Ah (4 cm) and AB (20 cm) horizon. Vegetation consists

  17. Numerical simulation of earthquake effects on rock slope.%地震作用下边坡动力响应的数值模拟研究

    陈晓利; 李杨; 洪启宇; 赵永红


    汶川地震中在硬岩、次硬岩区域出现的一些大规模斜坡破坏现象超出了以往对地震作用下边坡稳定性问题的认识.本文使用FEPG有限元程序分析了水平和垂直2种不同加载方式作用下,经过不同的震动持续时间,不含裂隙岩质坡体内部的应力场和位移场的变化规律.得出的结论认为,在输入震动振幅为0.1m的加载作用下,岩质边坡内部的应力和位移均出现极值:在边坡的顶部及坡面上最大拉伸应力值大于100MPa,超过了花岗岩、灰岩等硬岩、次硬岩的抗拉强度,可能使岩体产生破裂发生崩塌、滑坡灾害.研究结果还表明,与水平方向振动加载相比,垂直方向振动加载产生的响应结果要大,边坡顶端一点的在垂直方向位移的峰值达到0.43m,远远超过了输入的震动振幅,垂直方向的震动是引起边坡的不稳定的主要因素.此外,震动持续时间越长,造成的变形和破坏就越大.%During S. 12 Wenchuan Earthquake, there were lots of huge landslides and collapses occurred in hard rock areas. This uncommon phenomenon is beyond our knowledge. This paper discussed the different patterns of stress and displacement distributions within a perfect slope when it is subject to horizontal and vertical vibrational loads with various loading time. The analyses were performed using FEPG software. It is found that, both the stress and the displacement appear to reach their peak values when the amplitude of vibration load is 0. Lm. The maximum tensile stress at the top of a slope is bigger than around lOOMPa which exceeds the anti-tensile limit of typical hard rocks such as granite, and so on. As a result, the hard rock mass breaks and landslide occurs. The study results also show that vertical vibrational loads would cause bigger stress and displacement peaks than horizontal vibrational loads. Under vertical vibrational load, maximum vertical displacement reached 0. 43m which is much bigger

  18. Reliability analysis of slope stability involving correlated non-normal variables using subset simulation method%含相关非正态变量边坡可靠度分析的子集模拟方法

    张曼; 唐小松; 李典庆


    提出了分析含相关非正态变量高维小失效概率可靠度问题的子集模拟方法,采用Nataf变换方法成功地解决了输入变量相关时子集模拟方法样本点的模拟问题.编写了基于MATLAB语言的计算程序SUBSETREL,并以岩质边坡稳定可靠度问题为例证明了所提方法的有效性.结果表明:该子集模拟方法能够有效地分析含相关非正态变量高维小失效概率的边坡可靠度问题.子集模拟方法的计算精度和蒙特卡洛模拟方法相当,计算效率远远高于传统的蒙特卡洛模拟方法.此外,该方法在分析含有复杂的隐式及非线性功能函数的边坡可靠度问题方面体现出明显的优越性.研究成果极大地拓展了子集模拟方法在边坡可靠度分析中的应用.%This paper aims to propose a reliability method named subset simulation(SS) method for estimation of small failure probability in high dimensions of slope stability problems involving correlated non-normal random variables.The Nataf transformation is used to transform the correlated non-normal random variables into the independent standard normal variables,which facilitates the simulation of correlated non-normal samples in failure domain and reliability computation using the SS method.A MATLAB-language based computer program called SUBSETREL is developed to carry out the reliability computations.Two examples of reliability analysis for rock slope stability with plane failure are presented to demonstrate the validity and capability of the proposed method.The results indicate that the proposed SS method can compute small failure probability in high dimensions of rock slope stability involving correlated non-normal random variables accurately and efficiently.Furthermore,the proposed SS method can result in the same accuracy as the traditional Monte Carlo simulations;and its efficiency is significantly higher than the traditional Monte Carlo simulations,which can be considered as

  19. Development of GIS-based spatial three-dimensional slope stability analysis system: 3DSlopeGIS

    ESAKI, Tetsuro; XIE, Mowen; MITANI, Yasuhiro; ZHOU, Guoyun


    Based on a new IT technology-Geographic Information System (GIS), this paper presents a new slope analysis approach which can be used to identify the possible slope failure bodies from complicated topography...

