WorldWideScience

Sample records for pile groups

  1. A simplified analysis method for piled raft and pile group foundations with batter piles

    Science.gov (United States)

    Kitiyodom, Pastsakorn; Matsumoto, Tatsunori

    2002-11-01

    A simplified method of numerical analysis has been developed to estimate the deformation and load distribution of piled raft foundations subjected to vertical, lateral, and moment loads, using a hybrid model in which the flexible raft is modelled as thin plates and the piles as elastic beams and the soil is treated as springs. Both the vertical and lateral resistances of the piles as well as the raft base are incorporated into the model. Pile-soil-pile, pile-soil-raft and raft-soil-raft interactions are taken into account based on Mindlin's solutions for both vertical and lateral forces. The validity of the proposed method is verified through comparisons with several existing methods for single piles, pile groups and piled rafts. Workable design charts are given for the estimation of the lateral displacement and the load distribution of piled rafts from the stiffnesses of the raft alone and the pile group alone. Additionally, parametric studies were carried out concerning batter pile foundations. It was found that the use of batter piles can efficiently improve the deformation characteristics of pile foundations subjected to lateral loads.

  2. Global and local scour at pile groups

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

    2005-01-01

    This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: rigid-bed tests and actual scour tests. In these, the mean and turbulence properties of the flow were measured...... across the pile groups. The pile-group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

  3. Global and local scour at pile groups

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

    2005-01-01

    This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: (1) Rigid-bed tests, and (2) Actual scour tests. In the former tests, the mean and turbulence properties...... of the flow were measured across the pile groups. The pile group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

  4. Experimental Investigations on the Efficiency Coefficient of Pile Groups

    Directory of Open Access Journals (Sweden)

    Sara Darsi

    2016-06-01

    Full Text Available Several factors influence on behavior of piles group such as type of soil, number of piles in the group and the distance between piles. In this paper, using a small laboratory model, the influence of these factors on the behavior of piles group has been examined.For this purpose a group of piles in different distances and variable number of piles was allocated in sand under anpressure axial load. The piles are preferably metal; thus to reduce weight a hollow type has been selected.In order to calculate the coefficient of piles group efficiency, a single pile has been experimented. Experimental observations show that the number of piles in the group and the distances between piles in sand have considerable effect on bearing capacity and the coefficient of pile group efficiency and the coefficient of efficiency in this type of soil have constantly been more than 1 and limited to 1 by increasing the distance between piles.

  5. Effect of pile-cap connection on behavior of torsionally loaded pile groups

    Institute of Scientific and Technical Information of China (English)

    Ling-gang KONG; Li-min ZHANG

    2008-01-01

    To evaluate the respouses of fixed and pinned pile groups under torsiun, a method is presented to analyze the nonlinear behavior of free-standing pile groups with rigid pile caps. The method is capable of simulating the nonlinear soil response in the near field usingp-y and τ-θ curves, the far-field interactions through Mindlin's and Randolph's elastic solutions, and the coupling effect of lateral resistance on torsional resistance of the individual piles using an empirical factor. Based on comparisons of the solutions for fixedand pinned-head, 1×2, 2×2, and 3×3 pile groups subjected to torsion, it was found that pile-cap connection significantly influences the torsional capacity of pile groups and the assignment of applied torques in the pile groups. In this study, the applied torques for the pinned-head pile groups are only 44%~64% of those for the corresponding fixed-head pile groups at a twist angle of 2°. Such a difference is mainly due to the change of the lateral resistances of individual piles in the groups.

  6. The Effect of the Propeller Jet on Pile Groups

    Institute of Scientific and Technical Information of China (English)

    Kubilay Cihan

    2014-01-01

    The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of Rpm (690, 820, and 950) were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.

  7. 3D finite element analysis on pile-soil interaction of passive pile group

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming-hua; LIU Dun-ping; ZHANG Ling; JIANG Chong

    2008-01-01

    The interaction between pile and soft soil of the passive pile group subjected to soil movement was analyzed with three-dimensional finite element model by using ANSYS software. The soil was assumed to be elastic-plastic complying with the Drucker-Prager yield criterion in the analysis. The large displacement of soil was considered and contact elements were used to evaluate the interaction between pile and soil. The influences of soil depth of layer and number of piles on the lateral pressure of the pile were investigated, and the lateral pressure distributions on the (2×1) pile group and on the (2×2) pile group were compared. The results show that the adjacent surcharge may result in significant lateral movement of the soft soil and cousiderable pressure on the pile. The pressure acting on the row near the surcharge is higher than that on the other row, due to the "barrier" and arching effects in pile groups. The passive load and its distribution should be taken into account in the design of the passive piles.

  8. Centrifuge model test on dynamic behavior of group-pile foundation With inclined piles and its numerical simulation

    Institute of Scientific and Technical Information of China (English)

    Feng ZHANG; Katsunori OKAWA; Makoto KIMURA

    2008-01-01

    In this paper, dynamic behavior of a grouppile foundation with inclined piles in loose sand has been investigated with centrifuge model tests. The test results are also simulated with elastoplastic dynamic finite ele-ment method, in which, not only sectional force of piles, stress of ground, but also deformation of piles are calcu-lated using a three-dimensional elastoplastic dynamic finite element analysis (Code name: DGPILE-3D). The numerical analyses are conducted with a full system in which a superstructure, a pile foundation and surround-ing ground are considered together so that interaction between pile foundation and soils can be properly simu-lated because the nonlinearities of both the pile and the ground are described with suitable constitutive models. Different types of piles, vertical pile or inclined pile, are considered in order to verify the different characteristics of a group pile foundation with inclined piles. The validity of the calculation is verified by the model tests.

  9. WAVE CURRENT FORCES ON THE PILE GROUP OF BASE FOUNDATION FOR THE EAST SEA BRIDGE, CHINA

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of the two structures of the bridge foundation designed for the East Sea Bridge, the wave current forces on four types of oblique piles, the pile group and the single piles at different positions in the pile group considering the effect of the super structures were experimentally investigated. The relationship between the wave current forces and the associated wave parameters, and the comparison of the wave current forces on the pile groups and the single piles were systematically analyzed. The group effectiveness and the reduction coefficient for the wave current forces on the group were examined for engineering design.

  10. Behavior of Pile Group with Elevated Cap Subjected to Cyclic Lateral Loads

    Institute of Scientific and Technical Information of China (English)

    陈云敏; 顾明; 陈仁朋; 孔令刚; 张浙杭; 边学成

    2015-01-01

    The pile group with elevated cap is widely used as foundation of offshore structures such as turbines, power transmission towers and bridge piers, and understanding its behavior under cyclic lateral loads induced by waves, tide water and winds, is of great importance to designing. A large-scale model test on 3×3 pile group with elevated cap subjected to cyclic lateral loads was performed in saturated silts. The preparation and implementation of the test is presented. Steel pipes with the outer diameter of 114 mm, thickness of 4.5 mm, and length of 6 m were employed as model piles. The pile group was cyclic loaded in a multi-stage sequence with the lateral displacement controlled. In addition, a single pile test was also conducted at the same site for comparison. The displacement of the pile cap, the internal forces of individual piles, and the horizontal stiffness of the pile group are presented and discussed in detail. The results indicate that the lateral cyclic loads have a greater impact on pile group than that on a single pile, and give rise to the significant plastic strain in the soil around piles. The lateral loads carried by each row of piles within the group would be redistributed with loading cycles. The lateral stiffness of the pile group decreases gradually with cycles and broadly presents three different degradation patterns in the test. Significant axial forces were measured out in some piles within the group, owing to the strong restraint provided by the cap, and finally lead to a large settlement of the pile group. These findings can be referred for foundation designing of offshore structures.

  11. Behavior of pile group with elevated cap subjected to cyclic lateral loads

    Science.gov (United States)

    Chen, Yun-min; Gu, Ming; Chen, Ren-peng; Kong, Ling-gang; Zhang, Zhe-hang; Bian, Xue-cheng

    2015-06-01

    The pile group with elevated cap is widely used as foundation of offshore structures such as turbines, power transmission towers and bridge piers, and understanding its behavior under cyclic lateral loads induced by waves, tide water and winds, is of great importance to designing. A large-scale model test on 3×3 pile group with elevated cap subjected to cyclic lateral loads was performed in saturated silts. The preparation and implementation of the test is presented. Steel pipes with the outer diameter of 114 mm, thickness of 4.5 mm, and length of 6 m were employed as model piles. The pile group was cyclic loaded in a multi-stage sequence with the lateral displacement controlled. In addition, a single pile test was also conducted at the same site for comparison. The displacement of the pile cap, the internal forces of individual piles, and the horizontal stiffness of the pile group are presented and discussed in detail. The results indicate that the lateral cyclic loads have a greater impact on pile group than that on a single pile, and give rise to the significant plastic strain in the soil around piles. The lateral loads carried by each row of piles within the group would be redistributed with loading cycles. The lateral stiffness of the pile group decreases gradually with cycles and broadly presents three different degradation patterns in the test. Significant axial forces were measured out in some piles within the group, owing to the strong restraint provided by the cap, and finally lead to a large settlement of the pile group. These findings can be referred for foundation designing of offshore structures.

  12. Characterizing Axial Stiffness of Individual Batter Piles with Emphasis on Elevated, Laterally Loaded, Clustered Pile Groups

    Science.gov (United States)

    2016-11-01

    Ebeling1 investigated the minimum required depth of embedment for an example vertical pile bent system founded in a cohesionless sandy soil with two...vertical to 1 horizontal (4V:1H), angled toward shore . Prior to pile driving, the river bottom was dredged, or filled if needed, to elevation 650 ft

  13. Influence of axial load on the lateral pile groups response in cohesionless and cohesive soil

    Institute of Scientific and Technical Information of China (English)

    Jasim M. ABBASA[1; Zamri CHIK[2; Mohd Raihan TAHA[2

    2015-01-01

    The lateral response of single and group of piles under simultaneous vertical and lateral loads has been analyzed using a 3D finite element approach. The response in this assessment considered lateral pile displacement and lateral soil resistance and corresponding p-y curve. As a result, modified p-y curves for lateral single pile response were improved with respect to the influence of increasing axial load intensities. The improved plots can be used for lateral loaded pile design and to produce the group action design p-multiplier curves and equations. The effect of load combination on the lateral pile group response was performed on three pile group configurations (i.e., 2 × 1, 2 × 2 and 3 × 2) with four pile spacings (i.e., s = 2D, 4D, 6D and 8D). As a result, design curves were developed and applied on the actual case studies and similar expected cases for assessment of pile group behavior using improved p-multiplier. A design equation was derived from predicted design curves to be used in the evaluation of the lateral pile group action taking into account the effect of axial load intensities. It was found that the group interaction effect led to reduced lateral resistance for the pile in the group relative to that for the single pile in case of pure lateral load. While, in case of simultaneous combined loads, large axial load intensities (i.e., more than 6H, where H is lateral load values) will have an increase inp-multiplier by approximately 100% and will consequently contribute to greater group piles capacities.

  14. Comparative Model Tests of SDP and CFA Pile Groups in Non-Cohesive Soil

    Science.gov (United States)

    Krasiński, Adam; Kusio, Tomasz

    2015-02-01

    The research topic relates to the subject of deep foundations supported on continuous flight auger (CFA) piles and screw displacement piles (SDP). The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working as a single. The tests are ongoing in Geotechnical Laboratory of Gdaňsk University of Technology. The description of test procedure, interpretation and analysis of the preliminary testing series results are presented in the paper.

  15. Comparative Model Tests of SDP and CFA Pile Groups in Non-Cohesive Soil

    Directory of Open Access Journals (Sweden)

    Krasiński Adam

    2015-02-01

    Full Text Available The research topic relates to the subject of deep foundations supported on continuous flight auger (CFA piles and screw displacement piles (SDP. The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working as a single. The tests are ongoing in Geotechnical Laboratory of Gdaňsk University of Technology. The description of test procedure, interpretation and analysis of the preliminary testing series results are presented in the paper.

  16. Mathematical Model and Analysis of Negative Skin Friction of Pile Group in Consolidating Soil

    Directory of Open Access Journals (Sweden)

    Gangqiang Kong

    2013-01-01

    Full Text Available In order to calculate negative skin friction (NSF of pile group embedded in a consolidating soil, the dragload calculating formulas of single pile were established by considering Davis one-dimensional nonlinear consolidation soils settlement and hyperbolic load-transfer of pile-soil interface. Based on effective influence area theory, a simple semiempirical mathematical model of analysis for predicting the group effect of pile group under dragload was described. The accuracy and reliability of mathematical models built in this paper were verified by practical engineering comparative analysis. Case studies were studied, and the prediction values were found to be in good agreement with those of measured values. Then, the influences factors, such as, soil consolidation degree, the initial volume compressibility coefficient, and the stiffness of bearing soil, were analyzed and discussed. The results show that the mathematical models considering nonlinear soil consolidation and group effect can reflect the practical NSF of pile group effectively and accurately. The results of this paper can provide reference for practical pile group embedded in consolidating soil under NSF design and calculation.

  17. 锚杆静压桩群桩效应分析%Analysis of effect for anchored silent group pile

    Institute of Scientific and Technical Information of China (English)

    韩红娟; 郑七振

    2012-01-01

    In order to improve comprehension for the rule of interaction between pile, soil and pile caps, the software ABAQUS was applied to stimulate the different working properties of anchored silent group piles'foundation under different pile length, side length, pile spacing, number of pile and thickness of piles cap. The effect coefficient of group pile and undertaking ratio of pile cap will decreased with the increase of pile length and number of piles, but not the pile spacing. The results will be useful to the guidance of pile foundation design and make the design of pile to accord with real working conditions.%为促进对桩-土-承台相互作用规律的认识,本文主要运用ABAQUS模拟了锚杆静压桩(方桩)的不同桩长、桩边长、桩间距、桩数以及承台厚度情况下,锚杆静压桩群桩基础的工作性状.桩长的增长和桩数的增加,都会导致群桩效应系数和承台荷载分担比的降低;而随着桩间距增大群桩效应系数和承台荷载分担比增大.这些结论都有助于指导桩基设计,使得桩基设计更符合其实际工作状况.

  18. A simplified calculation approach for settlement of pile groups%群桩沉降简化计算方法

    Institute of Scientific and Technical Information of China (English)

    张乾青; 张忠苗

    2012-01-01

    将均质土和成层土中的单桩桩顶沉降分成桩端力引起的沉降、桩身压缩和桩侧阻力引起的沉降3部分分别计算,获得单桩沉降后,运用等代墩法可获得群桩的平均沉降.单桩沉降计算方法可考虑桩端力与桩端位移的非线性关系和桩侧阻力引起沉降的非线性特性,同时计算方法可考虑桩身压缩对桩顶沉降的贡献.算例分析表明,计算值与实测值和其他方法的计算值有较好的一致性,验证了该方法的合理性.%The pile head settlement of a single pile in homogeneous soil and multilayered soils can be subdivided into three aspects, including the pile tip settlement induced by mobilized load at the pile tip, the compression of pile shaft, and the settlement caused by the skin friction. Based on the settlement of a single pile and the equivalent pier method, a simplified calculation approach for average settlement of pile groups is obtained. The nonlinear relationship between the pile tip load and the settlement at the pile tip, and the nonlinear settlement induced by the skin friction can be taken into account, as well as the pile shaft compression. The settlements of a single pile and pile groups drawn from the present method are generally in good agreement with the measured values and the calculated values estimated from other methods.

  19. Dynamic response of a laterally loaded fixed-head pile group in a transversely isotropic multilayered half-space

    Science.gov (United States)

    Ai, Zhi Yong; Li, Zhi Xiong; Wang, Li Hua

    2016-12-01

    The time-harmonic response of a laterally loaded fixed-head pile group embedded in a transversely isotropic multilayered half-space is investigated using a finite element and indirect boundary element coupling method. The piles are solved by the finite element method (FEM), while the soil can be modeled by the indirect boundary element method (BEM) with the aid of the fundamental solution for a transversely isotropic multilayered half-space in a cylindrical coordinate system. The governing equation of the pile-soil-pile dynamic interaction is established by applying the FEM-BEM coupling method. Numerical examples are carried out to validate the presented theory and to investigate influences of the soil's anisotropy and layering on the dynamic response of pile groups.

  20. Study on load-bearing characteristics of a new pile group foundation for an offshore wind turbine.

    Science.gov (United States)

    Lang, Ruiqing; Liu, Run; Lian, Jijian; Ding, Hongyan

    2014-01-01

    Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect.

  1. Study on Load-Bearing Characteristics of a New Pile Group Foundation for an Offshore Wind Turbine

    Directory of Open Access Journals (Sweden)

    Ruiqing Lang

    2014-01-01

    Full Text Available Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect.

  2. Analysis of Pile Deformation Characters and Settlement of Pile Group Including New and Old Piles Considering Pile Timeliness%考虑沉桩时效性的新旧桩变形特性与沉降分析

    Institute of Scientific and Technical Information of China (English)

    孙晓晨; 朱杰江

    2016-01-01

    The bearing capacity of residue pile should be reassessed and then the internal relations and differences between the new pile and the residue one should be analyzed in soft soil area. Load⁃settlement relationship is expected to be obtained from above research. A three dimensional elastic⁃plastic finite element model is established by ABAQUS, old and new pile effect and the corresponding differential settlement are studied, and the load influencing factors of old and new piles are discussed. Research results show that with the increase of length to diameter ratio, the old and new pile settlement difference is slightly decreasing. With the increase of new pile diameter, pile of old and new different settlement are substantially reduced. With the increase of pile spacing and diameter ratio, the old pile settlement decreases sharply.%软土地区旧桩重新利用时须重新评估其承载能力,计算明确旧桩承载力与新桩承载力之间的内在联系与差异。采用ABAQUS软件构建新旧桩共同作用的三维弹塑性有限元分析模型,研究了新旧桩共同作用效应及相应的差异沉降,并对影响新旧桩荷载⁃沉桩关系的影响因素进行讨论。研究成果表明:随着长径比的增加,新旧桩的沉降差小幅减小;随着新桩桩径的增加,新旧桩的沉降差大幅减小;随着桩距与直径比值的增加,旧桩沉降大幅减小。

  3. 斜向荷载作用下桩群中设置斜桩对其沉降的影响分析%Effect analysis of battered pile on the settlement of pile group under inclined loadings

    Institute of Scientific and Technical Information of China (English)

    杨阳; 王国才; 金菲力

    2012-01-01

    The setting mode of pile group has much effect on pile group's bearing capacity and settlement under inclined loadings. In order to reveal this effect, the nonlinear finite element software is used and a 3-D model is developed to simulate the battered pile group under inclined loadings. The effect of inclined angle, pile-soil elastic modulus, battered pile length and number, etc. , on the settlement of battered pile group, is analyzed. The results indicate that: the geometry of soil, the inclined angle of battered pile, pile rigidity, length and number, etc. , has much effect on the settlement of battered pile group. Some useful conclusions are obtained for the design and construction of pile group that subjected to inclined loadings.%斜向荷载作用下桩群的设置方式对其承载力和沉降有较大影响.为揭示这一影响规律,采用非线性有限元软件对斜向荷载作用下桩群中设置的斜桩进行三维建模,分析了斜桩的倾角、桩-土弹性模量、斜桩桩长以及桩数等因素对群桩沉降的影响.结果表明:地基土质情况、斜桩的倾角、刚度和桩长与桩数等对倾斜群桩的沉降影响较大,所得结论对斜向荷载作用下群桩基础的设计与施工具有一定的指导意义.

  4. Experimental study on load bearing behavior of large-scaled caps with pile groups

    Institute of Scientific and Technical Information of China (English)

    Guo Chao; Lu Bo; Gong Weiming; Qiu Hongxing

    2009-01-01

    The objective of this investigation was to study the behavior of deep pile caps and the ultimate load-carrying capacity. Four 1/10 scaled models of nine-pile caps were cast and tested on vertical loads to failure. The destruction shapes of pile caps, the correlation between load and displacement, and the internal stresses were analyzed systematical-ly. The results demonstrated that the failures of all the four models are resulted from punching shear; the internal flow of the forces in nine-pile caps can be approximated by "strut-and-fie" model. Furthermore, the failure loads of these spec-imens were predicted by some of the present design methods and the calculated results were compared with the experi-mental loads. The comparative results also indicated that the "strut-and-tie" model is a more reasonable design method for deep pile caps design.

  5. Effect of Rigidity of Plinth Beam on Soil Interaction of Modeled Building Frame Supported on Pile Groups

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Reddy, C.

    2014-01-01

    Full Text Available This paper presents the effect of rigidity of plinth beam on a model building frame supported by pile groups embedded in cohesionless soil (sand through the results of static vertical load tests. The effect of rigidity of plinth beam on displacements and rotation at the column base and also shears and bending moments in the building frame were investigated. In the analytical model, soil nonlinearity in the axial direction is characterized by nonlinear vertical springs along the length of the pile (t-z curves and at the tip of the pile (Q-z curves while in the lateral direction by the p-y curves. Results revealed that, shear force and bending moment values which were back calculated from the experimental results, showed considerable reduction with the reduction of the rigidity of the plinth beam. The response of the frame from the experimental results is in good agreement with that obtained by the nonlinear finite element analysis.

  6. Seismic Material Properties of Reinforced Concrete and Steel Casing Composite Concrete in Elevated Pile-Group Foundation

    Directory of Open Access Journals (Sweden)

    Zhou Mi

    2015-09-01

    Full Text Available The paper focuses on the material mechanics properties of reinforced concrete and steel casing composite concrete under pseudo-static loads and their application in structure. Although elevated pile-group foundation is widely used in bridge, port and ocean engineering, the seismic performance of this type of foundation still need further study. Four scale-specimens of the elevated pile-group foundation were manufactured by these two kinds of concrete and seismic performance characteristic of each specimen were compared. Meanwhile, the special soil box was designed and built to consider soil-pile-superstructure interaction. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the RC specimens. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. The pinching effect of first two specimens is more obvious than latter two specimens and the hysteretic loops of reinforced specimens are more plumpness. The pseudo-static tests also provided the data to quantitatively assessment the positive effect of steel casing composite concrete in aseismatic design of bridge.

  7. 软土地层桥梁群桩基础沉降模型%Settlement model of bridge pile group foundation in soft soil stratum

    Institute of Scientific and Technical Information of China (English)

    汪优; 王星华; 刘建华; 蔡君君

    2012-01-01

    Based on the settlement characteristics of bridge pile foundation on soft soil stratum, the similarity rule of pile group model in this geological situation was derived. The indoor model of pile group foundation with pile cap was self-designed and analyzed. The test results show that the additional stress attenuates with the increase of depth and its distribution form approximates as triangular form within the scope of the pile body. At the same time, the vertical stress of pile-side soil increases as the settlement of pile top increases correspondingly. Moreover, the vertical stress of pile-side soil has not shown obvious converge even though the settlement of pile top is greater near the ultimate load. When the pile group foundation is under applied loads, representing different construction stages, the pile-side soil of upper pile body generates larger excess pore water pressure dissipating with time gradually, which indicates that the soil consolidation process needs some time to be finished. Furthermore, the relationship between load-settlement of pile group shows apparent non-linear characteristics, and its P-S curve can be divided into three /stages of linear phase, yielding stage and the overall destruction phase. In addition, the displacement rebound of pile group is small during unloading because the pile group generates large plastic deformation after the external load is applied. Therefore, the settlement of pile group foundation is one of the control conditions in the pile foundation design.%根据软土地层桥梁群桩基础的沉降特性,推导该地质环境下群桩模型试验相似法则,自行设计带承台群桩基础的室内模型并开展试验研究.试验结果表明:在桩身范围内,附加应力随深度衰减,在分布形式上,附加应力分布形式可近似为三角形;同时,桩侧土体的竖向应力随着桩顶沉降的增加而相应的增加,在接近极限荷载产生较大沉降时也没有表现出明显收敛的现

  8. Behavior of a Large-Scale Pile Group Subjected to Cyclic Lateral Loading.

    Science.gov (United States)

    1988-02-01

    Zee . N.Y. rang 1956 G steel pipe 6 22 soft cldy San Francisco Seed A Reese. ;95 £ steel pipe 12 O0 soft clay Michigan Housei 19S8 Oe precast 14 ,45 soft...approximate value of 0.5 for soft offshore clays of the Gulf of Mexico and a value of 0.25 for somewhat stiffer clays (used for this test site), and b = pile

  9. Big Pile or Small Pile?

    Science.gov (United States)

    Branca, Mario; Quidacciolu, Rossana G.; Soletta, Isabella

    2013-01-01

    The construction of a voltaic pile (battery) is a simple laboratory activity that commemorates the invention of this important device and is of great help in teaching physics. The voltaic pile is often seen as a scientific toy, with the "pile" being constructed from fruit. These toys use some strips of copper and zinc inserted in a piece…

  10. 液化地基中群桩基础地震响应分析%Seismic response analysis of pile groups in liquefiable foundations

    Institute of Scientific and Technical Information of China (English)

    刘星; 王睿; 张建民

    2015-01-01

    可液化地基中桩基础地震响应分析一直是岩土工程抗震研究的热点和难点。针对这一问题,采用砂土液化大变形统一本构模型来描述可液化地基土体的应力应变关系,建立了一个3×5的群桩三维计算模型,采用三维弹塑性有限元动力时程分析,将地基、群桩基础和上部结构作为一个系统研究群桩基础的地震动响应规律,重点关注桩与土的运动相互作用以及水平方向的弯矩在地震荷载作用下的分配情况。结果表明可液化地基中桩基础的弯矩受桩与土运动相互作用影响显著;不同桩的弯矩最大值不同,角桩最大,边桩次之,中心桩最小;弯矩最大值出现的位置不相同,角桩和边桩弯矩最大值出现在上部非液化层与液化层界面处,中心桩弯矩最大值出现在桩头处。%The seismic analysis of pile foundations in liquefiable ground is an important subject in geotechnical earthquake engineering. A computational model of a 3×5 pile group is established in OpenSees FEM program, and considering soil foundations, the pile group and the upper structure as a system, a unified plastic constitutive model for large post-liquefaction deformation of sand is employed. Special attention is given to the kinematic interaction between piles and soil and distribution of the moment in pile groups. The results show that the soil-pile kinematic interaction has a significant influence on the moment of piles in liquefiable ground. The moment distribution in pile groups indicates that the maximum moment of the corner piles is the largest, and that of the central piles is the smallest. The positions of the maximum moment of different piles are different. The maximum moments in the corner piles and the edge piles are at the interface between the upper layer and the liquefied layer, but the maximum moment in the central piles is at the pile top.

  11. Pile Driving

    Science.gov (United States)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  12. Modeling of Batter Pile Behavior under Lateral Soil Movement

    Science.gov (United States)

    Chen, C. Y.; Hsu, H. Q.

    2017-06-01

    Pile foundation is frequently used when structures are located on weak sublayers or are at risk from lateral loadings such as earthquakes. The design of pile foundations has recently become crucial to stop slope movement. To understand the behavior of pile foundations subjected to lateral soil movement, the three-dimensional Fast Lagrangian Analysis of Continua (FLAC3D) program was used to perform numerical simulations, which can reduce the cost of field testing. Vertical piles and batter piles were combined into 3 × 3 pile groups, and the response of batter piles to soil movement was analyzed. The outer batter piles led to an increased bending moment in the middle, vertical pile row. Increasing the pile spacing and the presence of battered piles reduced the pile group’s displacement. The batter pile group’s maximum bending moment was smaller than the vertical pile group’s in sand soil, but 5-8 times higher in clay soil.

  13. 软土地层桥梁群桩基础桩土共同作用性状的非线性有限元分析%Nonlinear finite element analysis of pile-soil interaction of bridge pile group foundation in soft soil stratum

    Institute of Scientific and Technical Information of China (English)

    汪优; 刘建华; 王星华; 蔡君君

    2012-01-01

    A three dimensional nonlinear finite element model of pile group foundation of a high-speed railway bridge was built. Combined with the corresponding data obtained from field tests, the rules of pile axial force, pile side friction force, soil additional stress, pore water pressure distribution, excess pore water pressure dissipation and settlement of pile group foundation were analyzed. The calculation results show that the axial forces of corner piles are larger than the side piles which are larger than the center piles; and the axial forces of corner piles and side piles reduce greatly along the pile body; and the axial forces of center piles decrease slowly. Moreover, the regular pattern of pile side friction is that the pile side friction measurement of corner piles are larger than the side piles which are larger than the center piles generally; and the amount of relative displacement between pile and soil is bigger on the upper and less on the lower. That is to say, the amount of relative displacement between pile and soil on the upper of pile is larger than on the middle and lower of pile. Furthermore, the soil additional stress and excess pore water pressure generated by external loads mainly concentrate in soil under the pile cap within a certain range; and their attenuation gradients decrease along the depth gradually. With the increasing of the consolidation time, the settlement of pile group foundation arrives to be stabilized.%通过对某高速铁路特大桥群桩基础进行三维非线性有限元分析,并结合现场试验得出的规律进行相应的对比分析,研究了软土地层桥梁群桩基础桩身轴力、桩侧摩阻力、基底土体附加应力、孔隙水压力分布、超孔隙水压力消散和群桩基础荷载沉降规律.计算结果表明,基桩所承受的轴力,角桩>边桩>中心桩,角桩和边桩的轴力沿桩身减小的幅度较大,而中心桩的轴力沿桩身减小的幅度稍小;各基桩桩侧摩阻力

  14. 大直径超长群桩有效桩长问题的有限元参数分析%Parametric finite element analysis of effective pile-length in super-long and large-diameter pile groups

    Institute of Scientific and Technical Information of China (English)

    陈培震; 栾茂田; 罗强

    2012-01-01

    采用大型有限元软件ABAQUS,针对大直径超长群桩的有效桩长进行三维有限元数值分析.采用极限承载力控制法,对竖向荷载下不同布桩形式的大直径超长群桩基础的有效桩长进行研究.结果表明:有效桩长随桩数的增多而增大,随桩距的增大而减小;桩数增多,有效桩长对应的群桩的极限承载力降低,桩距的变化对有效桩长对应的群桩的极限承载力影响不大.%Based on the framework of FEM software ABAUQS, the three-dimensional numerical analysis for effective length of super-long and large-diameter pile groups is provided. For the pile groups of different arrangements under vertical loading, the effective pile-length was analyzed with the method of bearing capacity control. The results show that the effective pile-length increases with pile number while decreases with the space between piles. The corresponding bearing capacity decreases with pile number while the space between piles has little effect on the corresponding bearing capacity.

  15. 竖向荷载下群桩-土-承台相互作用数值分析%Numerical analysis of interaction of pile group-soil-raft under vertical load

    Institute of Scientific and Technical Information of China (English)

    杜家庆; 杜守继; 赵丹蕾; 唐文勇

    2013-01-01

    Besides the interaction of the multiple stress superposition from piles shaft friction, pile bottom resistance and contact stress between low caps and soil, the clamping action makes the cap-pile-soil interaction more complicated in pile foundation with large pile diameter and small spacing. 3D finite difference program is employed to evaluate the pile-soil-cap interaction with the change of vertical load, while the pile spacing and pile diameter remain constant in the analysis procedure. Analysis is carried out to explain the interaction of cap-pile-soil from the following aspects such as the lateral friction of soil in each layer, load on the top of characteristic piles, load-settlement relationship, vertical displacement of soil between piles, etc. The results show that: the clamping action on the upper soil among piles will decrease, and the pile shaft friction in the upper part will increase when the load exceeds 117.8 MN which is slightly larger than Pu/2 (Pu means ultimate bearing capacity of piles group); the lower part of pile shaft friction shows a trend of decrease due to the influence of the multiple stress superposition, and the decrease trend in characteristic piles has different influence scope; the load, which makes settlement of piles group achieve 5% of pile diameter, can be regarded as the vertical ultimate bearing capacity of piles group, and it is reasonable; when the ratio of piles group’s settlement to pile diameter exceeds 1%, the proportion of the load carried by piles decreases because of the cap contribution.%  在大桩径、小桩距的群桩条件下,不仅有来自桩侧、桩端和承台传递的多重应力叠加,还有群桩对桩间土的夹持作用影响,桩-土-承台之间作用更加复杂。用有限差分软件模拟固定桩距、桩径,变化竖向荷载下桩-土-承台的相互作用。从各层土的侧摩阻力、不同位置桩的桩顶荷载、荷载-沉降关系、桩间土体位移等方面的计算

  16. Simplified Analysis Procedures for Flexible Approach Wall Systems Founded on Groups of Piles and Subjected to Barge Train Impact

    Science.gov (United States)

    2012-09-01

    reinforced concrete piles (Figure 2-4a, b, c) can be developed using procedures described in Derecho et al. (1978). The points on the interaction...Instruction Report ITL-94-6. US Army Engineer Waterways Experiment Station, Vicksburg, MS. Derecho , A. T., D. M. Schultz, and M. Fintel. 1978

  17. Letter of professional groups. Energies and fuel cells; La lettre des Groupe Professionnels, energies et piles a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Meunier, M. [Supelec, 91 - Gif sur Yvette (France); Serre Combe, P. [CEA Grenoble, 38 (France); Sartorelli, G. [Maxwell Technologie, San Diego, CA (United States); Lafont, G. [PILLER France S.A., 92 - Nanterre (France); Green, A. [SAFT, 93170 Bagnolet (France); Perrin, M. [CEA Cadarache, 13 - Saint Paul lez Durance (France); Fregere, J.P.

    2004-07-01

    These proceedings of the 'Arts et Metiers' professional groups treats of energy storage solutions for delocalized power generation units. Four types of energy storage systems are presented with their operation principle, advantages and drawbacks: fuel cells and hydrogen, super-capacitors, flywheels, conventional batteries (lithium-ion, lead, redox, nickel-cadmium, zinc-air), and comparison between the different energy storage solutions including compressed air. (J.S.)

  18. 水平偏心荷载下斜桩群桩受力性状的离心机模型试验%Centrifugal model tests on batter pile groups under eccentric lateral loads

    Institute of Scientific and Technical Information of China (English)

    顾明; 陈仁朋; 孔令刚; 陈云敏; 张浙杭

    2014-01-01

    A series of centrifugal model tests are conducted to investigate the behavior of pile groups in sand subjected to eccentric lateral loads, especially the role of batter pile groups in resisting lateral or eccentric loads. The preparation and the procedure of the tests are described. The test results reveal that the eccentric distance of the lateral loads will affect the lateral response of the pile groups to some extent within the experimental range, but have little effect on the torsional behavior of the pile groups. The bearing capacity of the plumb pile group under lateral loads with eccentric distance of 4.3D is higher than that of zero and 7.1D. The capacity of the batter pile groups subjected to lateral, eccentric or torsional loads is much higher than that of the plumb pile groups. Under the eccentric loads, the differences between the lateral displacements of individual piles within the batter pile groups are larger than those in the plumb pile groups, and they also increase with the eccentric distance of the lateral loads. The shear forces and lateral displacements at head of individual piles are different in direction. The axial forces of individual piles within the batter pile groups are dramatically larger than those in the plumb pile groups under the same load condition, which illustrates that batter pile groups can more effectively resist the lateral loads than the plumb pile groups by taking full advantages of the axial capacity of individual piles.%为研究斜桩群桩在水平偏心荷载下的受力性状,在砂土中开展了一系列离心机模型试验,着重对比了直桩群桩和斜桩群桩抵抗水平及偏心荷载的不同特性。详细介绍了模型试验的装置、方法以及内容。试验结果表明:水平荷载偏心距大小对群桩水平承载力有一定的影响,但是对群桩扭转承载力的影响较小。对于直桩群桩,在试验范围内小偏心距(4.3倍桩径)加载对应的水平承载力大

  19. 液化侧扩流场地桥梁群桩效应分析%Analysis of the Bridge Pile Group Effect in Liquefaction-induced Lateral Spreading Sites

    Institute of Scientific and Technical Information of China (English)

    刘春辉; 唐亮; 凌贤长

    2015-01-01

    The Finite Element method was used to analyze the dynamic response of pile groups in the ground subjected to the liquefaction-induced lateral flow of soils.The u-p Finite Element for-mulation was used to depict the coupling effect of water and sand soil particles in the Finite Ele-ment analysis.A 3D numerical model was developed to analyze the effect of a 2×2 pile group sub-jected to liquefaction-induced lateral spreading.In this model,sand was simulated using a pres-sure-independent multi-yield surface plastic model.Clay material served as a nonlinear hysteretic material with a multi-surface kinematic plasticity model,and the pile group maintained its linear behavior in the process of calculation.The clay layer and saturated sand layer were meshed in a 20-node brick element and separately in a 20-8 node element.The boundary of the numerical model was considered as the shear beam boundary,which simulated the shear effect of the soil layer dur-ing the earthquake.Finally,the Rayleigh damping method was used to model the damping of the system.The dynamic response of each pile in pile group was compared,and it showed that the bending moment and displacement time history of piles at different depths developed in the same way,and the time of maximum bending moment and displacement of the pile appears to lag be-hind the time of peak acceleration of the input seismic wave.The maximum bending moment and displacement of the leading pile were larger than the those of the back piles.By comparing the maximum bending moment and displacement,it can also be concluded that,as depth increases,the maximum bending moment first increases and then decreases.The bending moment of the pile at the 2.5 m depth was greater than those at other depths.In terms of displacement,as depth in-creased,the maximum pile displacement decreased,and the maximum displacement of the pile head was greater than other observed points on the pile.This demonstrated the different behaviors of the pile bending

  20. NONLINEAR STATIC CALCULATION MODEL AND PSEUDO-STATIC TEST OF PILE GROUP BRIDGE FOUNDATIONS%桥梁群桩基础非线性静力计算模型及拟静力试验研究

    Institute of Scientific and Technical Information of China (English)

    张永亮; 陈兴冲; 孙建飞

    2013-01-01

    Horizontal bearing characteristics of bridge pile foundations can be analyzed by using linear elastic subgrade reaction method(m-method) when displacement of pile foundation is generally smaller. However, displacement of pile foundations is often larger under the effect of strong earthquakes. In order to understand the horizontal bearing capacity and deformation characteristics of pile foundations considering nonlinear behaviors of pile shaft and subsoil,a model of pile foundations is constructed. Failure mechanism,bearing capacity, deformation characteristics and hysteresis characteristics of pile foundations are studied by using pseudo-static test. A nonlinear static calculation model of pile group foundations is put forward under horizontal load. The elastoplasticity of pile shafts in variable axial loads is simulated by distributed PMM plastic hinge;and nonlinearity of subsoil is simulated by the curves of p-y,t-z and q-z,respectively,which have been given in the code of American API;where p is horizontal soil resistance at lateral of pile shaft;y is horizontal displacement;t is vertical frictional resistance around piles shaft;q is vertical bearing resistance at pile tip;z is vertical relative displacement of interface between pile and soil. The results show that:(1) The numerical results are in good agreement with those obtained from experiments. (2) Hysteretic characteristics of pile foundations can be simulated using Clough degradation bilinear model. (3) Weak positions of pile shaft are 0-4 times around the radius of pile below pile top. The results can provide references for evaluating seismic performance of bridge pile foundation using capacity spectrum method.%线弹性地基反力法(m 法)仅适用于正常使用时桥梁桩基础变位较小的情况,但在强震作用下基础的变位较大。为了研究桩基础在地基土及桩身进入非线性状态下的水平承载能力及变形特性,通过群桩基础缩尺比例模型,采用拟

  1. Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

    Institute of Scientific and Technical Information of China (English)

    He Ping; Guan Yijun; Zhang Xiongwen; Zhang Qun; Zhou Jianhua

    2009-01-01

    Sutong Bridge, as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China, is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore, scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge. This paper, starting from structural description of deep-water group pile foundation, analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

  2. 考虑加筋与遮帘效应计算群桩沉降的相互作用系数法%Interaction coefficients method for calculating piles group settlements considering reinforcing and restraining effect

    Institute of Scientific and Technical Information of China (English)

    林智勇; 戴自航

    2014-01-01

    The reinforcing and restraining effect of piles embedded in soils is objective existence. However, the correlative research work on pile groups settlement methods is not deep enough and needs to be continued. Based on the shear displacement method, considering the reinforcing and restraining effect, the settlements of the analyzing pile caused by loads on the pile top were calculated, including the reduction effect caused by the existence of the other adjacent piles. And the additional settlements of the adjacent piles arising from the settlement of the loaded pile were obtained as well. Thus a simplified formula of interaction coefficients between any two piles was presented. Meanwhile, the equivalent shear stiffness coefficients of soil around each pile were developed; and an equation of displacements caused by load on top of the analyzing pile imbedded in multi-layered soils was built; so recurrence relations of settlement and axial force of pile shaft between upper and lower of each pile sections were respectively deduced; in the process of deduction, Boussinesq solution was modified to include the effect of different embedded depths, and then used to derive the equivalent stiffness coefficients of the soil under the pile tips. Lastly, the formula was extended to the settlements calculation of high and low cap pile groups. Different methods were compared with two engineering cases. The results show that the load-settlement curve computed by present method agreed well with those measured from real engineering cases; and the calculating interaction coefficients are much less than ones calculated by the elastic theory method.%群桩中各基桩在地基土中的加筋与遮帘效应是客观存在的,然而,在目前的桩基沉降理论与实践中,相关的研究仍显不足。基于剪切变形法理论,考虑桩的加筋与遮帘效应,求得各基桩在自身桩顶荷载作用下产生的沉降以及其引起相邻桩的附加沉降量,由此提

  3. The pile EL3; Pile EL3

    Energy Technology Data Exchange (ETDEWEB)

    Robert, J.; Raievski, V. [Commissariat a l' Energie Atomique, Paris (France). Centre d' Etudes Nucleaires; Hainzelin, J. [Chantiers de l' Atlantique (Penhoet-Loire), 75 - Paris (France)

    1959-07-01

    The programme of the high flux laboratory pile EL3 was laid down in october 1954. It is a heavy-water moderated and cooled pile. The fuel rods are of uranium metal with 1.6 per cent - 2 per cent of molybdenum, with aluminium canning. The maximum thermal flux in the moderator is 10{sup 14} n/cm{sup 2}/s. Studies began in january 1955, construction in may 1955, and the first divergence took place in July 1957. This report gives a general description of the pile and its adjacent buildings, the physical study of the pile, and certain technological studies carried out for the construction of EL3. (author) [French] Le programme de la pile laboratoire a haut flux EL3, a ete fixe en octobre 1954. C'est une pile moderee et refroidie a l'eau lourde. Les barres de combustible sont en uranium metal a 1,6 pour cent - 2 pour cent de molybdene, gainees a l'aluminium. Le flux thermique maximum dans le moderateur est de 10{sup 14} n/cm{sup 2}/s. Les etudes ont commence en janvier 1955, la construction en mai 1955, la premiere divergence a eu lieu en juillet 1957. On trouvera dans ce rapport, une description generale de la pile et de ses batiments annexes, l'etude physique de la pile et un certain nombre d'etudes technologiques executees pour la construction d'EL3. (auteur)

  4. Simulation and Advanced Second Moment Reliability Analyses of Pile Groups Using CPGA-R: Formulation, User’s Guide, and Example Problems

    Science.gov (United States)

    2013-09-01

    stiffness should be calculated numerically using methods described by Dawkins (1978). 2.7.3 Pile strength performance limits Pure axial load The...Univ. Dawkins , W. P. 1978. Pile head stiffness matrices (unpublished). Vicksburg, MS: US Army Engineer Waterways Experiment Station. Ditlevsen, O

  5. Piles of objects

    KAUST Repository

    Hsu, Shu-Wei

    2010-01-01

    We present a method for directly modeling piles of objects in multi-body simulations. Piles of objects represent some of the more interesting, but also most time-consuming portion of simulation. We propose a method for reducing computation in many of these situations by explicitly modeling the piles that the objects may form into. By modeling pile behavior rather than the behavior of all individual objects, we can achieve realistic results in less time, and without directly modeling the frictional component that leads to desired pile shapes. Our method is simple to implement and can be easily integrated with existing rigid body simulations. We observe notable speedups in several rigid body examples, and generate a wider variety of piled structures than possible with strict impulse-based simulation. © 2010 ACM.