  20. 降雨-地震耦合作用下边坡的稳定性分析%Slope Stability Analysis under Rainfall-Earthquake

    梅涛; 肖盛燮


    随着基础建设的发展,边坡稳定性问题也越来越受到重视,从降雨和地震两种灾害出发,分析边坡在降雨后的稳定性,及降雨后发生地震的稳定性问题。指出边坡未降雨时,在地震作用下稳定,在独立降雨后也处于稳定,但降雨后不能再次承受地震荷载,建议对处于地震区的边坡进行边坡降雨和抗震两种灾害耦合设防。%As the fundamental construction, we paid more and more attention to slope stability. This paper form rainfall and earthquake to consider slope stability separately; the slope stability under rainfall and earthquake after rainfall. Research shows that slope will be stable after rainfall, or earthquake. But it will be unstable when earthquake after rainfall. We suggest that slope should be considered of rainfall coupled with earthquake instead of considering them separately.


    Franto Novico


    Full Text Available This study is focused on access channel model that safety factors of some slopes stability would be investigated. Plaxis version 8 is applied to analyze a magnitude of safety factors and displacements based on three different slopes of access channel there are 30°, 45° and 60°. Furthermore, parameters are adopted from geotechnical drilling and laboratory tests. A finite element is applied as a simple model to analyze within a Mohr-coulomb equation. Based on soil data analyses on Marine Center Plan, indicates low safety factor and high deformation. As results, 10 to 40 meters deformation of the slopes and 0.80 to 2.34 of safety factor are obtained of the models. For that reason, a combination between slope channel and infrastructure must be considered.

  2. Study of Block Stability of Surrounding Rock Mass of Main Transformer Chamber Based on VATS Program

    Zhongchang Wang


    Full Text Available The fracture of rock mass for main transformer chamber in HuangGou hydropower station is very developed. The blocks slide along the discontinuous face or free face with the excavation of cavern. It leads to the failure of normal construction. In the study, according to geology of disclosed discontinuous face in detecting cavern and local three-dimensional coordinate of underground caverns, the vector analysis program for tunnel stability VATS is compiled by using the method of vector analysis of the block theory which is applicable to analyze the discontinuous rock mass and numerical software MATLAB. The occurrence of joints, the coordinate of measuring point, the radius and vertical wall height of underground caverns and other relevant engineering datum is required to input the program. The combination of discontinuous face, boundary condition, geometric parameter, the mode of failure and stability factor of existent unstable blocks is obtained. The geometry distributing characteristic of block and key discontinuous faces in different position is figured by the AUTOCAD software. The guidance for construction of underground caverns is provided.

  3. Geochemical alteration vs mechanical weathering on stability of unstable slope : Case of the deep seated landslide of Séchilienne (Isère, France)

    Bertrand, Catherine; Nevers, Pierre; Gaillardet, Jérôme; Dubois, Laurent


    The Séchilienne landslide is located on the right bank of the Romanche River, South East of Grenoble (Isère, France). The active zone of the gravitational instability involves several millions of cubic meters. The geology consists of fractured hard rocks (micaschists) with double permeability and strong spatial heterogeneities. The permeability of the basement areas is rather obtained by long term weathering, which can be associated with a mechanical action in high relief mountainous regions. Water plays two major roles, the first one being a hydrogeological process, which is a factor that worsens instability, and the second one being a geochemical factor that alters the massif, making it less cohesive. These two factors interact through time and modify permeability and therefore the flow of water within the rock. Hydrochemistry simultaneously provides information about water flows (location and amount of refill, types and flow patterns, storage, residence time), and also about the acquisition of the chemistry during its transit through the aquifer (water-rock interaction during the transit, quantification of the alteration). The issue is to improve the knowledge of the genesis of the chemical signal, and to define the contributions of the knowledge of this signal in terms of functioning, on the pressure transferring as well as on the mass transferring and its effects. Hydrogeochemistry, which is integrative of the entire "history" of the water in the different compartments, paired with geochemical modelling, which allow the discrimination of the chemical signal according to its path in the aquifer, turns out to be an appropriate method for the objective. These tools (hydrogeochemistry & geochemical modelling) are designed to understand the complex relationship between chemical weathering, hydromechanical changes and weakening / deformation of the unstable rock slope The deformation of the unstable slope is monitored by on-site extensometric gauges, inclinometers

  4. Aespoe Pillar Stability Experiment. Geology and mechanical properties of the rock in TASQ

    Staub, Isabelle [Golder Associates AB, Uppsala (Sweden); Andersson, J. Christer; Magnor, Bjoern