  6. A Plagioclase Ultraphyric Basalt group in the Neogene flood basalt piles of eastern Iceland: Volcanic architecture and mode of emplacement

    Science.gov (United States)

    Oskarsson, B. V.; Riishuus, M. S.

    2013-12-01

    3D photogrammetry in conjunction with ground mapping was applied in order to assess the architecture of a Plagioclase Ultraphyric Basalt (PUB) group in eastern Iceland, namely the Grænavatn group. The ~10 Myr old group is exposed in steep glacially carved fjords and can be traced over 60 km along strike. Two feeder dikes have been found and show that the group erupted along the trend of the dike swarm associated with the Breiddalur central volcano. The group has 9--14 flows where thickest, and thins to about 3--4 flows up-dip to the east within the distance of 15-20 km from the source. We have estimated the volume of the group to exceed 40 km3. The flows have mixed architecture of simple and compound morphology. The flow lobes have thicknesses from 1--24 m and many reach lengths over 1000 m. The surface morphology varies from rubbly to scoriaceous, but is dominantly of pahoehoe style. The internal structure of the lava flows is well preserved and the flows display abundant vesicle cylinders. The modal percentage of An-rich plagioclase macrocrysts varies from 25--50 % and they are in the range of 5--30 mm. The aspect ratio of the group and the nature of the flows indicate fissure-fed eruptions. A thick flow found at the base of the group in various locations seems to record the largest eruption episode in the formation of the group. This phase is also the most abundant in macrocryst. An asymmetric buildup is seen in one location and may have characterized the general buildup of the group. The general morphology of the lava flows suggests low viscous behavior, at odds with the high crystal content. Petrographic observations and mineral chemistry shows that the plagioclase macrocrysts are very calcic (An80-85) and in disequilibrium with the groundmass and plagioclases therein (An50-70). Thus the apparent lava rheology and emplacement of the PUBs was likely achieved due to fast ascent of the magma through the crust and transfer of heat from the primitive macrocrysts

  7. Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Eekelen, S.J.M.

    2015-01-01

    A basal reinforced piled embankment consists of a reinforced embankment on a pile foundation. The reinforcement consists of one or more horizontal layers of geosynthetic reinforcement (GR) installed at the base of the embankment. The design of the GR is the subject of this thesis. A basal

  8. Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Eekelen, S.J.M.

    2015-01-01

    A basal reinforced piled embankment consists of a reinforced embankment on a pile foundation. The reinforcement consists of one or more horizontal layers of geosynthetic reinforcement (GR) installed at the base of the embankment. The design of the GR is the subject of this thesis. A basal reinforce

  9. Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Eekelen, S.J.M.

    2015-01-01

    A basal reinforced piled embankment consists of a reinforced embankment on a pile foundation. The reinforcement consists of one or more horizontal layers of geosynthetic reinforcement (GR) installed at the base of the embankment. The design of the GR is the subject of this thesis. A basal reinforce

  10. A Pile of Legos.

    Science.gov (United States)

    DePino, Andrew, Jr.

    1994-01-01

    Describes the relationships a high school built with neighborhood industry, a national laboratory, a national museum, and a large university while trying to build a scale model of the original atomic pile. Provides suggestions for teachers. (MVL)

  11. Numerical analysis of pile lateral behavior of pile supported embankment

    Institute of Scientific and Technical Information of China (English)

    荆志东; 刘力; 郑刚; 姜岩

    2008-01-01

    A finite difference numerical method was adopted to evaluate the pile lateral behavior of pile supported embankment. A published case history was used to verify the proposed methodology. By simulating the case history, the determination of parameters needed were verified. Then three embankments constructed on different ground conditions with different soil-pile relative stiffnesses were analyzed to study pile lateral behaviors including pile deflection and bending moment. The results show that pile deflections and bending moments induced by soil lateral deformation and embankment vertical load are different for piles at different positions under the same embankment. The relative stiffness between pile and soil affected by the properties of different reinforcing piles such as concrete pile and deep mixing method pile exert important effects on the pile lateral behavior and the pile’s failure modes. Consequently, it is necessary to consider the different piles lateral behaviors and possible failure modes at different positions and the different piles proprieties with different reinforcing methods in the embankment stability analysis.

  12. Soil-Pile Interaction in the Pile Vertical Vibration Based on Fictitious Soil-Pile Model

    OpenAIRE

    Guodong Deng; Jiasheng Zhang; Wenbing Wu; Xiong Shi; Fei Meng

    2014-01-01

    By introducing the fictitious soil-pile model, the soil-pile interaction in the pile vertical vibration is investigated. Firstly, assuming the surrounding soil of pile to be viscoelastic material and considering its vertical wave effect, the governing equations of soil-pile system subjected to arbitrary harmonic dynamic force are founded based on the Euler-Bernoulli rod theory. Secondly, the analytical solution of velocity response in frequency domain and its corresponding semianalytical solu...

  13. SCOUR MITIGATION AT BRIDGE PIERS USING SACRIFICIAL PILES

    Institute of Scientific and Technical Information of China (English)

    M. Anisul HAQUE; Md. Munsur RAHMAN; G.M. Tarekul ISLAM; M. Asad HUSSAIN

    2007-01-01

    To mitigate scour around bridge piers, sacrificial piles are economic method where natural processes are involved. The arrangement should be such that scoured materials from the sacrificial piles should have enough volume to fill the scour hole created upstream of the pier in such a way that sediments are trapped inside the scour hole. This concept differs from earlier study made with sacrificial piles that mainly deals to reduce the strength of horseshoe vortex. To determine the effect of sacrificial piles for scour mitigation, alternative arrangements of piles were tested in front of a rectangular pier under clear-water condition and found that when the group of piles is placed at a distance of twice the projected width of the pier, for which percentage of blockage of the pier width is 60%, the scour volume can be reduced upto 61% while the maximum scour depth can be reduced upto 50%.

  14. Seismic response of tall building considering soil-pile-structure interaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The seismic behavior of tall buildings can be greatly affected by non-linear soil-pile interaction during strongearthquakes. In this study a 20-storey building is examined as a typical structure supported on a pile foundation for differentconditions: (1) rigid base, i.e. no deformation in the foundation: (2) linear soil-pile system; and (3) nonlinear soil-pile system.The effects of pile foundation displacements on the behavior of tall building are investigated, and compared with the behavior ofbuildings supported on shallow foundation. With a model of non-reflective boundary between the near field and far field,Novak's method of soil-pile interaction is improved. The computation method for vibration of pile foundations and DYNANcomputer program are introduced comprehensively. A series of dynamic experiments have been done on full-scale piles,including single pile and group, linear vibration and nonlinear vibration, to verify the validity of boundary zone model.

  15. Flexible pile thermal barrier insulator

    Science.gov (United States)

    Anderson, G. E.; Fell, D. M.; Tesinsky, J. S. (Inventor)

    1978-01-01

    A flexible pile thermal barrier insulator included a plurality of upstanding pile yarns. A generally planar backing section supported the upstanding pile yarns. The backing section included a plurality of filler yarns forming a mesh in a first direction. A plurality of warp yarns were looped around said filler yarns and pile yarns in the backing section and formed a mesh in a second direction. A binder prevented separation of the yarns in the backing section.

  16. Laterally Loaded Piles in Clay

    DEFF Research Database (Denmark)

    Christensen, Helle; Niewald, Gitte

    1992-01-01

    The ultimate lateral resistance of a pile element moved horizontally can be analyzed by the theory of plasticity. At a certain depth the movements around the pile are purely horizontal and upper bound solutions can be estimated theoretically under undrained circumstances. Model tests...... in the laboratory show ultimate resistances close to the estimated limits and p - y curves close to curves based on test results from full-scale piles. Rough and smooth piles with circular and square cross sections are investigated....

  17. 海上风电机组多桩承台基础结构设计与参数优化分析%Structure Design and Parameter Optimization Analysis on Pile Group Cap Foundation of Offshore Wind Power

    Institute of Scientific and Technical Information of China (English)

    李振作; 田伟辉; 胡永柱

    2015-01-01

    针对适用于软土海床地基条件的近海风电机组多桩承台基础结构型式,依据相关规范及工程经验,确定多桩承台基础结构尺寸设计原则,分析基础结构设计所应考虑的荷载及荷载组合方式,建立多桩承台基础结构分析模型,对基础结构设计的主要参数进行优化分析,为海上风电基础结构设计提供指导。%For studying the structural type of pile group cap foundation for offshore wind turbine which is suitable for soft clay seabed, the size design principles of this foundation are determined, the loads and load combinations of structure design are analyzed and then the structure analysis model of this foundation is established according to the relevant standards and engineering experiences. The main parameters in the structure design of pile group cap foundation are optimized by using the model to provide guidance for the structure design of offshore wind turbine.

  18. Test Exponential Pile

    Science.gov (United States)

    Fermi, Enrico

    The Patent contains an extremely detailed description of an atomic pile employing natural uranium as fissile material and graphite as moderator. It starts with the discussion of the theory of the intervening phenomena, in particular the evaluation of the reproduction or multiplication factor, K, that is the ratio of the number of fast neutrons produced in one generation by the fissions to the original number of fast neutrons, in a system of infinite size. The possibility of having a self-maintaining chain reaction in a system of finite size depends both on the facts that K is greater than unity and the overall size of the system is sufficiently large to minimize the percentage of neutrons escaping from the system. After the description of a possible realization of such a pile (with many detailed drawings), the various kinds of neutron losses in a pile are depicted. Particularly relevant is the reported "invention" of the exponential experiment: since theoretical calculations can determine whether or not a chain reaction will occur in a give system, but can be invalidated by uncertainties in the parameters of the problem, an experimental test of the pile is proposed, aimed at ascertaining if the pile under construction would be divergent (i.e. with a neutron multiplication factor K greater than 1) by making measurements on a smaller pile. The idea is to measure, by a detector containing an indium foil, the exponential decrease of the neutron density along the length of a column of uranium-graphite lattice, where a neutron source is placed near its base. Such an exponential decrease is greater or less than that expected due to leakage, according to whether the K factor is less or greater than 1, so that this experiment is able to test the criticality of the pile, its accuracy increasing with the size of the column. In order to perform this measure a mathematical description of the effect of neutron production, diffusion, and absorption on the neutron density in the

  19. Soil-Pile Interaction in the Pile Vertical Vibration Based on Fictitious Soil-Pile Model

    Directory of Open Access Journals (Sweden)

    Guodong Deng

    2014-01-01

    Full Text Available By introducing the fictitious soil-pile model, the soil-pile interaction in the pile vertical vibration is investigated. Firstly, assuming the surrounding soil of pile to be viscoelastic material and considering its vertical wave effect, the governing equations of soil-pile system subjected to arbitrary harmonic dynamic force are founded based on the Euler-Bernoulli rod theory. Secondly, the analytical solution of velocity response in frequency domain and its corresponding semianalytical solution of velocity response in time domain are derived by means of Laplace transform technique and separation of variables technique. Based on the obtained solutions, the influence of parameters of pile end soil on the dynamic response is studied in detail for different designing parameters of pile. Lastly, the fictitious soil-pile model and other pile end soil supporting models are compared. It is shown that the dynamic response obtained by the fictitious soil-pile model is among the dynamic responses obtained by other existing models if there are appropriate material parameters and thickness of pile end soil for the fictitious soil-pile model.

  20. When Rubble Piles Collide...

    Science.gov (United States)

    Richardson, D. C.; Leinhardt, Z. M.; Quinn, T.

    1999-09-01

    There is increasing evidence that many km-sized bodies in the Solar System may be rubble piles, gravitationally bound collections of solid material (Richardson, Bottke, & Love 1998, Icarus 134, 47). If true, then collisions may occur in free space between rubble piles. Here we present results from a project to map the parameter space of collisions between km-sized spherical rubble piles. The results will assist in parameterization of collision outcomes for Solar System formation models and may give insight into catastrophic disruption scaling laws. We use a direct numerical method (Richardson, Quinn, Stadel, & Lake 1999, Icarus, in press) to evolve the positions and velocities of the rubble pile particles under the constraints of gravity and physical collisions. We test the dependence of the collision outcomes on impact speed and angle, spin, mass ratio, and dissipation parameter. Speeds are kept low so that the maximum strain on the component material does not exceed the crushing strength, appropriate for dynamically cool systems such as the primordial disk during early planet formation. We compare our results with analytic estimates, laboratory experiments, hydrocode simulations, and stellar system collision models. We find that net accretion dominates the outcomes in head-on, slow encounters while net erosion dominates for off-axis, fast encounters. The dependence on impact angle is almost equally as important as the dependence on impact speed. Off-axis encounters can result in fast-spinning elongated remnants or contact binaries while fast encounters result in smaller fragments overall. Reaccumulation of debris escaping from the remnant can occur, leading to the formation of smaller rubble piles. Less than 2% of the system mass ends up in orbit around the remnant. Initial spin can reduce or enhance collision outcomes, depending on the relative orientation of the spin and orbital angular momenta. We derive a relationship between impact speed and angle for

  1. Ground Vibration Isolation of Multiple Scattering by Using Rows of Tubular Piles as Barriers

    Directory of Open Access Journals (Sweden)

    Miao-miao Sun

    2014-01-01

    Full Text Available A new formal solution for the multiple scattering of plane harmonic waves by a group of arbitrary configuration tubular piles in an elastic total space is derived. Each order of scattering satisfies prescribed boundary conditions at the interface of tubular piles, which is delivered as the sum of incident and scattering waves. The first order performs the scattering wave by each scattered pile and the subsequent orders resulted from the excitation of each pile of first order of scattering from the remaining tubular piles. Advanced scattering orders can be regarded as the same manners. Several series of scattering coefficients are figured out with the aids of addition theorem so that the exact steady-state solution for the scattered displacement and stress is obtained. Particularly, when internal diameter of tubular piles tends to be infinitely small, it degenerates to a solid pile problem. By imposing the normalized displacement amplitudes and transmissibility indices, the influences of specific parameters such as scattering orders, internal and external diameter ratio of piles, pile material rigidity, position and distances between tubular pile and pile rows, and pile numbers are discussed. Certain recommended conclusions have been drawn as the guidelines of practical engineering design for discontinuous barrier of tubular piles.

  2. Mono pile foundation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lyngesen, S.; Brendstrup, C.

    1997-02-01

    The use of mono piles as foundations for maritime structures has been developed during the last decades. The installation requirements within the offshore sector have resulted in equipment enabling driving of piles up to 3-4 m to large penetration depths. The availability of this equipment has made the use of large mono piles feasible as foundations for structures like wind turbines. The mono pile foundations consists of three parts; the bare pile, a conical transition and a boat landing. All parts are prefitted at the yard in order to minimise the installation work that has to be carried out offshore. The study of a mono pile foundations for a 1.5 MW wind turbine has been conducted for two locations, Horns Rev and Roedsand. Three different water depths: 5, 8 and 11 m have been investigated in the study. The on-site welding between pile and conical transition is performed by an automatic welding machine. Final testing and eventually repair of the weld are conducted at least 16 hours after welding. This is followed by final installation of J-tube, tie-in to subsea cables and installation of the impressed current system for corrosive protection of the mono pile. The total cost for procurement and installation of the mono pile using the welded connection is estimated. The price does not include procurement and installation of access platform and boat landing. These costs are estimated to 250.000 DKK. Depending on water depth the cost of the pile ranges from 2,2 to 2,7 million DKK. Procurement and fabrication of the pile are approx. 75% of the total costs. The remaining 25% are due to installation. The total costs are very sensitive to the unit price of pile steel. During the project it became obvious that ice load has a very large influence on the dimensions of the mono pile. (EG)

  3. Analysis of Negative Skin Friction on Single Pile above a Tunnel

    Institute of Scientific and Technical Information of China (English)

    王志亮; 刘学庆

    2003-01-01

    A finite element program with two different soil models is adopted to study the negative skin friction of an unloaded single pile embedded in the settlement trough of a tunnel. The results show that it is necessary to consider the nonlinear property of soil and to set interface elements between piles and soil in analysis of the negative skin friction of piles. Among a pile group, the pile located above the tunnel centerline bears larger downdrag than the ones far away from tunnel centerline.

  4. Use of geothermal piles combined with pile foundations

    Directory of Open Access Journals (Sweden)

    Ivan Kuzytskyi

    2016-07-01

    Full Text Available The possibility of use of geothermal piles in conditions of cold climate is considered. Full-scale experiment is conducted for using this technology in Kiev. Obtained results testify about a possibility for using the system in conditions of Ukraine, but this technology requires more detailed study and simulation of multiannual cycle of use of geothermal piles 

  5. Experimental study on pile-end post-grouting piles for super large bridge pile foundations

    Institute of Scientific and Technical Information of China (English)

    Weiming GONG; Guoliang DAI; Haowen ZHANG

    2009-01-01

    The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper. There are totally 21 test piles. The maximum pile diameter varies from 2.5 m to 3 m, and the maximum length is 125m; the bearing capacity of the post-grouting piles is over ten thousands tons. Based on the test results, the bearing capacity,displacement, and beating characteristics before and after grouting were analyzed. The results show that the beating capacity of the piles is increased in different degrees after grouting although the technical parameters, including the patterns of grouting pipes, pressure, dosages of cement, duration of grouting lasting time, are different. However,the obtained values are very discrete. In addition, the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles. The research results have been applied in the design of bridge foundation.

  6. Pressured Grouting Method (PGM) in Pile Engineering

    Institute of Scientific and Technical Information of China (English)

    吴兴序; 于志强; 王旭

    2002-01-01

    Application of pressured grouting method (PGM) in pile engineering can tackle problems encountered during construction of bored piles. Bearing capacity of piles can be increased through compaction of subsoils around piles. This paper reports research efforts of this technique by the pile research team in Southwest Jiaotong University in last decade with respect to the construction process, test findings, and primary research conclusions. The social-economical benefits of this method and application market in pile engineering are also analyzed.

  7. Grouting for Pile Foundation Improvement

    NARCIS (Netherlands)

    Van der Stoel, A.E.C.

    2001-01-01

    The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection (safeguar

  8. Three-dimensional analysis of slopes reinforced with piles

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 叶茂; 张飞

    2015-01-01

    Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.

  9. Introduction to Single Piles under Lateral Loading

    DEFF Research Database (Denmark)

    Augustesen, Anders; Ibsen, Lars Bo

    The purpose of this chapter is to give a short introduction to single piles subjected to lateral loading. First, the observed behaviour of laterally loaded piles is described, i.e. the effects of loading conditions, installation procedure, pile type etc. on pile behaviour are presented (section 1...

  10. Microbiologically Influenced Corrosion of Pilings

    Science.gov (United States)

    2014-03-04

    reported in all climatic conditions on unprotectej suJ pilings m contact with saline water (ie scawater and hrackisli ’.vater’’ tliat is siibj^ct... Pilings 6. AUTHOR(S) Brenda J. Little and Richard I. Ray 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Research Laboratory...ACRONYM(S) ONR 11. SPONSOR/MONITOR’S REPORT NUMBER(S| 13. SUPPLEMENTARY NOTES Ao/£/o/3lz<l 14. ABSTRACT Sheet piles , used as retaining walls

  11. Grouted Pile and Its Bearing Capacity

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The grouting method applied in bored pile is an improvement to the conventional bored pile. Load tests have proved that grouting under the bored pile tip is an effective method to enhance the bearing capacity of the pile and to reduce the pile settlement. In this paper, the grouting technology is described and pile-load test results are discussed. In order to put the grouting method into design practice, the authors analyze the working mechanism of soil compaction. And, based on the theory of cavities expansion in soil mass, approximate formulae are proposed for estimating the bearing capacity of the grouted pile. The theoretical prediction agrees well with the load test results.

  12. THE NEW STRUCTURE OF A PLATE-PILE FOUNDATION

    Directory of Open Access Journals (Sweden)

    SAMORODOV О. V.

    2016-01-01

    Full Text Available Raising of problem. In the construction of high-rise buildings with significant loads on foundations and bedding at the base of not rocky soils tend to use the most common pile foundation to reduce the deformation and correspond to regulations [1] on the maximum permissible deformation. Monitoring of the stress-strain state (SSS pile foundations constructed buildings shows the existing reserves of bearing capacity on the one hand - soil bases of the second group of limit states, on the other - the foundation of the first group of limit states by regulating the SSS foundation during construction and exploitation. Therefore, are increasingly using more progressive structure of foundations consisting of piles and of plate, as well as methods for their construction [2 - 10], however, in their design there are a number of disadvantages associated with the ambiguity of the application of methods for the calculation of such structures, which allows to do only partial conclusions and recommendations. Purpose. Is proposing the new structure of a plate-pile foundation, which overcomes the drawbacks of the existing design solutions and methods of consruction their, as well as is proposing an engineering method of a determination of basic parameters. Conclusion. Is proposes the new structure of a plate-pile foundation and the method of a determination of basic parameters his in the design of a soil base to the maximum permissible deformation Su buildings. Efficiency of application this type plate-pile foundation obtained by rational distribution resistance between a plate and piles, when under load from the building to the first work fully incorporated plate that allows maximum deformed for plate, and then the piles - due to of the hinge connection with the plate. Thus, depending on the maximum permissible deformation for buildings resistance of plate part of a full load of more than 50%, that significantly reduces the consumption of concrete.

  13. Optimal Pile Arrangement for Minimizing Excess Pore Water Pressure Build-Up

    DEFF Research Database (Denmark)

    Barari, Amin; Saadati, Meysam; Ibsen, Lars Bo

    2013-01-01

    Numerical analysis of pile group in a liquefiable soil was considered to investigate the influence of pile spacing on excess pore pressure distribution and liquefaction potential. The analysis is conducted using a two-dimensional plain strain finite difference program considering a nonlinear...... constitutive model for sandy soil, strength and stiffness reduction, and pile-soil interaction. The Mohr-Coulomb constitutive model coupled with Byrne pore pressure build-up model have been employed in the analysis. Numerical analysis results show that pile groups have significant influence on the dynamic...... response of sandy soil as they reduce the amount of excess pore pressure development during seismic shaking and may even prevent liquefaction....

  14. Optimal Pile Arrangement for Minimizing Excess Pore Water Pressure Build-Up

    DEFF Research Database (Denmark)

    Barari, Amin; Saadati, Meysam; Ibsen, Lars Bo

    2013-01-01

    Numerical analysis of pile group in a liquefiable soil was considered to investigate the influence of pile spacing on excess pore pressure distribution and liquefaction potential. The analysis is conducted using a two-dimensional plain strain finite difference program considering a nonlinear...... constitutive model for sandy soil, strength and stiffness reduction, and pile-soil interaction. The Mohr-Coulomb constitutive model coupled with Byrne pore pressure build-up model have been employed in the analysis. Numerical analysis results show that pile groups have significant influence on the dynamic...... response of sandy soil as they reduce the amount of excess pore pressure development during seismic shaking and may even prevent liquefaction....

  15. Viscoelastic behavior of concrete pile

    Institute of Scientific and Technical Information of China (English)

    丁科; 唐小弟

    2008-01-01

    Based on constitutive theory of viscoelasticity,the viscoelastic behaviour of concrete pile was investigated.The influence of viscosity coefficient on the stress,displacement and velocity response was discussed.With the increase of viscosity coefficient,the amplitude of stress wave decreases,and the maximum value of the stress wave shifts to deeper position of the pile.In other words,the viscosity coefficient behaves as lag effect to stress wave.

  16. DETERMINING DRIVING RESISTANCE WITH REBOUND OF PILE-TOP DURING PILE DRIVING

    Institute of Scientific and Technical Information of China (English)

    陈仁朋; 胡亚元; 陈云敏

    2001-01-01

    This paper presents a method to determine driving resistance with rebound of pile-top during pile driving. The soil around the pile shaft is assumed to be rigid-plastic, while that under the pile-tip is assumed to be ideally elastoplastic. The driving force acting on the pile-top is simplified to a triangular impact force. The kinematic equation of the pile-tip is established. From the one-dimensional wave equation, the movements of the pile-tip and pile-top are determined. The rebound at the pile-top can be written in a very concise form. It is shown that the shaft resistance makes the rebound at the pile-top decrease. In particular, when the pile is very long or the soil around the pile is very stiff, the decrease is very obvious.

  17. Simulation analysis for O-cell test of pile and the interaction of upper pile and lower pile

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ying-jie; ZHANG Ke-xu; ZHANG Er-qi

    2009-01-01

    In this paper, the soil-pile system of O-cell test of pile is simplified as an axi-symmetrie problem.By using aggregation of quadrilateral isoparametrie elements to simulate pile and soil, setting Goodman' s elements between pile and soils, a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the a-nalysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted, and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore, the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine me-chanical behavior, the interaction of upper pile and lower pile in O-cell test can be ignored generally.

  18. Effect of Passive Pile on 3D Ground Deformation and on Active Pile Response

    OpenAIRE

    Bingxiang Yuan; Rui Chen; Jun Teng; Tao Peng; Zhongwen Feng

    2014-01-01

    Using a series of model tests, this study investigated the effect of a passive pile on 3D ground deformation around a laterally loaded pile and on that laterally loaded pile’s response in sand. The active pile head was subjected to lateral loads, and the passive pile was arranged in front of the active pile. In the model tests, the distance between the two pile centers was set to zero (i.e., a single pile test), 2.5, 4, and 6 times the pile width (B). The 3D ground surface deformations around...

  19. Analysis of Interaction Factors Between Two Piles

    Institute of Scientific and Technical Information of China (English)

    CAO Ming; CHEN Long-zhu

    2008-01-01

    A rigorous analytical method is presented for calculating the interaction factor between two identical piles subjected to vertical loads. Following the technique proposed by Muki and Sternberg, the problem is decomposed into an extended soil mass and two fictitious piles characterized respectively by Young's modulus of the soil and that of the difference between the pile and soil. The unknown axial forces along fictitious piles are determined by solving a Fredholm integral equation of the second kind, which imposes the compatibility condition that the axial strains of the fictitious piles are equal to those corresponding to the centroidal axes of the extended soil. The real pile forces and displacements can subequally be calculated based on the determined fictitious pile forces, and finally, the desired pile interaction factors may be obtained. Results confirm the validity of the proposed approach and portray the influence of the governing parameters on the pile interaction.

  20. Pile-up glass microreactor.

    Science.gov (United States)

    Kikutani, Yoshikuni; Hibara, Akihide; Uchiyama, Kenji; Hisamoto, Hideaki; Tokeshi, Manabu; Kitamori, Takehiko

    2002-11-01

    We made a 'pile-up' microreactor in which ten levels of microchannel circuits were integrated to form a single glass entity. Solutions were distributed to each layer via cylindrical holes with a diameter much larger than that of the microchannel. Fabrication of the pile-up reactor was completed using only conventional photolithography, wet etching and thermal bonding techniques, and no special facilities or instruments were required. An amide formation reaction between amine in aqueous solution and acid chloride in organic solution was carried out using the pile-up reactor. The yield of the amide formation reaction is dependent on the size of the specific surface area between the two solutions, and the small space inside the microchannels is good for acquiring a large specific surface area without any stirring processes. The maximum throughput for the ten-layered pile-up reactor was ten times larger than that of a single-layered one, yet the reaction yield was still high. Productivity of the pile-up reactor for the reaction was as high as on a gram per hour scale. This value suggests that many conventional plants producing fine chemicals can be replaced by microreactors through the numbering-up technology.

  1. Energy piles. A fundamental energy pile; Energiepfaehle. Eine fundamentale Energiequelle

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Holger; Beldermann, Nico [GF-Tec GmbH, Roedermark (Germany)

    2013-03-01

    The Maintower, the new airport in Berlin/Brandenburg, a lot of Ikea buildings, and also small office buildings or residential buildings may exchange energy with the underground by means of pile fundaments. At the correct planning and execution, energy piles are low-cost geothermal power plants which sustainable generate heating and cooling for the buildings standing on them. Even more energy can be generated safely under compliance with the groundwater protection by means of a new development of the material and the transfer.

  2. Displacement and deformation analysis for uplift piles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    On the assumptions that the shear resistance increases linearly with increasing shear displacement between the uplift pile and surrounding soil,that the axis force is distributed as parabola along the pile length,that elastic distortion occurs when the pile is loaded,that the displacement of pile is in accord with that of the soil,and that the uplift pile failure is regarded as the soil failure,arational calculation method was proposed for calculating the deformation,ultimate displacement and shear resistance of piles.The distributions of frictional resistance and the shear displacement along the pile length were obtained with the method.The comparisons were made between the measurement results and the present results.The present theoretical results agree well with the measurement results,with the average difference being less than 12% before failure.The comparisons show that the proposed method is reasonable for uplift design and engineering construction of piles.

  3. Field test study of DX piles%DX桩群桩现场试验研究

    Institute of Scientific and Technical Information of China (English)

    陈立宏; 唐松涛; 贺德新

    2011-01-01

    DX桩(三岔双向挤扩灌注桩)作为一种新型的变截面桩型在承载力和沉降方面比普通直孔灌注桩具有明显的优势.但对于DX桩的承载机制和沉降特性的研究,特别是DX桩群桩的研究还不充分.主要通过现场的模型桩试验,对DX桩单桩和群桩的承载力和沉降特性进行了研究.分析了相同条件下单桩和群桩的特性,同时比较了相同桩长、桩径以及相同承载力条件下DX桩和直孔桩的差异,为DX桩的设计提供了参考.%Cast-in-place pile with expanded branches and bells by 3-way extruding arms (DX pile), a new variable cross-section pile,has obvious advantages in bearing capacity and settlement control compared to conventional pile.However, studies of bearing mechanism and settlement characteristic.especially group DX piles.are not sufficient.The bearing capacity and settlement characteristics of single DX pilc and group DX piles are analyzed via in-situ model test.Special attention is paid on single and group DX piles comparison under same conditions; at the meantime, the single DX pile and conventional pile with the same pile length,diameter, and the same bearing capacity are compared so as to provide the theoretical references for the bearing capacity design of the DX piles in the engineering practice.

  4. DRIVEN POLYSTRONG REINFORCED CONCRETE PILES AND NEW DESIGN OF PILE CAPS

    Directory of Open Access Journals (Sweden)

    I. I. Bekbasarov

    2015-01-01

    Full Text Available The paper presents constructional and technological features for manufacturing driven piles with variable strength of pile shaft. Economical efficiency of their production has been shown in the paper. The paper provides a pile cap design that ensures perception of hammer impacts with the help of lateral edges of the pile cap. Driven reinforced concrete piles which are manufactured from three shaft sections having various strength have been proposed in the paper. Material strength (concrete grade and diameter of bars and length of shaft sections are given on a case by case basis in accordance with nature and rate of stresses in piles during their driving process. Manufacturing of polystrong piles provides an opportunity to select them for a particular construction site with due account of their preservation during driving process.A pile cap has been developed that as opposed to existing analogous designs makes it possible to transmit impact efforts from a hammer to the pile through lateral surface of its head part. The pile cap provides the possibility to increase an area for perception of hammer impact efforts by the pile and in doing so it is possible significantly to reduce a damage risk and destruction of pile concrete during its driving. Application of polystrong piles and their driving with the help of new pile cap are considered as a basis for defect-free and resource-saving technology for pile foundations in the construction.

  5. Pullout capacity of batter pile in sand.

    Science.gov (United States)

    Nazir, Ashraf; Nasr, Ahmed

    2013-03-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21-31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18-75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  6. Pullout capacity of batter pile in sand

    Directory of Open Access Journals (Sweden)

    Ashraf Nazir

    2013-03-01

    Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  7. Pile Load Capacity – Calculation Methods

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-12-01

    Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.

  8. Crack initiation ahead of piled-up of dislocations emitted from a mode Ⅱ blunt crack

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In situ tensile tests in a transmission electron microscope (TEM) show that dislocations emitted from a mode II crack tip will form a inverse piled-up group after equilibrium or a double piled-up group when they meet a obstruction, e.g., grain boundary or second phase. A microcrack can initiates in front of the piled-up group of dislocations. Micromechanics analysis shows that dislocations emitted from a mode II blunt crack tip can form a inverse piled-up or double piled-up group, depending upon the applied stress intensity factor KIIa, latticefriction stress and the distance of the obstruction from the crack tip L. The maximum normal stress in front of the double piled-up group which is located at the direction of €? Increases with the increase in the stress intensity KIIa and the obstruction site L, and the decrease in the friction stress . When it increases to equate the cohesive strength, a microcrack will initiate in front of the piled-up group.

  9. Erective Sea Embankment with PCC Piles

    Institute of Scientific and Technical Information of China (English)

    LIU Han-long; FEI Kang; DENG An; ZHANG Ting

    2005-01-01

    The sea embankment is a critical civil works in marine and coastal engineering. In this study, an innovative technique is proposed for constructing erective sea embankments. In the construction of sea embankments, this technique integrates PCC pile installation, PVDs drainage systems, and geotextile reinforcements, resulting in sea embankments with PCC piles. In the application of a sea embankment with PCC piles, PCC piles are employed as the retaining structures;the soft sea ground inside PCC piles is drained and improved by PVDs and vacuum-surcharge combined preloading; geotextile-reinforced backfills lying over the improved soft ground form the embankment body. Brief descrptions of the fundamentals, design and construction of the sea embankment with PCC piles are presented. A case study on the stability of sea embankment with PCC piles is presented as well.

  10. Optimization Mathematical Model of Pile Forces for Offshore Piled Breasting Dolphins

    Institute of Scientific and Technical Information of China (English)

    周锡礽; 王东芹; 王晖; 朱福明

    2004-01-01

    An optimization mathematical model of the pile forces for piled breasting dolphins in the open sea under various loading conditions is presented. The optimum layout with the well distributed pile forces and the least number of piles is achieved by the multiplier penalty function method. Several engineering cases have been calculated and compared with the result of the conventional design method. It is shown that the number of piles can be reduced at least by 10% ~ 20%and the piles' bearing state is improved greatly.

  11. Thermal Conductivity Of Rubble Piles

    CERN Document Server

    Luan, Jing

    2015-01-01

    Rubble piles are a common feature of solar system bodies. They are composed of monolithic elements of ice or rock bound by gravity. Voids occupy a significant fraction of the volume of a rubble pile. They can exist up to pressure $P\\approx \\epsy\\mu$, where $\\epsy$ is the monolithic material's yield strain and $\\mu$ its rigidity. At low $P$, contacts between neighboring elements are confined to a small fraction of their surface areas. As a result, the effective thermal conductivity of a rubble pile, $\\kcon\\approx k(P/(\\epsy\\mu))^{1/2}$, can be orders of magnitude smaller than, $k$, the thermal conductivity of its monolithic elements. In a fluid-free environment, only radiation can transfer energy across voids. It contributes an additional component, $\\krad=16\\ell\\sigma T^3/3$, to the total effective conductivity, $\\keff=\\kcon +\\krad$. Here $\\ell$, the inverse of the opacity per unit volume, is of order the size of the elements and voids. An important distinction between $\\kcon$ and $\\krad$ is that the former i...

  12. Test Setup for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...... in offshore pile foundations today....

  13. Static Tension Tests on Axially Loaded Pile Segments in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...

  14. Experiments of Multi-element Composite Foundation with Steel Pipe Pile and Gravel Pile

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-zhi; ZHENG Jun-jie

    2008-01-01

    A set of self-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.

  15. Pile Spacing Optimization of Short Piled Raft Foundation System for Obtaining Minimum Settlement on Peat

    Science.gov (United States)

    Suro, S. M.; Bakar, I.; Sulaeman, A.

    2016-07-01

    Short Piled Raft is a modified piled raft foundation system, which represents combination between raft foundation and pile foundation, but the length of pile is relatively shorter. The basic concept of the Short Piled Raft foundation system considers the passive soil pressure creating a stiff condition of slab-pile system. This means that the thin concrete slab floats on the supporting soil, while the piles serve as stiffeners concrete slab and also to reduce settlement of the foundation. Slab to pile ratio of such system has been mentioned by several researchers, however the optimum pile spacing of stability performance for obtaining minimum settlement on peat haven't been clearly discussed. In this study, finite element method to simulate the stability performance related to settlement of Short Piled Raft foundation system was used. Short Piled Raft foundation system with concrete slab of 7.0 m x 7.0 m square was assumed to be built on peat with the thickness of 3.5 m. The material properties of pile and raft were constant. The outer diameter of galvanized steel pipe as pile was 0.30 m; raft thickness was considered to be constant of 0.15 m and the length of pile was 3.0 m, while the pile spacing varied from 0.50 to 3.00 m. Point load varied from 0 to 100 kN with increment of 20 kN was also considered as a static load, acted on the centre of the concrete slab. Optimization was done by comparing each numerical result of simulations, thus conclusion can easily be drawn. The optimum pile spacing was 1.00 m which produced minimum settlement of 30.11 mm under the load of 100 kN.

  16. Influence of reaction piles on test pile response in a static load test

    Institute of Scientific and Technical Information of China (English)

    Qian-qing ZHANG; Shu-cai LI; Zhong-miao ZHANG

    2013-01-01

    This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test.In our method,the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile response.Moreover,the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into account.Two cases are analyzed to verify the rationality and efficiency of the present method.This method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil,and the validity is also demonstrated using centrifuge model tests and a computer program presented in the literature.The present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.

  17. Tension Tests On Bored Piles In Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2006-01-01

    The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different...

  18. Steel Sheet Pile Walls in Soft Soil

    NARCIS (Netherlands)

    Kort, D.A.

    2002-01-01

    For almost a century, steel sheet pile walls are applied worldwide as earth retaining structures for excavations and quay walls. Within the framework of the development of European structural codes for Civil Engineering works, the Eurocodes, Eurocode 3 Part 5 for design of steel sheet pile walls was

  19. Analysis of pile load-transfer under pile-side softening

    Institute of Scientific and Technical Information of China (English)

    刘杰; 张可能

    2003-01-01

    A set of analytical equations for the variation of the axial force along depth and the pile-top load-settle-ment curve were established, using tri-linear softening model to pile-side soil and bilinear hardening model to pile-end soil . Influences of the pile-side and pile-end soil behavior on the load-settlement curve were discussed, indica-ting that the lowering reason for the variation step degree of the axial force along depth is the softening of the pile-side soil to result in the side friction lowering when the pile-top load is increased. To verify the reliability of thismethod, the parameters used in calculation are obtained from the test in Zhuzhou area. The obtained results are thencompared with the tested results. Contrast shows that the calculated results and the tested values are very close,which illustrates that the proposed method is reliable.

  20. Model Tests of Pile Defect Detection

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The pile, as an important foundation style, is being used in engineering practice. Defects of different types and damages of different degrees easily occur during the process of pile construction. So,dietecting defects of the pile is very important. As so far, there are some difficult problems in pile defect detection. Based on stress wave theory, some of these typical difficult problems were studied through model tests. The analyses of the test results are carried out and some significant results of the low-strain method are obtained, when a pile has a gradually-decreasing crosssection part, the amplitude of the reflective signal originating from the defect is dependent on the decreasing value of the rate of crosssection β. No apparent signal reflected from the necking appeares on the velocity response curve when the value of β is less than about 3.5 %.

  1. 复杂地质条件下泥水盾构过群桩施工技术研究%Research on Construction Technology of Slurry Shield through the Pile Group under Complicated Geological Conditions

    Institute of Scientific and Technical Information of China (English)

    黄怀朋

    2012-01-01

    Research purposes: There are many uncertainties in the construction of shield directly cutting pile, the technology is not mature enough. In this thesis, relying on the actual project, the experience and the technical parameters of the construction aspects of the shield directly over the pile were summed up for further study of the shield directly over the pile technology to make a direct reference for similar projects.Research conclusions: Through the study of the problem, such conclusions are obtained: (1) To control the the incisions pressure fluctuations in the value of less than 0. 1 bar; (2) Difference of the slurry flow and the promoting speed should be match, at the same time ,to control the amount of overbreak; (3) The thrust should be in the range of 9 500 ~ 100 000 kN; Shield driving speed is controlled at 10 ~ 20 mm/min. Cutter speed in control of 1. 0 ~ 1.2 rpm/min is appropriate, and at the same time to control the cutter torque between the range of 0.9 ~ 1.2 MN ·m.%研究目的:盾构直接切断桩基施工存在诸多不确定性,该技术在目前还不够成熟,本文以实际工程为依托,总结盾构直接过桩的经验和各个施工环节的技术参数,为进一步研究盾构直接过桩技术提供参考和依据,同时为类似工程做直接参考.研究结论:通过对软弱地层中盾构过群桩施工技术的研究,得出:(1)控制住切口压力波动值小于0.1 bar;(2)进排浆流量差与推进速度相匹配,控制超挖量;(3)推力在9500 ~100000 kN范围之间;(4)推进速度控制在10~20 mm/min,同时刀盘转速为1.0~1.2 rpm是合适的,控制刀盘扭矩在0.9~1.2 MN·m范围之间.

  2. Vertical vibration of a large diameter pipe pile considering transverse inertia effect of pile

    Institute of Scientific and Technical Information of China (English)

    郑长杰; 刘汉龙; 丁选明; 周航

    2016-01-01

    Considering the transverse inertia effect of pile, the vertical dynamic response of a large diameter pipe pile in viscoelastic soil layer is studied. The wave propagations in the outer and inner soil are simulated by three-dimensional elastodynamic theory and those in the pile are simulated by Rayleigh-Love rod theory. The vertical and radial displacements of the outer and inner soil are obtained by utilizing Laplace transform technique and differentiation on the governing equations of soils. Then, based on the continuous conditions between the pile and soils, the displacements of the pile are derived. The frequency domain velocity admittance and time domain velocity response of the pile top are also presented. The solution is compared to a classical rod model solution to verify the validity. The influences of the radii and Poisson ratio of pile on the transverse inertia effect of pile are analyzed. The parametric study shows that Poisson ratio and outer radius of pile have significant influence on the transverse inertia effect of large diameter pipe piles, while the inner radius has little effect.

  3. Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hongbo; CHEN Zhuchang

    2007-01-01

    Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile),the end effect on skin friction of bored pile is studied.The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end.The degradation degree of skin friction is deduced with the increase of the distance from pile end.The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile.The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.

  4. Safety precautions in atomic pile control (1962); Securite dans le controle des piles atomiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author) [French] Nous avons aborde le probleme de la securite dans le controle des piles atomiques a la suite de notre participation d'une part aux avant rojets de piles atomiques du CE.A. et d'autre part a l'examen au sein de la sous ommission de surete des piles, de la securite des piles du CE.A. en fonctionnement ou en projet. Nous avons ete amenes a nous interesser alors aux risques encourus par les piles pendant leur fonctionnement et par la meme a leur comportement en regime dynamique. Ce travail traite principalement de l'importance des securites intrinseques, de l'influence des variations de reactivite sur les evolutions de puissance en regime d'accident et du developpement d'appareillages de securite robustes et de fonctionnement tres sur. L'accident de demarrage a ete particulierement

  5. 30 CFR 77.214 - Refuse piles; general.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; general. 77.214 Section 77.214... Installations § 77.214 Refuse piles; general. (a) Refuse piles constructed on or after July 1, 1971, shall be..., tipples, or other surface installations and such piles shall not be located over abandoned openings...

  6. 30 CFR 77.215-4 - Refuse piles; abandonment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; abandonment. 77.215-4 Section 77... MINES Surface Installations § 77.215-4 Refuse piles; abandonment. When a refuse pile is to be abandoned... refuse pile shall be abandoned in accordance with a plan submitted by the operator and approved by...

  7. Numerical Analysis of Piles in Layered Soils: A Parametric Study

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Reddy C

    2015-04-01

    Full Text Available In this paper, numerical analysis of a pile-soil interaction problem is presented considering the parameters influencing the axial load-deformation behavior of the pile embedded in a layered soil medium. The analysis is demonstrated with parametric solutions of a pile with underlain model soil strata under the axial force. An attempt is made to ascertain the extent of influence of elastic properties of the pile, geometry of the pile, end conditions of the pile and the elastic properties of the underlain soil strata on the response of the piles under axial loads lying in a model soil layers in terms of the settlement of the pile and the internal deformation of the pile. The study revealed that the increase in modulus of elasticity of pile improves the settlement resistance of the pile, increase in the ratio of cross sectional dimensions causes decrease in the top deformations of the pile, the settlement of the pile reduced to a great extent when the cross section of the pile adopted is non circular instead of circular and increase in the elastic modulii of top and bottom layers of soil has decreased the settlement of the pile to a great extent, but elastic modulus of soil layers other than top and bottom has got negligible influence on the settlement of the pile.

  8. Reliability-Based Design and Quality Control of Bored Piles

    NARCIS (Netherlands)

    Bach, D.

    2014-01-01

    Bored piles are a type of deep foundations which have been and are being widely used in construction engineering such as high-rise buildings, bridges, jetties, and so on. Although bored piles have remarkable advantages over driven piles, the quality of bored piles is frequently affected by many caus

  9. Reliability-Based Design and Quality Control of Bored Piles

    NARCIS (Netherlands)

    Bach, D.

    2014-01-01

    Bored piles are a type of deep foundations which have been and are being widely used in construction engineering such as high-rise buildings, bridges, jetties, and so on. Although bored piles have remarkable advantages over driven piles, the quality of bored piles is frequently affected by many

  10. Efficient stock piling of 40mm shells

    Directory of Open Access Journals (Sweden)

    J. N. Nanda

    1958-10-01

    Full Text Available A problem was posed as to discuss efficient stock-piling of 40mm shells. There is, in fact no data from which emergency requirements can be deduced. A figure has been quoted by Army authorities that E rounds per month are required during an emergency. The size of the emergency stock pile will depend upon the difference of the normal peace time production, and also on the time taken for the crash programme of emergency production to come into fulfillment. In addition the delivery time from factories to the stock piles is also kept in view.

  11. Research on method of pressure grouting piling of driven tube

    Institute of Scientific and Technical Information of China (English)

    Dianqi PAN; Zupei ZHANG; Diancai PAN; Yong CHEN; Maosen TAN

    2006-01-01

    The pressure grouting pile of driven tube can improve the load bearing capacity of the single pile from the mechanism of pressure grouting pile of driven tube. On the basis of analyzing the mechanism, the authors designed the machines and tools of pressure grouting, determined the operating manufacture and technology parameter on the pressure grouting secondly. The result shows that the pressure grouting pile of driven tube not only changes the pile type but also reduce the length of the pile and its engineering cost, it enhances the load bearing capacity of single pile an the same time.

  12. Ground vibrations due to pile and sheet pile driving : prediction models of today

    OpenAIRE

    Deckner, Fanny; Viking, Kenneth; Hintze, Staffan

    2012-01-01

    As part of aconstruction work pile and sheet pile driving unavoidably generates vibrations.As of today construction works are often located in urban areas and along withsociety’s increasing concern of environmental impact the need for vibrationprediction prior to construction is of immediate interest. This study presents a review of the predictionmodels existing today. For prediction of ground vibrations from pile and sheetpile driving there are roughly three different types of models; empiri...

  13. The Effect of Soil-Pile Interface Behaviour on Laterally Loaded Piles

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole

    2011-01-01

    In current practice it is either the p – y curve concept, or analytical solutions assuming different formulations for ultimate soil resistance that are being used to evaluate the lateral pile response. The adequacy of the p – y curves or of the assumed pressure distribution and ultimate soil...... resistance have been questioned. In this study the lateral capacity of three-dimensional numerical models of rigid piles embedded in cohesionless soil was estimated. The potential variability of the friction properties along the perimeter of the pile was considered. The interface properties affect...... the ultimate soil resistance and the stiffness of the soil–pile response....

  14. Introduction of effective piles in a base structure

    Directory of Open Access Journals (Sweden)

    В.Б. Кашка

    2005-03-01

    Full Text Available  Design features of effective piles such as СВ and their advantages in use are considered at the device of the pile bases in comparison with widely widespread types of piles. From results of comparative tests of piles under static pressing loading in different earth conditions the tendency of redistribution of bearing (carrying ability between a trunk and expansions an effective pile such as СВ was determined on earth conditions.

  15. ATLAS Pile-up and Overlay Simulation

    CERN Document Server

    Novak, Tadej; The ATLAS collaboration

    2017-01-01

    The high luminosity of the LHC results in a significant background to interesting physics events known as pile-up. ATLAS uses several methods for simulating the effects of pile-up. The mostly used method is a direct simulation of background events where multiple simulated background events are combined for each physics event. For some physics processes, a more accurate simulation can be achieved by overlaying real proton-proton collisions on a simulated hard-scatter process. Overlay is also being investigated for a premixed pile-up background to reduce CPU usage and I/O stress during the simulation. Embedding replaces the muons found in Z→mumu decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. This talk compares the pile-up simulation methods used at the ATLAS experiment pointing their benefits and drawbacks.

  16. Local Scour Around Piles Under Wave Action

    Institute of Scientific and Technical Information of China (English)

    陈国平; 左其华; 黄海龙

    2004-01-01

    The model tests are performed with regular waves, and the effect of wave height, wave period, water depth, scdiment size and pile diameter is evaluated. The shape and size of local scour around piles are studied. There are three typical scour patterns due to wave action. It is found that a relationship exists between the erosion depth and the wave number. An empirical formula of the maximum local scour is thus derived.

  17. Nonlinear calculating method of pile settlement

    Institute of Scientific and Technical Information of China (English)

    贺炜; 王桂尧; 王泓华

    2008-01-01

    To study calculating method of settlement on top of extra-long large-diameter pile, the relevant research results were summarized. The hyperbola model, a nonlinear load transfer function, was introduced to establish the basic differential equation with load transfer method. Assumed that the displacement of pile shaft was the high order power series of buried depth, through merging the same orthometric items and arranging the relevant coefficients, the solution which could take the nonlinear pile-soil interaction and stratum properties of soil into account was solved by power series. On the basis of the solution, by determining the load transfer depth with criterion of settlement on pile tip, the method by making boundary conditions compatible was advised to solve the load-settlement curve of pile. The relevant flow chart and mathematic expressions of boundary conditions were also listed. Lastly, the load transfer methods based on both two-broken-line model and hyperbola model were applied to analyzing a real project. The related coefficients of fitting curves by hyperbola were not less than 0.96, which shows that the hyperbola model is truthfulness, and is propitious to avoid personal error. The calculating value of load-settlement curve agrees well with the measured one, which indicates that it can be applied in engineering practice and making the theory that limits the design bearing capacity by settlement on pile top comes true.

  18. Long-term settlement prediction of high-speed railway bridge pile foundation

    Institute of Scientific and Technical Information of China (English)

    杨奇; 冷伍明; 张升; 聂如松; 魏丽敏; 赵春彦; 刘维正

    2014-01-01

    The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis, and the corresponding loading function was presented. One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading. Moreover, the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform. The three-dimensional composite analysis method of bridge pile group was improved, where the actual load conditions of pile foundation could be simulated, and the consolidation characteristics of soil layers beneath pile were also taken into account. Eventually, a corresponding program named LTPGS was developed to improve the calculation efficiency. The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated, and a close agreement is obtained. The error between computed and measured results is less than 1 mm, and it gradually reduces with time. It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.

  19. Static nonlinear analysis of piles cap based on the Continuum Damage Mechanics

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Farani de Souza

    2015-10-01

    Full Text Available The piles cap is an important structural element whose function is to transfer the actions of the superstructure for a group of piles. The visual inspection of the piles cap behavior under service conditions is not possible and, in addition, the knowledge of its actual structural performance is a vital necessity for the constructions overall stability. In this paper, a two-dimensional nonlinear analysis is carried out, by means of Finite Element Method, of a reinforced concrete pile caps with two piles found in the literature. It adopts for the material concrete a constitutive model based on the Continuum Damage Mechanics, with the possibility to provide a tensile and compression differentiated behavior. The steel is described by an elastoplastic bilinear model. The equilibrium path is achieved by Arc Length iteration technique in association with the Newton - Raphson Method. The numerical results obtained with the developed computational code are compared with the available experimental and numerical results and the analytical solution, and have the objective of evaluate the potential of the proposed modeling as an investigation numerical tool to determine the rupture force and the damage distribution in the piles cap.

  20. Study on pile drivability with one dimensional wave propagation theory

    Institute of Scientific and Technical Information of China (English)

    陈仁朋; 王仕方; 陈云敏

    2003-01-01

    Pile drivability is a key problem during the stage of design and construction installation of pile foundations. The solution to the one dimensional wave equation was used to determine the impact force at the top of a concrete pile for a given ram mass, cushion stiffness, and pile impedance. The kinematic equation of pile toe was established and solved based on wave equation theory. The movements of the pile top and pile toe were presented, which clearly showed the dynamic displacement, including rebound and penetration of pile top and toe. A parametric study was made with a full range of practical values of ram weight, cushion stiffness, dropheight, and pile impedance. Suggestions for optimizing the parameters were also presented. Comparisons between the results obtained by the present solution and in-situ measurements indicated the reliability and validity of the method.

  1. Test Procedure for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test procedure described in the following is used when examining the effects of static or cyclic loading on the skin friction of an axially loaded pile in dense sand. The pile specimen is only loaded in tension to avoid any contribution from the base resistance. The pile dimensions are chosen...... to resemble full scale dimension of piles used in offshore pile foundations today. In this report is given a detailed description of the soil preparation and pile installation procedures as well data acquisition methods....

  2. Wavelet analyses for stress wave detection of piles

    Institute of Scientific and Technical Information of China (English)

    WANG; Jingtao; (王靖涛)

    2003-01-01

    The theoretical foundation for application of wavelet analysis to pile integrity detection has been presented. The mechanism of spectral variations of reflected pulse from various defects in piles is explained by using the wave scattering theory. The theoretical analyses have been verified through the tests of model piles and a lot of engineering piles. A quantitative evaluation method for estimating damage degree of piles is proposed. The characteristic indexes describing spectrum variations of reflected signals and their critical values are given. They can be used not only to evaluate the damage degree but also to identify the kinds of pile defects.

  3. Influence of pile inclination on the lateral capacity of batter piles in clays

    Energy Technology Data Exchange (ETDEWEB)

    Rao, S.N.; Veeresh, C. [Indian Inst. of Tech., Madras (India)

    1994-12-31

    In many coastal and offshore areas, there are several soft clay deposits and in such soils pile foundations are used to support structures. The foundations of these structures are usually subjected to large amounts of lateral loads. In such cases, inclined piles or batter piles are better suited to resist lateral loads as a part of lateral load is converted into axial load. This paper refers to an experimental investigation carried out on model piles installed in soft clayey soils. Tests were conducted on model aluminum pile of diameter 12mm embedded in soft clay bed with batter angle (angle of inclination with vertical varying from {minus}30 to +30) and at each of these inclinations piles were tested for embedment ratios of 30, 40 and 50. The results indicate that the lateral capacity of pile is influenced by angle of inclination and the direction of the load application, and depth of embedment. A method is proposed to predict the load deflection behavior with different inclinations using the results of load tests conducted at a particular inclination.

  4. Picking up Clues from the Discard Pile

    Science.gov (United States)

    2008-01-01

    As NASA's Phoenix Mars Lander excavates trenches, it also builds piles with most of the material scooped from the holes. The piles, like this one called 'Caterpillar,' provide researchers some information about the soil. On Aug. 24, 2008, during the late afternoon of the 88th Martian day after landing, Phoenix's Surface Stereo Imager took separate exposures through red, green and blue filters that have been combined into this approximately true-color image. This conical pile of soil is about 10 centimeters (4 inches) tall. The sources of material that the robotic arm has dropped onto the Caterpillar pile have included the 'Dodo' and ''Upper Cupboard' trenches and, more recently, the deeper 'Stone Soup' trench. Observations of the pile provide information, such as the slope of the cone and the textures of the soil, that helps scientists understand properties of material excavated from the trenches. For the Stone Soup trench in particular, which is about 18 centimeters (7 inches) deep, the bottom of the trench is in shadow and more difficult to observe than other trenches that Phoenix has dug. The Phoenix team obtained spectral clues about the composition of material from the bottom of Stone Soup by photographing Caterpillar through 15 different filters of the Surface Stereo Imager when the pile was covered in freshly excavated material from the trench. The spectral observation did not produce any sign of water-ice, just typical soil for the site. However, the bigger clumps do show a platy texture that could be consistent with elevated concentration of salts in the soil from deep in Stone Soup. The team chose that location as the source for a soil sample to be analyzed in the lander's wet chemistry laboratory, which can identify soluble salts in the soil. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed

  5. Transient response of piles-bridge under horizontal excitation

    Institute of Scientific and Technical Information of China (English)

    朱斌; 陈仁朋; 陈云敏

    2003-01-01

    Moving ships and other objects drifting on water often impact a bridge's pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach. The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.

  6. Transient response of piles-bridge under horizontal excitation

    Institute of Scientific and Technical Information of China (English)

    朱斌; 陈仁朋; 陈云敏

    2003-01-01

    Moving ships and other objects drifting on water often impact a bridge' s pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach.The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.

  7. Structural and functional studies of the Pseudomonas aeruginosa minor pilin, PilE.

    Science.gov (United States)

    Nguyen, Ylan; Harvey, Hanjeong; Sugiman-Marangos, Seiji; Bell, Stephanie D; Buensuceso, Ryan N C; Junop, Murray S; Burrows, Lori L

    2015-10-30

    Many bacterial pathogens, including Pseudomonas aeruginosa, use type IVa pili (T4aP) for attachment and twitching motility. T4aP are composed primarily of major pilin subunits, which are repeatedly assembled and disassembled to mediate function. A group of pilin-like proteins, the minor pilins FimU and PilVWXE, prime pilus assembly and are incorporated into the pilus. We showed previously that minor pilin PilE depends on the putative priming subcomplex PilVWX and the non-pilin protein PilY1 for incorporation into pili, and that with FimU, PilE may couple the priming subcomplex to the major pilin PilA, allowing for efficient pilus assembly. Here we provide further support for this model, showing interaction of PilE with other minor pilins and the major pilin. A 1.25 Å crystal structure of PilEΔ1-28 shows a typical type IV pilin fold, demonstrating how it may be incorporated into the pilus. Despite limited sequence identity, PilE is structurally similar to Neisseria meningitidis minor pilins PilXNm and PilVNm, recently suggested via characterization of mCherry fusions to modulate pilus assembly from within the periplasm. A P. aeruginosa PilE-mCherry fusion failed to complement twitching motility or piliation of a pilE mutant. However, in a retraction-deficient strain where surface piliation depends solely on PilE, the fusion construct restored some surface piliation. PilE-mCherry was present in sheared surface fractions, suggesting that it was incorporated into pili. Together, these data provide evidence that PilE, the sole P. aeruginosa equivalent of PilXNm and PilVNm, likely connects a priming subcomplex to the major pilin, promoting efficient assembly of T4aP.

  8. Pile-up detector for LHCb

    CERN Document Server

    Baskov, V A; Kim, V; Polyansky, V V; Verdi, A; Verdi, A.

    1999-01-01

    99-014 In this article we propose to use a dedicated pile-up detector --- 180 degree Cherenkov calorimeter which measures energies of gamma-quanta being produced in ppinteractions by the Cherenkov radiation intensity --- to ensure the conditions which will allow LHCb to work with luminosity 4--5 10 32 cm -2 s -1 . The calorimeter consists of a multiplicator with the width corresponding to the maximum of particles in an electromagnetic shower, behind which a quartz plate is situated where shower particles produce Cherenkov radiation. The pile-up detector is situated at the 180 degree angle relative to the LHCb spectrometer.

  9. 30 CFR 77.215-3 - Refuse piles: certification.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles: certification. 77.215-3 Section... COAL MINES Surface Installations § 77.215-3 Refuse piles: certification. (a) Within 180 days following written notification by the District Manager that a refuse pile can present a hazard, the person...

  10. 30 CFR 77.215-1 - Refuse piles; identification.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; identification. 77.215-1 Section... COAL MINES Surface Installations § 77.215-1 Refuse piles; identification. A permanent identification marker, at least six feet high and showing the refuse pile identification number as assigned by...

  11. 30 CFR 77.215-2 - Refuse piles; reporting requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; reporting requirements. 77.215-2... COAL MINES Surface Installations § 77.215-2 Refuse piles; reporting requirements. (a) The proposed location of a new refuse pile shall be reported to and acknowledged in writing by the District...

  12. 30 CFR 77.215 - Refuse piles; construction requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Refuse piles; construction requirements. 77.215... COAL MINES Surface Installations § 77.215 Refuse piles; construction requirements. (a) Refuse deposited on a pile shall be spread in layers and compacted in such a manner so as to minimize the flow of...

  13. 29 CFR 1926.603 - Pile driving equipment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Pile driving equipment. 1926.603 Section 1926.603 Labor... Operations § 1926.603 Pile driving equipment. (a) General requirements. (1) Boilers and piping systems which are a part of, or used with, pile driving equipment shall meet the applicable requirements of...

  14. 30 CFR 77.209 - Surge and storage piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Surge and storage piles. 77.209 Section 77.209... Installations § 77.209 Surge and storage piles. No person shall be permitted to walk or stand immediately above a reclaiming area or in any other area at or near a surge or storage pile where the...

  15. Stress wave propagation in reinforced concrete piles during driving

    NARCIS (Netherlands)

    Zorn, N.F.

    1983-01-01

    The aim of this report is to give an insight into what happens in a reinforced concrete pile during driving, and to contribute to design requirements for the loading case pile driving. Since the behaviour of stress waves in piles is influenced by a various number of parameters, the fewest of which r

  16. Stress wave propagation in reinforced concrete piles during driving

    NARCIS (Netherlands)

    Zorn, N.F.

    1983-01-01

    The aim of this report is to give an insight into what happens in a reinforced concrete pile during driving, and to contribute to design requirements for the loading case pile driving. Since the behaviour of stress waves in piles is influenced by a various number of parameters, the fewest of which

  17. The Tensile Capacity Of Bored Piles In Frictional Soils

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Andersen, Allan; Damkilde, Lars

    2008-01-01

    Three series of 10 piles each were installed in two different locations. The length of the piles varied from 2 to 6 m and the diameters were 14 and 25 cm. The piles were constructed above the groundwater table using continuous flight augers and the concrete was placed by gravity free fall. The pi...

  18. Design Optimization of Piles for Offshore Wind Turbine Jacket Foundations

    DEFF Research Database (Denmark)

    Sandal, Kasper; Zania, Varvara

    Numerical methods can optimize the pile design. The aim of this study is to automatically design optimal piles for offshore wind turbine jacket foundations (Figure 1). Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil...

  19. Design Optimization of Piles for Offshore Wind Turbine Jacket Foundations

    OpenAIRE

    Sandal, Kasper; Zania, Varvara

    2016-01-01

    Numerical methods can optimize the pile design. The aim of this study is to automatically design optimal piles for offshore wind turbine jacket foundations (Figure 1). Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil characteristics can translate into significant cost reductions.

  20. Responses of reinforced concrete pile group in two-layered liquefied soils:shake-table investigations%两层土液化场地混凝土群桩基础动力反应振动台试验研究

    Institute of Scientific and Technical Information of China (English)

    Lei SU; Liang TANG; Xian-zhang LING; Neng-pan JU; Xia GAO

    2015-01-01

    目的:探讨中密和密实砂液化场地混凝土低承台群桩和地基动力响应存在的差异性,并揭示引起这种差异性的原因,以期获得加密后砂土液化场地混凝土低承台群桩和地基动力反应的基本特征与规律。创新点:1.利用振动台试验,成功实施中密和密实砂液化场地低承台群桩基振动台试验;2.基于试验结果,对比中密和密实砂层液化场地群桩和地基的动力响应规律,考察两种液化场地条件下群桩效应基本特征。方法:1.通过对比白噪声扫频,获得中密砂和密实砂层液化场地下体系模态参数的差异性(图2和表1);2.通过对比砂层孔压、加速度和位移(图3–8),获得中密砂和密实砂液化场地动力反应显著的差异性;3.基于上部结构和承台的位移与加速度,讨论中密砂和密实砂液化场地上部结构动力反应与回复力特性(图9和10);4.基于桩上记录的应变时程,考虑桩的非线性,反算混凝土桩的弯矩时程,对比两类场地群桩弯矩存在的差异性,获得两类场地对群桩效应的影响效应(图12–14)。结论:1.密实砂液化场地加速度在砂层液化后未出现弱化现象,表现出明显的循环流动性,密实砂液化场地比中密砂液化场地刚度更大;2.上部结构动力响应与砂土密实状态密切相关;3.中密砂液化场地桩的最大弯矩发生在土层分界处,而密实砂液化场地中桩的最大弯矩发生在桩头处;4.群桩效应在密砂层中更显著,而在中密砂层并不显著。%During earthquakes, the response of pile foundations in liquefiable sand reinforced by densification techniques is still a very complex dynamic soil-structure interaction problem. Two shake-table experiments were conducted to investigate the be-havior of a reinforced concrete (RC) low-cap pile group embedded in liquefiable soils. Discussion is focused on the

  1. Mechanical analysis about the influence of tunnel excavation on vertical effect of adjacent bridge pile

    Science.gov (United States)

    Tian, Xiaoyan

    2017-08-01

    Tunnel excavation will bring additional deformation and internal force of adjacent bridge piles, if the deformation is large, it will threat the upper structure safety of the bridge. According to the complexity of the existing three - dimensional numerical simulation modeling and the time - consuming calculation, a two - stage analysis method of tunnel excavation based on Winkler foundation model was proposed. Firstly, Loganathan and Polous solutions were used to obtain the vertical displacement of the soil free field at the pile position when tunnel excavated, and the corresponding polynomial fitting displacement curve was taken. Secondly, the differential equation was established by means of the equilibrium condition of micro - element physical force and considering the pile group effect. Then, through the logical derivation, the calculation expressions of the tunnel excavation on the effect of the adjacent bridge pile (settlement, axial force and friction resistance) were obtained. Finally, based on the background of the tunnel project of Yanxing Door Station ∼ Xianning Road Station in Xi’an Metro Line 3, the feasibility and applicability of the proposed method were proved by comparing the calculated values with the numerical simulation values. It provides theoretical guidance for the effective analysis about the influence of tunnel excavation on the adjacent pile foundation effect.

  2. On the Modelling of Pile Installation

    NARCIS (Netherlands)

    Dijkstra, J.

    2009-01-01

    This thesis introduces two different types of physical model tests to investigate the stress and density change in the soil during installation of a jacked pile as well as two numerical modelling approaches to model the same process in a finite element code capable of large deformations.

  3. Full size testing of sheet pile walls

    NARCIS (Netherlands)

    Kuilen, J.W.G. van de; Linden, M.L.R. van der; Katsma, H.; Stolle, P.

    1996-01-01

    Azobé (Lophira alata) is widely used in timber sheet pile walls in the Netherlands. The boards in these walls are coupled and therefore load-sharing can be expected. A simulation model based on the finite element method DIANA (DIANA, 1992) was developed and load-sharing could be calculated. To check

  4. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a small-scal

  5. Underwater noise generated by offshore pile driving

    NARCIS (Netherlands)

    Tsouvalas, A.

    2015-01-01

    Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly attri

  6. Literature review Quasi-static and Dynamic pile load tests: Primarily report on non-static pile load tests

    NARCIS (Netherlands)

    Huy, N.Q.

    2010-01-01

    Pile testing, which plays an importance role in the field of deep foundation design, is performed by static and non-static methods to provide information about the following issues: (Poulos, 1998) - The ultimate capacity of a single pile. - The load-displacement behavior of a pile. - The performance

  7. Literature review Quasi-static and Dynamic pile load tests: Primarily report on non-static pile load tests

    NARCIS (Netherlands)

    Huy, N.Q.

    2010-01-01

    Pile testing, which plays an importance role in the field of deep foundation design, is performed by static and non-static methods to provide information about the following issues: (Poulos, 1998) - The ultimate capacity of a single pile. - The load-displacement behavior of a pile. - The performance

  8. Seismic Response Analysis of Portal Water Injection Sheet Pile

    Institute of Scientific and Technical Information of China (English)

    WANG Yuanbin; GUO Haiyan; ZHANG Chunhui

    2007-01-01

    To further the study on the newly developed portal water injection sheet pile under static loads, in this paper, by adopting the nonlinear calculation module of FEM software ANSYS, a model for the interaction between the soil and the sheet piles is set up,and the seismic response analysis for this type of space-retaining structure is performed. The effects of the embedded depth and the distance between the front pile and the back pile on the dynamic characteristics of the portal water injection sheet pile are studied.

  9. NONLINEAR DYNAMICAL CHARACTERISTICS OF PILES UNDER HORIZONTAL VIBRATION

    Institute of Scientific and Technical Information of China (English)

    HU Yu-jia; CHENG Chang-jun; YANG Xiao

    2005-01-01

    The pile-soil system is regarded as a visco-elastic half-space embedded pile. Based on the method of continuum mechanics, a nonlinear mathematical model of pilesoil interaction was established-a coupling nonlinear boundary value problem. Under the case of horizontal vibration, the nonlinearly dynamical characteristics of pile applying the axis force were studied in horizontal direction in frequency domain. The effects of parameters, especially the axis force on the stiffness were studied in detail. The numerical results suggest that it is possible that the pile applying an axis force will lose its stability. So, the effect of the axis force on the pile is considered.

  10. On Bearing Behavior of Rigid - flexible Multi-pile Composite Sub-grades%刚柔多元桩复合地基承载性能有限元分析

    Institute of Scientific and Technical Information of China (English)

    阎风翔

    2014-01-01

    The present research imitates the bearing behavior of rigid - flexible multi - pile composite foundation using finite element software ABAQUS and obtains the pile body stress characteristics and deformation law. The load of rigid pile is obviously bigger than that of the flexible pile. As for the same type pile,stress of angle pile is the largest,stress of side pile is smaller,and stress of center pile is the smallest. The biggest pile body stress is not at the top of piles,but in a certain position of them. Laws of deformation and bearing capacity of composite foundation are opposite:the deformation of pile top is largest,the deformation of pile group center is the largest,that of the side pile is smaller,and that of the angle pile is the smallest.%采用有限元软件ABAQUS模拟刚柔多元桩复合地基,得出其桩顶、桩身应力特点和变形规律。刚性桩承担的荷载明显大于柔性桩承担的荷载;对于同种桩型,角桩的应力最大,边桩次之,中桩最小;沿桩身应力最大部位不在桩顶,而是位于桩身的某一位置;复合地基的变形规律与承载力规律恰好相反,桩顶处变形最大,并且群桩中心处变形最大,边桩次之,角桩最小。

  11. Friction effects on lateral loading behavior of rigid piles

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole

    2012-01-01

    The adequacy of the p -y curves used in the current practice for the design of rigid pile foundations with large diameter, like in the case of monopile foundations of offshore wind turbines, has been widely questioned. The current study aims at analyzing the lateral behavior of rigid piles, while...... taking into account the shear frictional resistance along the pile. For this purpose efficient three dimensional finite element models of different diameter have been developed. The increase of the side friction and of the diameter of the pile is shown to alter the failure pattern and increase...... the lateral capacity of the pile. The obtained p - y curves demonstrate the importance of the aforementioned parameters in the design of rigid piles, as the reduction of friction along the interface reduces not only the ultimate load but also the stiffness of the soil-pile response. Read More: http...

  12. Laboratory Test Setup for Cyclic Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2017-01-01

    conditions for all tests. For verifications purposes six static tension tests conducted at three different vertical effective stress levels of 0, 35 and 70 kPa. The load-displacement curves showed that the test setup provides repeatable test results. A preliminary comparison between the unit shaft friction......This paper presents a comprehensive description and the considerations regarding the design of a new laboratory test setup for testing cyclic axially loaded piles in sand. The test setup aims at analysing the effect of axial one-way cyclic loading on pile capacity and accumulated displacements....... Another aim was to test a large diameter pile segment with dimensions resembling full-scale piles to model the interface properties between pile and sand correctly. The pile segment was an open-ended steel pipe pile with a diameter of 0.5 m and a length of 1 m. The sand conditions resembled the dense sand...

  13. A semi-analytical method for the analysis of pile-supported embankments

    Institute of Scientific and Technical Information of China (English)

    Wan-huan ZHOU; Ren-peng CHEN; Lin-shuang ZHAO; Zheng-zhong XU; Yun-min CHEN

    2012-01-01

    In this paper,a semi-analytical method for the analysis of pile-supported embankments is proposed.The mathematic model describes the cooperative behavior of pile,pile cap,foundation soil,and embankment fills.Based on Terzaghi's ID consolidation theory of saturated soil,the consolidation of foundation soil is calculated.The embankments with two different types of piles:floating piles and end-bearing piles are investigated and discussed.The results of axial force and skin friction distributions along the pile and the settlements of pile-supported embankments are presented.It is found that it takes a longer time for soil consolidation in the embankment with floating piles,compared with the case using end-bearing piles.The differential settlement between the pile and surrounding soil at the pile top is larger for the embankment with end-bearing piles,compared with the case of floating piles.

  14. The mechanical response of piles with consideration of pile-soil interactions under a periodic wave pressure

    Institute of Scientific and Technical Information of China (English)

    朱峰; 徐卫亚; 王环玲

    2014-01-01

    The pile-soil interaction under wave loads is an extremely complex and difficult issue in engineering. In this study, a physical model test is designed based on the principle of the gravity similarity to obtain time histories of wave forces of unsteady regular waves, and to measure the magnitude and the distribution of wave forces acting on the piles. A numerical model and relevant numerical methods for the pile-soil contact surface are adopted based on the principles of elastic dynamics. For a practical project, the time histories of wave forces on the piles are obtained through physical model tests. The deformations of the piles in the pile-soil interactions and the distribution of the bending moment on the piles are studied. It is shown that, with the increase of the period of wave pressures, the absolute value of the horizontal displacement of the piles increases, the embedment depth of the piles increases, and the scope of influence of soils increases. The change of the bending moment on the piles is consistent with that of its theoretical results, and the proposed numerical method can very well simulate the properties of the piles.

  15. Are cometary nuclei primordial rubble piles?

    Science.gov (United States)

    Weissman, P. R.

    1986-01-01

    Whipple's icy conglomerate model for the cometary nucleus has had considerable sucess in explaining a variety of cometary phenomena such as gas production rates and nongravitational forces. However, as discussed here, both observational evidence and theoretical considerations suggest that the cometary nucleus may not be a well-consolidated single body, but may instead be a loosely bound agglomeration of smaller fragments, weakly bonded and subject to occasional or even frequent disruptive events. The proposed model is analogous to the 'rubble pile' model suggested for the larger main-belt asteroids, although the larger cometary fragments are expected to be primordial condensations rather than collisionally derived debris as in the asteroid case. The concept of cometary nuclei as primordial rubble piles is proposed as a modification of the basic Whipple model, not as a replacement for it.

  16. Behavior of instrumented model batter piles in clay

    Energy Technology Data Exchange (ETDEWEB)

    Narasimha Rao, S.; Veeresh, C. [Indian Inst. of Technology, Madras (India). Ocean Engineering Centre

    1995-12-31

    Pile foundations in several coastal and offshore structures are subjected to significant amounts of lateral loads due to wave action. Usually batter piles are adopted to resist large lateral loads. In this investigation an attempt has been made to study the behavior of batter pile in clayey soils through an experimental program carried out on instrumented model aluminium piles of 26 mm diameter in a test tank of size, 1,200 mm x 800mm x 1,100 mm. The pile was instrumented with electrical resistance type strain gauges to determine the bending moment variations along the depth of embedment of pile. Bending moment vis depth relationships were used to determine the Soil reaction (p) and lateral displacement (y) along the length of the pile for the applied load. From the bending moment vs depth curves it is found that depth of maximum bending moment is greater for negative batter pile than for vertical and positive batter pile. The data of soil reaction and lateral displacement against depth can be used to develop p-y relationships which are useful in the design of laterally loaded piles.