    An extensive characterization programme has been performed in the drift, TASQ, excavated for the Aespoe Pillar Stability Experiment, APSE, including the rock volume that will host the experiment pillar between the two deposition holes. The two major objectives with the characterization has been to 1) derive material properties for the final numerical modelling of the experiment and 2) to ensure that the pillar location is suitable from a structural and rock mechanical point of view. In summary the following activities have been performed: Geological mapping of the drift, the pilot holes cores and deposition hole DQ0066G01. 3D-visualisation of the geological mapping in the experiment (pillar) volume of TASQ. Convergence measurements during the excavation and back calculation of the results for determination of the stress tensor and the rock mass Young's modulus. Laboratory tests on core samples from the 15{phi}76 mm core boreholes drilled around the pillar volume for determination of: compressive strength, thermal properties and fracture properties. P-wave velocity measurements on core samples and between boreholes for estimation of the excavation damaged zone and rock mass properties. The geological mapping and the 3D-visualisation gives a good description of the TASQ drift in general and the experiment volume in the drift in particular. The fracturing of the drift follows the pattern of the rest of Aespoe. Three fracture sets have been mapped in TASQ. The major fracture set is sub-vertical and trending NW, in principle parallel to {sigma}{sub 1}. This set is the most conductive at Aespoe and is the only water bearing set in TASQ. A second less pronounced set is trending NE, parallel to TASQ, and is also sub-vertical. The third set is sub-horizontal. It is interesting to note that the third set is the only one that almost completely consists of sealed fractures. The first two sets have mostly open fractures. One unique feature in the drift is a heavily

  5. Physically-based slope stability modelling and parameter sensitivity: a case study in the Quitite and Papagaio catchments, Rio de Janeiro, Brazil

    de Lima Neves Seefelder, Carolina; Mergili, Martin


    We use the software tools r.slope.stability and TRIGRS to produce factor of safety and slope failure susceptibility maps for the Quitite and Papagaio catchments, Rio de Janeiro, Brazil. The key objective of the work consists in exploring the sensitivity of the geotechnical (r.slope.stability) and geohydraulic (TRIGRS) parameterization on the model outcomes in order to define suitable parameterization strategies for future slope stability modelling. The two landslide-prone catchments Quitite and Papagaio together cover an area of 4.4 km², extending between 12 and 995 m a.s.l. The study area is dominated by granitic bedrock and soil depths of 1-3 m. Ranges of geotechnical and geohydraulic parameters are derived from literature values. A landslide inventory related to a rainfall event in 1996 (250 mm in 48 hours) is used for model evaluation. We attempt to identify those combinations of effective cohesion and effective internal friction angle yielding the best correspondence with the observed landslide release areas in terms of the area under the ROC Curve (AUCROC), and in terms of the fraction of the area affected by the release of landslides. Thereby we test multiple parameter combinations within defined ranges to derive the slope failure susceptibility (fraction of tested parameter combinations yielding a factor of safety smaller than 1). We use the tool r.slope.stability (comparing the infinite slope stability model and an ellipsoid-based sliding surface model) to test and to optimize the geotechnical parameters, and TRIGRS (a coupled hydraulic-infinite slope stability model) to explore the sensitivity of the model results to the geohydraulic parameters. The model performance in terms of AUCROC is insensitive to the variation of the geotechnical parameterization within much of the tested ranges. Assuming fully saturated soils, r.slope.stability produces rather conservative predictions, whereby the results yielded with the sliding surface model are more

  6. Rock Mass Strength Assessment and Significance to Edifice Stability, Mount Rainier and Mount Hood, Cascade Range Volcanoes

    Watters, R. J.; Zimbelman, D. R.; Bowman, S. D.; Crowley, J. K.

    Catastrophic edifice and sector failure occur commonly on stratovolcanoes worldwide and in some cases leave telltale horseshoe-shaped calderas. Many of these failures are now recognised as having resulted from large-scale landsliding. These slides often transform into debris avalanches and lahars that can devastate populations downstream of the volcano. Research on these phenomena has been directed mainly at understanding avalanche mechanics and travel distances and related socioeconomic impacts. Few investigations have examined volcanic avalanche source characteristics. The focus of this paper is to 1) describe a methodology for obtaining rock strengths that control initial failure and 2) report results of rock mass strength testing from Mount Rainier and Mount Hood. Rock mass and shear strength for fresh and hydrothermally altered rocks were obtained by 1) utilizing rock strength and structural information obtained from field studies and 2) applying rock mechanics techniques common in mining and civil engineering to the edifice region. Rock mass and intact rock strength differences greatly in excess of one order of magnitude were obtained when comparing strength behavior of fresh and completely altered volcanic rock. The recognition and determination of marked strength differences existing on the volcano edifice and flank, when combined with detailed geologic mapping, can be used to quantify volcano stability assessment and improve hazard mitigation efforts.