  17. Bearing Behaviors of Stiffened Deep Cement Mixed Pile

    Institute of Scientific and Technical Information of China (English)

    WU Mai; ZHAO Xin

    2006-01-01

    A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed (SDCM) pile.Laboratory tests including six specimens were conducted to investigate the frictional resistance between the concrete core and the cementsoil.Two model piles and twenty-four full-scale piles were tested to examine the bearing behavior of single pile.Laboratory and model tests results indicate that the cohesive strength is large enough to ensure the interaction between core pile and the outer cement-soil.The full-scale test results show that the SDCM piles exhibit similar bearing behavior to bored and cast-in-place concrete piles.In general, with the rational composite structure the SDCM piles can transmit the applied load effectively, and due to the addition of the stiffer core, the SDCM piles possess high bearing capacity.Based on the findings of these experimental investigations and theoretical analysis, a practical design method is developed to predict the vertical bearing capacity of SDCM pile.

  18. FORECASTING PILE SETTLEMENT ON CLAYSTONE USING NUMERICAL AND ANALYTICAL METHODS

    Directory of Open Access Journals (Sweden)

    Ponomarev Andrey Budimirovich

    2016-06-01

    Full Text Available In the article the problem of designing pile foundations on claystones is reviewed. The purpose of this paper is comparative analysis of the analytical and numerical methods for forecasting the settlement of piles on claystones. The following tasks were solved during the study: 1 The existing researches of pile settlement are analyzed; 2 The characteristics of experimental studies and the parameters for numerical modeling are presented, methods of field research of single piles’ operation are described; 3 Calculation of single pile settlement is performed using numerical methods in the software package Plaxis 2D and analytical method according to the requirements SP 24.13330.2011; 4 Experimental data is compared with the results of analytical and numerical calculations; 5 Basing on these results recommendations for forecasting pile settlement on claystone are presented. Much attention is paid to the calculation of pile settlement considering the impacted areas in ground space beside pile and the comparison with the results of field experiments. Basing on the obtained results, for the prediction of settlement of single pile on claystone the authors recommend using the analytical method considered in SP 24.13330.2011 with account for the impacted areas in ground space beside driven pile. In the case of forecasting the settlement of single pile on claystone by numerical methods in Plaxis 2D the authors recommend using the Hardening Soil model considering the impacted areas in ground space beside the driven pile. The analyses of the results and calculations are presented for examination and verification; therefore it is necessary to continue the research work of deep foundation at another experimental sites to improve the reliability of the calculation of pile foundation settlement. The work is of great interest for geotechnical engineers engaged in research, design and construction of pile foundations.

  19. Hydrodynamic Behavior of Curtainwall-Pile Breakwaters

    Institute of Scientific and Technical Information of China (English)

    O.Nejadkazem; A.R.M.Gharabaghi

    2012-01-01

    A numerical model is developed that can predict the interaction of regular waves normally incident upon a curtainwall-pile breakwater; the upper part of which is a vertical wall and the lower part consists of an array of vertical piles.The numerical model is based on an eigenfunetion expansion method,and utilizes a boundary condition nearby the vertical piles that accounts for wave energy dissipation.Numerical solution comprises a finite number of terms,which is a superposition of propagating waves and a series of evanescent waves.The modeling is validated by comparison with previous experimental studies and overall agreement between measurement and calculation is fairly good.The numerical results are related to reflection,transmission,and dissipation coefficient; wave run-up,wave force,and wave overturning moment are also presented.Effect of porosity,relative draft,and relative water depth are discussed; the choice of suitable range of them is described.The relative draft is more effective for shallow water waves.Model shows decrease in relative draft and leads to reduction of relative wave force,overturning moment,and nunup.It is shown that curtainwallpile breakwaters can operate both effectively and efficiently in the range of relative draft between 0.15 and 0.75.The range 0.5 to 0.2 is also recommended for porosity.

  20. Morphological clues to wet granular pile stability

    Science.gov (United States)

    Scheel, M.; Seemann, R.; Brinkmann, M.; di Michiel, M.; Sheppard, A.; Breidenbach, B.; Herminghaus, S.

    2008-03-01

    When a granular material such as sand is mixed with a certain amount of liquid, the surface tension of the latter bestows considerable stiffness to the material, which enables, for example, sand castles to be sculpted. The geometry of the liquid interface within the granular pile is of extraordinary complexity and strongly varies with the liquid content. Surprisingly, the mechanical properties of the pile are largely independent of the amount of liquid over a wide range. We resolve this puzzle with the help of X-ray microtomography, showing that the remarkable insensitivity of the mechanical properties to the liquid content is due to the particular organization of the liquid in the pile into open structures. For spherical grains, a simple geometric rule is established, which relates the macroscopic properties to the internal liquid morphologies. We present evidence that this concept is also valid for systems with non-spherical grains. Hence, our results provide new insight towards understanding the complex physics of a large variety of wet granular systems including land slides, as well as mixing and agglomeration problems.

  1. Soil Plug Effect Prediction and Pile Driveability Analysis for Large-Diameter Steel Piles in Ocean Engineering

    Institute of Scientific and Technical Information of China (English)

    LIU Run; YAN Shu-wang; LI Zhi-hua

    2009-01-01

    Long steel piles with large diameters have been more widely used in the field of ocean engineering.Owing to the pile with a large diameter,soil plug development during pile driving has great influences on pile driveability and beating capacity.The response of soil plug developed inside the open-ended pipe pile during the dynamic condition of pile-driving is different from the response under the static condition of loading during service.This paper addresses the former aspect.A numerical procedure for soil plng effect prediction and pile driveability analysis is proposed and described.By taking into consideration of the pile dimension effect on side and tip resistance,this approach introduces a dimensional coefficient to the conventional static equilibrium equations for the plug differential unit and proposes an improved static equity method for the plug effect prediction.At the same time,this approach introduces a simplified model by use of one-dimensional stress wave equation to simulate the interaction between soft ping and pile inner wall.The proposed approach has been applied in practical engineering analyses.Results show that the calculated plug effect and pile driveability based on the proposed approach agree well with the observed data.

  2. 77 FR 15045 - Takes of Marine Mammals Incidental to Specified Activities; Pile Placement for ORPC Maine's...

    Science.gov (United States)

    2012-03-14

    ... pile bent arrangement consisting of 10 steel pipe piles. Each foundation pile will have a 76-centimeter... will be located in an area with up to 12 m (40 ft) of marine clay and some thin layers of glacial till... pile will be two m (six ft) in diameter, or consist of an array of three piles not greater than 76 cm...

  3. The Effects of Time on Soil Behaviour and Pile Capacity

    DEFF Research Database (Denmark)

    Augustesen, Anders

    this into account. This implies that the design methods used today do not in general make use of the full capacity of piles. This thesis is based on a number of scientific papers and reports that deal with elements of pile design and time effects in soils in general. With regard to pile design, focus is placed...... foundations. Further, design methods that take no account of time will be subject to considerable error unless they consider a tightly specified age range. Time functions (relation between time after installation and capacity), which have been offered for quantifying set-up for piles in clay, are investigated....... Therefore, the design of piles has remained a constant source of attention, especially with regard to the methodology for predicting the capacity. Three very different design methods for piles in both clay and sand are assessed by comparing predicted capacities with measured capacities from established...

  4. Settlement calculation for long-short composite piled raft foundation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming-hua; ZHANG Ling; YANG Ming-hui

    2006-01-01

    The mechanism of long-short composite piled raft foundation was discussed. Assuming the relationship between shear stress and shear strain of the surrounding soil was elasto-plastic, shear displacement method was employed to establish the different explicit relational equations between the load and the displacement at the top of pile in either elastic or elasto-plastic period. Then Mylonakis & Gazetas model was introduced to simulate the interaction between two piles or between piles and soil. Considering the effect of cushion, the flexible coefficients of interaction were provided. With the addition of a relevant program, the settlement calculation for long-short composite piled raft foundation was developed which could be used to account for the interaction of piles,soil and cushion. Finally, the calculation method was used to analyze an engineering example. The calculated value of settlement is 10.2 mm, which is close to the observed value 8.8 mm.

  5. Vertical bearing capacity of pile based on load transfer model

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming-hua; YANG Ming-hui; ZOU Xin-jun

    2005-01-01

    The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-softening, ideal elasto-plastic and work-hardening, a universal tri-linear load transfer model is suggested for the development of side and tip resistance by various types of soil (rock) with the consideration of sediment at the bottom of the pile. Based on the model, a formula is derived for the relationship between the settlement and load on the pile top to determine the vertical bearing capacity, taking into account such factors as the characteristics of the stratum, the side resistance along the shaft, and tip resistance under the pile tip. A close agreement of the calculated results with the measured data from a field test pile lends confidence to the future application of the present approach in engineering practice.

  6. The reactor Cabri; La pile cabri

    Energy Technology Data Exchange (ETDEWEB)

    Ailloud, J.; Millot, J.P. [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    exceptional circumstances... - experimental investigations on power excursions linked with precise initial conditions: the aim of this work is to define the basis for theoretical research, and the limits beyond which the risks of explosion cease to be negligible. The research work will be done so as to enable checking with outside reactor experiments and to continue them in the explosion field. - studies of the behaviour of the reactor control-instrumentation. - experimental investigations related with transient operation with initial short life (study of boiling, temperature measurements, vacuum pressure and fraction...) with the aim of defining the hypotheses of a theory on swimming-pool reactor kinetics related to heat transfer phenomena, - investigations of the behaviour of fuels in reactors (these experiments are planned to be carried out in loops) Preliminary experimental results. CABRI went critical on the 21 December 1963. The first transient experiments are expected for March 1964. (authors) [French] II devenait necessaire de construire en France une pile qui permette d'etudier les conditions de fonctionnement des installations futures, de choisir, tester et mettre au point les dispositifs de securite a adopter. On a choisi une pile a eau, type de pile qui correspond aux constructions les plus nouvelles du CEA en matiere de piles laboratoire ou d'universite; il importe en effet de pouvoir evaluer les risques presentes et d'etudier les possibilites d'augmentation de puissance constamment demandees par les utilisateurs: il est particulierement interessant d'eclaircir les phenomenes d'oscillation de puissance et les risques de calefaction (burn out). Les programmes de travaux sur CABRI seront harmonises avec les travaux effectues sur les Spert americains de meme type; lors de sa construction des contacts fructueux ont ete etablis avec les specialistes americains qui ont defini les premiers de ces reacteurs. La communication donne une

  7. Assessment of Time Functions for Piles Driven in Clay

    DEFF Research Database (Denmark)

    Augustesen, Anders; Andersen, Lars; Sørensen, Carsten Steen

    The vertical bearing capacity of piles situated in clay is studied with regard to the long-term set-up. A statistical analysis is carried out on the basis of data from numerous static loading tests. The database covers a wide range of both soil and pile properties, which ensures a general....... Hence, it is suggested that a constant set-up factor should be applied for the prediction of pile capacities at a given time after initial driving....

  8. 双速度法检测基桩完整性试验研究%Experimental Study on Integrity Inspection of Foundation Pile by Double Speed Test

    Institute of Scientific and Technical Information of China (English)

    唐勇

    2012-01-01

    The low strain test method of foundation pile is applied to check the integrity of bridge foundation pile, driven pile and anti-sliding pile extensively, but the check is difficult to be carried out in case of restrained pile top. Then the double speed test could be used, which could be also applied in case of the foundation pile of existing building, the foundation pile being connected to upper structure, and the pile length unknown. Through single and double speed tests for 16 model piles with and without cap, 766 groups of data are obtained for analysis. As a result, it is proved that the method could be absolutely applied in engineering foundation pile inspection and has realistic meaning about the related integrity check.%基桩低应变测试法被广泛应用于测试桥梁基桩、打入桩和抗滑桩等的完整性。但是,桩顶非自由的情况测试就非常困难。此时可采用双速度法检测,此方法也适于测试已有建筑物下的基桩及基桩与上部结构相连且桩长未知的情况。通过16根有承台和无承台模型桩的单速度和双速度测试,取得766组数据进行分析,得出此方法完全可以应用于工程基桩检测中,对基桩完整性检测具有现实意义。

  9. Bearing Capacity of Mixed Pile with Stiffness Core

    Institute of Scientific and Technical Information of China (English)

    YUE Jianwei; JIANG Xinliang; LING Guangrong

    2006-01-01

    To study load transfer mechanism and bearing capacity of a mixed pile with stiffness core (MPSC), which is formed by inserting a precast reinforced concrete pile (PRCP), in-situ tests involving MPSCs with different lengths, diameters, water cement ratios and PRCPs, cement mixed piles, and drilling hole piles, were carried out.Limit bearing capacities, load-settlement curves and stress distribution of MPSCs and mixed piles were obtained.The load transfer between cement soil and PRCP was analyzed by finite element method (FEM).Test results and FEM analysis show that an MPSC has fully utilized the big friction from a cement mixed pile and the high compressive strength from a PRCP which transfers outer top load into the inner cement soil, and that inserting a PRCP into a mixed pile changes the stress distribution of a mixed pile and improves frictional resistance between a mixed pile and soil.The length and the section area on PRCP of an MPSC both have an optimum value.Adopting MPSC is effective in improving the bearing capacity of soft soil ground.

  10. Bearing capacity and mechanical behavior of CFG pile composite foundation

    Institute of Scientific and Technical Information of China (English)

    陈秋南; 赵明华; 周国华; 张主华

    2008-01-01

    CFG pile (i.e., pile constructed by granular materials of cement, fly-ash and gravel) composite foundation is applied in subsoil treatment widely and successfully. In order to have a further study of this kind of subsoil treatment technology, the influencing factors and calculation methods of the vertical bearing capacity of single CFG pile and the CFG pile composite foundation were discussed respectively. And based on the obtained solutions, effects by the cushion and measurements to reduce negative friction area were analyzed. Moreover, the developing law of settlement and bearing capacity eigenvalue controlled by the material strength with the increase of load were given for the CFG composite foundation. The in-situ static load test was tested for CFG pile. The results of test show that the maximum test load or half of the ultimate load is used from all the points of test, the average bearing capacity eigenvalue of single pile is 390 kN, and slightly greater than the design value of bearing capacity. The bearing capacity eigenvalues of composite foundation for 3 piles are greater than 300 kPa, and the mechanical properties of CFG pile composite foundation are almost identical in the case of the same load and cushion thickness. The pile-soil stress ratio and the load-sharing ratio can be adjusted through setting up cushion thickness.

  11. Vertical Dynamic Impedance of Tapered Pile considering Compacting Effect

    Directory of Open Access Journals (Sweden)

    Wenbing Wu

    2013-01-01

    Full Text Available Based on complex stiffness transfer model, the vertical vibration of tapered pile embedded in layered soil is theoretically investigated by considering the compacting effect of the soil layer surrounding the tapered pile in the piling process. Allowing for the stratification of the surrounding soil and variable crosssection of the tapered pile, the pile-soil system is discretized into finite segments. By virtue of the complex stiffness transfer model to simulate the compacting effect, the complex stiffness of different soil segments surrounding the tapered pile is obtained. Then, substituting the complex stiffness into the vertical dynamic governing equation of tapered pile, the analytical solution of vertical dynamic impedance of tapered pile under vertical exciting force is derived by means of the Laplace technique and impedance function transfer method. Based on the presented solutions, the influence of compacting effect of surrounding soil on vertical dynamic impedance at the pile head is investigated within the low frequency range concerned in the design of dynamic foundation.

  12. In situ mortality experiments with juvenile sea bass (Dicentrarchus labrax in relation to impulsive sound levels caused by pile driving of windmill foundations.

    Directory of Open Access Journals (Sweden)

    Elisabeth Debusschere

    Full Text Available Impact assessments of offshore wind farm installations and operations on the marine fauna are performed in many countries. Yet, only limited quantitative data on the physiological impact of impulsive sounds on (juvenile fishes during pile driving of offshore wind farm foundations are available. Our current knowledge on fish injury and mortality due to pile driving is mainly based on laboratory experiments, in which high-intensity pile driving sounds are generated inside acoustic chambers. To validate these lab results, an in situ field experiment was carried out on board of a pile driving vessel. Juvenile European sea bass (Dicentrarchus labrax of 68 and 115 days post hatching were exposed to pile-driving sounds as close as 45 m from the actual pile driving activity. Fish were exposed to strikes with a sound exposure level between 181 and 188 dB re 1 µPa².s. The number of strikes ranged from 1739 to 3067, resulting in a cumulative sound exposure level between 215 and 222 dB re 1 µPa².s. Control treatments consisted of fish not exposed to pile driving sounds. No differences in immediate mortality were found between exposed and control fish groups. Also no differences were noted in the delayed mortality up to 14 days after exposure between both groups. Our in situ experiments largely confirm the mortality results of the lab experiments found in other studies.

  13. Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

    Directory of Open Access Journals (Sweden)

    Wang Duanduan

    2015-01-01

    Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

  14. Longitudinal vibration of pile in layered soil based on Rayleigh-Love rod theory and fictitious soil-pile model

    Institute of Scientific and Technical Information of China (English)

    Lü Shu-hui; WANG Kui-hua; WU Wen-bing; C. J. LEO

    2015-01-01

    The dynamic response of pile in layered soil is theoretically investigated when considering the transverse inertia effect. Firstly, the fictitious soil-pile model is employed to simulate the dynamic interaction between the pile and the soil layers beneath pile toe. The dynamic interactions of adjacent soil layers along the vertical direction are simplified as distributed Voigt models. Meanwhile, the pile and fictitious soil-pile are assumed to be viscoelastic Rayleigh-Love rods, and both the radial and vertical displacement continuity conditions at the soil-pile interface are taken into consideration. On this basis, the analytical solution for dynamic response at the pile head is derived in the frequency domain and the corresponding quasi-analytical solution in the time domain is then obtained by means of the convolution theorem. Following this, the accuracy and parameter value of the hypothetical boundaries for soil-layer interfaces are discussed. Comparisons with published solution and measured data are carried out to verify the rationality of the present solution. Parametric analyses are further conducted by using the present solution to investigate the relationships between the transverse inertia effects and soil-pile parameters.

  15. 等径桩、挤扩支盘桩相互作用系数数值研究%Numerical Analysis on Pile-pile Interaction Coefficient Between Equal Pile , Squeezed Branch Pile

    Institute of Scientific and Technical Information of China (English)

    丰土根; 宋海洋; 王路博; 陈阳; 胡松

    2015-01-01

    Using Abaqus numerical analysis method,double equal piles,one equal pile and one squeezed branch pile,double squeezed branch piles models were built. Through lots of numerical simulation,analysis of the pile interaction coefficient under different situations,including pile load,pile spacing,soil Poisson's ratio and analysis of the influence to different double piles in surrounding load were carried out. Result shows that the pile-pile influence coefficient is approximately constant value in liner elastic deformation of loading piles ,and irrelevant to the load level and piles characters,but it decreased gradually until close to 0 in plase state,with the Poisson's ratio becomes large. The interaction coefficient gradually decreases,under the same conditions,the surrounding load have a greater impact on double equal piles than double squeezed branch piles and gradually decreases with the increase of poisson's ratio. The study provides a reference in practical engineering between different piles.%采用Abaqus数值分析方法,建立双等径桩、一等径桩一支盘桩、双挤扩支盘桩模型,通过大量的数值模拟计算,分析在不同桩顶荷载、不同桩间距、不同土体泊松比条件下桩的相互影响系数以及在桩周荷载条件下对不同双桩的影响,分析表明,在线弹性变形阶段,桩与桩的影响系数近似为恒定值,与荷载水平及桩的性状无关,进入塑性阶段后,则逐渐减小最后趋于0,随着泊松比的变大,桩之间的相互作用系数逐渐减小,在相同条件下,桩周荷载对双支盘桩的影响大于双等径桩且随泊松比的增大而减小. 研究结果为实际工程中桩之间的影响情况提供参考.

  16. The homogenisation of bulk material in blending piles.

    NARCIS (Netherlands)

    Gerstel, A.W.

    1979-01-01

    In this thesis the homogenisation of bulk material in three types of piles is dealt with. The homogenisation implies that the fluctuations of a material proprety in the input flow of the pile are transformed into output fluctuations, whereby the latter ones are evened out. Analyses are presented con

  17. Effect of piles on the seismic response of mosques minarets

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Abdel-Motaal

    2014-03-01

    Minaret (60.0-m height was studied to investigate the effects of soil stiffness, pile length, diameter, and arrangement, on the minaret and pile dynamic behavior. Comparison between study results and conventional analysis method is illustrated. Study results, discussion, and conclusion are given.

  18. Visualization of soil arching in flexible piled embankments

    Indian Academy of Sciences (India)

    Tuğba Eskışar

    2015-10-01

    Piled embankments rely on soil arching, but, when geogrid reinforcements are used, membrane action within the reinforcement contributes to load distribution. The arching of soil in unreinforced and reinforced piled embankments is evaluated in this study. A small-scale test apparatus is used to model the settlement up to 5 mm in an embankment with four pile elements. Visual inspection of the soil settlement and soil-reinforcement interaction is important to explain the mechanism of arching. In this study, X-ray Computed Tomography (CT) method was used as a non-destructive technique. The arching of soil between the piles was observed in the case of rigid piles and in the case of flexible piles with grid type of reinforcement. The load carrying capacity increased up to 33% in the case of geogrid reinforcement, and the differential settlement decreased around 35%, proving the efficiency of piled embankments with geogrid reinforcements. It is also shown that, using X-ray CT method and visualization techniques provides a better understanding of soil behavior in a reinforced embankment with the flexible pile foundation system.

  19. Cause Analysis of Wuhan Tianheng Building Pile Accident

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The geological condition and the original structure feature and foundation design of Wuhan Tianheng building are described. The accident appearance of pile foundation in the construction execution of work is illustrated. The generating source of this pile foundation accident is analyzed in great details.``

  20. Optimization of pile design for offshore wind turbine jacket foundations

    DEFF Research Database (Denmark)

    Sandal, Kasper; Zania, Varvara

    The aim of this study is to use numerical methods of structural design optimization to design piles for offshore wind turbine jacket foundations. Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil characteristics can translate...

  1. Optimization of pile design for offshore wind turbine jacket foundations

    OpenAIRE

    Sandal, Kasper; Zania, Varvara

    2016-01-01

    The aim of this study is to use numerical methods of structural design optimization to design piles for offshore wind turbine jacket foundations. Pile mass is minimized with constraints on axial and lateral capacity. Results indicate that accurate knowledge about soil characteristics can translate into significant cost reductions.

  2. Perturbation analysis on post-buckling behavior of pile

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The nonlinear large deflection differential equation, based on the assumption that the subsoil coefficient is the 2nd root of the depth, was established by energy method. The perturbation parameter was introduced to transform the equation to a series of linear differential equations to be solved, and the deflection function according with the boundary condition was considered. Then,the nonlinear higher-order asymptotic solution of post-buckling behavior of a pile was obtained by parameter-substituting. The influencing factors such as bury-depth ratio and stiffness ratio of soil to pile, slenderness ratio on the post-buckling behavior of a pile were analyzed. The results show that the pile is more unstable when the bury-depth ratio and stiffness ratio of soil to pile increase,and although the buckling load increases with the stiffness of soil, the pile may ruin for its brittleness. Thus, in the region where buckling behavior of pile must be taken into account, the high grade concrete is supposed to be applied, and the dynamic buckling behavior of pile needs to be further studied.

  3. Assessment of timber piles in Clallam County, Washington

    Science.gov (United States)

    Pandey, Arun K.; Tyler, Ross; Arnette, Clyde G.; Anthony, Ronald W.

    1998-03-01

    Timber bridges are very common in state and rural highway systems. According to the National Bridge Inventory (NBI), there are 41,743 timber bridges in the United States and another 42,102 bridges with timber decks as a part of the superstructure. As these bridges age, there is a critical need for reliable inspection and assessment methods for evaluating timber members. Under an FHWA mandate, these bridges also need to be evaluated for scour susceptibility. Knowledge of the length of timber piles supporting the bridge is a vital component in calculating scour resistance of a bridge. However, records of timber pile lengths are often nonexistent or incomplete due to the construction practices for timber piles. This paper presents nondestructive evaluation (NDE) techniques used for assessing timber piles on 10 bridges in Clallam County, Washington. Stress wave velocity and resistance drilling techniques were used to determine the presence of and quantify the extent of decay in the piles. A longitudinal stress wave technique was used for determining the length of timber piles. Determination of piles with decay aided in establishing maintenance and repair needs on the bridge substructures. Pile length estimates enabled Clallam County Road Department to determine the scour-susceptibility of these bridges.

  4. Physical Modelling of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Hansen, Mette; Wolf, Torben K.; Rasmussen, Kristian L.

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical in the service...

  5. The Settlement Behavior of Piled Raft Interaction in Undrained Soil

    DEFF Research Database (Denmark)

    Ghalesari, Abbasali Taghavi; Barari, Amin; Amini, Pedram Fardad

    2013-01-01

    Offshore piled raft foundations are one of the most commonly used foundations in offshore structures. When a raft foundation alone does not satisfy the design requirements, the addition of piles may improve both the ultimate load capacity and the settlement performance of the raft. In this paper,...

  6. Hazardous gases and oxygen depletion in a wet paddy pile: an experimental study in a simulating underground rice mill pit, Thailand.

    Science.gov (United States)

    Yenjai, Pornthip; Chaiear, Naesinee; Charerntanyarak, Lertchai; Boonmee, Mallika

    2012-01-01

    During the rice harvesting season in Thailand, large amounts of fresh paddy are sent to rice mills immediately after harvesting due to a lack of proper farm storage space. At certain levels of moisture content, rice grains may generate hazardous gases, which can replace oxygen (O(2)) in the confined spaces of underground rice mill pits. This phenomenon has been observed in a fatal accident in Thailand. Our study aimed to investigate the type of gases and their air concentrations emitted from the paddy piles at different levels of moisture content and duration of piling time. Four levels of moisture content in the paddy piles were investigated, including dry paddy group (levels of carbon dioxide (CO(2)) (range 5,864-8,419 ppm) in all wet paddy groups, which gradually increased over time. The concentration of carbon monoxide (CO), methane (CH(4)), nitromethane (CH(3)NO(2)) and nitrous oxide (N(2)O) in all wet paddy groups increased with piling time and with moisture content, with ranges of 11-289; 2-8; 36-374; and 4-26 ppm, respectively. The highest levels of moisture content in the paddy piles were in the range 28-30%wb. Nitrogen dioxide (NO(2)) concentrations were low in all paddy groups. The percentage of O(2) in the wet paddy groups decreased with piling time and moisture content (from 18.7% to 4.1%). This study suggested that hazardous gases could be emitted in moist paddy piles, and their concentrations could increase with increasing moisture content and piling time period.

  7. The Analysis of Soil Resistance During Screw Displacement Pile Installation

    Directory of Open Access Journals (Sweden)

    Krasinski Adam

    2015-02-01

    Full Text Available The application of screw displacement piles (SDP is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

  8. Method of extracting coal from a coal refuse pile

    Science.gov (United States)

    Yavorsky, Paul M.

    1991-01-01

    A method of extracting coal from a coal refuse pile comprises soaking the coal refuse pile with an aqueous alkali solution and distributing an oxygen-containing gas throughout the coal refuse pile for a time period sufficient to effect oxidation of coal contained in the coal refuse pile. The method further comprises leaching the coal refuse pile with an aqueous alkali solution to solubilize and extract the oxidized coal as alkali salts of humic acids and collecting the resulting solution containing the alkali salts of humic acids. Calcium hydroxide may be added to the solution of alkali salts of humic acid to form precipitated humates useable as a low-ash, low-sulfur solid fuel.

  9. Distributed fibre optic strain measurements on a driven pile

    Science.gov (United States)

    Woschitz, Helmut; Monsberger, Christoph; Hayden, Martin

    2016-05-01

    In civil engineering pile systems are used in unstable areas as a foundation of buildings or other structures. Among other parameters, the load capacity of the piles depends on their length. A better understanding of the mechanism of load-transfer to the soil would allow selective optimisation of the system. Thereby, the strain variations along the loaded pile are of major interest. In this paper, we report about a field trial using an optical backscatter reflectometer for distributed fibre-optic strain measurements along a driven pile. The most significant results gathered in a field trial with artificial pile loadings are presented. Calibration results show the performance of the fibre-optic system with variations in the strain-optic coefficient.

  10. Pre-Stressed Rope Reinforced Anti-Sliding Pile

    Institute of Scientific and Technical Information of China (English)

    XU Jun; WANG Chenghua

    2006-01-01

    Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti-sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic.

  11. The Analysis of Soil Resistance During Screw Displacement Pile Installation

    Science.gov (United States)

    Krasinski, Adam

    2015-02-01

    The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

  12. Application of PCC pile in soil improvement of highway

    Institute of Scientific and Technical Information of China (English)

    刘芝平; 刘汉龙; 谭慧明

    2008-01-01

    The construction process and load-bearing behaviors of Cast-in-place concrete thin-wall pipe piles are analyzed based on its application on Yantong Expressway Project. The low strain test, static load test and field excavation were also carried out, and the bearing capacity of the new pile can meet the requirements of design. With the increase of pile diameter, the bearing capacity is increased. The settlement of composite foundation is decreased, when the replacement ratio of pile is increased. The test results also show that the load carried by inner soils is neglectable. According to the tests and application, it can be concluded that the new type of pile is convenient to construction with high bearing capacity and reliable quality, which has great potential in practical engineering.

  13. Optimum design methodologies for pile foundations in London

    Directory of Open Access Journals (Sweden)

    Christos Letsios

    2014-12-01

    Full Text Available Given the importance of pile foundations in geotechnical engineering for supporting high-significance structures such as bridges, high-rise buildings, power plant stations, offshore platforms and museums, it becomes a necessity to find the best pile foundation design in terms of performance and economy. The number of piles required might exceed several hundreds or even thousands while the pile foundation cost might exceed 20% of the construction cost of the superstructure. In this work the problem of finding optimized designs of pile foundations is examined and is performed in accordance to two design code recommendations, namely Eurocode 7 and DIN 4014. The proposed structural optimization procedure is implemented in two real-world cases both located in London, UK in order to assess the efficiency of the proposed design formulation.

  14. Centrifuge modelling of drained lateral pile - soil response

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte

    of rigid piles. The tests have been performed in homogeneously dense dry or saturated Fontainebleau sand in order to mimic simplified drained offshore soil conditions. Approximately half of the tests have been carried out to investigate the centrifuge procedure in order to create a methodology of testing...... for monopiles today. Therefore it appears that the methodology for monopiles lacks scientific justification and a better understanding of rigid piles is needed. More than 70 centrifuge tests on laterally loaded rigid model piles have been carried out in connection with this thesis to get a better understanding...... that enables the transformation of result from tests in model scale to prototype scale. The grain size to pile diameter ratio, the non-linear stress distribution and the pile installation was identified from this investigation as important parameters in reliable scaling of centrifuge results. The remaining...

  15. Influence of space of double row piles on soil arching effect

    Directory of Open Access Journals (Sweden)

    Zhao bo

    2015-02-01

    Full Text Available FLAC3d software, based on continuous theory, is used to analysis influence of space of double row piles on soil arching effect. The result shows that different from single row pile, double row piles will produce soil arching effect at front pile and rear pile severally, this phenomenon is called multiple soil arching effect; the residual load of front of front row pile will increase,the soil arch zone and the soil arching effect will decrease with the continuous increase of double row pile spacing.At the same time the soil arching effect of rear pile decreases, while the soil arching effect of front pile increases and finally the soil arching effect between front pile and rear pile will be equal.

  16. The influence of connecting pile cap-column in the mechanisms of break in the two pile caps

    Directory of Open Access Journals (Sweden)

    A. C. MESQUITA

    Full Text Available Abstract The paper analyzes the two pile caps with partially embedded socket and subject a center load. Three models were experimentally tested, varying the type of conformation of the column and walls of the socket, with a smooth, the other rough, and a monolithic two pile cap, used for reference. The roughening of the column-socket interface was examined with the aim of verifying the difference of the distribution of compressive and tensile stresses in the strut an tie model used for design. The experimental test to show that the two pile caps with conformation rough of the column and walls of the socket, support more load in comparison with two pile caps with smooth of the column and walls of the socket. Both however underperformed the monolithic two pile cap, with values of 66% and 36% respectively.

  17. Analysis of Wave Fields induced by Offshore Pile Driving

    Science.gov (United States)

    Ruhnau, M.; Heitmann, K.; Lippert, T.; Lippert, S.; von Estorff, O.

    2015-12-01

    Impact pile driving is the common technique to install foundations for offshore wind turbines. With each hammer strike the steel pile - often exceeding 6 m in diameter and 80 m in length - radiates energy into the surrounding water and soil, until reaching its targeted penetration depth. Several European authorities introduced limitations regarding hydroacoustic emissions during the construction process to protect marine wildlife. Satisfying these regulations made the development and application of sound mitigation systems (e.g. bubble curtains or insulation screens) inevitable, which are commonly installed within the water column surrounding the pile or even the complete construction site. Last years' advances have led to a point, where the seismic energy tunneling the sound mitigation systems through the soil and radiating back towards the water column gains importance, as it confines the maximum achievable sound mitigation. From an engineering point of view, the challenge of deciding on an effective noise mitigation layout arises, which especially requires a good understanding of the soil-dependent wave field. From a geophysical point of view, the pile acts like a very unique line source, generating a characteristic wave field dominated by inclined wave fronts, diving as well as head waves. Monitoring the seismic arrivals while the pile penetration steadily increases enables to perform quasi-vertical seismic profiling. This work is based on datasets that have been collected within the frame of three comprehensive offshore measurement campaigns during pile driving and demonstrates the potential of seismic arrivals induced by pile driving for further soil characterization.

  18. Analysis of static and dynamic pile-soil-jacket behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Mohammad Reza Emami

    1998-12-31

    In the offshore industry, recent extreme storms, severe earthquakes and subsidence of the foundation of jacket platforms have shown that new models and methods must take into account the jacket- pile-soil foundation interaction as well as the non-linear dynamic performance/loading effects. This thesis begins with a review of the state of art pile-soil interaction model, recognizing that most existing pile-soil models have been established based on large diameter pile tests on specific sites. The need for site independent and mechanistic pile-soil interaction models led to the development of new (t-z) and (p-y) disk models. These are validated using the available database from recent large diameter pile tests in the North Sea and Gulf of Mexico. The established static disk models are applied for non-linear static analysis of the jacket-pile-soil system under extreme wave loading. Dynamic pile-soil interaction is studied and a new disk-cone model is developed for the non-linear and non-homogeneous soils. This model is applied to both surface and embedded disks in a soil layer with non-linear properties. Simplified non-linear as well as more complex analysis methods are used to study the dynamic response of the jacket platform under extreme sea and seismic loading. Ductility spectra analysis is introduced and used to study the dynamic performance of the jacket systems near collapse. Case studies are used to illustrate the effects of structural, foundation failure characteristics as well as dynamic loading effects on the overall performance of the jacket-pile-soil systems near ultimate collapse. 175 refs., 429 figs., 70 tabs.

  19. The effect of loading rate on pile bearing capacity of saturated sand

    NARCIS (Netherlands)

    Archeewa, E.

    2005-01-01

    Pile load tests are commonly used by engineers to determine its bearing capacity. At present, there are three methods of pile load tests: the static, the dynamic and the quasi-static test. The static pile load test is done by applying an axial load on the pile with a long duration. The dynamic and q

  20. 40 CFR 761.347 - First level sampling-waste from existing piles.

    Science.gov (United States)

    2010-07-01

    ... existing piles. 761.347 Section 761.347 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... from existing piles. (a) General. Sample piles that are either specifically configured for sampling... alternate sampling plan in accordance with § 761.62(c). (b) Specifically configured piles. A...

  1. Pile mixing increases greenhouse gas emissions during composting of dairy manure

    Science.gov (United States)

    The effect of pile mixing on greenhouse gas (GHG) emissions from stored dairy manure was determined using large flux chambers designed to completely cover pilot-scale manure piles. GHG emissions from piles that were mixed four times during the 80 day trial were about 20% higher than unmixed piles. ...

  2. The effect of loading rate on pile bearing capacity of saturated sand

    NARCIS (Netherlands)

    Archeewa, E.

    2005-01-01

    Pile load tests are commonly used by engineers to determine its bearing capacity. At present, there are three methods of pile load tests: the static, the dynamic and the quasi-static test. The static pile load test is done by applying an axial load on the pile with a long duration. The dynamic and q

  3. Laboratory Testing of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Ibsen, Lars Bo; Hansen, Mette;

    2013-01-01

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical...... in the serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...

  4. Discrimination of pile up in a fission fragment detection experiment

    CERN Document Server

    Dematte, L; Bax, H

    2002-01-01

    In this work the problem introduced in a fission experiment by the pile-up due to a strong alpha-background has been addressed. A novel scheme has been developed, able to reject more than 90% of pile-up affected pulses in a plutonium sample with an activity of approx 1 MBq. This procedure is necessary in order to improve the resolution to an acceptable level. With a proper calibration, however, the global mean energy and mass of the fragments are correctly reproduced both with and without pile-up rejection.

  5. Numerical Simulation for the Soil-Pile-Structure Interaction under Seismic Loading

    Directory of Open Access Journals (Sweden)

    Lifeng Luan

    2015-01-01

    Full Text Available Piles are widely used as reinforcement structures in geotechnical engineering designs. If the settlement of the soil is greater than the pile, the pile is pulled down by the soil, and negative friction force is produced. Previous studies have mainly focused on the interaction of pile-soil under static condition. However, many pile projects are located in earthquake-prone areas, which indicate the importance of determining the response of the pile-soil structure under seismic load. In this paper, the nonlinear, explicit, and finite difference program FLAC3D, which considers the mechanical behavior of soil-pile interaction, is used to establish an underconsolidated soil-pile mode. The response processes of the pile side friction force, the pile axial force, and the soil response under seismic load are also analyzed.

  6. Optimising the bio-piling of weathered hydrocarbons within a risk management framework

    Energy Technology Data Exchange (ETDEWEB)

    Hough, R.; Brassington, K.; Sinke, A.; Crossley, J.; Paton, G.; Semple, K.; Risdon, G.; Jacobson, Ch.; Daly, P.; Jackman, S.; Lethbridge, G.; Pollard, S. [Cranfield Univ. (United Kingdom)

    2005-07-01

    Thirty years of research into petroleum microbiology and bio-remediation have bypassed an important observation - that many hydrocarbon contaminated sites posing potential risks to human health harbour weathered, 'mid-distillate' or heavy oils rather than 'fresh product'. Ex-situ bio-piling is an important technology for treating soils contaminated with weathered hydrocarbons. However, its performance continues to be represented by reference to reductions in the hydrocarbon 'load' in the soils being treated, rather than reductions in the risks posed by the hydrocarbon contamination. The absence of 'risk' from the vocabulary of many operators and remediation projects reduces stakeholder (regulatory, investor, landowner, and public) confidence in remediation technologies, and subsequently limits the market potential of these technologies. Stakeholder confidence in the bio-piling of weathered hydrocarbons may be improved by demonstrating process optimisation within a validated risk management framework. To address these issues, a consortium led by Cranfield University's Integrated Waste Management Centre has secured funding from the UK Government's Bio-remediation LINK programme. Project PROMISE (involving BP, SecondSite Regeneration Ltd., Dew Remediation Ltd., TES Bretby (Mowlem Group), technology translators PERA, and academics from Aberdeen, Cranfield and Lancaster Universities) aims to improve market confidence in bio-piling by demonstrating how this treatment may be applied within a risk management context. For weathered hydrocarbons in particular, the underpinning scientific components of process control, waste diagnostics, environmental fate modelling, and risk assessment have yet to be fully integrated to allow bio-piling projects to be verified with improved confidence. The Joint Research Council Review of Bio-remediation recognised this in calling explicitly for the positioning of bio-remediation within a

  7. Litter use by laying hens in a commercial aviary: dust bathing and piling.

    Science.gov (United States)

    Campbell, D L M; Makagon, M M; Swanson, J C; Siegford, J M

    2016-01-01

    The laying hen industry, including in the United States, is responding to social concerns about hen welfare by implementing alternative housing systems such as the aviary, to provide more space and resources to large groups of hens. Data detailing the behavior of hens in commercial aviaries is needed to determine hens' use of the resources in order to understand their impact on hen welfare. The open litter area of aviaries provides additional space for hens during the day. Litter is also a substrate for dust bathing which is a strongly motivated natural behavior. Hens are often synchronous in their performance of dust bathing, which may lead to overcrowding in the litter area. Additionally, the open litter area can facilitate expression of unusual behavior such as flock piling (defined as the occurrence of densely grouped clusters of hens, resulting from no obvious cause and occurring randomly throughout the day and flock cycle) which may be a welfare concern. Therefore, we conducted observations of hen occupancy of the open litter area and the performance of dust bathing and flock piling across 3 production points (peak lay, mid lay and end of lay) for two flocks of Lohmann White laying hens housed in a commercial aviary. All areas of the open litter area were occupied to the same degree. Hens performed dust bathing throughout the day but showed peak dust bathing activity in the afternoon for Flock 1 (all P litter area sometimes occurred during peak periods of synchronous dust bathing and when hens piled. Further research is needed to understand the welfare implications of individual hen use of the open litter area and the causes and welfare implications of hen piling.

  8. The Influence of Time on Bearing Capacity of Driven Piles

    DEFF Research Database (Denmark)

    Jensen, J. Lysebjerg; Augustesen, A.; Sørensen, Carsten S.

    2004-01-01

    In Danish engineering practice, one of the ways to determine the ultimate bearing capacity of an axially loaded pile is by means of geostatic formulas. In the equation describing the contribution from the shaft friction to the total bearing capacity for piles located entirely or partly in clay......, a regeneration factor appears. The regeneration factor accounts for effects of dissipation of pore pressure due to pile driving and true time effects such as ageing on the ultimate bearing capacity. Normally the factor is 0.4 but in this paper, the influence of the undrained shear strength and time...... on the regeneration factor is investigated. A relation between the quantities is proposed, which in the end may imply an economical benefit in the design of pile foundations....

  9. Residual settlement calculation of geocell cushion over gravel piles

    Institute of Scientific and Technical Information of China (English)

    陈昌富; 杨宇; 肖淑君; 周志军

    2008-01-01

    The calculation of residual settlement of bidirectional reinforced composite foundation, which is composed of geocell cushion over gravel piles, was studied. The geocell cushion was modeled as a thin flexible plate with large deflection. Based on the Kirchhoff hypothesis, the governing differential equations and boundary conditions of the deformation of geocell cushion under working load were founded using von Karman method and solved by Galerkin method. On theses bases, the gravel piles and inter-pile soils were assumed as Winkler ground with variable spring stiffness so as to execute the approximate calculation of the residual settlement of the bidirectional reinforced composite foundation. The calculation method was verified by two laboratory experiments concerning settlement of embankments. One experiment was with just geocell cushion installed to treat the soft clay under embankments; another one was with both geocell cushion and gravel piles installed. The results show that the calculated settlement curve and the maximum settlement are closed to the observed ones.

  10. Airborne thermography of temperature patterns in sugar beet piles

    Science.gov (United States)

    Moore, D. G.; Bichsel, S.

    1975-01-01

    An investigation was conducted to evaluate the use of thermography for locating spoilage areas (chimneys) within storage piles and to subsequently use the information for the scheduling of their processing. Thermal-infrared quantitative scanner data were acquired initially on January 16, 1975, over the storage piles at Moorhead, Minnesota, both during the day and predawn. Photographic data were acquired during the day mission to evaluate the effect of uneven snow cover on the thermal emittance, and the predawn thermography was used to locate potential chimneys. The piles were examined the day prior for indications of spoilage areas, and the ground crew indicated that no spoilage areas were located using their existing methods. Nine spoilage areas were interpreted from the thermography. The piles were rechecked by ground methods three days following the flights. Six of the nine areas delineated by thermography were actual spoilage areas.

  11. Lateral response of pile foundations in liquefiable soils

    Directory of Open Access Journals (Sweden)

    Asskar Janalizadeh

    2015-10-01

    Full Text Available Liquefaction has been a main cause of damage to civil engineering structures in seismically active areas. The effects of damage of liquefaction on deep foundations are very destructive. Seismic behavior of pile foundations is widely discussed by many researchers for safer and more economic design purposes. This paper presents a pseudo-static method for analysis of piles in liquefiable soil under seismic loads. A free-field site response analysis using three-dimensional (3D numerical modeling was performed to determine kinematic loads from lateral ground displacements and inertial loads from vibration of the superstructure. The effects of various parameters, such as soil layering, kinematic and inertial forces, boundary condition of pile head and ground slope, on pile response were studied. By comparing the numerical results with the centrifuge test results, it can be concluded that the use of the p-y curves with various degradation factors in liquefiable sand gives reasonable results.

  12. Computerised analysis of sulphate action on model concrete piles

    Digital Repository Service at National Institute of Oceanography (India)

    Deshmukh, A.M.; Balasubramanian, S.; Venugopal, C.

    Sulphate action severely affects the durability of marine structures. It is imperative to study precisely the effects of magnesium sulphate on pile foundations in the marine environment. In the present paper an attempt is made to assess and analyse...

  13. As Traffic Piles Up, So Does Air Pollution

    Science.gov (United States)

    ... 160914.html As Traffic Piles Up, So Does Air Pollution To minimize exposure, researchers recommend shutting windows and ... Doing so can reduce your exposure to toxic air pollution from a traffic jam by up to 76 ...

  14. New Mathematical Modelling of Stabilizing Pile with Prestressed Tieback Anchors

    Directory of Open Access Journals (Sweden)

    Cheng Huang

    2013-01-01

    Full Text Available This paper presents a novel mathematical modelling for analyzing stabilizing piles with prestressed tieback anchors. The new differential equations governing the mechanical response of the stabilizing pile are formulated and the boundary conditions considering the tie-back anchors are mathematically specified. Then, the system of differential equations is numerically solved by the high-accuracy Runge-Kutta finite difference method. A simple computer program has been written on the platform of MATLAB to run the procedure of the proposed algorithm. This approach is entirely different from the traditional finite element method used to design the anchored piles. The FEM is employed to verify the feasibility of the developed method. The comparative case study indicates that the proposed method has more higher modeling and computing efficiency than the FEM and can be an alternative method for designing the anchored pile used for slope stabilization.

  15. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    in dry sand by use of centrifuge modelling and to compare the findings with the standard p-y curves. It has been chosen to apply piles with an embedment length of 6 to 10 times the diameter of the applied piles. The general static behaviour of monopiles in dry sand has based on centrifuge tests been...... in sand by use of physical modelling and comparison of the findings with standard p-y curves. The present research is based on use of the centrifuge facilities at Danish Technical University (DTU), the sole geotechnical centrifuge in Scandinavia. It became evident in the initial phase of the research...... that the available centrifuge facilities at DTU was outdated and the focus was changed to establish up-to-date centrifuge facilities for medium to large diameter piles, and to initiate the research on the behaviour of large diameter piles in sand under static and cyclic loading. Key elements in the establishment...

  16. Processing Satellite Imagery To Detect Waste Tire Piles

    Science.gov (United States)

    Skiles, Joseph; Schmidt, Cynthia; Wuinlan, Becky; Huybrechts, Catherine

    2007-01-01

    A methodology for processing commercially available satellite spectral imagery has been developed to enable identification and mapping of waste tire piles in California. The California Integrated Waste Management Board initiated the project and provided funding for the method s development. The methodology includes the use of a combination of previously commercially available image-processing and georeferencing software used to develop a model that specifically distinguishes between tire piles and other objects. The methodology reduces the time that must be spent to initially survey a region for tire sites, thereby increasing inspectors and managers time available for remediation of the sites. Remediation is needed because millions of used tires are discarded every year, waste tire piles pose fire hazards, and mosquitoes often breed in water trapped in tires. It should be possible to adapt the methodology to regions outside California by modifying some of the algorithms implemented in the software to account for geographic differences in spectral characteristics associated with terrain and climate. The task of identifying tire piles in satellite imagery is uniquely challenging because of their low reflectance levels: Tires tend to be spectrally confused with shadows and deep water, both of which reflect little light to satellite-borne imaging systems. In this methodology, the challenge is met, in part, by use of software that implements the Tire Identification from Reflectance (TIRe) model. The development of the TIRe model included incorporation of lessons learned in previous research on the detection and mapping of tire piles by use of manual/ visual and/or computational analysis of aerial and satellite imagery. The TIRe model is a computational model for identifying tire piles and discriminating between tire piles and other objects. The input to the TIRe model is the georeferenced but otherwise raw satellite spectral images of a geographic region to be surveyed

  17. 20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia

    DEFF Research Database (Denmark)

    Augustesen, Anders

    This document is the second of four notes concerning the effects of time (in this case ageing) on the vertical capacity of piles. It includes a critical review of the relevant publications described in note a.......This document is the second of four notes concerning the effects of time (in this case ageing) on the vertical capacity of piles. It includes a critical review of the relevant publications described in note a....

  18. 20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia

    DEFF Research Database (Denmark)

    Augustesen, Anders; Andersen, Lars

    This document is the third of four notes concerning the vertical capacity of piles. It includes an assessment of the effect of previous static load testing upon the measured capacity, i.e. preshearing effects.......This document is the third of four notes concerning the vertical capacity of piles. It includes an assessment of the effect of previous static load testing upon the measured capacity, i.e. preshearing effects....

  19. Pile Structure Program, Projected Start Date : January 1, 2010 (Implementation).

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Chris; Corbett, Catherine [Lower Columbia River Estuary Partnership; Ebberts, Blaine [U.S. Army Corps of Engineers

    2009-07-27

    The 2008 Federal Columbia River Power System Biological Opinion includes Reasonable and Prudent Alternative 38-Piling and Piling Dike Removal Program. This RPA directs the Action Agencies to work with the Estuary Partnership to develop and implement a piling and pile dike removal program. The program has since evolved to include modifying pile structures to enhance their habitat value and complexity by adding large woody debris. The geographic extent of the Pile Structure Program (PSP) includes all tidally-influenced portions of the lower Columbia River below Bonneville Dam; however, it will focus on the mainstem. The overarching goal of the PSP is to enhance and restore ecosystem structure and function for the recovery of federally listed salmonids through the active management of pile structures. To attain this goal, the program team developed the following objectives: (1) Develop a plan to remove or modify pile structures that have lower value to navigation channel maintenance, and in which removal or modification will present low-risk to adjacent land use, is cost-effective, and would result in increased ecosystem function. (2) Determine program benefits for juvenile salmonids and the ecosystem through a series of intensively monitored pilot projects. (3) Incorporate best available science and pilot project results into an adaptive management framework that will guide future management by prioritizing projects with the highest benefits. The PSP's hypotheses, which form the basis of the pilot project experiments, are organized into five categories: Sediment and Habitat-forming Processes, Habitat Conditions and Food Web, Piscivorous Fish, Piscivorous Birds, and Toxic Contaminant Reduction. These hypotheses are based on the effects listed in the Estuary Module (NOAA Fisheries in press) and others that emerged during literature reviews, discussions with scientists, and field visits. Using pilot project findings, future implementation will be adaptively managed

  20. Review of the literature on leachates from coal storage piles

    Energy Technology Data Exchange (ETDEWEB)

    Davis, E.C.; Boegly, W.J. Jr.

    1978-01-01

    Runoff from coal storage piles associated with coal conversion or combustion facilities may represent a potential source of environmental pollution. This report is an assessment of existing information on coal pile leachate. The assessment indicates that few detailed studies have been conducted to date, and these are limited and the results are highly variable. More detailed long-range studies using various types of coal are recommended. These studies should be carried out both in the laboratory and in field-scale experiments.

  1. Numerical modeling of centrifuge cyclic lateral pile load experiments

    Institute of Scientific and Technical Information of China (English)

    Nikos Gerolymos; Sandra Escoffer; George Gazetas; Jacques Gamier

    2009-01-01

    To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoire Central des Ponts et Chaussees. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimental p-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including: soil plastification at an early stage of loading, "pinching" behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. (1974) for sand, is also presented.

  2. Emissions from prescribed burning of timber slash piles in Oregon

    Science.gov (United States)

    Aurell, Johanna; Gullett, Brian K.; Tabor, Dennis; Yonker, Nick

    2017-02-01

    Emissions from burning piles of post-harvest timber slash (Douglas-fir) in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5), black carbon, ultraviolet absorbing PM, elemental/organic carbon, filter-based metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins/dibenzofurans (PCDD/PCDF), and volatile organic compounds (VOCs) were sampled to determine emission factors, the amount of pollutant formed per amount of biomass burned. The effect on emissions from covering the piles with polyethylene (PE) sheets to prevent fuel wetting versus uncovered piles was also determined. Results showed that the uncovered ("wet") piles burned with lower combustion efficiency and higher emission factors for VOCs, PM2.5, PCDD/PCDF, and PAHs. Removal of the PE prior to ignition, variation of PE size, and changing PE thickness resulted in no statistical distinction between emissions. Results suggest that dry piles, whether covered with PE or not, exhibited statistically significant lower emissions than wet piles due to better combustion efficiency.

  3. Slime thickness evaluation of bored piles by electrical resistivity probe

    Science.gov (United States)

    Chun, Ok-Hyun; Yoon, Hyung-Koo; Park, Min-Chul; Lee, Jong-Sub

    2014-09-01

    The bottoms of bored piles are generally stacked with soil particles, both while boreholes are being drilled, and afterward. The stacked soils are called slime, and when loads are applied on the pile, increase the pile settlement. Thus to guarantee the end bearing capacity of bored piles, the slime thickness should be precisely detected. The objective of this study is to suggest a new method for evaluating the slime thickness, using temperature compensated electrical resistivity. Laboratory studies are performed in advance, to estimate and compare the resolution of the electrical resistivity probe (ERP) and time domain reflectometry (TDR). The electrical properties of the ERP and TDR are measured using coaxial type electrodes and parallel type two-wire electrodes, respectively. Penetration tests, conducted in the fully saturated sand-clay mixtures, demonstrate that the ERP produces a better resolution of layer detection than TDR. Thus, field application tests using the ERP with a diameter of 35.7 mm are conducted for the investigation of slime thickness in large diameter bored piles. Field tests show that the slime layers are clearly identified by the ERP: the electrical resistivity dramatically increases at the interface between the slurry and slime layer. The electrical resistivity in the slurry layer inversely correlates with the amount of circulated water. This study suggests that the new electrical resistivity method may be a useful method for the investigation of the slime thickness in bored piles.

  4. PROCESS DIAGRAMS FOR INSTALLATION OF DRIVEN PILES IN PENETRATED WELLS

    Directory of Open Access Journals (Sweden)

    Kovalev Vladimir Aleksandrovich

    2017-03-01

    Full Text Available This article presents the main options of improved and newly devised designs and process diagrams for installation of foundations made of driven, or jack, piles in the penetrated wells with expanded shoe, mainly in weak wet (waterlogged and water-saturated soils. The article presents six options of process diagrams for installation of driven piles in penetrated wells, listing the main procedures: for well-compacted weak soils, for the case when the water ingress is excluded, for the case when it is necessary to increase the load-bearing capacity of pile's bearing face in the waterlogged soils, for the case when the load-bearing capacity of the pile shall be increased both for the end and for the sides, for the case when peat or other biogenous water-saturated soils are present at the bottom of the well, and for the case when there is no contracted zone nor practical possibility to ensure the stability of the walls. The proposed six options of process diagrams for installation of the driven piles in penetrated wells provide expansion of their area of application regarding the soil conditions, increase of load-bearing capacity, and possibility of using jack systems for driving the piles under conditions of dense urban development.

  5. Corrosion Activity on CFRP-Strengthened RC Piles of High-Pile Wharf in a Simulated Marine Environment

    Directory of Open Access Journals (Sweden)

    Ning Zhuang

    2017-01-01

    Full Text Available We report test results from an experimental study to investigate the effectiveness of carbon fiber-reinforced polymer (CFRP against reinforcing steel bar corrosion. Twelve reinforced-concrete pile specimens of 180 mm square by 1,600 mm long were cast. Three pile specimens were corroded to 5% steel mass loss and then strengthened with CFRP sheets; four specimens were strengthened by using CFRP sheets, whereas the remaining five specimens were not strengthened. The specimens were placed in a simulated marine environment, and corrosion was induced by an impressed current technique. At different theoretical corrosion degrees, nondestructive tests were performed to investigate the corrosion activity of the pile specimens, and destructive tests were performed to determine reinforcing steel bar mass loss. Based on the findings, the effectiveness of the CFRP-strengthened RC piles under aggressive marine environmental conditions was established.

  6. Preliminary report on coal pile, coal pile runoff basins, and ash basins at the Savannah River Site: effects on groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, E. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1997-04-28

    Coal storage piles, their associated coal pile runoff basins and ash basins could potentially have adverse environmental impacts, especially on groundwater. This report presents and summarizes SRS groundwater and soil data that have been compiled. Also, a result of research conducted on the subject topics, discussions from noted experts in the field are cited. Recommendations are made for additional monitor wells to be installed and site assessments to be conducted.

  7. The Supercritical Pile Model for GRBs

    Science.gov (United States)

    Kazanas, Demos

    2006-01-01

    We present the spectral and temporal radiative signatures expected within the Supercritical Pile model of Gamma Ray Bursts (GRB). This model is motivated by the need for a process that provides the dissipation necessary in GRB and presents a well defined scheme for converting the energy stored in the relativistic protons of the Relativistic Blast Waves (RBW) associated with GRB into radiation; at the same time it leads to spectra which exhibit a peak in the burst nuF(sub nu) distribution at an energy E(sub p) approximately equal to 1 MeV in the observer s frame, in agreement with observation and largely independent of the Lorentz factor GAMMA of the associated relativistic outflow. Furthermore, this scheme does not require (but does not preclude) acceleration of particles at the shock other than that provided by the isotropization of the flow bulk kinetic energy on the RBW frame. In the present paper we model in detail the evolution of protons, electrons and photons from a RBW to produce detailed spectra of the prompt GRB phase as a function of time from across a very broad range spanning roughly 4 log10 GAMMA decades in frequency. The model spectra are in general agreement with observations and provide a means for the delineating of the model parameters through direct comparison with trends observed in GRB properties.

  8. Common sole larvae survive high levels of pile-driving sound in controlled exposure experiments.

    Directory of Open Access Journals (Sweden)

    Loes J Bolle

    Full Text Available In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa(2 (zero to peak pressures up to 32 kPa and single pulse sound exposure levels up to 186 dB re 1µPa(2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa(2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised.

  9. Parametric study on the effects of pile inclination angle on the response of batter piles in offshore jacket platforms

    Science.gov (United States)

    Aminfar, Ali; Ahmadi, Hamid; Aminfar, Mohammad Hossein

    2016-06-01

    Offshore jacket-type platforms are attached to the seabed by long batter piles. In this paper, results from a finite element analysis, verified against experimental data, are used to study the effect of the pile's inclination angle, and its interaction with the geometrical properties of the pile and the geotechnical characteristics of the surrounding soil on the behavior of the inclined piles supporting the jacket platforms. Results show that the inclination angle is one of the main parameters affecting the behavior of an offshore pile. We investigated the effect of the inclination angle on the maximum von Mises stress, maximum von Mises elastic strain, maximum displacement vector sum, maximum displacement in the horizontal direction, and maximum displacement in the vertical direction. The pile seems to have an operationally optimal degree of inclination of approximately 5°. By exceeding this value, the instability in the surrounding soil under applied loads grows extensively in all the geotechnical properties considered. Cohesive soils tend to display poorer results compared to grained soils.

  10. Experimental Investigations of Tension Piles in Sand Subjected to Static and Cyclic Loading

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The present thesis regards the behavior of the piles in jacket pile foundations used for offshore wind turbines. The piles are often loaded in tension because of the combination of wind and wave conditions and the low self-weight of the wind turbine. The repeated cyclic loading can lead...... to accumulated upwards displacement of the piles and, thus, undesired deflection of the wind turbine structure. This study concerns the effect of cyclic loading on a pile installed in dense sand and loaded in tension. A new laboratory test setup was constructed to make these pile load tests. The thesis discusses...... the advantages and disadvantages of the test setup. The results of cyclic loading tests showed that the loading conditions are very important for the behavior of piles. Some wind and wave conditions can be beneficial and increase the pile capacity while other conditions can be damaging and reduce the pile...

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

    Institute of Scientific and Technical Information of China (English)

    CUI Wei; ZHANG Zhigeng; YAN Shuwang

    2007-01-01

    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.

  12. 轴向荷载对斜桩水平承载特性影响试验及理论研究%Test and theoretical research on influence of axial load on lateral bearing capacity of batter piles

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      斜群桩受水平荷载作用时,群桩中的基桩受到径向荷载、轴向荷载和弯矩的共同作用。为研究轴向荷载对斜桩水平承载特性的影响,完成了3根单桩以及1组1×2斜桩的大尺寸模型试验。试验结果表明:轴向拉力作用会降低斜桩的水平刚度和极限承载力;而轴向压力作用则会使其水平刚度和极限承载力提高。基于桩侧浅层土体楔形破坏假定,推导了考虑轴向荷载影响的斜桩水平极限土抗力计算公式,提出了桩侧土抗力的p-y曲线方法,并通过模型试验及现场试验验证其合理性。%When batter pile group are under lateral load, the foundation piles in pile group are subjected to radial load, axial load and bending moment. In order to study the influence of axial load on lateral bearing capacity of batter piles, large-scale model tests of three single piles and a 1×2 batter pile group have been conducted in a larger soil tank. It is found that the upward axial force on the pile top decreases the lateral stiffness and the lateral ultimate bearing capacity of batter pile; while the downward axial force enhances the horizontal stiffness and the lateral ultimate bearing capacity of batter pile. Based on the assumption of wedge failure of the shallow soil around piles, considering the influence of axial load on piles, a formula for calculating the lateral ultimate resistance force of soil is deduced. Then, a p-y curve method for resistance force of soil around piles is proposed. Finally, the formula and the proposed p-y curve method for batter pile are verified by model tests and field tests.

  13. Development technology of rigidity-drain pile and numerical analysis of its anti-liquefaction characteristics

    Institute of Scientific and Technical Information of China (English)

    刘汉龙; 陈育民; 赵楠

    2008-01-01

    Pile foundation is widely used in the offshore engineering. The pile can be seriously destroyed by the soil liquefaction during strong earthquakes. The potentials of liquefaction and damages of pile foundation due to the liquefaction can be reduced by the implementation of the drainage in the liquefiable foundation. A patented pile technology, named rigidity-drain pile, was introduced. The partial section of the pile body was filled by materials with higher penetrability which forms some effective drainage channels in the pile. The principles and construction methods were presented. 3D models for both rigidity-drain pile and ordinary pile were built in FLAC3D code. The dynamic loadings were applied on the bottom of the model. According to the numerical results, in the case of the rigidity-drain pile, the water in the relevant distance range around the pile flows toward the pile drainage, the contour of the pore pressure shows a funnel form. Contrast to the ordinary pile, the rigidity-drain pile can dissipate the accumulated excess pore water, maintain effective stress and obviously reduce the possibility of surrounding soil liquefaction.

  14. Analytical model of vertical vibrations in piles for different tip boundary conditions: parametric study and applications

    Institute of Scientific and Technical Information of China (English)

    Ning WANG; Kui-hua WANG; Wen-bing WU

    2013-01-01

    In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile tip.In the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local soil.The tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was allowed.In combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex impedances.Finally,two applications of the analytical model were presented.One is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile defects.Another application of the model is to identify the sediment thickness under the pile tip.The results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load.

  15. Capacity and failure mechanism of laterally loaded jet-grouting reinforced piles: Field and numerical investigation

    Institute of Scientific and Technical Information of China (English)

    HE Ben; WANG LiZhong; HONG Yi

    2016-01-01

    This study presents the results of field and numerical investigations of lateral stiffness,capacity,and failure mechanisms for plain piles and reinforced concrete piles in soft clay.A plastic-damage model is used to simulate concrete piles and jet-grouting in the numerical analyses.The field study and numerical investigations show that by applying jet-grouting surrounding the upper 7.5D (D =pile diameter) of a pile,lateral stiffness and bearing capacity of the pile are increased by about 110% and 100%,respectively.This is partially because the jet-grouting increases the apparent diameter of the pile,so as to enlarge the extent of failure wedge and hence passive resistance in front of the reinforced pile.Moreover,the jet-grouting provides a circumferential confinement to the concrete pile,which suppresses development of tensile stress in the pile.Correspondingly,tension-induced plastic damage in the concrete pile is reduced,causing less degradation of stiffness and strength of the pile than that of a plain pile.Effectiveness of the circumferential confinement provided by the jet-grouting,however,diminishes once the grouting cracks because of the significant vertical and circumferential tensile stress near its mid-depth.The lateral capacity of the jet-grouting reinforced pile is,therefore,governed by mobilized passive resistance of soil and plastic damage of jet-grouting.

  16. Seismic Demands for Pile-Supported Wharf Structures with Batter Piles

    Directory of Open Access Journals (Sweden)

    Rouhollah Amirabadi

    2012-09-01

    Full Text Available This study develops an optimal Probabilistic Seismic Demand Model (PSDM for pile-supported wharves whit batter plies. Four bins with twenty non-near-field ground motions and three typical pile-supported wharf structures from western United States ports are used to determine an optimal PSDM by using Probabilistic Seismic Demand Analysis (PSDA. PSDA is used to compute the relationship between Engineering Demand Parameters (EDPs and earthquake Intensity Measures (IMs. An optimal PSDM should be practical, sufficient, effective and efficient-all tested through several IM-EDP pairs. It has been found that for these types of structures, the optimal model comprises a spectral IM, such as spectral acceleration and one of several EDPs. These EDPs are considered for local (moment curvature ductility factor, intermediate (displacement ductility factor and horizontal displacement of embankment and global (differential settlement between deck and behind land response quantities. The considered PSDMs are a critical component in performance-based seismic design and seismic risk assessment. Results can be used in probabilistic framework for performance-based design developed by Pacific Earthquake Engineering Research (PEER center.

  17. Mechanism Research on the Improvement of Bearing Capacity of Single Pile by Pile-base Post Grouting Technique and Estimation of Bearing Capacity

    Directory of Open Access Journals (Sweden)

    Zhao Feng

    2015-01-01

    Full Text Available The slurry wall bored grouting has some defects. The pile-base post grouting technique can efficiently make up these defects and greatly improve the bearing capacity. Based on the pile-base post grouting technique and its process analysis, this paper carries out a detailed analysis about the improvement of mechanism of bearing capacity and mechanism of spherical expansion by the use of pile-base post grouting technique, as well as the estimation method of the bearing capacity of pile-base post grouting pile, which has a certain reference value for theoretical research and technical application of the technique.

  18. INTERACTION OF A LONG SINGLE PILE THAT HAS A DOUBLE-LAYER BASE WITH ACCOUNT FOR COMPRESSIBILITY OF THE PILE SHAFT

    Directory of Open Access Journals (Sweden)

    Ter-Martirosyan Zaven Grigor'evich

    2012-07-01

    The authors provide their solution to the problem of interaction of a long compressible pile that has a double-layer linear deformable base. The paper demonstrates that taking account of compressible properties of the pile material leads to qualitatively new distribution of shearing stresses over the surface of a cylindrical pile. It is noteworthy that increase of the pile length and stiffness of the upper section of the base raise the share of the load perceived by the surface of the pile. Besides, in particular conditions of the soil environment, the load perceived by the lower section of the base may reach approximately 20-30 % of the total load.

  19. Estimation of volume and mass and of changes in volume and mass of selected chat piles in the Picher mining district, Ottawa County, Oklahoma, 2005-10

    Science.gov (United States)

    Smith, S. Jerrod

    2013-01-01

    From the 1890s through the 1970s the Picher mining district in northeastern Ottawa County, Oklahoma, was the site of mining and processing of lead and zinc ore. When mining ceased in about 1979, as much as 165–300 million tons of mine tailings, locally referred to as “chat,” remained in the Picher mining district. Since 1979, some chat piles have been mined for aggregate materials and have decreased in volume and mass. Currently (2013), the land surface in the Picher mining district is covered by thousands of acres of chat, much of which remains on Indian trust land owned by allottees. The Bureau of Indian Affairs manages these allotted lands and oversees the sale and removal of chat from these properties. To help the Bureau of Indian Affairs better manage the sale and removal of chat, the U.S. Geological Survey, in cooperation with the Bureau of Indian Affairs, estimated the 2005 and 2010 volumes and masses of selected chat piles remaining on allotted lands in the Picher mining district. The U.S. Geological Survey also estimated the changes in volume and mass of these chat piles for the period 2005 through 2010. The 2005 and 2010 chat-pile volume and mass estimates were computed for 34 selected chat piles on 16 properties in the study area. All computations of volume and mass were performed on individual chat piles and on groups of chat piles in the same property. The Sooner property had the greatest estimated volume (4.644 million cubic yards) and mass (5.253 ± 0.473 million tons) of chat in 2010. Five of the selected properties (Sooner, Western, Lawyers, Skelton, and St. Joe) contained estimated chat volumes exceeding 1 million cubic yards and estimated chat masses exceeding 1 million tons in 2010. Four of the selected properties (Lucky Bill Humbah, Ta Mee Heh, Bird Dog, and St. Louis No. 6) contained estimated chat volumes of less than 0.1 million cubic yards and estimated chat masses of less than 0.1 million tons in 2010. The total volume of all

  20. FIELD INVESTIGATIONS OF PILED-RAFT FOUNDATIONS WITH SHORT-LENGTH CONIC PILES IN BUILDING AREAS OF MINSK

    Directory of Open Access Journals (Sweden)

    V. A. Sernov

    2015-01-01

    Full Text Available In recent time piled foundations are extensively applied due to an increase of storeys in buildings constructed in Minsk and load increment on the soil. Preference is given to this approach even in the case when relatively firm soil occurs in the top part of the foundation bed. In this case maximum usage of the foundation bed bearing capacity and reduction of foundation cost are considered as top-priority tasks for designers. One of the ways to increase the bearing capacity of piled foundations is the necessity to take into account resistance of foundation bed soil located under raft bottom. The raft as well as a shallow foundation is capable to transfer a significant part of building load into the soil. Such approach makes it possible to reduce a number of piles in the foundation or shorten their length. Then it results in shortening of the construction period and significant reduction in zero cycle. However up to the present moment reliable calculation methods that permit to take into account soil resistance in the raft base. An analysis of previous investigations on the matter executed by various researchers and a number of field investigations have been carried out with the purpose to develop the proposed methods.The paper presents results of field investigations on foundations consisting of short stamped tapered piles which are joined together with the help of the raft fragment. Strength and deformation characteristics of the bases are increasing while making such foundations in the fill-up soil. In this case the filled-up ground layer becomes a bearing layer both for piles and rafts as well. Improvement of high-plastic clay-bearing soil properties is ensured by ramming dry concrete mix under pile foot. The paper describes an experience on application of the piled-raft foundation in complicated engineering and geological conditions while constructing the Orthodox Church in Minsk.

  1. Contribution to Estimating Bearing Capacity of Pile in Clayey Soils

    Science.gov (United States)

    Drusa, Marián; Gago, Filip; Vlček, Jozef

    2016-12-01

    The estimation of real geotechnical parameters is key factor for safe and economic design of geotechnical structures. One of these are pile foundations, which require proper design and evaluation due to accessing more deep foundation soil and because remediation work of not bearable piles or broken piles is a crucial operation. For this reason, geotechnical field testing like cone penetration test (CPT), standard penetration (SPT) or dynamic penetration test (DP) are realized in order to receive continuous information about soil strata. Comparing with rotary core drilling type of survey with sampling, these methods are more progressive. From engineering geologist point of view, it is more important to know geological characterization of locality but geotechnical engineers have more interest above the real geotechnical parameters of foundation soils. The role of engineering geologist cannot be underestimated because important geological processes in origin or during history can explain behaviour of a geological environment. In effort to streamline the survey, investigation by penetration tests is done as it is able to provide enough information for designers. This paper deals with actual trends in pile foundation design; because there are no new standards and usable standards are very old. Estimation of the bearing capacity of a single pile can be demonstrated on the example of determination of the cone factor Nk from CPT testing. Then results were compared with other common methods.

  2. Contribution to Estimating Bearing Capacity of Pile in Clayey Soils

    Directory of Open Access Journals (Sweden)

    Drusa Marián

    2016-12-01

    Full Text Available The estimation of real geotechnical parameters is key factor for safe and economic design of geotechnical structures. One of these are pile foundations, which require proper design and evaluation due to accessing more deep foundation soil and because remediation work of not bearable piles or broken piles is a crucial operation. For this reason, geotechnical field testing like cone penetration test (CPT, standard penetration (SPT or dynamic penetration test (DP are realized in order to receive continuous information about soil strata. Comparing with rotary core drilling type of survey with sampling, these methods are more progressive. From engineering geologist point of view, it is more important to know geological characterization of locality but geotechnical engineers have more interest above the real geotechnical parameters of foundation soils. The role of engineering geologist cannot be underestimated because important geological processes in origin or during history can explain behaviour of a geological environment. In effort to streamline the survey, investigation by penetration tests is done as it is able to provide enough information for designers. This paper deals with actual trends in pile foundation design; because there are no new standards and usable standards are very old. Estimation of the bearing capacity of a single pile can be demonstrated on the example of determination of the cone factor Nk from CPT testing. Then results were compared with other common methods.

  3. ESTIMATION OF AGING EFFECTS OF PILES IN MALAYSIAN OFFSHORE LOCATIONS

    Directory of Open Access Journals (Sweden)

    JERIN M. GEORGE

    2017-04-01

    Full Text Available An increasing demand for extending life and subsequently higher loading requirements of offshore jacket platforms are among the key problems faced by the offshore industry. The Aging effect has been proved to increase the axial capacity of piles, but proper methods to estimate and quantify these effects have not been developed. Borehole data from ten different Malaysian offshore locations have been analysed and they were employed to estimate the setup factor for different locations using AAU method. The setup factors found were used in the Skov and Denver equation to calculate capacity ratios of the offshore piles. The study showed that there will be an average improvement in the axial capacity of offshore piles by 42.2% and 34.9% for clayey and mixed soils respectively after a time equal to the normal design life (25 years of a jacket platform.

  4. Design of Jetty Piles Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Yongjei Lee

    2014-01-01

    Full Text Available To overcome the complication of jetty pile design process, artificial neural networks (ANN are adopted. To generate the training samples for training ANN, finite element (FE analysis was performed 50 times for 50 different design cases. The trained ANN was verified with another FE analysis case and then used as a structural analyzer. The multilayer neural network (MBPNN with two hidden layers was used for ANN. The framework of MBPNN was defined as the input with the lateral forces on the jetty structure and the type of piles and the output with the stress ratio of the piles. The results from the MBPNN agree well with those from FE analysis. Particularly for more complex modes with hundreds of different design cases, the MBPNN would possibly substitute parametric studies with FE analysis saving design time and cost.

  5. Probabilistic Assessment for Seismic Performance of Pile-Supported Wharves

    Directory of Open Access Journals (Sweden)

    Hamid Heidary Torkamani

    2013-03-01

    Full Text Available The main objective of this study is to investigate the influence of uncertainties associated with the material properties on the seismic performance of pile-supported wharves. For this purpose a two-dimensional finite difference model, representing typical pile-supported wharf structures from western United States has been constructed using software FLAC2D. Incremental dynamic analysis has been applied to evaluate the response of wharf structure under different levels of seismic loading. The uncertainties at both structural and geotechnical parameters have been investigated using a tornado diagram and a first-Order Second-Moment (FOSM analysis. It has been found that the uncertainties at the dead load of structure, friction angle of rock fill and the porosity of rock fill contribute most to the variability of the displacement ductility factor of the pile-supported wharf structures. Based on the results, design considerations have been provided.

  6. Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Foglia, Aligi; Ibsen, Lars Bo

    2012-01-01

    Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that......Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank...... such that it was possible to apply an overburden pressure to the soil. Hereby, the traditional uncertainties related to low effective stresses for small-scale tests has been avoided. A scaling law for laterally loaded piles has been proposed based on dimensional analysis. The novel testing method has been validated against...

  7. A Simple Pile-up Model for Time Series Analysis

    Science.gov (United States)

    Sevilla, Diego J. R.

    2017-07-01

    In this paper, a simple pile-up model is presented. This model calculates the probability P(n| N) of having n counts if N particles collide with a sensor during an exposure time. Through some approximations, an analytic expression depending on only one parameter is obtained. This parameter characterizes the pile-up magnitude, and depends on features of the instrument and the source. The statistical model obtained permits the determination of probability distributions of measured counts from the probability distributions of incoming particles, which is valuable for time series analysis. Applicability limits are discussed, and an example of the improvement that can be achieved in the statistical analysis considering the proposed pile-up model is shown by analyzing real data.

  8. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    . The expected development of offshore wind farms is towards larger farms, larger turbines and larger water depths. Monopiles have been applied widely and it is of interest to investigate the possibilities to further optimize the design and in particular the modelling of the soil-structure interaction...... on the structure and the productivity of the turbine. Current design practice for monopiles are based on p-y curves developed for slender piles with a diameter of 0.6 m. The focus on the structure stiffness has entailed a significant research on the soil-structure interaction for large diameter monopiles...... in dry sand by use of centrifuge modelling and to compare the findings with the standard p-y curves. It has been chosen to apply piles with an embedment length of 6 to 10 times the diameter of the applied piles. The general static behaviour of monopiles in dry sand has based on centrifuge tests been...

  9. The Pressure Limitations on Flux Pile-Up Magnetic Reconnection

    Science.gov (United States)

    Litvinenko, Y. E.

    1999-05-01

    Flux pile-up magnetic reconnection was thought to be able to provide fast energy dissipation a strongly magnetized plasma, for example, in solar flares. We examine the problem of the plasma pressure limitations on the rapidity of flux pile-up reconnection. It is shown that for a two-dimensional stagnation point flow with nonzero vorticity the magnetic merging rate cannot exceed the Sweet-Parker scaling in a low-beta plasma, which is too slow to explain flares. Moreover, the solution has some undesireable properties such as a diffusion layer at the external boundary and the massively increasing inflow speed. The pressure limitation appears to be somewhat less restrictive for three-dimensional flux pile-up. This work was supported by NSF grant ATM-9813933.

  10. Grouting Control for Deep-Water Jacket Skirt Pile

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing; ZHANG Jianxin; XU Lianjiang

    2006-01-01

    Deep-water jacket skirt pile grouting is a critical step in ocean platform construction. Because of the complexity of the skirt pile structure and grouting pipeline, the calculation of grouting pressure and the control of output pressure are involved. Beginning with the jacket skirt pile grouting construction scheme, grouting pressure is estimated on the basis of engineering fluid mechanics theory and variable frequency control technique. Programmable logic controller is the center of grouting pressure control system, which accomplishes the flow control of cement buffer tank water buffer tank, additive buffer tank, cement metering tank, water metering tank, additive metering tank, mixer and agitator. Based on PROFIBUS-DP network, the output pressure of the slurry pump is controlled by the inverter. This method has been applied successfully in JZ20-2 Nor. high spot jacket platform construction.