    蒋水华; 彭铭; 李典庆; 张利民; 周创兵


    A non-intrusive stochastic finite element method for time-variant serviceability reliability analysis of anchored rock slopes with consideration of rock bolt corrosion is proposed.A rock bolt corrosion model reflecting the variation of the anchored force of each rock bolt with service time is established.Consequently,the computational procedure for time-variant serviceability reliability analysis of the slope deformation using the non-intrusive stochastic finite element method is proposed.The relationship between the probability of failure for slope deformation and the maximum allowable deformation is investigated; and a method for determining the maximum allowable deformation of the slope is proposed based on parametric sensitivity analysis.An example of reliability analysis of anchored rock slope deformation subjected to surcharge loading is illustrated to demonstrate the validity and capability of the proposed method.The results indicate that the proposed non-intrusive stochastic finite element method can effectively evaluate time-variant serviceability reliability of rock slopes.The rock bolt corrosion has a significant influence on the serviceability reliability of rock slopes as the service time of rock bolts increases.In addition,an approximate linear relationship exists between the logarithm of the time-variant probability of failure for slope deformation,lgpf,and the maximum allowable deformation; and this linear relationship becomes more obvious as the reliability level of the slope increases.%提出基于非侵入式随机有限元法的岩质边坡变形可靠度分析方法.建立考虑腐蚀效应的锚杆锚固力随服役时间变化模型.给出边坡变形可靠度分析非侵入式随机有限元法的计算步骤.研究锚固边坡变形失效概率与最大允许变形值之间的关系,并基于参数敏感性分析提出边坡最大允许变形取值方法.以锚固岩质边坡为例,证明所提方法的有效性.结果表明:非侵入式

  8. Analysis on Yellow River dike slope stability with strength reduction method%黄河大堤边坡稳定的强度折减法分析



    The article calculates and analyzes Yellow River dike slope stability with finite element strength reduction method, and respectively calculates the dike slope stability security coefficients under two conditions of riverside upstream and riverside levee. Results show that : under the first condition, the security coefficient Fs = 1. 963 〉 1, which shows that the dike slope is safe and stable, under the second condition, the securi- ty coefficient Fs = 1. 395 〉 1, the security coefficient reduces a little, while the dike slope is still safe. Thus, the Yellow River dike slope is safe and reliable.%采用有限元强度折减法对黄河大堤边坡稳定问题进行了计算和分析,分别计算了临河堤坡未迎水和河床水位达到堤顶两种工况下的堤坡稳定安全系数,结果表明,第一种工况下安全系数Fs=1.963〉1,堤坡安全稳定,第二种工况下安全系数F=1.395〉1,安全系数有所减小,但堤坡仍然是安全的,由此可知黄河大堤的边坡是安全可靠的。

  9. A reservoir on the right bank slope stability analysis%某水库右岸斜坡体稳定性分析研究

    杜飞翔; 张德成


    以长兴水库右岸斜坡体为例,研究了库岸失稳的机理,运用 geostudio 软件对斜坡体的渗流情况进行了模拟,得出不同水位变化情况下斜坡体内的孔隙水压力和渗流力,并分析了不同的水库水位变化情况对斜坡稳定性的影响,得到多种工况下斜坡体的稳定系数,为实际工程建设提供了科学的理论依据。%Taking Changxing reservoir as an example,the mechanism of slope instability is studied,using geostudio software in the seepage con-dition of the slope body is simulated,obtained under different water level changes in pore water pressure and seepage force of slope body,it ana-lyzes the different changes of reservoir water level on slope stability influence. Get a variety of conditions the stability coefficient of slope body, provides scientific theoretical basis for practical engineering construction.

  10. Physical modeling of river spanning rock structures: Evaluating interstitial flow, local hydraulics, downstream scour development, and structure stability

    Collins, K.L.; Thornton, C.I.; Mefford, B.; Holmquist-Johnson, C. L.


    Rock weir and ramp structures uniquely serve a necessary role in river management: to meet water deliveries in an ecologically sound manner. Uses include functioning as low head diversion dams, permitting fish passage, creating habitat diversity, and stabilizing stream banks and profiles. Existing information on design and performance of in-stream rock structures does not provide the guidance necessary to implement repeatable and sustainable construction and retrofit techniques. As widespread use of rock structures increases, the need for reliable design methods with a broad range of applicability at individual sites grows as well. Rigorous laboratory testing programs were implemented at the U.S. Bureau of Reclamation (Reclamation) and at Colorado State University (CSU) as part of a multifaceted research project focused on expanding the current knowledge base and developing design methods to improve the success rate of river spanning rock structures in meeting project goals. Physical modeling at Reclamation is being used to measure, predict, and reduce interstitial flow through rock ramps. CSU is using physical testing to quantify and predict scour development downstream of rock weirs and its impact on the stability of rock structures. ?? 2009 ASCE.

  11. Effects of statistical distribution of joint trace length on the stability of tunnel excavated in jointed rock mass

    Kayvan Ghorbani


    Full Text Available The rock masses in a construction site of underground cavern are generally not continuous, due to the presence of discontinuities, such as bedding, joints, faults, and fractures. The performance of an underground cavern is principally ruled by the mechanical behaviors of the discontinuities in the vicinity of the cavern. During underground excavation, many surrounding rock failures have close relationship with joints. The stability study on tunnel in jointed rock mass is of importance to rock engineering, especially tunneling and underground space development. In this study, using the probability density distribution functions of negative exponential, log-normal and normal, we investigated the effect of joint trace length on the stability parameters such as stress and displacement of tunnel constructed in rock mass using UDEC (Universal Distinct Element Code. It was obtained that normal distribution function of joint trace length is more critical on the stability of tunnel, and exponential distribution function has less effect on the tunnel stability compared to the two other distribution functions.

  12. 高填方土工格栅加筋土边坡稳定性研究%Stability Analysis of High Backifll Slope Reinforced by Geogrids

    金永军; 燕慧晓; 阙金声; 何坤


    According to the stress characteristics of geogrids in the high backifll slope, based on simpliifed Bishop method,the calculation formula of slope stability coefifcient is deduced to consider earthquake, groundwater, slope surface load, slope top (foot) load, geogrids and other factors, which provides a method for more precise evaluation the stability of high backifll geogrids reinforced soil slope. According to the characteristics of high backifll slope with multiple steps, through the cut-into-point, cut-out-point and midpoint of sliding arc, a method of controlling position of sliding surface is proposed to determine the range of sliding arc midpoint, makes the slope potential arc sliding surface search experiential assumptions aren't required, programming simple, and the calculation efifciency of the minimum stability coefifcient of complex slope is effectively improved. This method also provides a good basis for the sensitivity analysis and reliability analysis of the slope design parameters.%针对高填方边坡中土工格栅的受力特点,在简化Bishop法的基础上推导了可以考虑地震、地下水、坡面荷载、坡顶(脚)荷载、土工格栅等因素的边坡稳定系数计算公式,为更精确地评价高填方土工格栅加筋土边坡稳定性研究提供了方法。针对高填方多台阶边坡的特点,通过滑动面剪入点、剪出点和滑弧中点控制滑动面位置,提出了确定滑弧中点取值范围的方法,使得边坡潜在圆弧滑动面的搜索范围不再需要经验假定,编程简单,并可有效提高复杂边坡最小稳定系数的计算效率,也为边坡设计参数的敏感性分析、可靠性分析提供很好的计算基础。

  13. Utilizing the Analytic Hierarchy Process to Establish Weighted Values for Evaluating the Stability of Slope Revegetation based on Hydroseeding Applications in South Korea

    Sung-Ho Kil


    Full Text Available The aim of this study was to identify the major variables identified as important for considering the stabilization of slope revegetation based on hydroseeding applications and evaluate weights of each variable using the analytic hierarchy process (AHP with both environmental experts and civil engineers. Twenty-five variables were selected by the experts’ survey from a total of 65 from the existing literature, with each variable considered as an important factor for slope stabilization in South Korea. The final results from the AHP method showed that variables associated with the driving force of water resources showed higher values in all expert groups such as rain intensity, seepage water and drainage condition. Other important variables were related to plant growth such as vegetation community, vegetation coverage and quality of soil ameliorant produced in an artificial factory such as tensile strength, permeability coefficient, soil texture and organic matter. The five highest-ranked variables that satisfied both environmental experts and civil engineers were rain intensity, seepage water, slope angle, drainage condition and ground layer. The findings of this research could be helpful for developing a more accurate rating system to evaluate the stability of slope revegetation.