  11. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    of up-to-date facilities has been: Equipment for controlling centrifuge tests, data acquisition, preparation of test samples and equipment for and making of lateral load tests. The present research has been narrowed to investigate the static and cyclic behaviour of stiff piles with a diameter of 1-3 m...... on the structure and the productivity of the turbine. Current design practice for monopiles are based on p-y curves developed for slender piles with a diameter of 0.6 m. The focus on the structure stiffness has entailed a significant research on the soil-structure interaction for large diameter monopiles....... Comparison of the different approaches shows some discrepancy and conflicting statements, but the main findings can be summarized as: • The standard p-y curves are inadequate to describe the behaviour of lateral loaded large diameter rigid piles. • Initial stiffness of the p-y curves is depended...

  12. X-ray spectroscopy around the pile-up region

    CERN Document Server

    Sharma, Gaurav; Kumar, Basu; Puri, Nitin Kumar; Nandi, Tapan

    2015-01-01

    We report a pile-up rejection technique based on X-ray absorption concept of Beer-Lambert law for measuring true events in the pile-up region. We have detected a four orders times weaker peak in the pile-up region. This technique also enables one to resolve the weak peaks adjacent to an intense peak provided the latter lies in the lower energy side, and the peaks are at least theoretically resolvable by the detector used. We have resolved such peaks by reducing the intensity ratios in our experiment. The technique allows us to obtain the actual intensities of the observed peaks to have been measured without any attenuator. The possible applications of this technique can be to study the physics of two electron one-photon transition as well as the properties of projectile-like or target-like ions.

  13. Cumulative Damage in Strength-Dominated Collisions of Rocky Asteroids: Rubble Piles and Brick Piles

    Science.gov (United States)

    Housen, Kevin

    2009-01-01

    Laboratory impact experiments were performed to investigate the conditions that produce large-scale damage in rock targets. Aluminum cylinders (6.3 mm diameter) impacted basalt cylinders (69 mm diameter) at speeds ranging from 0.7 to 2.0 km/s. Diagnostics included measurements of the largest fragment mass, velocities of the largest remnant and large fragments ejected from the periphery of the target, and X-ray computed tomography imaging to inspect some of the impacted targets for internal damage. Significant damage to the target occurred when the kinetic energy per unit target mass exceeded roughly 1/4 of the energy required for catastrophic shattering (where the target is reduced to one-half its original mass). Scaling laws based on a rate-dependent strength were developed that provide a basis for extrapolating the results to larger strength-dominated collisions. The threshold specific energy for widespread damage was found to scale with event size in the same manner as that for catastrophic shattering. Therefore, the factor of four difference between the two thresholds observed in the lab also applies to larger collisions. The scaling laws showed that for a sequence of collisions that are similar in that they produce the same ratio of largest fragment mass to original target mass, the fragment velocities decrease with increasing event size. As a result, rocky asteroids a couple hundred meters in diameter should retain their large ejecta fragments in a jumbled rubble-pile state. For somewhat larger bodies, the ejection velocities are sufficiently low that large fragments are essentially retained in place, possibly forming ordered "brick-pile" structures.

  14. Target reliability index for serviceability limit state of single piles

    Institute of Scientific and Technical Information of China (English)

    边晓亚; 郑俊杰; 徐志军; 章荣军

    2015-01-01

    The objective is to develop an approach for the determination of the target reliability index for serviceability limit state (SLS) of single piles. This contributes to conducting the SLS reliability-based design (RBD) of piles. Based on a two-parameter, hyperbolic curve-fitting equation describing the load−settlement relation of piles, the SLS model factor is defined. Then, taking into account the uncertainties of load−settlement model, load and bearing capacity of piles, the formula for computing the SLS reliability index (βsls) is obtained using the mean value first order second moment (MVFOSM) method. Meanwhile, the limit state function for conducting the SLS reliability analysis by the Monte Carlo simulation (MCS) method is established. These two methods are finally applied to determine the SLS target reliability index. Herein, the limiting tolerable settlement (slt) is treated as a random variable. For illustration, four load test databases from South Africa are compiled again to conduct reliability analysis and present the recommended target reliability indices. The results indicate that the MVFOSM method overestimatesβsls compared to that computed by the MCS method. Besides, both factor of safety (FS) and slt are key factors influencingβsls, so the combination of FS andβsls is welcome to be used for the SLS reliability analysis of piles when slt is determined. For smaller slt, pile types and soils conditions have significant influence on the SLS target reliability indices; for larger slt, slt is the major factor having influence on the SLS target reliability indices. This proves that slt is the most key parameter for the determination of the SLS target reliability index.

  15. AN ANALYTICAL SOLUTION TO LONGITUDINAL VIBRATION OF A PILE OF ARBITRARY SEGMENTS WITH VARIABLE MODULUS

    Institute of Scientific and Technical Information of China (English)

    Wang Teng; Wang Kuihua; Xie Kanghe

    2001-01-01

    The vibration problem of a pile of arbitrary segments with variable modulus under exciting force is established, in which the influence of the soil under pile toe and the surroundings is taken into account. With Laplace transforms, the transmit functions for velocity and displacement of pile are derived. Furthermore, in terms of the convolution theorem and inversed Laplace transform, an analytical solution for the time domain response of a pile subjected to a semi-sine impulse is developed,which is the theoretical basis of the sonic method in pile integrity testing. Based on the solution, the vibration properties of pile with sharp or continuous modulus are studied. The validity of this approach is verified through fidd dynamic tests on some engineering piles. It shows that the theoretical prediction and the response of the pile are in good agreement.

  16. Experimental study on DX pile performance in frozen soils under lateral loading

    Institute of Scientific and Technical Information of China (English)

    XiaoBing Liu; LiHong Chen; ZhongYang Yu; JianXiao Hu; Wen Peng

    2013-01-01

    Experiments about working mechanism and mechanical characteristics of the DX model pile foundation under lateral dynamic and static loading were conducted by using a model system of the dynamic frozen soil-pile interaction. The horizontal displacement-force relationship of the pile head and bending moment distribution along the body in frozen soils of different temperatures were discussed. According to test results, both the horizontal displacement-force relationship of the DX pile head and bending moment distribution of the DX pile body are smaller than that of equal-diameter piles under same lateral loads. The piles with different plate positions show different displacements and bending moments. This phenomenon is mainly related to the soil temperature and bearing plates locations. Thus, dynamic response analysis of the pile foundation should be taken into account.

  17. Numerical Analysis of Interaction Between Pile-Supported Pier and Bank Slope

    Institute of Scientific and Technical Information of China (English)

    王年香

    2001-01-01

    Two- and three-dimensional finite element analysis programs for pile-soil interaction are compiled. Duncan-Chang's Model is used. The construction sequence of the pier is modeled. The pile-soil interface element is used. The influence of the combination type of piles on the deformation of bank slope and pile behaviour is analyzed. Different designs of a pile-supported pier are compared thoroughly. Calculation results show that the stresses and displacements of the pile are directly related to the distance from the bank slope and the direction of inclination. An inclined prop pile set in the rear platform would remarkably reduce the stresses of piles and the displacement of the pier.

  18. 刚性桩复合地基模型拟动力试验研究%Pseudo-dynamic test study on rigid-pile composite foundation

    Institute of Scientific and Technical Information of China (English)

    鲍鹏; 刘德辉

    2013-01-01

    为了研究刚性桩复合地基的抗震性能,依据相似理论,建立几何相似比为1∶10的3×3刚性桩复合地基群桩模型,采用拟动力的试验方法,研制一套试验系统.通过在桩身粘贴电阻应变片、垫层中埋设应变片、砂箱外壁连接位移传感器等方法分别测出桩身应变、垫层变形值、砂箱位移,并对上述数值进行分析研究,得出刚性桩复合地基在地震作用下的响应规律,为刚性桩复合地基在抗震设防地区的应用提供理论指导.%In order to study the seismic performance of rigid-pile composite foundation,a 3 × 3 rigid-pile composite foundation pile group model with geometric similarity ratio of 1:10 was established based on the similarity theory.A test system was developed by using pseudo-dynamic test methods.The pile strain,cushion deformation and sandbox displacement were measured by pasting resistance strain gauges in the pile,burying strain gauges in the cushion and connecting displacement sensors between the outer walls of the sandbox respectively.The above data was analyzed and the response of rigid-pile composite foundation under seismic action was obtained,which can be theoretical guidance for the application of the rigid-pile composite foundation in seismic fortification areas.

  19. Wave Run-up on Slender Piles in Design Conditions

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Frigaard, Peter; Damsgaard, M. L.;

    2011-01-01

    in the design of Horns Reef 1. As a consequence damage was observed on the platforms. This has been the situation for several sites and design tools for platform loads are lacking. As a consequence a physical model test study was initiated at Aalborg University to clarify wave run-up on cylindrical piles...... to the pile an empirical factor is included on the velocity head. The evaluation of the calculation model shows that an accurate design rule can be established even in breaking wave conditions. However, calibration of a load model showed that it was necessary to increase the run-up factor on the velocity head...

  20. Experimental Investigations of Ice Rubble: Shear Box and Pile Testing

    OpenAIRE

    Astrup, Oda Skog

    2012-01-01

    The largest part of an ice ridge consists of unconsolidated ice rubble, whose material properties decide the load from ridges on ships and structures. Material resistance is attributed to the initial freeze-bonds and the friction and interlocking between blocks. The objective of the thesis was to investigate rubble behaviour by two tests: shear box test at NTNU and pile test at HSVA. The shear box test was aimed at investigating freeze-bond mechanisms in rubble. The pile test was aimed at sug...

  1. Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi

    2015-01-01

    Small-scale tests have been conducted to investigate the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that it was possible...... to apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...

  2. Constituent-level pile-up mitigation techniques in ATLAS

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    Pile-up of simultaneous proton-proton collisions at the LHC has a significant impact on jet reconstruction. In this note the performance of several pile-up mitigation techniques is evaluated in detailed simulations of the ATLAS experiment. Four algorithms that act on the jet-constituent level are evaluated: SoftKiller, the cluster vertex fraction algorithm and Voronoi and constituent subtraction. We find that application of these constituent-level algorithms improves the resolution of low-transverse-momentum jets. The improvement is significant for collisions with 80-200 simultaneous proton-proton collisions envisaged in future runs of the LHC.

  3. Centrifuge modelling of a laterally cyclic loaded pile

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  4. Effects of Impulsive Pile-Driving Exposure on Fishes.

    Science.gov (United States)

    Casper, Brandon M; Carlson, Thomas J; Halvorsen, Michele B; Popper, Arthur N

    2016-01-01

    Six species of fishes were tested under aquatic far-field, plane-wave acoustic conditions to answer several key questions regarding the effects of exposure to impulsive pile driving. The issues addressed included which sound levels lead to the onset of barotrauma injuries, how these levels differ between fishes with different types of swim bladders, the recovery from barotrauma injuries, and the potential effects exposure might have on the auditory system. The results demonstrate that the current interim criteria for pile-driving sound exposures are 20 dB or more below the actual sound levels that result in the onset of physiological effects on fishes.

  5. Seismic Dynamic Damage Characteristics of Vertical and Batter Pile-supported Wharf Structure Systems

    Directory of Open Access Journals (Sweden)

    Li Jiren

    2015-10-01

    Full Text Available Considering a typical steel pipe pile-supported wharf as the research object, finite element analytical models of batter and vertical pile structures were established under the same construction site, service, and geological conditions to investigate the seismic dynamic damage characteristics of vertical and batter pile-supported wharf structures. By the numerical simulation and the nonlinear time history response analysis of structure system and the moment–axial force relation curve, we analyzed the dynamic damage characteristics of the two different structures of batter and vertical piles under different seismic ground motions to provide reasonable basis and reference for designing and selecting a pile-supported wharf structure. Results showed that the axial force of batter piles was dominant in the batter pile structure and that batter piles could effectively bear and share seismic load. Under the seismic ground motion with peak ground acceleration (PGA of 350 Gal and in consideration of the factors of the design requirement of horizontal displacement, the seismic performance of the batter pile structure was better than that of the vertical pile structure. Under the seismic ground motion with a PGA of 1000 Gal, plastic failure occurred in two different structures. The contrastive analysis of the development of plastic damage and the absorption and dissipation for seismic energy indicated that the seismic performance of the vertical pile structure was better than that of the batter pile structure.

  6. 16 CFR 300.26 - Pile fabrics and products composed thereof.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Pile fabrics and products composed thereof... CONGRESS RULES AND REGULATIONS UNDER THE WOOL PRODUCTS LABELING ACT OF 1939 Labeling § 300.26 Pile fabrics and products composed thereof. The fiber content of pile fabrics or products made thereof may...

  7. Bending behavior of double-row stabilizing piles with constructional time delay

    Institute of Scientific and Technical Information of China (English)

    Yang YU; Yue-quan SHANG; Hong-yue SUN

    2012-01-01

    The bending behavior of double-row stabilizing plies is associated with the constructional time delay (CTD),which can be defined as the time interval between the installations of the front stabilizing pile and the rear stabilizing pile.This paper investigates the effect of CTD on the bending moments of double-row stabilizing piles and a method for determining the optimal CTD is proposed.The stabilizing pile is modeled as a cantilever pile embedded in the Winkler elastic foundation.A triangular distributed earth pressure is assumed on the pile segment in the sliding layer.The front stabilizing pile and the rear stabilizing pile are connected by a beam with pinned joints.The analytical solutions of bending moments on the front and the rear stabilizing piles are derived and the accuracy of bending moment solutions is validated by comparing the tensile strain measured from the Hongyan landslide project,Taizhou,Zhejiang,China.It is concluded that CTD has a significant influence on the bending moments of double-row stabilizing piles.An optimal CTD can be obtained when the maximum tensile stress in the front stabilizing pile is equal to that in the rear stabilizing pile,which is 1.4 months for the Hongyan landslide project.

  8. Centrifuge modeling of rapid load tests with open-ended piles

    NARCIS (Netherlands)

    Nguyen, T.C.; Van Lottum, H.; Holscher, P.; Van Tol, A.F.

    2012-01-01

    Rapid and static load tests were conducted on open-ended and close-ended piles in the Deltares GeoCentriflige. hi flight, a pile was driven into the soil. Both fme-grained sand and silt beds were tested. Both the rapid and static soil resistances o f a close-ended pile were higher than the soil resi

  9. Response of single piles and pipelines in liquefaction-induced lateral spreads using controlled blasting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two full-scale experiments using controlled blasting were conducted in the Port of Tokachi on Hokkaido Island,Japan, to assess the behavior of piles and pipelines subjected to lateral spreading. Test specimens were extensively instrumented with strain gauges to measure the distribution of moment during lateral spreading. This allowed us to compute the loading condition, as well as to conduct damage and performance assessments on the piles and pipelines. This paper presents the test results and discussions on the response of single piles and pipelines observed from the full-scale experiments. Based on the test results, it can be concluded that using controlled blasting successfully liquefied the soil, and subsequently induced lateral spreading. The movements of the single pile, as well as the transverse pipelines, were approximately the same as the free field soil movement. Observed moment distribution of the single pile indicated that global translation of the liquefied soil layer provided insignificant force to the pile. In addition, the degree of fixity at the pile tip significantly affected the moment along the pile as well as the pile head displacement. The pile with a higher degree of fixity at the pile tip had smaller pile head displacement but larger maximum moment.

  10. 16 CFR 303.24 - Pile fabrics and products composed thereof.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Pile fabrics and products composed thereof... CONGRESS RULES AND REGULATIONS UNDER THE TEXTILE FIBER PRODUCTS IDENTIFICATION ACT § 303.24 Pile fabrics and products composed thereof. The fiber content of pile fabrics or products composed thereof may...

  11. New method of designing anti-slide piles-the strength reduction FEM

    Institute of Scientific and Technical Information of China (English)

    Zheng Yingren; Zhao Shangyi; Lei Wenjie; Tang Xiaosong

    2010-01-01

    At present,the thrust of an anti-slide pile can be worked out with some calculation methods.However,the resistance in front of the pile,the distributions of resistance and thrust,and appropriate pile length cannot be easily obtained.In this paper,the authors applied the strength-reduction finite element method(FEM)to several design cases of anti-slide piles.Using this method,it is possible to take the pile-soil interactions into consideration,obtain reasonable resistance in front of pile and the distributions of thrust and resistance,and reasonable lengths of anti-slide piles.In particular,the thrust and resistance imposed on embedded anti-slide piles can be calculated and composite anti-slide pile structures such as anchored piles and braced piles can be optimized.It is proved through the calculation examples that this method is more reliable and economical in the design of anti-slide pile.

  12. 30 CFR 57.16002 - Bins, hoppers, silos, tanks, and surge piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... NONMETAL MINES Materials Storage and Handling § 57.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored,...

  13. 30 CFR 56.16002 - Bins, hoppers, silos, tanks, and surge piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... MINES Materials Storage and Handling § 56.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled...

  14. Greenhouse gas emissions during composting of dairy manure: Delaying pile mixing does not reduce overall emissions

    Science.gov (United States)

    The effect of the timing of pile mixing on greenhouse gas (GHG) emissions during dairy manure composting was determined using large flux chambers designed to completely cover replicate pilot-scale compost piles. GHG emissions from compost piles that were mixed at 2, 3, 4, or 5 weeks after initial c...

  15. Recovery of small pile burn scars in conifer forests of the Colorado Front Range

    Science.gov (United States)

    Charles C. Rhoades; Paula J. Fornwalt; Mark W. Paschke; Amber Shanklin; Jayne L. Jonas

    2015-01-01

    The ecological consequences of slash pile burning are a concern for land managers charged with maintaining forest soil productivity and native plant diversity. Fuel reduction and forest health management projects have created nearly 150,000 slash piles scheduled for burning on US Forest Service land in northern Colorado. The vast majority of these are small piles (

  16. The Underwater Sound Field from Impact Pile Driving and Its Potential Effects on Marine Life

    NARCIS (Netherlands)

    Dahl, P.H.; Jong, C.A.F. de; Popper, A.N.

    2015-01-01

    Impact pile driving is a method used to install piles for marine and inland water construction projects using high-energy impact hammers. The installation of hollow steel piles in this manner can produce extremely high sound levels in the surrounding waters (as well as in the air). Given the large-

  17. Experimental assessment of the insertion loss of an underwater noise mitigation screen for marine pile driving

    NARCIS (Netherlands)

    Jansen, H.W.; Jong, C.A.F. de; Jung, B.

    2012-01-01

    Because of the concern about potential effects on marine pile driving, the industry is developing silent marine pile driving concepts. One of the new concepts, which has been engineered by IHC Hydrohammer in the Netherlands, is the application of a steel Noise Mitigation Screen (NMS) around the pile

  18. Finite Element Investigations on the Interaction between a Pile and Swelling Clay

    DEFF Research Database (Denmark)

    Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    . For the investigated case study, the influence of the pile is observed in a radius of approximately 3 pile diameters from the pile centre creating a weak zone inside this radius. The maximum heave of the excavation level inside this radius decreases polynomially with increasing interface strength. The swelling...

  19. Study on the Deformation Measurement of the Cast-In-Place Large-Diameter Pile Using Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2017-03-01

    Full Text Available Compared with conventional piles such as the circle pile, the cast-in-place large-diameter pile (PCC pile has many advantages: the lateral area of PCC pile is larger and the bearing capacity of PCC pile is higher. It is more cost-effective than other piles such as square pile under the same condition. The deformation of the PCC pile is very important for its application. In order to obtain the deformation of the PCC pile, a new type of quasi-distributed optical fiber sensing technology named a fiber Bragg grating (FBG is used to monitor the deformation of the PCC pile. The PCC model pile is made, the packaging process of the PCC model pile and the layout of fiber sensors are designed, and the strains of the PCC model pile based on FBG sensors are monitored. The strain of the PCC pile is analyzed by the static load test. The results show that FBG technology is successfully applied for monitoring the deformation of the PCC pile, the monitoring data is more useful for the PCC pile. It will provide a reference for the engineering applications.

  20. Aerial sampling of emissions from biomass pile burns in Oregon

    Science.gov (United States)

    Emissions from burning piles of post-harvest timber slash in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5 µm), ...

  1. Numerical experiments with rubble piles : equilibrium shapes and spins

    NARCIS (Netherlands)

    Richardson, Derek C.; Elankumaran, Pradeep; Sanderson, Robyn E.

    2005-01-01

    We present numerical experiments investigating the shape and spin limits of self-gravitating "perfect" rubble piles that consist of identical, smooth, rigid, spherical particles with configurable normal coefficient of restitution and no sliding friction. Such constructs are currently employed in a v

  2. 20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia

    DEFF Research Database (Denmark)

    Augustesen, Anders

    This document is one of four notes concerning the effects of time (in this case ageing) on the vertical capacity of piles. It includes summaries of relevant publications related to the topic. Further, focus has been paid to publications that deal with quantification of setup and not the mechanisms...

  3. Assessment of Cumulative Sound Exposure Levels for Marine Piling Events

    NARCIS (Netherlands)

    Lepper, P.A.; Robinson, S.P.; Ainslie, M.A.; Theobald, P.D.; Jong, C.A.F. de

    2012-01-01

    The installation of offshore wind farms in European waters and the scale of the planned activity have led to concern over the generation of noise and its potential impact on marine life. Much of this concern is centered around the noise generated by pile driving, which is used for the installation o

  4. 30 CFR 816.83 - Coal mine waste: Refuse piles.

    Science.gov (United States)

    2010-07-01

    .... Critical construction periods shall include at a minimum: (i) Foundation preparation including the removal... revegetated upon completion of construction. (c) Placement. (1) All vegetative and organic materials shall be... professional engineer, shall inspect the refuse pile during construction. The professional engineer...

  5. 30 CFR 817.83 - Coal mine waste: Refuse piles.

    Science.gov (United States)

    2010-07-01

    .... Critical construction periods shall include at a minimum: (i) Foundation preparation including the removal... revegetated upon completion of construction. (c) Placement. (1) All vegetative and organic materials shall be... professional engineer, shall inspect the refuse pile during construction. The professional engineer...

  6. Centrifuge modelling of rigid piles in soft clay

    DEFF Research Database (Denmark)

    Klinkvort, R.T.; Poder, M.; Truong, P.

    2016-01-01

    of this study is to employ centrifuge modelling in order to derive experimental p-y curves for rigid piles embedded in over-consolidated soft clay. A kaolin clay sample was prepared and pre-consolidated by applying a constant pressure at the soil surface, while different over-consolidation ratios were achieved...

  7. Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi

    2015-01-01

    to apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...

  8. Airborne sound propagation over sea during offshore wind farm piling.

    Science.gov (United States)

    Van Renterghem, T; Botteldooren, D; Dekoninck, L

    2014-02-01

    Offshore piling for wind farm construction has attracted a lot of attention in recent years due to the extremely high noise emission levels associated with such operations. While underwater noise levels were shown to be harmful for the marine biology, the propagation of airborne piling noise over sea has not been studied in detail before. In this study, detailed numerical calculations have been performed with the Green's Function Parabolic Equation (GFPE) method to estimate noise levels up to a distance of 10 km. Measured noise emission levels during piling of pinpiles for a jacket-foundation wind turbine were assessed and used together with combinations of the sea surface state and idealized vertical sound speed profiles (downwind sound propagation). Effective impedances were found and used to represent non-flat sea surfaces at low-wind sea states 2, 3, and 4. Calculations show that scattering by a rough sea surface, which decreases sound pressure levels, exceeds refractive effects, which increase sound pressure levels under downwind conditions. This suggests that the presence of wind, even when blowing downwind to potential receivers, is beneficial to increase the attenuation of piling sound over the sea. A fully flat sea surface therefore represents a worst-case scenario.

  9. Aerial sampling of emissions from biomass pile burns in ...

    Science.gov (United States)

    Emissions from burning piles of post-harvest timber slash in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5 µm), black carbon, ultraviolet absorbing PM, elemental/organic carbon, semi-volatile organics (polycyclic aromatic hydrocarbons and polychlorinated dibenzodioxins/dibenzofurans), filter-based metals, and volatile organics were sampled for determination of emission factors. The effect on emissions from covering or not covering piles with polyethylene sheets to prevent fuel wetting was determined. Results showed that the uncovered (“wet”) piles burned with lower combustion efficiency and higher emissions of volatile organic compounds. Results for other pollutants will also be discussed. This work determined the emissions from open burning of forest slash wood, with and without plastic sheeting. The foresters advocate the use of plastic to keep the slash wood dry and aid in the controlled combustion of the slash to reduce fuel loading. Concerns about the emissions from the burning plastic prompted this work which conducted an extensive characterization of dry, wet, and dry with plastic slash pile emissions.

  10. 20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia

    DEFF Research Database (Denmark)

    Augustesen, Anders

    This report presents the results of work carried out by Aalborg Univesity for NGI related to the effects of ageing on the axial capacity of piles in clay and sand. The document is the fourth of four notes regarding the subject and it includes a recommended approach to account for ageing effects...

  11. Rapid pile load tests in the geotechnical centrifuge

    NARCIS (Netherlands)

    Holscher, P.; Van Tol, A.F.; Huy, N.Q.

    2012-01-01

    Centrifiige experiments were carried out to gain insight into the factors that affect the mobilized resistance during rapid load testing on piles in sand. The influence of generated pore water pressure during rapid load tests is shidied, and its effect on the commonly used unloadmg point method to d

  12. Assessment of Cumulative Sound Exposure Levels for Marine Piling Events

    NARCIS (Netherlands)

    Lepper, P.A.; Robinson, S.P.; Ainslie, M.A.; Theobald, P.D.; Jong, C.A.F. de

    2012-01-01

    The installation of offshore wind farms in European waters and the scale of the planned activity have led to concern over the generation of noise and its potential impact on marine life. Much of this concern is centered around the noise generated by pile driving, which is used for the installation

  13. Rapid pile load tests in the geotechnical centrifuge

    NARCIS (Netherlands)

    Holscher, P.; Van Tol, A.F.; Huy, N.Q.

    2012-01-01

    Centrifiige experiments were carried out to gain insight into the factors that affect the mobilized resistance during rapid load testing on piles in sand. The influence of generated pore water pressure during rapid load tests is shidied, and its effect on the commonly used unloadmg point method to d

  14. The impact of wind energy turbine piles on ocean dynamics

    Science.gov (United States)

    Grashorn, Sebastian; Stanev, Emil V.

    2016-04-01

    The small- and meso-scale ocean response to wind parks has not been investigated in the southern North Sea until now with the help of high-resolution numerical modelling. Obstacles such as e.g. wind turbine piles may influence the ocean current system and produce turbulent kinetic energy which could affect sediment dynamics in the surrounding area. Two setups of the unstructured-grid model SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model) have been developed for an idealized channel including a surface piercing cylindrical obstacle representing the pile and a more realistic test case including four exemplary piles. Experiments using a constant flow around the obstacles and a rotating M2 tidal wave are carried out. The resulting current and turbulence patterns are investigated to estimate the influence of the obstacles on the surrounding ocean dynamics. We demonstrate that using an unstructured ocean model provides the opportunity to embed a high-resolution representation of a wind park turbine pile system into a coarser North Sea setup, which is needed in order to perform a seamless investigation of the resulting geophysical processes.

  15. Calibration of Partial Factors for Basal Reinforced Piled Embankments

    NARCIS (Netherlands)

    Van Duijnen, P.G.; Schweckendiek, T.; Calle, E.O.F.; Van Eekelen, S.J.M.

    2015-01-01

    In the Netherlands, the design guideline for basal reinforced piled embankments has been revised (CUR226:2015) adopting a new analytical design model (The Concentric Arches (CA) model, Van Eekelen et al., 2013; 2015). The CA model provides geosynthetic reinforcement (GR) strains which were compared

  16. Effect of sediment on vertical dynamic impedance of rock-socketed pile with large diameter

    Institute of Scientific and Technical Information of China (English)

    俞缙; 蔡燕燕; 吴文兵

    2013-01-01

    Based on the fictitious soil pile model, the effect of sediment on the vertical dynamic impedance of rock-socketed pile with large diameter was theoretically studied by means of Laplace transform technique and impedance function transfer method. Firstly, the sediment under rock-socketed pile was assumed to be fictitious soil pile with the same sectional area. The Rayleigh-Love rode model was used to simulate the rock-socketed pile and the fictitious soil pile with the consideration of the lateral inertial effect of large-diameter pile. The layered surrounding soils and bedrock were modeled by the plane strain model. Then, by virtue of the initial conditions and boundary conditions of the soil pile system, the analytical solution of the vertical dynamic impedance at the head of rock-socketed pile was derived for the arbitrary excitation acting on the pile head. Lastly, based on the presented analytical solution, the effect of sediment properties, bedrock property and lateral inertial effect on the vertical dynamic impedance at rock-socketed pile head were investigated in detail. It is shown that the sediment properties have significant effect on the vertical dynamic impedance at the rock-socketed pile head. The ability of soil-pile system to resist dynamic vertical deformation is weakened with the increase of sediment thickness, but amplified with the increase of shear wave velocity of sediment. The ability of soil pile system to resist dynamic vertical deformation is amplified with the bedrock property improving, but the ability of soil-pile system to resist vertical vibration is weakened with the improvement of bedrock property.

  17. Enhanced mixing downstream of a pile in an estuarine flow

    Science.gov (United States)

    Lass, H. U.; Mohrholz, V.; Knoll, M.; Prandke, H.

    2008-11-01

    We studied the impact on stratification and mixing of a bridge pile in a stratified shear flow at the Western Bridge of the Great Belt Fixed Link, Denmark, in January and April 2006. Stratification was measured with high horizontal resolution by towed CTD chains and dissipation of turbulent kinetic energy was measured by a free-falling MSS 90 microstructure profiler equipped with shear probes. Background stratification and current were measured by standard CTD and a bottom-mounted ADCP, respectively. The spatial and temporal variability of the flow field close behind a single pile was measured by an ADCP mounted on a small catamaran tethered to this pile. A shear background flow of varying strength was observed with an inflow of up to 80 cm s - 1 in the surface layer and an outflow of 10 cm s - 1 in the bottom layer. The brackish surface layer was separated from the saline Kattegat water in the bottom layer by an intermediate layer resulting in a Brunt-Väisälä frequency of up to 100 cycles per hour (cph). The maximum Reynolds number ( Re) and internal Froude number ( Fr) were 4.6 × 10 6 and 1.3, respectively. Eddies occurred downstream of a pile with a characteristic diameter of the pile and a frequency corresponding to a von Kármán vortex street when near-surface Fr > 0.7. Enhanced mixing was observed in the von Kármán vortex streets, which caused an increase in salinity by a few psu in the surface mixed layer of the eddy up to 400 m downstream of the piles. Differential advection by cross-channel circulation smeared out laterally from the wakes' salinity anomalies and turbulence. The dissipation of turbulent kinetic energy in the intermediate layer increased by an order of magnitude downstream of the piles as a function of Fr when Fr > 0.7. This enhanced mixing reduced the mean potential energy anomaly downstream by some 10 Jm - 3 in the upper 15 m depth and caused an upstream-directed baroclinic pressure gradient of the same order as the barotropic

  18. Digitalisation in atomic pile control (1962); La digitalisation dans le controle des piles atomiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Furet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    A brief survey is first given of the general theorems of Boodle's algebra and of sequence systems using D.A. Huffmans theory. Some indications are then given concerning the setting-up and the operation of digital computers and also of the principal codes used in digital techniques. It is then shown how digitalisation in atomic pile control makes it possible to use new techniques having the following advantages in particular: greater working safety, a higher degree of centralisation, and suppression of the linear elements. A few examples are given of the application of these techniques to control, particularly with respect to the measurement of the neutronic power and of the period and also of course, to the treatment of the data and the sequence automatisms. The advantage of using digital techniques in the shutdown channels is also examined. Finally a review is given of the technology and the viability of the control devices used. (author) [French] On rappelle d'abord ici les theoremes generaux de l'algebre de Boole et des systemes a sequences en s'appuyant sur la theorie de D.A. Huffmann. On donne ensuite quelques indications sur l'agencement et le fonctionnement des calculateurs digitaux ainsi que les principaux codes utilises dans les techniques digitales. On montre alors comment la digitalisation dans le controle des piles atomiques permet d'utiliser de nouvelles techniques presentant principalement les avantages suivants: securite de fonctionnement plus grande, centralisation plus elevee et suppression des elements lineaires. Un certain nombre d'exemples sont donnes sur l'application de ces techniques au controle, particulierement en ce qui concerne la mesure de la puissance neutronique, de la periode et aussi bien entendu du traitement des informations et des automatismes a sequences. On analyse aussi l'avantage de l'utilisation des techniques digitales dans les chaines de securite. Enfin, un apercu est donne

  19. Reliability Analysis of Bearing Capacity of Large-Diameter Piles under Osterberg Test

    Directory of Open Access Journals (Sweden)

    Lei Nie

    2013-05-01

    Full Text Available This study gives the reliability analysis of bearing capacity of large-diameter piles under osterberg test. The limit state equation of dimensionless random variables is utilized in the reliability analysis of vertical bearing capacity of large-diameter piles based on Osterberg loading tests. And the reliability index and the resistance partial coefficient under the current specifications are calculated using calibration method. The results show: the reliable index of large-diameter piles is correlated with the load effect ratio and is smaller than the ordinary piles; resistance partial coefficient of 1.53 is proper in design of large-diameter piles.

  20. Bearing Capacity Estimation of Bridge Piles Using the Impulse Transient Response Method

    Directory of Open Access Journals (Sweden)

    Meng Ma

    2016-01-01

    Full Text Available A bearing capacity estimation method for bridge piles was developed. In this method, the pulse echo test was used to select the intact piles; the dynamic stiffness was obtained by the impulse transient response test. A total of 680 bridge piles were tested, and their capacities were estimated. Finally, core drilling analysis was used to check the reliability of this method. The results show that, for intact piles, an obvious positive correlation exits between the dynamic stiffness and bearing capacity of the piles. The core drilling analysis proved that the estimation method was reliable.

  1. Experimental Research on Large Diameter Cast-in-Place Piles Embedded in Rock

    Institute of Scientific and Technical Information of China (English)

    衡朝阳; 何满潮; 姚爱军

    2001-01-01

    This paper expatiated the field test of large diameter cast-in-place piles embedded in soft rock, including static loading test, high or low strain dynamic test, measurement of stresses and strains of pile body, and pressure measurements between pile tip and soft rock. The relative in-situ test problems are discussed. Based on the limit equilibrium theory and the load transfer equation, a synthesis method of analyzing the ultimate carrying capacity of single large diameter pile is put forward. The research results show that the key to determining the ultimate carrying capacity of single pile with a large diameter is the analysis of the intensity of soft rock.

  2. Some Consideration on Elastic Pile Foundation Analysis by Poulos%对Poulos弹性桩基分析的考察(英文)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The elastic pile foundation analysis by Poulos is well developed and has been adopted by some countries in their design guideline. In the vertical load analysis,the author has discovered that the approach by Poulos is sensitive to the number of segments used for analysis and can lead to some unreasonable results for pile in finite depth of soil. In the lateral load analysis,the group interaction factor which is claimed to be a linear relation of the departure angleby Poulos is found to be a linear relation of by the author.

  3. Dynamic-stiffness matrix of embedded and pile foundations by indirect boundary-element method

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, J.P.; Darbre, G.R. (Electrowatt Engineering Services Ltd., Zurich (Switzerland))

    1984-08-01

    The boundary-integral equation method is well suited for the calculation of the dynamic-stiffness matrix of foundations embedded in a layered visco-elastic halfspace (or a transmitting boundary of arbitrary shape), which represents an unbounded domain. It also allows pile groups to be analyzed, taking pile-soil-pile interaction into account. The discretization of this boundary-element method is restricted to the structure-soil interface. All trial functions satisfy exactly the field equations and the radiation condition at infinity. In the indirect boundary-element method distributed source loads of initially unknown intensities act on a source line located in the excavated part of the soil and are determined such that the prescribed boundary conditions on the structure-soil interface are satisfied in an average sense. In the two-dimensional case the variables are expanded in a Fourier integral in the wave number domain, while in three dimensions, Fourier series in the circumferential direction and Bessel functions of the wave number domain, while in three dimensions, Fourier series in the circumferential direction and Bessel functions of the wave number in the radial direction are selected. Accurate results arise with a small number of parameters of the loads acting on a source line which should coincide with the structure-soil interface. In a parametric study the dynamic-stiffness matrices of rectangular foundations of various aspect ratios embedded in a halfplane and in a layer built-in at its base are calculated. For the halfplane, the spring coefficients for the translational directions hardly depend on the embedment, while the corresponding damping coefficients increase for larger embedments, this tendency being more pronounced in the horizontal direction.

  4. Field Tests to Investigate the Penetration Rate of Piles Driven by Vibratory Installation

    Directory of Open Access Journals (Sweden)

    Zhaohui Qin

    2017-01-01

    Full Text Available Factors directly affecting the penetration rate of piles installed by vibratory driving technique are summarized and classified into seven aspects which are driving force, resistance, vibratory amplitude, energy consumption, speeding up at the beginning, pile plumbness keeping, and slowing down at the end, from the mechanism and engineering practice of the vibratory pile driving. In order to find out how these factors affect the penetration rate of the pile in three major actors of vibratory pile driving: (i the pile to be driven, (ii the selected driving system, and (iii the imposed soil conditions, field tests on steel sheet piles driven by vibratory driving technique in different soil conditions are conducted. The penetration rates of three different sheet pile types having up to four different lengths installed using two different vibratory driving systems are documented. Piles with different lengths and types driven with or without clutch have different penetration rates. The working parameters of vibratory hammer, such as driving force and vibratory amplitude, have great influences on the penetration rate of the pile, especially at the later stages of the sinking process. Penetration rate of piles driven in different soil conditions is uniform because of the different penetration resistance including shaft friction and toe resistance.

  5. Bending Moment Calculations for Piles Based on the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Yu-xin Jie

    2013-01-01

    Full Text Available Using the finite element analysis program ABAQUS, a series of calculations on a cantilever beam, pile, and sheet pile wall were made to investigate the bending moment computational methods. The analyses demonstrated that the shear locking is not significant for the passive pile embedded in soil. Therefore, higher-order elements are not always necessary in the computation. The number of grids across the pile section is important for bending moment calculated with stress and less significant for that calculated with displacement. Although computing bending moment with displacement requires fewer grid numbers across the pile section, it sometimes results in variation of the results. For displacement calculation, a pile row can be suitably represented by an equivalent sheet pile wall, whereas the resulting bending moments may be different. Calculated results of bending moment may differ greatly with different grid partitions and computational methods. Therefore, a comparison of results is necessary when performing the analysis.

  6. Nonlinear analysis of pile load-settlement behavior in layered soil

    Institute of Scientific and Technical Information of China (English)

    吕述晖; 王奎华; 张鹏; C. J. LEO3

    2015-01-01

    A simplified approach is presented to analyze the single pile settlement in multilayered soil. First, a fictitious soil−pile model is employed to consider the effect of layered soil beneath pile toe on pile settlement behavior. Two approximation methods are proposed to simplify the nonlinear load transfer function and simulate the nonlinear compression of fictitious soil−pile, respectively. On this basis, an efficient program is developed. The procedures for determining the main parameters of mathematical model are discussed. Comparisons with two well-documented field experimental pile loading tests are conducted to verify the rationality of the present method. Further studies are also made to evaluate the practicability of the proposed approach when a soft substratum exists, and the results suggest that the proposed method can provide a constructive means for assessing the settlement of a single pile for use in engineering design.

  7. Réparation des pieux battus dans les sables carbonatés Repair of Driven Piles in Calcareous Formations

    Directory of Open Access Journals (Sweden)

    Nauroy J. F.