  14. HSDP II Drill Core: Preliminary Rock Strength Results and Implications to Flank Stability, Mauna Kea Volcano

    Thompson, N.; Watters, R. J.; Schiffman, P.


    Selected portions of the 3-km HSDP II core were tested to provide unconfined rock strength data from hyaloclastite alteration zones and pillow lavas. Though the drilling project was not originally intended for strength purpose, it is believed the core can provide unique rock strength insights into the flank stability of the Hawaiian Islands. The testing showed that very weak rock exists in the hyaloclastite abundant zones in the lower 2-km of the core with strength dependent on the degree of consolidation and type of alteration. Walton and Schiffman identified three zones of alteration, an upper incipient alteration zone (1080-1335m), a smectitic zone (1405-1573m) and a lower palagonitic zone from about 1573 m to the base of the core. These three zones were sampled and tested together with pillow lava horizons for comparison. Traditional cylindrical core was not available as a consequence of the entire core having been split lengthwise for archival purposes. Hence, point load strength testing was utilized which provides the unconfined compressive strength on irregular shaped samples. The lowest unconfined strengths were recorded from incipient alteration zones with a mean value of 9.5 MPa. Smectitic alteration zones yielded mean values of 16.4 MPa, with the highest measured alteration strengths from the palagonite zones with a mean value of 32.1 MPa. As anticipated, the highest strengths were from essentially unaltered lavas with a mean value of 173 MPa. Strength variations of between one to two orders of magnitude were identified in comparing the submarine hyaloclastite with the intercalated submarine lavas. The weakest zones within the hyaloclastites may provide horizons for assisting flank collapse by serving as potential thrust zones and landslide surfaces.

  15. Improved response surface method and its application in stability reliability degree analysis of tunnel surrounding rock


    An approach of limit state equation for surrounding rock was put forward based on deformation criterion. A method of symmetrical sampling of basic random variables adopted by classical response surface method was mended, and peak value and deflection degree of basic random variables distribution curve were took into account in the mended sampling method. A calculation way of probability moment, based on mended Rosenbluth method, suitable for non-explicit performance function was put forward.The first, second, third and fourth order moments of functional function value were calculated by mended Rosenbluth method through the first, second, third and fourth order moments of basic random variable. A probability density the function(PDF) of functional function was deduced through its first, second, third and fourth moments, the PDF in the new method took the place of the method of quadratic polynomial to approximate real functional function and reliability probability was calculated through integral by the PDF for random variable of functional function value in the new method. The result shows that the improved response surface method can adapt to various statistic distribution types of basic random variables, its calculation process is legible and need not iterative circulation. In addition, a stability probability of surrounding rock for a tunnel was calculated by the improved method,whose workload is only 30% of classical method and its accuracy is comparative.

  16. Use of Structure-from-Motion Photogrammetry Technique to model Danxia red bed landform slope stability by discrete element modeling - case study at Mt. Langshan, Hunan Province, China

    Simonson, Scott; Hua, Peng; Luobin, Yan; Zhi, Chen


    Important to the evolution of Danxia landforms is how the rock cliffs are in large part shaped by rock collapse events, ranging from small break offs to large collapses. Quantitative research of Danxia landform evolution is still relatively young. In 2013-2014, Chinese and Slovak researchers conducted joint research to measure deformation of two large rock walls. In situ measurements of one rock wall found it to be stable, and Ps-InSAR measurements of the other were too few to be validated. Research conducted this year by Chinese researchers modeled the stress states of a stone pillar at Mt. Langshan, in Hunan Province, that toppled over in 2009. The model was able to demonstrate how stress states within the pillar changed as the soft basal layer retreated, but was not able to show the stress states at the point of complete collapse. According to field observations, the back side of the pillar fell away from the entire cliff mass before the complete collapse, and no models have been able to demonstrate the mechanisms behind this behavior. A further understanding of the mechanisms controlling rockfall events in Danxia landforms is extremely important because these stunning sceneries draw millions of tourists each year. Protecting the tourists and the infrastructure constructed to accommodate tourism is of utmost concern. This research will employ a UAV to as universally as possible photograph a stone pillar at Mt. Langshan that stands next to where the stone pillar collapsed in 2009. Using the recently developed structure-from-motion technique, a 3D model of the pillar will be constructed in order to extract geometrical data of the entire slope and its structural fabric. Also in situ measurements will be taken of the slope's toe during the field work exercises. These data are essential to constructing a realistic discrete element model using the 3DEC code and perform a kinematic analysis of the rock mass. Intact rock behavior will be based on the Mohr Coulomb

  17. 4D understanding of failures in soft sedimentary rocks using repetitive terrestrial stereo-photogrammetry: the case of the Rosselin deep-seated slope instability, Valais, Switzerland.