    2006-11-01

    Full Text Available Les formations carbonatées rencontrées en de nombreuses zones d'activités pétrolières en mer posent de difficiles problèmes de dimensionnement et de mise en place des pieux. Sur plusieurs sites de sable carbonaté, la capacité portante des pieux battus se révèle beaucoup plus faible que prévu et des techniques de réparation doivent être étudiées. Dans ce contexte, l'ARGEMA (Association de Recherche en Géotechnique Marine, groupement français d'organismes de recherche, de compagnies pétrolières et de contracteurs offshore, a expérimenté une réparation d'un pieu expérimental de 30 cm de diamètre et 23 m de long battu dans un sable carbonaté. Le frottement latéral de ce pieu mobilisé juste après battage était très faible. La réparation a consisté à injecter du coulis de ciment à partir d'un forage situé à 40 cm du pieu. Cet article décrit les procédures et les caractéristiques des injections réalisées et leurs conséquences sur la capacité portante du pieu. Le frottement entre le pieu et le terrain s'accroît avec le volume de ciment injecté; les valeurs maximales obtenues sont du même ordre de grandeur que celles observées avec un pieu foré-cimenté. The calcareous formations encountered in many zones of offshore petroleum activity raise difficult problems for designing and installing foundation piles. On several sites with calcareous sands, the bearing capacity of driven piles proves to be much less than had been planned, and repair techniques have to be examined. Within this context, ARGEMA (Association de Recherche en Géotechnique Marine, a french group of research organizations, oil companies and offshore contractors, has tested a repair of an experimental pile 30 cm in diameter and 23 m long driven into a calcareous sand. The skin friction of this pile, mobilized just after driving, was found to be very low. The repair-job consisted in injecting grout from a drilled borehole located at some tens

  8. Analysis of concrete foundation piles using structure-integrated fibre-optic sensors; Strukturanalyse von Betonpfaehlen durch eingebettete faseroptische Sensoren

    Energy Technology Data Exchange (ETDEWEB)

    Schallert, Matthias [Gesellschaft fuer Schwingungsuntersuchungen und Dynamische Pruefmethoden (GSP) mbH, Mannheim (Germany); Hofmann, Detlef; Habel, Wolfgang R. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2008-07-01

    Reinforced concrete piles are often used for structures on non-sufficiently bearing soil areas. Assessment of bearing capacity and bearing behaviour of large concrete piles remains a difficult task under specific soil conditions and pile geometries. Usually static and dynamic pile tests are carried out for quality assurance. From dynamic measurements taken only from the pile head, the bearing behaviour and structural integrity can be derived using the one-dimensional theory of wave propagation. More precise information about the pile features can be achieved by highly resolving fibre-optic sensors based on Fabry-Perot technology, distributed over several locations along the pile length. Small scale piles and real driven piles have been tested. This paper describes the sensor, the sensor installation, and experimental results of tests in laboratory as well as test results for recording the wave propagation in the small scale piles. (orig.)

  9. Conditions of Proper Interaction of Low-Pressure Injection Piles (LIP) with Structure and Soil, Carrying Capacity of Pile Anchorage in Foundation

    Science.gov (United States)

    Pachla, Henryk

    2016-12-01

    The formation of a pile in the existing foundation and soil creates a new foundation construction which has a structure of foundation-pile-soil. This construction must be able to transfer loads from the foundation to the pile and from the pile to the soil. The pile structure has to transfer an imposed load. From the point of view of continuum mechanics determination of the capacity of such a system is preceded by the analysis of contact problem of three contact surfaces. Each of these surfaces is determined by different pairs of materials. The pair which creates a pile anchorage is a material from which the foundation is built (structure of stone and grout, brick and grout, concrete or reinforced concrete and grout. The pile structure is formed by grout and steel rebar. The pile formed in soil is created by a pair of grout and soil. What is important is that on contact surfaces the materials adhering to one another are subjected to different deformation types that are controlled by mechanical properties and geometry of these surfaces. In the paper, additional conditions that should be fulfilled for the foundation-pile-soil system to make load transfer from foundation to soil possible and safe are presented. The results of research done by the author on foundation-pile contact surface are discussed. The tests were targeted at verifying the bearing capacity of anchorage and deformation of piles made of grout and other materials from which foundations are built. The specimens were tested in tension and compression. The experiments were conducted on the amount specimens which is regarded as small sample to enable the statistical analysis of the results.

  10. Picking up Clues from the Discard Pile (Stereo)

    Science.gov (United States)

    2008-01-01

    As NASA's Phoenix Mars Lander excavates trenches, it also builds piles with most of the material scooped from the holes. The piles, like this one called 'Caterpillar,' provide researchers some information about the soil. On Aug. 24, 2008, during the late afternoon of the 88th Martian day after landing, Phoenix's Surface Stereo Imager took separate exposures through its left eye and right eye that have been combined into this stereo view. The image appears three dimensional when seen through red-blue glasses. This conical pile of soil is about 10 centimeters (4 inches) tall. The sources of material that the robotic arm has dropped onto the Caterpillar pile have included the 'Dodo' and ''Upper Cupboard' trenches and, more recently, the deeper 'Stone Soup' trench. Observations of the pile provide information, such as the slope of the cone and the textures of the soil, that helps scientists understand properties of material excavated from the trenches. For the Stone Soup trench in particular, which is about 18 centimeters (7 inches) deep, the bottom of the trench is in shadow and more difficult to observe than other trenches that Phoenix has dug. The Phoenix team obtained spectral clues about the composition of material from the bottom of Stone Soup by photographing Caterpillar through 15 different filters of the Surface Stereo Imager when the pile was covered in freshly excavated material from the trench. The spectral observation did not produce any sign of water-ice, just typical soil for the site. However, the bigger clumps do show a platy texture that could be consistent with elevated concentration of salts in the soil from deep in Stone Soup. The team chose that location as the source for a soil sample to be analyzed in the lander's wet chemistry laboratory, which can identify soluble salts in the soil. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory

  11. Piles, Tabs and Overlaps in Navigation among Documents

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper Anders Søren

    2010-01-01

    documents worked well for tasks that involved visual features of the documents, but the utility of recency or stable ordering of documents was task dependent. Based on the results, we discuss the effects of spatial arrangement, visibility, and task-dependency, and suggest areas for future research......Navigation among documents is a frequent, but ill supported activity. Overlapping or tabbed documents are widespread, but they offer limited visibility of their content. We explore variations on navigation support: arranging documents with tabs, as overlapping windows, and in piles....... In an experiment we compared 11 participants’ navigation with these variations and found strong task effects. Overall, overlapping windows were preferred and their structured layout worked well with some tasks. Surprisingly, tabbed documents were efficient in tasks requiring simply finding a document. Piled...

  12. The Pressure Limitations on Flux Pile-up Reconnection

    Science.gov (United States)

    Litvinenko, Yuri E.

    1999-05-01

    The problem of the plasma pressure limitations on the rapidity of flux pile-up magnetic reconnection is re-examined, following the claim made by Jardine and Allen (1998) that the limitations can be removed by relaxing the assumption of zero-vorticity two-dimensional plasma flows. It is shown that for a two-dimensional stagnation point flow with nonzero vorticity the magnetic merging rate cannot exceed the Sweet-Parker scaling in a low-beta plasma. The pressure limitation appears to be much less restrictive for weak three-dimensional flux pile-up, provided the perturbation length scale in the third dimension is much less than the global length scale. The actual reconnection rate in the latter case, however, is much lower than this upper estimate unless the current sheet width is also much less than the global scale.

  13. The Supercritical Pile Model: Prompt Emission Across the Electromagnetic Spectrum

    Science.gov (United States)

    Kazanas, Demos; Mastichiadis, A.

    2008-01-01

    The "Supercritical Pile" GRB model is an economical model that provides the dissipation necessary to convert explosively the energy stored in relativistic protons in the blast wave of a GRB into radiation; at the same time it produces spectra whose luminosity peaks at 1 MeV in the lab frame, the result of the kinematics of the proton-photon - pair production reaction that effects the conversion of proton energy to radiation. We outline the fundamental notions behind the "Supercritical Pile" model and discuss the resulting spectra of the prompt emission from optical to gamma-ray energies of order Gamma^2 m_ec^2, (Gamma is the Lorentz factor of the blast wave) present even in the absence of an accelerated particle distribution and compare our results to bursts that cover this entire energy range. Particular emphasis is given on the emission at the GLAST energy range both in the prompt and the afterglow stages of the burst.

  14. ESTIMATION OF SCOUR HOLE PROPERTIES AROUND VERTICAL PILE USING ANNs

    Institute of Scientific and Technical Information of China (English)

    A.KHOSRONEJAD; G. A. MONTAZER; M. GHODSIAN

    2003-01-01

    Correct estimation of the scour around vertical piles in the field exposed to oscillatory waves is very important for many offshore structures and coastal engineering projects. Conventional predictive formulas for the geometric properties of scour hole, however, are not able to provide sufficiently accurate results. Artificial Neural Networks (ANNs) are simplified mathematical representation of the human brain. Three-layer normal feed-forward ANN is a powerful tool for input-output mapping and has been widely used in civil engineering problems. In this article the ANNs approach is used to predict the geometric properties of the scour around vertical pile. Two different ANNs including multilayer perceptron (with four different learning rules) and radial basis functions neural networks are used for this purpose. The results show that a three-layer normal feed-forward multilayer perceptron with quick propagation (QP) learning rule can predict the scour hole properties successfully.

  15. The Supercritical Pile Model: Prompt Emission Across the Electromagnetic Spectrum

    Science.gov (United States)

    Kazanas, Demos; Mastichiadis, A.

    2008-01-01

    The "Supercritical Pile" GRB model is an economical model that provides the dissipation necessary to convert explosively the energy stored in relativistic protons in the blast wave of a GRB into radiation; at the same time it produces spectra whose luminosity peaks at 1 MeV in the lab frame, the result of the kinematics of the proton-photon - pair production reaction that effects the conversion of proton energy to radiation. We outline the fundamental notions behind the "Supercritical Pile" model and discuss the resulting spectra of the prompt emission from optical to gamma-ray energies of order Gamma^2 m_ec^2, (Gamma is the Lorentz factor of the blast wave) present even in the absence of an accelerated particle distribution and compare our results to bursts that cover this entire energy range. Particular emphasis is given on the emission at the GLAST energy range both in the prompt and the afterglow stages of the burst.

  16. Probability distributions for Poisson processes with pile-up

    CERN Document Server

    Sevilla, Diego J R

    2013-01-01

    In this paper, two parametric probability distributions capable to describe the statistics of X-ray photon detection by a CCD are presented. They are formulated from simple models that account for the pile-up phenomenon, in which two or more photons are counted as one. These models are based on the Poisson process, but they have an extra parameter which includes all the detailed mechanisms of the pile-up process that must be fitted to the data statistics simultaneously with the rate parameter. The new probability distributions, one for number of counts per time bins (Poisson-like), and the other for waiting times (exponential-like) are tested fitting them to statistics of real data, and between them through numerical simulations, and their results are analyzed and compared. The probability distributions presented here can be used as background statistical models to derive likelihood functions for statistical methods in signal analysis.

  17. Resolution of Identity Crisis of Events in Pile-up

    CERN Document Server

    Deshpande, Avinash A

    2012-01-01

    Mutually uncorrelated random discrete events, manifesting a common basic process, are examined often in terms of their occurrence rate as a function of one or more of their distinguishing attributes, such as measurements of photon spectrum as a function of energy. Such rate distributions obtained from the observed attribute values for an ensemble of events will correspond to the "true" distribution only if the event occurrence were {\\it mutually exclusive}. However, due to finite resolution in such measurements, the problem of event {\\it pile-up} is not only unavoidable, but also increases with event rate. Although extensive simulations to estimate the distortion due to pile-up in the observed rate distribution are available, no restoration procedure has yet been suggested. Here we present an elegant analytical solution to recover the underlying {\\it true} distribution. Our method, based on Poisson statistics and Fourier transforms, is shown to perform as desired even when applied to distributions that are si...

  18. Calculation method of composite foundation sedimentation of grouting pile with cover plate under embankment load

    Institute of Scientific and Technical Information of China (English)

    顾长存; 洪昌地; 马文彬; 李雪平

    2008-01-01

    Grouting pile is a new soft soil foundation treatment method with characteristics such as no vibration, no noise, no soil compaction, light construction machines and quick construction velocity and so on. At present, study on reinforcement mechanism and design calculation method of composite foundation of grouting pile is initially started without design specifications, so it is usually required to draw on design specifications of stump pile when designing composite foundation of grouting pile while grouting pile has its characteristics and difference although reinforcement mechanisms and construction processes of two types of piles are similar. Sedimentation formula of composite foundation of grouting pile with cover plate is educed and a suitable deformation mode is proposed by aiming to deformation characteristics of composite foundation of grouting pile with cover plate under embankment load on basis of relevant sedimentation theories of composite foundation by combination of characteristics of composite foundation of grouting pile. The sedimentation calculation formula of grouting pile with cover plate under embankment load is educed according to balance relation of force and displacement coordination conditions by elastic theory and sedimentation calculation model established is validated by sedimentation monitoring documents of one expressway in China.

  19. New Analysis Techniques for Avalanches in a Conical Bead Pile with Cohesion

    Science.gov (United States)

    Tieman, Catherine; Lehman, Susan

    2015-03-01

    Avalanche statistics and pile geometry for 3 mm steel spheres dropped on a conical bead pile were studied at different drop heights and different cohesion strengths. The pile is initially built on a circular base and is subsequently slowly driven by adding one bead at a time to the apex of the pile. We investigate the dynamic response of the pile by recording avalanches off the pile over the course of tens of thousands of bead drops. The level of cohesion is tuned through use of an applied uniform magnetic field. Changes in the pile mass and geometry were investigated to determine the effect of cohesion and drop height on the angle of repose. The angle of repose increased with cohesion strength, and decreased somewhat for higher drop heights. The packing density of beads is expected to decrease as magnetic cohesion increases, but for our 20 000-bead pile, this effect has not been observed. The proportion of beads removed from the pile by different avalanche sizes was also calculated. Although larger avalanches are much rarer occurrences, they carry away a larger fraction of the total avalanched mass than small avalanches. As the pile cohesion increases, the number of small and medium avalanches decreases so that this mass loss distribution shifts more strongly to large sizes.

  20. Collapse mechanisms and strength prediction of reinforced concrete pile caps

    DEFF Research Database (Denmark)

    Jensen, Uffe G.; Hoang, Linh Cao

    2012-01-01

    This paper describes an upper bound plasticity approach for strength prediction of reinforced concrete pile caps. A number of collapse mechanisms are identified and analysed. The procedure leads to an estimate of the load-carrying capacity and an identification of the critical collapse mechanism....... It is argued that the upper bound approach may be a useful complement to the widely used lower bound strut-and-tie method. Especially when dealing with strength assessment of existing structures....

  1. Chestnut Ridge Borrow Area Waste Pile work plan

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R. (Oak Ridge Y-12 Plant, TN (United States))

    1991-08-01

    The US Department of Energy (DOE), through its contractor Martin Marietta Energy Systems, Inc., has constructed a storage facility, the Chestnut Ridge Borrow Area Waste Pile (CRBAWP), for mercury-contaminated soil excavated from the Oak Ridge Civic Center properties and the Oak Ridge Sewer Line Beltway. Excavation of the soil from the Civic Center began in September 1984 and was completed in early 1985. Similar soils from other areas of the city were added to the pile until 1987. Approximately 3000 yd{sup 3} are stored at the present time. An Interim Status RCRA permit was initially sought for this facility. Samples from the waste pile passed the Extraction Procedure Toxicity Test (EP Tox). The Tennessee Department of Health and Environment (now the Tennessee Department of Conservation-TDC) denied the permit based on their conclusion that the waste was not a RCRA-regulated waste. On September 25, 1990 the Toxicity Characteristic Leaching Procedure (TCLP) superseded the EP Tox test. TCLP tests are not proposed to satisfy a request by TDC and to make a final determination of the nature of the soils in order to close the CRBAWP as a solid waste disposal facility under Tennessee State rule 1200-1-7-.04. The objectives of this work are to summarize existing site information and detail actions necessary to sample and characterize soils from the waste pile as hazardous or nonhazardous per the Toxicity Characteristic Leaching Procedure (TCLP). Within the scope of this plan, a site investigation will be discussed; a field sampling plan will be described in terms of sampling locations, procedures, and quality assurance; and ancillary activities such as waste management, data management, and health and safety will be outlines. 15 refs., 7 figs., 2 tabs.

  2. CFG Pile Quality Investigation and Production of Pile-cutting Equipment%CFG桩头质量调查及截桩设备的制作

    Institute of Scientific and Technical Information of China (English)

    刘红峰

    2013-01-01

    本文在总结钻孔桩桩头超灌高度的基础上,通过试验,提出CFG桩超灌高度为0.5m以上,制作并使用特制截桩设备大大减小了截桩对CFG桩的扰动,此外还对桩间土的开挖进行了详细论述。%Based on the summary of extra filling height of bored pile, through experiment, the paper points out the extra filling height of CFG pile is above 0.5m. The special pile-cutting equipment greatly reduced the disturbance of CFG pile. Additionally, it describes the excavation of soil between piles in detail.

  3. NEET In-Pile Ultrasonic Sensor Enablement-Final Report

    Energy Technology Data Exchange (ETDEWEB)

    J. Daw; J. Rempe; J. Palmer; P. Ramuhalli; R. Montgomery; H.T. Chien; B. Tittmann; B. Reinhardt; P. Keller

    2014-09-01

    Ultrasonic technologies offer the potential to measure a range of parameters during irradiation of fuels and materials, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes under harsh irradiation test conditions. There are two primary issues that currently limit in-pile deployment of ultrasonic sensors. The first is transducer survivability. The ability of ultrasonic transducer materials to maintain their useful properties during an irradiation must be demonstrated. The second issue is signal processing. Ultrasonic testing is typically performed in a lab or field environment, where the sensor and sample are accessible. The harsh nature of in-pile testing and the variety of desired measurements demand that an enhanced signal processing capability be developed to make in-pile ultrasonic sensors viable. To address these issues, the NEET ASI program funded a three year Ultrasonic Transducer Irradiation and Signal Processing Enhancements project, which is a collaborative effort between the Idaho National Laboratory, the Pacific Northwest National Laboratory, the Argonne National Laboratory, and the Pennsylvania State University. The objective of this report is to document the objectives and accomplishments from this three year project. As summarized within this document, significant work has been accomplished during this three year project.

  4. Radiocarbon from Pile Graphite; Chemical Methods for Its Concentrations

    Science.gov (United States)

    Arnold, J. R.; Libby, W. F.

    1946-10-10

    Samples of pile graphite, irradiated in a test-hole at Hanford for 15 months, have been assayed for radioactive C{sup 14} yielding 0.38 ± 0.04 microcuries per gram. At this level of activity, the pile graphite contains very valuable amounts of C{sup14}. The relation between the above assay and the probable average assay of pile graphite is discussed, and it is concluded that the latter is almost certainly above 0.3 microcuries/gram. Controlled oxidation of this graphite, either with oxygen at ~750ºC, or with chromic acid "cleaning solution" at room temperature, yields early fractions which are highly enriched in C{sup 14}. Concentrations of 5-fold with oxygen, and 50-fold with CrO{sub 3}, have been observed. The relation between the observed enrichment and the Wigner effect is discussed, and a mechanism accounting for the observations put forward. According to this, about 25% of the stable carbon atoms in the lattice have been displaced by Wigner effect, a large fraction of which have healed by migrating to crystal edges. All the C{sup 14} atoms have been displaced, and the same fraction of these migrate to the edges. The enrichment then results from surface oxidation, in the oxygen case. Predictions are made on the basis of this hypothesis. A technique of counting radioactive CO{sub 2} in the gas phase is described.

  5. Avalanche Structure in the Kadanoff Sand Pile Model

    CERN Document Server

    Perrot, Kevin

    2011-01-01

    Sand pile models are dynamical systems emphasizing the phenomenon of Self Organized Criticality (SOC). From N stacked grains, iterating evolution rules leads to some critical configuration where a small disturbance has deep consequences on the system, involving numerous steps of grain fall. Physicists L. Kadanoff et al. inspire KSPM, a model presenting a sharp SOC behavior, extending the well known Sand Pile Model. In KSPM with parameter D we start from a pile of N stacked grains and apply the rule: D-1 grains can fall from column i onto the D-1 adjacent columns to the right if the difference of height between columns i and i+1 is greater or equal to D. We propose an iterative study of KSPM evolution where one single grain addition is repeated on a heap of sand. The sequence of grain falls following a single grain addition is called an avalanche. From a certain column precisely studied for D=3, we provide a plain process describing avalanches.

  6. Cost analysis of continuous flight auger piles construction in Egypt

    Directory of Open Access Journals (Sweden)

    Hossam E. Hosny

    2016-09-01

    Full Text Available Continuous Flight Auger (CFA piling is widely used in the Egyptian construction industry. There is a dramatic fluctuation in pricing of executing this work package within short periods as a result of unsteady changes in supply-demand equilibrium. Consequently, there is an urgent need for the use of a scientific approach in estimating construction costs. Accordingly, it is crucial to consider the different cost elements of CFA piling construction as a step to reach an accurate and realistic cost estimate to be used by contractors in tendering. This research aims to study these cost elements based on an expert judgment, site observations and statistical analysis in order to develop an effective tool to estimate the total construction cost of the CFA piles in any future project. Expert survey was performed to draw detailed information to construct a cost breakdown structure (CBS that was used as a basis for developing the proposed cost model. The developed cost model is then validated through the application on fifty two projects. Such projects were carefully selected in different sizes, purposes and locations. Then the collected data were exposed to statistical analysis techniques. An average percentage error of 4.1% was observed upon comparing the estimated costs with the actual costs of these projects. A sensitivity analysis was then performed to recognize the most effective cost factors. The developed recommended model was used by some experienced contractors in the Egyptian market who expressed their satisfaction with the model.

  7. Enhanced in-pile instrumentation at the advanced test reactor

    Energy Technology Data Exchange (ETDEWEB)

    Rempe, J. L.; Knudson, D. L.; Daw, J. E.; Unruh, T.; Chase, B. M.; Palmer, J.; Condie, K. G.; Davis, K. L. [Idaho National Laboratory, MS 3840, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

    2011-07-01

    Many of the sensors deployed at materials and test reactors cannot withstand the high flux/high temperature test conditions often requested by users at U.S. test reactors, such as the Advanced Test Reactor (ATR) at the Idaho National Laboratory. To address this issue, an instrumentation development effort was initiated as part of the ATR National Scientific User Facility in 2007 to support the development and deployment of enhanced in-pile sensors. This paper reports results from this effort. Specifically, this paper identifies the types of sensors currently available to support in-pile irradiations and those sensors currently available to ATR users. Accomplishments from new sensor technology deployment efforts are highlighted by describing new temperature and thermal conductivity sensors now available to ATR users. Efforts to deploy enhanced in-pile sensors for detecting elongation and realtime flux detectors are also reported, and recently-initiated research to evaluate the viability of advanced technologies to provide enhanced accuracy for measuring key parameters during irradiation testing are noted. (authors)

  8. Response of carrying capacity of piles induced by adjacent Metro tunneling

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-jie; DENG Fei-huang; WU Jia-jia; LIU Jian; WANG Fu-qiang

    2009-01-01

    Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tun-neling (deactivation of soil element and activation of the lining). The adjacent stratum around the tunnel is classified into three re-gions: Zone Ⅰ(upper adjacent stratum of tunnel), Zone Ⅱ (45°-upper-lateral adjacent stratum of tunnel) and Zone Ⅲ (lateral adjacent stratum of tunnel). In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft: the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying ca-pacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, ete

  9. The Shielding Effect of Multi-Pile Structures on Ice Force

    Institute of Scientific and Technical Information of China (English)

    史庆增; 黄焱; 宋安

    2004-01-01

    The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.

  10. Mechanical response of bridge piles in high-steep slopes and sensitivity study

    Institute of Scientific and Technical Information of China (English)

    赵衡; 尹平保; 李夕兵

    2015-01-01

    The bridge piles located in high-steep slopes not only endure the loads from superstructure, but also the residual sliding force as well as the resistance from the slope. By introducing the Winkler foundation theory, the mechanical model of piles−soils−slopes system was established, and the equilibrium differential equations of pile were derived. Moreover, an analytic solution for identifying the model parameters was provided by means of power series method. A project with field measurement was compared with the proposed method. It is indicated that the lateral loads have great influences on the pile, the steep slope effect is indispensable, and reasonable diameter of the pile could enhance the bending ability. The internal force and displacements of pile are largely based upon the horizontal loads applied on pile, especially in upper part.

  11. Non-probabilistic fuzzy reliability analysis of pile foundation stability by interval theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Randomness and fuzziness are among the attributes of the influential factors for stability assessment of pile foundation.According to these two characteristics, the triangular fuzzy number analysis approach was introduced to determine the probability-distributed function of mechanical parameters. Then the functional function of reliability analysis was constructed based on the study of bearing mechanism of pile foundation, and the way to calculate interval values of the functional function was developed by using improved interval-truncation approach and operation rules of interval numbers. Afterwards, the non-probabilistic fuzzy reliability analysis method was applied to assessing the pile foundation, from which a method was presented for nonprobabilistic fuzzy reliability analysis of pile foundation stability by interval theory. Finally, the probability distribution curve of nonprobabilistic fuzzy reliability indexes of practical pile foundation was concluded. Its failure possibility is 0.91%, which shows that the pile foundation is stable and reliable.

  12. Case Study of CPT-based Design Methods for Axial Capacity of Driven Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2012-01-01

    Today the design of onshore axially loaded driven piles in cohesionless soil is commonly made on basis of CPT-based methods because field investigations have shown strong correlation between the local shaft friction and the CPT cone resistance. However, the recommended design method for axially....... Thus, several CPT-based methods have been proposed for the design of offshore driven piles in cohesionless soil such as the UWA-05, ICP-05, and NGI-99 methods. This article treats a case study where the API-method as well as the UWA-05 and NGI-99 methods are compared using CPT-data from an offshore...... location with dense to very dense sand. The design of the piles in the jacket foundation shows that API-00 for both the tension and the compression loads predicted much longer piles than the CPT-based methods. Variation of the pile length and pile diameter shows that NGI-99 and UWA-05 predicts almost...

  13. EURIPIDES, load tests on large driven piles in dense silica sands

    Energy Technology Data Exchange (ETDEWEB)

    Zuidberg, H.M.; Vergobbi, P.

    1996-12-31

    In 1995 an extensive load testing program was conducted on 30 inch pipe piles in dense silica sands similar to those found in the southern North Sea. A highly instrumented pile was driven at one location, extracted and redriven at a second location. A total of twelve static compression and tension load tests were performed at three penetration depths between 30 and 47 meters. Test objectives included acquiring reliable data on capacity of offshore type piles in sands which hitherto were hardly available and to understand the failure mechanisms in order to improve current foundation design. The paper describes the design of the testing program and project organization and funding. Details of the test pile and instrumentation to measure the loads in the pile and the pile-sand interaction are highlighted with an emphasis on quality of the measurements. The field-work and innovative testing facilities are also described.

  14. Field study of plastic tube cast-in-place concrete pile

    Institute of Scientific and Technical Information of China (English)

    陈永辉; 曹德洪; 王新泉; 杜海伟; 张霆

    2008-01-01

    The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.

  15. Numerical Simulations of Pile Supported Protective System Subjected to Ship Impact

    Institute of Scientific and Technical Information of China (English)

    SUN Zhen; WANG Junjie

    2006-01-01

    The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA.The influences of pile non-linearity and soil non-linearity on impact force,ship crush depth and the cap displacement of pile supported protective system are discussed.It's shown that for both severe impact case and non-severe impact case,the non-linearity of pile material influence the impact force history,ship crush depth.The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case.These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.

  16. Comprehensive Detection and Analysis of Defects in Foundation Pile of Bridge

    Institute of Scientific and Technical Information of China (English)

    WANG Qi-ren; HE Ji-shan; YANG Tian-chun

    2003-01-01

    In the process of piling ,there are many various defects in foundation pile of bridge such as mud-bearing,sediment-bearing, isolation, honeycomb, broken piles, and so on, showing physical and mechanical features of low-density and low-intensity. In fact, by using the comprehensive detection of acoustic transmission method, the reflected wave method as well as drill coring sample method, and the rational utilization of engineering geological condition in field, the characteristics, size and location of common defects of foundation pile of bridge can be accurately detected and judged and the integrity of piles and the quality of concrete can be impersonally estimated.comprehensive detecting and analyzing methods on this kind of piles are introduced briefly. The physical characters of defects and basic features of detecting curves and their corresponding relation are emphasized, and causes are analyzed in in detail in this paper.

  17. Numerical modeling of Thermal Response Tests in Energy Piles

    Science.gov (United States)

    Franco, A.; Toledo, M.; Moffat, R.; Herrera, P. A.

    2013-05-01

    Nowadays, thermal response tests (TRT) are used as the main tools for the evaluation of low enthalpy geothermal systems such as heat exchangers. The results of TRT are used for estimating thermal conductivity and thermal resistance values of those systems. We present results of synthetic TRT simulations that model the behavior observed in an experimental energy pile system, which was installed at the new building of the Faculty of Engineering of Universidad de Chile. Moreover, we also present a parametric study to identify the most influent parameters in the performance of this type of tests. The modeling was developed using the finite element software COMSOL Multiphysics, which allows the incorporation of flow and heat transport processes. The modeled system consists on a concrete pile with 1 m diameter and 28 m deep, which contains a 28 mm diameter PEX pipe arranged in a closed circuit. Three configurations were analyzed: a U pipe, a triple U and a helicoid shape implemented at the experimental site. All simulations were run considering transient response in a three-dimensional domain. The simulation results provided the temperature distribution on the pile for a set of different geometry and physical properties of the materials. These results were compared with analytical solutions which are commonly used to interpret TRT data. This analysis demonstrated that there are several parameters that affect the system response in a synthetic TRT. For example, the diameter of the simulated pile affects the estimated effective thermal conductivity of the system. Moreover, the simulation results show that the estimated thermal conductivity for a 1 m diameter pile did not stabilize even after 100 hours since the beginning of the test, when it reached a value 30% below value used to set up the material properties in the simulation. Furthermore, we observed different behaviors depending on the thermal properties of concrete and soil. According to the simulations, the thermal

  18. State of the Art for Design and Construction of Sand Compaction Piles

    Science.gov (United States)

    1987-11-01

    Wire Vibrator Hopper Casing Pipe Air Line Power Line Sand Skip Bucket Front End Loader Figure 2. Typical equipment used to construct a sand...varying from 200 to 300 psf that have been reinforced with sand compaction piles. 78. Sand compaction piles are constructed by driving a steel casing ... pipe ) filled with sand to the desired elevation using a heavy vertical vibrator placed at the top of the pile. The casing is then gradually

  19. Control of floor heaves with steel pile in gob-side entry retaining

    Institute of Scientific and Technical Information of China (English)

    Xu Ying; Chen Jin; Bai Jianbiao

    2016-01-01

    A new approach named as steel pile method is innovatively proposed in this study to control severe floor heaves in gob-side entry retaining. It is required that the steel piles be installed in the floor corners with a certain interval before the influence of the dynamic pressure induced by current panel extraction. Using numerical simulation and theoretical analysis, this study investigated the interaction between the steel piles and the floor rocks during the service life of the steel piles, and revealed the mechanism of the steel piles in controlling floor heaves. The effect of the steel pile parameters on the control of floor heaves was presented and elaborated. It is found that the effectiveness of the steel piles in controlling floor heaves can be enhanced with greater installed dip angle, longer length and smaller interval of the steel piles. Compared with traditional methods, e.g., using floor anchor bolts and floor restoration, the advantages using steel pile were successfully defined in terms of controlling effect and economic benefits. It is hoped that the proposed method can contribute to the development of gob-side entry retaining technique.

  20. Reduction Rate of Dragload and Downdrag of Piles by Taper Angles

    Institute of Scientific and Technical Information of China (English)

    孔纲强; 周立朵; 彭怀风; 顾红伟

    2016-01-01

    Taper angle is one of the effective methods to reduce the dragload and downdrag of piles under the surcharge load. The model tests on the tapered pile and uniform cross-section pile embedded in sand were carried out under the surcharge load. The values of dragload and downdrag of piles versus the surcharge loads were meas-ured. Based on the concentric cylinder shearing theory, a simplified theoretical model for calculating the dragload and downdrag of tapered piles with small taper angles under the surcharge load was proposed considering the angle effect. The correctness of the developed theoretical model was validated through comparing with the model test results obtained in this study and previous literature. Then the parametric studies of the taper angle, surcharge, strength and modulus of soil were discussed. It is shown that the tapered pile with the taper angle of 3° can reduce approximately 65% of the maximum dragload value and 30% of the downdrag value compared with a uniform cross-section pile. The value of downdrag can be decreased by approximately 50% compared with a uniform cross-section pile in the same average pile diameter.

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

    Science.gov (United States)

    Zhou, Chunmei; van Westen, Cees

    2013-04-01

    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

  2. Theoretical study on setup of expanded-base pile considering cavity contraction

    Institute of Scientific and Technical Information of China (English)

    齐昌广; 刘干斌; 王艳; 邓岳保

    2015-01-01

    When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio (base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5−3.0 times the measured values.

  3. Theoretical study on setup of expanded-base pile considering cavity contraction

    Institute of Scientific and Technical Information of China (English)

    齐昌广; 刘干斌; 王艳; 邓岳保

    2015-01-01

    When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

    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.

  5. Multifield coupling model and its applications for pile foundation in permafrost

    Institute of Scientific and Technical Information of China (English)

    WU; Yaping; ZHU; Yuanlin; GUO; Chunxiang; SU; Qiang; MA; We

    2005-01-01

    Importing the interface element which links the frozen soil base with concrete piles and considering the couplings of stress field, temperature field and moisture field, this paper establishes the nonlinear visco-elastic plastic finite element model of pile-soil. For a practical bridge structure the stress field and displacement field of single pile in freezing process are calculated.This paper emphatically studies the process of the tangential frost heave stress field, freezing stress field and displacement field varying with time, and ulteriorly studies time variation process of single pile carrying capacity in freezing process.

  6. Pile-soil stress ratio in bidirectionally reinforced composite ground by considering soil arching effect

    Institute of Scientific and Technical Information of China (English)

    邹新军; 杨眉; 赵明华; 杨小礼

    2008-01-01

    To discuss the soil arching effect on the load transferring model and sharing ratios by the piles and inter-pile subsoil in the bidirectionally reinforced composite ground, the forming mechanism, mechanical behavior and its effect factors were discussed in detail. Then, the unified strength theory was introduced to set up the elastoplastic equilibrium differential equation of the subsoil under the limit equilibrium state. And from the equation, the solutions were derived with the corresponding formulas presented to calculate the earth pressure over and beneath the horizontal reinforced cushion or pillow, the stress of inter-pile subsoil and the pile-soil stress ratio. Based on the obtained solutions and measured data from an engineering project, the influence rules by the soil property parameters (i.e., the cohesion c and internal friction angle φ) and pile spacing on the pile-soil stress ratio n were discussed respectively. The results show that to improve the load sharing ratio by the piles, the more effective means for filling materials with a larger value of φ is to increase the ratio of pile cap size to spacing, while to reduce the pile spacing properly and increase the value of cohesion c is advisable for those filling materials with a smaller value of φ.

  7. Estimate of the residual loads obtained in the end of piles driven in porous soils

    Directory of Open Access Journals (Sweden)

    David de Carvalho

    2005-02-01

    Full Text Available In the geotechnical engineering the study about the quantification of the residual loads in the pile end, after the end of the first loading of the load test attempt, highlighted some works on its interpretation in the curve load versus pile settlement. The construction of a mathematical model to study such a phenomenon is based on the Relations of Cambefort Precast-concrete piles were specially built for this research. They have special elements installed all along their length where the residual loads inlaid in the pile end region could be measured by means of deformation strain gauges.

  8. Effects of pile driving by high frequency hammers on adjacent piles%高频振动打桩对邻近基桩影响分析

    Institute of Scientific and Technical Information of China (English)

    杨祁; 陈福全; 刘建鹏

    2014-01-01

    The stress waves caused by pile driving will disturb surrounding buildings and affect the normal serv-ice of underground facilities. The technique of high frequency hydraulic vibratory pile driving has been widely ap-plied to solve this problem. The effects of pile driving on adjacent piles are investigated by numerical analysis meth-od using software package ABAQUS. A 1. 0 mm radius rigid tube is modeled along the axis of penetration. At the beginning of the analysis this tube is in frictionless contact with the surrounding soils. During pile penetration the pile slides over the tube and the soil separates from the tube to establish the contact between the penetrating pile and the surrounding soil. The driven pile and the tube are simulated with rigid body,and the soils with Mohr-Cou-lomb model. Then the three-dimensional model of high frequency hydraulic vibratory pile driving is established. Tn this way,a numerical analysis for the effects of the full process of pile driving by using high frequency hammers on the adjacent piles are performed. The numerical simulation analysis of pile penetration process shows that the stress concentration occurred around the pile tip. The effect on existing piles is smaller with the larger distance from the driven pile. The analysis also shows the high frequency vibratory pile driving has small effect on adjacent piles.%为解决在城市里桩基施工引起的环境问题,国外开发并推广应用了高频液压振动锤技术。通过有限元软件Abaqus对高频振动打桩对邻近桩基影响进行模拟。模拟中桩轴线处建立半径为1mm的管,管土接触设为光滑,打桩时土管分离,桩随着管向下贯入,形成打入桩和周围土体之间的接触关系。打入桩和圆管采用刚体模拟,土体单元则采用摩尔库伦本构模型,建立高频打桩的三维模型,很好的实现高频液压振动沉桩整个过程的数值分析。贯入模拟过程表明打入桩桩尖深度

  9. OPAL Cold Neutron Guide In-Pile Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Rownes, T.; Eltobaji, A.; Bell, M.; Klose, F. [Nuclear Operations, Baitain (Australia)

    2013-07-01

    The 20 MW{sub th} OPAL research reactor has five neutron beam assemblies. These provide cold and thermal neutrons to various neutron guides and associated neutron beam instruments. In 2010 a project was initiated to install a new cold neutron guide, CG2, in one of the assemblies. This installation would allow up to four new neutron beam instruments to be built, significantly expanding the reactor's capabilities. The project concluded in December 2012 with the successful installation of CG2. Each neutron beam assembly has an in-pile plug, a primary shutter and a front cover. Together these constitute the neutron guide's in-pile components, with a total mass of over 12 tonnes. The CG2 installation required the complete replacement of the existing components. This replacement was scheduled to coincide with OPAL's first major shutdown. With a budget of $2.3 million and an expected dose of 50 man.mSv, the CG2 installation was a large and complex task. Work during the shutdown involved over 40 ANSTO personnel and radiation fields approached 1 Sv/h in some areas. Despite this, the installation team received a collective dose of only 10 man.mSv, and the project was completed to budget and within schedule. This paper will outline the details of the project, focusing on lessons learned and recommended practices. Each OPAL in-pile plug has a design life of 10 years at full power operation, and similar replacements will be performed regularly as the reactor ages. It is hoped that this information will be useful for other research reactors planning large capital engineering projects.

  10. Pile-Up Discrimination Algorithms for the HOLMES Experiment

    Science.gov (United States)

    Ferri, E.; Alpert, B.; Bennett, D.; Faverzani, M.; Fowler, J.; Giachero, A.; Hays-Wehle, J.; Maino, M.; Nucciotti, A.; Puiu, A.; Ullom, J.

    2016-07-01

    The HOLMES experiment is a new large-scale experiment for the electron neutrino mass determination by means of the electron capture decay of ^{163}Ho. In such an experiment, random coincidence events are one of the main sources of background which impair the ability to identify the effect of a non-vanishing neutrino mass. In order to resolve these spurious events, detectors characterized by a fast response are needed as well as pile-up recognition algorithms. For that reason, we have developed a code for testing the discrimination efficiency of various algorithms in recognizing pile up events in dependence of the time separation between two pulses. The tests are performed on simulated realistic TES signals and noise. Indeed, the pulse profile is obtained by solving the two coupled differential equations which describe the response of the TES according to the Irwin-Hilton model. To these pulses, a noise waveform which takes into account all the noise sources regularly present in a real TES is added. The amplitude of the generated pulses is distributed as the ^{163}Ho calorimetric spectrum. Furthermore, the rise time of these pulses has been chosen taking into account the constraints given by both the bandwidth of the microwave multiplexing read out with a flux ramp demodulation and the bandwidth of the ADC boards currently available for ROACH2. Among the different rejection techniques evaluated, the Wiener Filter technique, a digital filter to gain time resolution, has shown an excellent pile-up rejection efficiency. The obtained time resolution closely matches the baseline specifications of the HOLMES experiment. We report here a description of our simulation code and a comparison of the different rejection techniques.