    Travelletti, Julien; Monnet, Régis


    The objective of this study is (i) to highlight the potential of low-cost stereo-photogrammetry to monitor the 4D deformation of rock instabilities and (ii) to add to the 4D understanding of failure development in soft sedimentary rocks. The Rosselin instability is located in a landslides prone area in the municipality of Riddes, canton of Valais, Switzerland. This deep-seated slope instability has developed in Triassic dolomitic carbonates overlaid by highly fractured Cretaceous conglomerates and schists. Its estimated volume is of 300'000 m3. A catastrophic scenario can cause the obstruction of a river located 400 m beneath. The sudden failure of the landslide dam would then threaten the municipality of Riddes of major floods and debris flows. On May 14, 2013, precursor signs of activity (minor rockfalls, developments of tension cracks) in a part of the Rosselin instability were observed after a relatively wet period. Therefore, in complement to risk mitigation planning a monitoring strategy was set up. In addition to the installation of extensometers, repetitive terrestrial stereo-photogrammetry surveys were acquired at a distance of 100 m of the instability in order to build a four-dimensional understanding of the failure. Seventeen high-resolution photogrammetric acquisitions were realized between the 15th and the 17th of May the day the main failure occurred. The comparison of the states before and after the event of May 17 allowed to compute a mobilized volume of 30'000 m3 (1/10 of the total volume of the Rosselin instability). 3D displacements are derived from the photogrammetric acquisition and obtained with a cross-correlation technique. The kinematics analysis allowed the highlighting of (i) strong deformations during the pre-failure stage within the mass probably induced by progressive brittle fracture damages and of (ii) a control of pre-existing regional discontinuities in the failure stage leading to a general wedge sliding. It also shows that in the

  18. Stability control of surrounding rocks for a coal roadway in a deep tectonic region

    Xiao Tongqiang; Wang Xiangyu; Zhang Zhigao


    In order to effectively control the deformation and failure of surrounding rocks in a coal roadway in a deep tectonic region, the deformation and failure mechanism and stability control mechanism were stud-ied. With such methods as numerical simulation and field testing, the distribution law of the displace-ment, stress and plastic zone in the surrounding rocks was analyzed. The deformation and failure mechanisms of coal roadways in deep tectonic areas were revealed:under high tectonic stress, two sides will slide along the roof or floor;while the plastic zone of the two sides will extend along the roof or floor, leading to more serious deformation and failure in the corner of two sides and the bolt supporting the corners is readily cut off by the shear force or tension force. Aimed at controlling the large slippage defor-mation of the two sides, serious deformation and failure in the corners of the two sides and massive bolt breakage, a ‘controlling and yielding coupling support’ control technology is proposed. Firstly, bolts which do not pass through the bedding plane should be used in the corners of the roadway, allowing the two sides to have some degree of sliding to achieve the purpose of ‘yielding’ support, and which avoid breakage of the bolts in the corner. After yielding support, bolts in the corner of the roadway and which pass through the bedding plane should be used to control the deformation and failure of the coal in the corner. ‘Controlling and yielding coupling support’ technology has been successfully applied in engineering practice, and the stability of deep coal roadway has been greatly improved.

  19. Stability Evaluation of Volcanic Slope Subjected to Rainfall and Freeze-Thaw Action Based on Field Monitoring

    Shima Kawamura


    Full Text Available Rainfall-induced failures of natural and artificial slopes such as cut slopes, which are subjected to freezing and thawing, have been frequently reported in Hokkaido, Japan. In particular, many failures occur intensively from spring to summer seasons. Despite numerous field studies, explanation of their mechanical behavior based on in situ data has not yet been completely achieved due to the difficulty in grasping failure conditions. This study aims at clarifying the aspects of in-situ volcanic slopes subjected to rainfall and freeze-thaw action. The changes in soil moisture, pore pressure, deformations, and temperatures in the slope were investigated using soil moisture meters, tensiometers, thermocouple sensors, clinometers, settlement gauges, an anemovane, a snow gauge, and a rainfall gauge. The data generated from these measures indicated deformation in the slope examined mainly proceeded during the drainage process according to changes in soil moisture. Based on this data, a prediction method for failures is discussed in detail.

  20. Low-altitude permafrost research in an overcooled talus slope-rock glacier system in the Romanian Carpathians (Detunata Goală, Apuseni Mountains)

    Popescu, Răzvan; Vespremeanu-Stroe, Alfred; Onaca, Alexandru; Vasile, Mirela; Cruceru, Nicolae; Pop, Olimpiu


    Ground and air temperature monitoring, geophysical soundings and dendrological investigations were applied to a basaltic talus slope-rock glacier system from Detunata site in the Apuseni Mountains (Western Romanian Carpathians) to verify the presence of sporadic permafrost at 1020-1110 m asl, well below the regional limit of mountain permafrost. The near 0 °C mean annual ground surface temperatures imposed by the large negative annual thermal anomalies of the ground (up to 7.4 °C), together with the high resistivity values and the occurrence of trees with severe growth anomalies, support the presence of permafrost at this location. Temperature measurements and ground air circulation experiments proved that the so-called "chimney effect" is the main process favoring the ground overcooling and allowed for the construction of a model of ground air circulation in complex morphology deposits. The texture and porosity of the debris were quantified along with the local morphology in order to evaluate their role upon the chimney circulation. The debris porosity was found to be very high promoting intense ground overcooling during the cold season, including the periods of high snow cover due to the development of snow funnels. It efficiently reduces the heat transfer during summer thus contributing essentially to permafrost preservation. In compound morphologies, the depressed and low-lying features are the cold zones subjected to winter overcooling and summer chill, while the high-positioned and convex-up landforms become warm air evacuation features with positive thermal anomalies. Tree-ring measurements showed that the growth of cold-affected trees is higher during colder intervals (years to decades) probably as a consequence of the weakened katabatic air outflow during cooler summers. The dendrological analysis of multi-centennial spruces and their growth rates also provided palaeoclimatic inferences for the last 200 years. Dendrological data describe the multi

  1. 边坡稳定性分析最小二乘法%Least Square Method of Slope Stability Analysis



    In this article, the author points out that using MATLAB program and the principle of the least squares to calculate the liner equations can get a more accurate safety factor when under the following situations. Firstly, the author use the classical earth pressure theory and Mohr-Coulomb failure criterion to set-up the reasonable thrust line position of soil slice. Secondly, according to static equilibrium equation and torque equilibrium equation, the liner equations are established. This assumption is set by a reasonable thrust line position and avoiding any unreasonable interaction forces. MATLAB is the method for solving linear equations, it overcomes the shortcomings, in which other methods to solve nonlinear equations cannot iterative to converge. The results show the xassumption is more reliable in precision. The study is a guide for evaluating the stability of slopes.%利用经典土压力理论设定合理土条推力线位置,对土条底滑面采用摩尔-库伦破坏准则,根据静力平衡及力矩平衡条件建立线性超定方程组,应用MATLAB软件基于最小二乘法原理对此方程组求解,得到比较精确的安全系数。该法从设定合理土条推力线位置出发,避免了对条间力函数的不合理设定,采用MATLAB求解线性超定方程组得解,克服了求解非线性方程组不能迭代收敛得解的缺点,经算例验证其在精度方面比较可靠,对于评价边坡的稳定性具有参考意义。

  2. Impact of weathering on the geomechanical properties of rocks along thermal metamorphic contact belts and morpho-evolutionary processes: The deep-seated gravitational slope deformations of Mt. Granieri Salincriti (Calabria Italy)

    Pellegrino, A.; Prestininzi, A.


    Numerous Deep-Seated Gravitational Slope Deformations (DSGSDs) occur throughout Italy, that originate from particular tectono-stratigraphic settings, relief, seismicity, deglaciation, as well as from intense and deep processes of chemico-physical weathering of crystalline-metamorphic rocks. These DSGSDs are particularly widespread in the Calabrian mountains. This study is focused on the Mt. Granieri-Salincriti slope, on the Ionian side of the Serre Massif, where granites and granodiorites (Stilo Unit, Palaeozoic) are in contact with metamorphites through a thermal-metamorphic aureole. This setting generates deep geochemical processes, inducing intense chemical weathering. These processes are mainly due to