  11. Method and apparatus for analog pulse pile-up rejection

    Science.gov (United States)

    De Geronimo, Gianluigi

    2013-12-31

    A method and apparatus for pulse pile-up rejection are disclosed. The apparatus comprises a delay value application constituent configured to receive a threshold-crossing time value, and provide an adjustable value according to a delay value and the threshold-crossing time value; and a comparison constituent configured to receive a peak-occurrence time value and the adjustable value, compare the peak-occurrence time value with the adjustable value, indicate pulse acceptance if the peak-occurrence time value is less than or equal to the adjustable value, and indicate pulse rejection if the peak-occurrence time value is greater than the adjustable value.

  12. Dislocation Pile-Ups, Material Strength Levels, and Thermal Activation

    Science.gov (United States)

    Armstrong, Ronald W.

    2016-12-01

    A review dedicated to James C.M. Li is given of dislocation pile-ups and their connection to the Hall-Petch dependence of polycrystalline strength and fracture mechanics properties on an inverse square root of grain size basis, with such grain size dependence now very importantly extended to nanopolycrystalline material behaviors. An analogous H-P dependence is described for the inverse activation volume parameter obtained from the strain rate (and thermal) dependencies contained in the model dislocation thermal activation-strain rate analysis, also relating to pioneering contributions of Li to the topic of thermally activated dislocation dynamics.

  13. A randomized trial of rubber band ligation with or without injection sclerotherapy in the treatment of piles.

    Science.gov (United States)

    Ackroyd; Dicks; Shorthouse

    1999-07-01

     Rubber band ligation (RBL) is an effective treatment for piles but may be followed by pain and bleeding. It is postulated that the addition of injection sclerotherapy (IS) may reduce these complications. This trial aims to compare the use of RBL alone with RBL + IS in the treatment of piles.  Sixty patients with piles were randomized to RBL alone (n=30) or RBL + IS (n=30). Each patient was given a pro forma on which to record the amount of pain (on a visual analogue scale) and bleeding (none, slight or heavy) for 10 days following treatment. Patients were subsequently asked to describe the overall symptomatic outcome in the 6-week follow-up clinic (worse, same, slightly better, much better). Long-term outcome was ascertained by a telephone survey.  Symptomatic improvement was similar in both groups (median score (range)=1.5 (0-2) vs 2 (0-2); P=NS), and there was no difference in pain (median score (range)=6 (0-77) vs 6 (0-50); P=NS). However, the amount of bleeding was significantly less in the RBL + IS group (median score (range)=3.5 (0-12) vs 0 (0-10); P < 0.001). The long-term outcome was similar in both groups.  The addition of IS to RBL does not affect procedure-related pain or symptomatic outcome, but significantly reduces the risk of post-bleeding.

  14. 77 FR 32943 - Takes of Marine Mammals Incidental to Specified Activities; Pile Driving in the Columbia River, WA

    Science.gov (United States)

    2012-06-04

    ... piles' strength. Vibratory and impact pile driving may result in anticipated hydroacoustic levels... range-finder) in order to determine if animals have entered into the exclusion zone or Level...

  15. In-pile and out-of-pile testing of a molybdenum-uranium dioxide cermet fueled themionic diode

    Science.gov (United States)

    Diianni, D. C.

    1972-01-01

    The behavior of Mo-UO2 cermet fuel in a diode for thermionic reactor application was studied. The diode had a Mo-0.5 Ti emitter and niobium collector. Output power ranged from 1.4 to 2.8 W/cm squared at emitter and collector temperatures of 1500 deg and 540 C. Thermionic performance was stable within the limits of the instrumentation sensitivity. Through 1000 hours of in-pile operation the emitter was dimensionally stable. However, some fission gases (15 percent) leaked through an inner clad imperfection that occurred during fuel fabrication.

  16. A performance case study of energy pile foundation at Rosborg Gymnasium (Denmark)

    DEFF Research Database (Denmark)

    Pagola, Maria Alberdi; Jensen, Rasmus Lund; Poulsen, Søren Erbs

    2016-01-01

    The Rosborg Gymnasium building in Vejle (Denmark) is partially founded on 200 foundation pile heat exchangers (energy piles). The thermo-active foundation has supplemented the heating and free cooling needs of the building since 2011 (4,000 m2 living area). Operational data from the ground source...

  17. Time scale of scour around a pile in combined waves and current

    DEFF Research Database (Denmark)

    Petersen, Thor Ugelvig; Sumer, B. Mutlu; Fredsøe, Jørgen

    The time scale of the scour process around a circular vertical pile is studied in combined waves and current. A series of tests were carried out in a flume with pile diameters 40 mm and 75 mm, in both steady current, waves and combined waves and current. In the combined wave and current flow regime...

  18. Effect of Welding Methods on the Structure and Mechanical Properties of Welded Joints of Screw Piles

    Science.gov (United States)

    Golikov, N. I.; Sidorov, M. M.; Stepanova, K. V.

    2016-11-01

    Mechanical properties and characteristics of the structure of welded joints of screw piles are studied. It is shown that cast tips from steel 25L do not meet the performance specifications for operation in the Northern climatic zone. Quality welded joints of screw piles can be obtained by semiautomatic welding in an environment of CO2 with Sv-08G2S welding wire.

  19. Influences of Family Management and Spousal Perceptions on Stressor Pile-up.

    Science.gov (United States)

    Imig, David R.; Imig, Gail L.

    1986-01-01

    Describes the contingent influence of family managerial efficacy and related spousal perceptions on the relationship between stressor pile-up and family cohesion. Perceived loss of managerial efficacy in conjunction with discrepant spousal perceptions of such change substantially increased the family's vulnerability to stressor pile-up. A…

  20. Hearing thresholds of a harbor porpoise (Phocoena phocoena) for playbacks of multiple pile driving strike sounds

    NARCIS (Netherlands)

    Kastelein, R.A.; Hoek, L.; Gransier, R.; Jong, C.A.F. de

    2013-01-01

    Pile driving is presently the most common method used to attach wind turbines to the sea bed. To assess the impact of pile driving sounds on harbor porpoises, it is important to know at what distance these sounds can be detected. Using a psychophysical technique, a male porpoise’s hearing thresholds

  1. An efficient model for prediction of underwater noise due to pile driving at large ranges

    NARCIS (Netherlands)

    Nijhof, M.J.J.; Binnerts, B.; Jong, C.A.F. de; Ainslie, M.A.

    2014-01-01

    Modelling the sound levels in the water column due to pile driving operations nearby and out to large distances from the pile is crucial in assessing the likely impact on marine life. Standard numerical techniques for modelling the sound radiation from mechanical structures such as the finite elemen

  2. 77 FR 43259 - Takes of Marine Mammals Incidental to Specified Activities; Pile Driving for Honolulu Seawater...

    Science.gov (United States)

    2012-07-24

    ... Specified Activities; Pile Driving for Honolulu Seawater Air Conditioning Project AGENCY: National Marine... Harassment Authorization (IHA) to take marine mammals, by harassment, incidental to pile driving offshore... for the take, by Level B harassment, of small numbers of 17 marine mammal species incidental to...

  3. 40 CFR 411.30 - Applicability; description of the materials storage piles runoff subcategory.

    Science.gov (United States)

    2010-07-01

    ... runoff of rainfall which derives from the storage of materials including raw materials, intermediate... materials storage piles runoff subcategory. 411.30 Section 411.30 Protection of Environment ENVIRONMENTAL... Materials Storage Piles Runoff Subcategory § 411.30 Applicability; description of the materials...

  4. Formation and remediation of drill-cutting piles in the North Sea

    Science.gov (United States)

    Eames, I.; de Leeuw, B.; Conniff, P.

    2002-01-01

    Drill cuttings generated during borehole excavation have been routinely dumped into the North Sea, where they now represent a significant environmental hazard owing to contamination by oil residues and heavy metals. In-situ measurements of the structure of drill-cutting piles are relatively poor owing to the difficulty of accessing water depths of 60-180 m. In an effort to understand how drill-cutting piles are formed, laboratory-scale experiments were undertaken to investigate how granular material, poured into a tank of water, spreads along a rigid horizontal wall. The laboratory study examined how the pile radius varied as a function of particle size (90 µm to 3 mm), source height above the wall, particle volume flux and volume deposited. A model of drill-cutting pile formation is developed by combining descriptions of descent as a plume and propagation along the wall as a gravity current. Satisfactory agreement is obtained between experimental measurements and model predictions, which are applied to interpret available field data. The implications of this research for drill-cutting pile remediation are discussed. The model indicates that when natural bioremediation has broken down a 5-cm layer of a drill-cutting pile, only 50-100% of the pile area (or 75-95% of the pile volume) requires treatment.

  5. Behaviour of Single Pile in Reinforced Slope Subjected to Inclined Load

    Directory of Open Access Journals (Sweden)

    Dr. A. I. Dhatrak

    2016-09-01

    Full Text Available Deep foundations, including driven piles, are used to support vertical loads of structures and lateral forces. Typical structures subjected to lateral loads include bridge abutments, transmission tower, sand offshore platforms. Traffic, wind, wave, and seismic forces are common types of lateral loads subjected to pile foundations. The present work is focused on understanding the lateral load capacity of vertical piles located near crest of the slope and subjected to the lateral and inclined loads. The experimental investigation was carried out to study the effect of reinforcing an earth slope on the inclined loading behavior of a single vertical pile located near the slope. Layers of geogrid were used to reinforce a sandy slope of 1V:2H. The parametric studies were performed by varying the length of pile(L, angle of inclination of load (θ, number of geogrid reinforcement (Nr and crest distance. It was observed that the lateral load capacity of pile depends upon these parameters. The lateral load capacity of pile increases with increase in inclination of load, length of pile(L, number of geogrid reinforcement (Nr and crest distance.

  6. Pile-up correction by Genetic Algorithm and Artificial Neural Network

    Science.gov (United States)

    Kafaee, M.; Saramad, S.

    2009-08-01

    Pile-up distortion is a common problem for high counting rates radiation spectroscopy in many fields such as industrial, nuclear and medical applications. It is possible to reduce pulse pile-up using hardware-based pile-up rejections. However, this phenomenon may not be eliminated completely by this approach and the spectrum distortion caused by pile-up rejection can be increased as well. In addition, inaccurate correction or rejection of pile-up artifacts in applications such as energy dispersive X-ray (EDX) spectrometers can lead to losses of counts, will give poor quantitative results and even false element identification. Therefore, it is highly desirable to use software-based models to predict and correct any recognized pile-up signals in data acquisition systems. The present paper describes two new intelligent approaches for pile-up correction; the Genetic Algorithm (GA) and Artificial Neural Networks (ANNs). The validation and testing results of these new methods have been compared, which shows excellent agreement with the measured data with 60Co source and NaI detector. The Monte Carlo simulation of these new intelligent algorithms also shows their advantages over hardware-based pulse pile-up rejection methods.

  7. In-situ grouting of uranium-mill-tailings piles: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, T.; Boegly, W.J. Jr.

    1983-05-01

    Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles.

  8. Pile-up corrections in laser-driven pulsed x-ray sources

    CERN Document Server

    Hernández, Guillermo

    2016-01-01

    A formalism for treating the pile-up produced in laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector. The influence of the pile-up on the overestimation of temperature parameters is shown up.

  9. In-Situ Test and Numerical Analysis of Bore Pressure on Sheet-Pile Groin

    Institute of Scientific and Technical Information of China (English)

    XU Chang-jie; CAI Yuan-qiang; XUAN Wei-li; CHEN Hai-jun; SONG Yang

    2006-01-01

    An in-situ test of bore pressure on a sheet-pile groin is carried out to investigate the characteristics of the bore pressure of tide in the Qian-tang River. The histories of bore pressure and the rule of the distribution of bore pressure on the sheet-pile groin are obtained through the test, which shows that the bore pressure on the sheet-pile groin are varies with time and space. The peak value of bore pressure on sheet-pile groin at different heights occurs almost at the same time. The vertical distribution of bore pressure on the sheet-pile groin is linear above the still water level. The maximum bore pressure on the sheet-pile groin occurs at the still water level. Then a numerical method is also used to further study the characteristics of bore pressure. The standard κ-ε turbulence model and VOF (volume of fluid) method for surface tracking are used to simulate the bore against the sheet-pile groin. The numerical results show flow fields, the position of free surface and time history and spatial distribution of bore pressure on the sheet-pile groin. The numerical and test results show good agreement.

  10. Pile-up correction method for fission work with active targets

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, B.; Caitucoli, F.; Audouard, P.; Asghar, M.; Barreau, G.; Doan, T.P.; Sicre, A. (CEA Centre d' Etudes Nucleaires de Bordeaux-Gradignan, 33 - Gradignan (France))

    1983-02-15

    A method which forms a part of a multiparametric set-up for fission work on very ..cap alpha..-particle active fissile targets is presented here. It helps to identify a piled-up fission event and to correct off-line for the amount of pile-up present. Some results are presented for the spontaneous fission of /sup 244/Cm.

  11. Small-Scale Cyclic Tests on Nonslender Piles Situated in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    In the period from August 2011 till October 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests, the piles have been exposed to cyclic loading consisting of 20-25 load cycles and all the tests have been conducted in a pressure tank...

  12. Small-Scale Quasi-Static Tests on Non-Slender Piles Situated in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    In the period from February 2009 till March 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests the piles have been exposed to quasi-static loading and all the tests have been conducted in a pressure tank. The objective of the tests has...

  13. An efficient model for prediction of underwater noise due to pile driving at large ranges

    NARCIS (Netherlands)

    Nijhof, M.J.J.; Binnerts, B.; Jong, C.A.F. de; Ainslie, M.A.

    2014-01-01

    Modelling the sound levels in the water column due to pile driving operations nearby and out to large distances from the pile is crucial in assessing the likely impact on marine life. Standard numerical techniques for modelling the sound radiation from mechanical structures such as the finite elemen

  14. Study on the squeezing effect of open-ended pipe piles

    Institute of Scientific and Technical Information of China (English)

    Yan-er Lu; Jun-jie Zheng; Jian-hua Yin

    2009-01-01

    During the installation of a pipe pile, the soil around the pile will be squeezed out. This paper deals with this squeezing effect of open-ended pipe piles using the cylindrical cavity expansion theory. The characteristics of soil with different tension and compression modnli and dilation are involved by applying the elastic theory with different moduli and logarithmic strain. The closed-form solutions of the radius of the plastic region, the displacement of the boundary between the plastic region and the elastic region and the expansion pressure on the external surface of the pipe piles are obtained. When obtaining these solutions, the soil ping in the open-ended pipe pile is considered by employing an incremental filling ratio to quantify the degree of soil plugging. Moreover, the effects of the ratio of tension and compression moduli, angle of dilation and incremental filling ratio on the radius of the plastic region and the expansion pressure on the external surface of the pipe pile are investigated. The parametric analyses show that it is necessary and important to consider the difference between the tension modulus and compression modulus, dilation angle and incremental filling ratio for studying the squeezing effect of open-ended pipe pile installation. It is concluded that the analytical solutions presented in this paper are suitable for studying the squeezing effect of open-ended pipe piles.

  15. Response of stiff piles in sand to long-term cyclic lateral loading

    DEFF Research Database (Denmark)

    Bakmar, Christian LeBlanc; Houlsby, Guy T.; Byrne, Byron W.

    2010-01-01

    and loading ranges were realistic. A complete non-dimensional framework for stiff piles in sand is presented and applied to interpret the test results. The accumulated rotation was found to be dependent on relative density and was strongly affected by the characteristics of the applied cyclic load. The pile...

  16. Effect of relative pile’s stiffness on lateral pile response under loading of large eccentricity

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole; Klinkvort, R.T.

    2015-01-01

    of the relative pile’s stiffness, when it is subjected to lateral load of large eccentricity. Employing centrifuge experiments, a hollow steel pile well instrumented with strain gauge pairs has been subjected to lateral load. The bending moment distribution of the model pile embedded in uniform, dense, dry sand...

  17. CONDUCTING AND ANALYZING THE RESULTS OF THE EXPERIMENTAL BOX TEST OF RETAINING WALL MODELS WITHOUT PILES AND ON THE PILE FOUNDATION

    Directory of Open Access Journals (Sweden)

    M. A. Lisnevskyi

    2015-08-01

    Full Text Available Purpose. Taking into consideration that the bearing capacity of the foundation may be insufficient, in the study it is assumed that pile foundation can be used to reduce the impact of the construction of new retaining structures on roads and railways near the existing buildings or in areas of dense urban development and ensure the stability of the foundation. To reduce the volume of excavation it is necessary to choose the economic structure of the retaining wall. To do this, one should explore stress-strain state (SSS of the retaining walls, to develop methods to improve their strength and stability, as well as to choose the most appropriate method of their analysis. Methodology. In the design of retaining walls foundation mat and piles are considered as independent elements. Since the combined effect of the retaining wall, piles and foundation mat as well as the effect of soil or rock foundation on the structure are considered not fully, so there are some limitations in the existing design techniques. To achieve the purpose the box tests of retaining walls models without piles and with piles for studying their interaction with the surrounding soil massif were conducted. Findings. Laboratory simulation of complex systems «surrounding soil – retaining wall – pile» was carried out and on the basis of the box test results were analyzed strains and its main parameters of the stress-strain state. Analysis of the results showed that the structure of a retaining wall with piles is steady and stable. Originality. So far, in Ukraine has not been carried out similar experimental box tests with models of retaining walls in such combinations. In the article has been presented unique photos and test results, as well as their analysis. Practical value. Using the methodology of experimental tests of the retaining wall models with piles and without them gives a wider opportunity to study stress-strain state of such structures.

  18. UNMANNED AERIAL VEHICLE USE FOR WOOD CHIPS PILE VOLUME ESTIMATION

    Directory of Open Access Journals (Sweden)

    M. Mokroš

    2016-06-01

    Full Text Available The rapid development of unmanned aerial vehicles is a challenge for applied research. Many technologies are developed and then researcher are looking up for their application in different sectors. Therefore, we decided to verify the use of the unmanned aerial vehicle for wood chips pile monitoring. We compared the use of GNSS device and unmanned aerial vehicle for volume estimation of four wood chips piles. We used DJI Phantom 3 Professional with the built-in camera and GNSS device (geoexplorer 6000. We used Agisoft photoscan for processing photos and ArcGIS for processing points. Volumes calculated from pictures were not statistically significantly different from amounts calculated from GNSS data and high correlation between them was found (p = 0.9993. We conclude that the use of unmanned aerial vehicle instead of the GNSS device does not lead to significantly different results. Tthe data collection consumed from almost 12 to 20 times less time with the use of UAV. Additionally, UAV provides documentation trough orthomosaic.

  19. Evaluation of Candidate In-Pile Thermal Conductivity Techniques

    Energy Technology Data Exchange (ETDEWEB)

    B. Fox; H. Ban; J. Daw; K. Condie; D. Knudson; J. Rempe

    2009-05-01

    Thermophysical properties of materials must be known for proper design, test, and application of new fuels and structural properties in nuclear reactors. In the case of nuclear fuels during irradiation, the physical structure and chemical composition change as a function of time and position within the rod. Typically, thermal conductivity changes, as well as other thermophysical properties being evaluated during irradiation in a materials and test reactor, are measured out-of-pile in “hot-cells.” Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provide understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for the development of next generation reactors and advanced fuels for existing nuclear plants. Having the capacity to effectively and quickly characterize fuels and material properties during irradiation has the potential to improve the fidelity of nuclear fuel data and reduce irradiation testing costs.

  20. Unmanned Aerial Vehicle Use for Wood Chips Pile Volume Estimation

    Science.gov (United States)

    Mokroš, M.; Tabačák, M.; Lieskovský, M.; Fabrika, M.

    2016-06-01

    The rapid development of unmanned aerial vehicles is a challenge for applied research. Many technologies are developed and then researcher are looking up for their application in different sectors. Therefore, we decided to verify the use of the unmanned aerial vehicle for wood chips pile monitoring. We compared the use of GNSS device and unmanned aerial vehicle for volume estimation of four wood chips piles. We used DJI Phantom 3 Professional with the built-in camera and GNSS device (geoexplorer 6000). We used Agisoft photoscan for processing photos and ArcGIS for processing points. Volumes calculated from pictures were not statistically significantly different from amounts calculated from GNSS data and high correlation between them was found (p = 0.9993). We conclude that the use of unmanned aerial vehicle instead of the GNSS device does not lead to significantly different results. Tthe data collection consumed from almost 12 to 20 times less time with the use of UAV. Additionally, UAV provides documentation trough orthomosaic.

  1. In-Pile Thermal Conductivity Measurement Method for Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Joy L. Rempe; Brandon Fox; Heng Ban; Joshua E. Daw; Darrell L. Knudson; Keith G. Condie

    2009-08-01

    Thermophysical properties of advanced nuclear fuels and materials during irradiation must be known prior to their use in existing, advanced, or next generation reactors. Thermal conductivity is one of the most important properties for predicting fuel and material performance. A joint Utah State University (USU) / Idaho National Laboratory (INL) project, which is being conducted with assistance from the Institute for Energy Technology at the Norway Halden Reactor Project, is investigating in-pile fuel thermal conductivity measurement methods. This paper focuses on one of these methods – a multiple thermocouple method. This two-thermocouple method uses a surrogate fuel rod with Joule heating to simulate volumetric heat generation to gain insights about in-pile detection of thermal conductivity. Preliminary results indicated that this method can measure thermal conductivity over a specific temperature range. This paper reports the thermal conductivity values obtained by this technique and compares these values with thermal property data obtained from standard thermal property measurement techniques available at INL’s High Test Temperature Laboratory. Experimental results and material properties data are also compared to finite element analysis results.

  2. Economic evaluation of recirculation as a method of pile cooling

    Energy Technology Data Exchange (ETDEWEB)

    Carson, A.B.; Purcell, R.H.; McEwen, L.H.

    1954-04-07

    Reductions in irradiation costs and increases in production rate have provided a continuing incentive for more efficient operation of the Hanford Piles. These improvements have been obtained by means of higher specific powers, greater water flow rates, and better water utilization. However, the extent of the improvements which can be made in this manner may be limited by such factors as tube and slug corrosion, slug stability, and graphite damage rates at higher operating temperatures. Water purification and pumping costs are also factors to be considered. New slug designs are being developed which may be capable of much higher specific power operation. Higher graphite temperatures may also prove feasible, but the water plant performance limitations for the present single pass cooling systems may prove much more expensive to relieve. The use of recirculating cooling water as a means of attaining higher temperature, higher power operation has received preliminary study. A preliminary economic evaluation of an operating area equipped for recirculation versus single pass cooling is needed to better determine the relative merits of the two cooling methods. This report presents the results of such an evaluation and discusses the direction of future development work in the field of pile cooling.

  3. Free vibration of semi-rigid connected Reddy–Bickford piles embedded in elastic soil

    Indian Academy of Sciences (India)

    Yusuf Yesilce; Hikmet H Catal

    2008-12-01

    The literature on free vibration analysis of Bernoulli–Euler and timoshenko piles embedded in elastic soil is plenty, but that of Reddy–Bickford piles partially embedded in elastic soil with/without axial force effect is fewer. The soil that the pile partially embedded in is idealized by Winkler model and is assumed to be two-layered. The pile part above the soil is called the first region and the parts embedded in the soil are called the second and the third region, respectively. It is assumed that the behaviour of the material is linear-elastic, that axial force along the pile length to be constant and the upper end of the pile that is semi-rigid supported against rotation is modelled by an elastic spring. The governing differential equations of motion of the rectangular pile in free vibration are derived using Hamilton’s principle and Winkler hypothesis. The terms are found directly from the solutions of the differential equations that describe the deformations of the cross-section according to the high-order theory. The models have six degrees of freedom at the two ends, one transverse displacement and two rotations, and the end forces are a shear force and two end moments. Natural frequencies of the pile are calculated using transfer matrix and the secant method for non-trivial solution of linear homogeneous system of equations obtained due to values of axial forces acting on the pile, total and embedded lengths of the pile, the linear-elastic rotational restraining stiffness at the upper end of the pile and to the boundary conditions of the pile. Two different boundary conditions are considered in the study. For the first boundary condition, the pile’s end at the first region is semi-rigid connected and not restricted for horizontal displacement and the end at the third region is free and for the second boundary condition, the pile’s end at the first region is semi-rigid connected and restricted for horizontal displacement and the end at the

  4. A numerical study of the effect of groundwater on spiral coil energy piles

    Science.gov (United States)

    Kim, Seong-Kyun; Lee, Youngmin

    2016-04-01

    Numerical simulations were performed to investigate effects of groundwater on the thermal performance of the geothermal energy pile. Energy piles, a part of the closed-loop geothermal heat pump systems, are used to exchange heat between the ground and the heat pump. A heat-carrying fluid circulates the ground through a coiled pipe installed in pile foundations. The COMSOL multiphysics was used as a simulator, which can solve the equations for the temperature and fluid flow in the pipe system, as well as those in the ground. Water temperatures at the pipe outlet after 90-day injection of warm water (30℃) were calculated from following cases: (1) one energy pile installed at the fully saturated medium with regional groundwater flow (100 m/year), (2) one energy pile installed at the partially saturated medium (water table is located 13.5 m below the ground surface) with regional groundwater flow (1,000 m/year), (3) one energy pile installed at the fully saturated medium with no regional groundwater flow, (4) one energy pile installed at the partially saturated medium with no regional groundwater flow, (5), (6), (7) four energy piles (distance between energy piles is 10, 5 ,2 m) installed at the fully saturated medium with regional groundwater flow, and (8), (9), (10) four energy piles installed at the partially saturated medium with regional groundwater flow. The outlet temperature of each case is (1) 28.11℃, (2) 28.84℃, (3) 28.97℃, (4) 29.09℃, (5) 28.19℃ (mean value), (6) 28.24℃ (mean value), (7) 28.33℃ (mean value), (8) 28.84℃ (mean value), (9) 28.90℃ (mean value), and (10) 29.10℃ (mean value), respectively. The thermal power ratio of the energy pile of each case (standard case is case 1) is (1) 0%, (2) -46%, (3) -39%, (4) -52%, (5) -4%, (6) -7%, (7) -12%, (8) -39%, (9) -42%, and (10) -53%, respectively. Numerical results show that the performance of the energy pile installed at the fully saturated medium with regional groundwater flow (case 1

  5. Coupled 3D discrete-continuum numerical modeling of pile penetration in sand

    Institute of Scientific and Technical Information of China (English)

    Jian ZHOU; Qi-wei JIAN; Jiao ZHANG; Jian-jun GUO

    2012-01-01

    A coupled discrete-continuum simulation incorporating a 3D aspect and non-circular particles was performed to analyze soil-pile interactions during pile penetration in sand.A self-developed non-circular particle numerical simulation program was used which considered sand near the pile as interacted particles using a discrete element method; the sand away from the pile was simulated as a continuous medium exhibiting linear elastic behaviors.The domain analyzed was divided into two zones.Contact forces at the interface between the two zones were obtained from a discrete zone and applied to the continuum boundaries as nodal forces,while the interface velocities were obtained from the continuum zone and applied to the discrete boundaries.We show that the coupled discrete-continuum simulation can give a microscopic description of the pile penetration process without losing the discrete nature of the zone concerned,and may significantly improve computational efticiency.

  6. Performance of pile-up mitigation techniques for jets in pp collisions with the ATLAS detector

    CERN Document Server

    Testa, Marianna; The ATLAS collaboration

    2015-01-01

    The large rate of multiple simultaneous proton-proton interactions, or pile-up, generated by the Large Hadron Collider in Run I required the development of many new techniques to mitigate the adverse effects of these conditions. This presentation shows the methods employed to correct for the impact of pile-up on jet energy, jet shapes, and even spurious additional jets. Energy correction techniques that incorporate sophisticated estimates of the average pile-up energy density and tracking information are described in detail. Jet-to-vertex association techniques are also presented. We also describe the extension of these techniques to ameliorate the effect of pile-up on jet shapes using both subtraction and grooming procedures. Prospects for pile-up suppression at the HL-LHC will be also discussed.

  7. Performance of pile-up mitigation techniques for jets in pp collisions with the ATLAS detector

    CERN Document Server

    Testa, Marianna; The ATLAS collaboration

    2015-01-01

    The large rate of multiple simultaneous proton-proton interactions, or pile-up, generated by the Large Hadron Collider in Run I required the development of many new techniques to mitigate the adverse effects of these conditions. The methods employed to correct for the impact of pile-up on jet energy, shapes and multiplicity with the ATLAS detector are here presented. They include energy correction techniques based on estimates of the average pile-up energy density and jet-to-vertex association techniques. Extensions of these methods to reduce the impact of pile-up on jet shapes use both subtraction and grooming procedures. Prospects for pile-up suppression at the HL-LHC are also shown.

  8. Performance of pile-up mitigation techniques for jets in pp collisions with the ATLAS detector

    Science.gov (United States)

    Testa, M.

    2016-07-01

    The large rate of multiple simultaneous proton-proton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the adverse effects of these conditions. The methods employed to correct for the impact of pile-up on jet energy, shapes and multiplicity with the ATLAS detector are presented here. They include energy correction techniques based on estimates of the average pile-up energy density and jet-to-vertex association techniques. Extensions of these methods to reduce the impact of pile-up on jet shapes use both subtraction and grooming procedures. Prospects for pile-up suppression at the HL-LHC are also shown.

  9. Catastrophic model for stability analysis of high pile-column bridge pier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential function and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.

  10. Numeric simulation analysis of load-settlement relation of pile in layer foundation

    Institute of Scientific and Technical Information of China (English)

    WANG You-qing

    2006-01-01

    Considering the level distribution of soil layers, the soils surrounding pile are simulated with level finite layer elements. Supposing that the vertical deformation of the soil elements surrounding pile varies in the form of exponent function with radial distance, and considering the nonlinear constitutive relation of stress and strain, the stiffness matrix is established. The mechanics behavior of the pile-soil interface is simulated with a nonlinear interface element. This method can truly express the behavior of the pile-soil system. The load-settlement relation Q-S curves of two big diameter prototype piles on bearing test are analyzed, and satisfying results are obtained. This method is reasonable in theory and feasible in engineering.

  11. Dynamic soil-pile-interaction effects on eigenfrequency and damping of slender structures

    DEFF Research Database (Denmark)

    Zania, Varvara

    2014-01-01

    of the dynamic soil-pile-interaction on the natural vibration characteristics of the flexibly supported structure. For this purpose a two-step iterative procedure has been developed based on two analytical solutions. The frequency dependent dynamic stiffness and damping coefficients are taken into consideration...... after a rigorous solution of horizontal soil – pile vibration, while the modified SSI eigenperiod and damping are calculated accounting for the cross coupling stiffness and damping terms of the soil – pile system. Disregarding the off diagonal terms is considered inappropriate since it results to non......-conservative overestimation of the eigenfrequency and underestimation of damping especially for small slenderness ratios and high flexibility factor of the soil – pile system (short, rigid piles). The observed trends become even more prominent as the height of the slender structure increases. The effect of the monopile...

  12. Performance of pile-up mitigation techniques for jets in pp collisions with the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Testa, M., E-mail: marianna.testa@lnf.infn.it

    2016-07-11

    The large rate of multiple simultaneous proton–proton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the adverse effects of these conditions. The methods employed to correct for the impact of pile-up on jet energy, shapes and multiplicity with the ATLAS detector are presented here. They include energy correction techniques based on estimates of the average pile-up energy density and jet-to-vertex association techniques. Extensions of these methods to reduce the impact of pile-up on jet shapes use both subtraction and grooming procedures. Prospects for pile-up suppression at the HL-LHC are also shown.

  13. Experimental study on settlement of model piles in frozen soil under dynamic loading

    Institute of Scientific and Technical Information of China (English)

    张建明; 朱元林; 张家懿

    1999-01-01

    Test results show that the settlement process of model piles is mainly the rheological process of frozen soil under shear loading. The settlement rate of model piles increases with increasing temperature of frozen soil, decreasing roughness of pile surface and increasing rigidity of pile foundation. As the water content of frozen soil reaches its saturation value, the settlement rate is the least. When the level of loading is higher, the settlement rate under dynamic loading is less than that under static loading. With the level of loading lowering, the effect between dynamic and static loading on the settlement rate becomes close gradually. Under the present test conditions, the settlement rate of model piles is independent of the frequency of dynamic loads.

  14. Evaluation of an Improved Technique for Geosynthetic-Reinforced and Pile-Supported Embankment

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2015-01-01

    Full Text Available With a large number of applications of conventional technique for geosynthetic-reinforced and pile-supported (GRPS embankment (called CT embankment, many deficiencies have been exposed. In view of the deficiencies, an improved technique, fixed-geosynthetic-reinforced and pile-supported embankment (called FGT embankment, is developed. To investigate the performance of the FGT embankment, the comparison analyses and parametric studies are conducted by Finite Element Method (FEM. The influencing factors investigated include elastic modulus of soil, tensile stiffness of geosynthetics, pile length, pile spacing, and pile elastic modulus. In addition, the cost evaluation for the FGT embankment and CT embankment is also made. The results show that the FGT embankment can significantly reduce the settlement and differential settlement, enhance the stability, and provide an economical and effective measure for the construction of high embankment at the bridge approach.

  15. Comparative Analysis of Seismic Response Characteristics of Pile-Soil-Structure Interaction System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, are established by the finite element method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite element method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.

  16. 路堤荷载下Y形桩与常规桩型对比研究%Comparative Study on Bearing Characteristics of Y - Section Pile and Common Piles under Embankment Load

    Institute of Scientific and Technical Information of China (English)

    王新泉; 陈永辉; 陈龙; 齐昌广

    2011-01-01

    研究目的:利用ABAQUS有限元分析软件,建立Y形桩、圆形桩和方形桩三种桩型的有限元计算模型,桩采用弹性模型,土体采用Mohr -Coulomb弹塑性模型.在相同布桩方式和相同面积置换率工况下,研究在路堤荷载分级加载过程中,三种桩型的盖板顶沉降、桩间土沉降、盖板顶和桩间土差异沉降、盖板顶平均应力、桩底平均应力等的变化规律.研究结论:通过对比得知:在相同荷载作用下,圆形桩盖板顶产生的沉降最大,其次为方形桩、Y形桩;圆形桩桩间土产生的沉降最大,方形桩前期大于Y形桩,之后又小于Y形桩;盖板顶与桩间土差异沉降基本呈现圆形桩最大,其次为Y形桩、方形桩;盖板顶和桩底平均应力,呈现方形桩最大,其次为圆形桩、Y形桩.%Research purposes: Based on the ABAQUS finite element analysis software, three kinds of finite element calculation models for Y - Section Pile, square pile and circular pile were established. The elastic model was employed for the pile, while Mohr - Coulomb elastic - plastic model for the soil. Under the case with the same pile layout and area exchange rate, the variations of the total and different settlements of cover plate and soil among adjacent piles, pile - top and pile - end average stress were investigated in the process of stage embankment loading.Research conclusions: It is known by comparison that the maximum settlement of cover plate occurs in the circular pile, followed by the square and Y - section piles; the settlement of soil between piles for circular pile is largest, while that for square pile firstly greater and then less than Y - section pile; the different settlement between cover plate and inter - pile soil for circular pile is of maximum, followed by Y - section and square piles; the pile - top and pile - end average stress for square pile is greater than circular and Y - section piles in turn.

  17. Les piles à combustible. Bilan des travaux de recherches. Perspectives Fuel Cells. Review of Research. Outlook

    Directory of Open Access Journals (Sweden)

    Breelle Y.

    2006-11-01

    Full Text Available Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité. This article reviews and sums up the research and development done by Institut Français du Pétrole (IFP in the last 20 years in the field of fuel cells, including the selection of direct methods leading to the choice of low-temperature basic-electrolyte hydrogen/air cells and the development of methanol-powered hydrogen generators. The results obtained are desceibed along with the conclusions of surveys made in the field of electric generators and special applications in the fields of automotive traction and massive electricity production.

  18. Analysis on factors of having influences on the pile quality and loading capacity of the bored pile%影响钻孔灌注桩桩身质量和承载力的因素分析

    Institute of Scientific and Technical Information of China (English)

    梁亦垅

    2009-01-01

    结合工程实践,对影响钻孔灌注桩柱身质量和承载力的因素进行了分析,从成孔和成桩两方面提出了确保钻孔灌注桩桩身质量的方法,以积累钻孔灌注桩施工经验,推广钻孔灌注桩在工程中的应用.%Combining with project practice, the author analyzes the factors of having influences on the pile quality and loading capacity of the bored pile, provides methods of ensuring the pile quality of the bored pile from two aspects of hole forming and pile forming, so as to accumulate the constructionm experiences of the bored pile, improving the application of the bored pile on project.

  19. 桩帽垫层对锤击沉桩的影响数值分析%Numerical Analysis of Influence of Pile Cap Cushion on Driving Pile

    Institute of Scientific and Technical Information of China (English)

    王继成; 倪占东; 柳爱; 周向阳

    2011-01-01

    Elastic pile cap cushion and hardwood cushion are simulated by ABAQUS, the famous finite element software, in order to study the influence of pile cap cushion on driving pile in this paper. It is discovered that elastic cushion can reduce the stress of the driven pile evidently during the driving process,but the capacity of reducing the pile stress of hardwood is poor. The penetration can be increased greatly with suitable thickness and stiffness of the cushion. There is certain relationship among hammering energy, thickness and stiffness of the cushion. A certain stiffness corresponds to an optimal thickness, the optimal thickness and the range of optimal thickness is enlarged with the increase of stiffness. Much better effectiveness of driving pile with thicker and suitable pile cap cushion can be obtained.%为了研究桩帽垫层对锤击沉桩效果的影响,采用有限元软件ABAQUS对弹性桩帽垫层和硬木垫层进行了模拟,发现弹性垫层在锤击过程中可显著降低桩身应力,而硬木板降低桩身应力的能力有限.采用合适厚度、刚度的垫层时,可显著增加贯人度.锤击能、垫层厚度、垫层刚度之间存在一定关系.对于某一垫层刚度,存在一最优垫层厚度,垫层刚度增加,最优垫层厚度范围也增加了.厚度较厚、刚度稍大的垫层能取得较好的沉桩效果.

  20. 桩伴侣与基桩抗震的概念设计%Pile Partner and the Conceptual Earthquake-resistant Design of Foundation Pile

    Institute of Scientific and Technical Information of China (English)

    薛江炜; 葛忻声; 蔡景珞; 杨勇

    2013-01-01

    It is uncertain that the lateral components such as basement wall and cap side wall bearing horizontal load,so the conventional pile foundation with low cap might endure lateral force that is larger,and even cause its damage.The applying of pile partner to improve traditional foundation pile structure form is put for ward,especially when there is few frictional force between pile cap and soil,or the soil modulus is small.The partner can be component for anti-earthquake concept design under rare earthquake action,pile partner may be sacrificed firstly to keep pile perform well.The improper design of composite foundation will destroy or weaken the isolation effect of pillow,and can be solved by reserving buffer space between pile and partner.%地下室外墙、承台侧壁等侧向构件承担水平荷载具有很大的不确定性,常规采用的低承台桩基有可能承受较大的甚至导致破坏的水平力,建议用桩伴侣改善传统基桩的构造形式,特别是对于承台与桩间土摩擦力小或者桩身范围地基土模量低的两类状况.在罕遇地震时,作为抗震概念设计的耗能构件,首先牺牲伴侣,避免或延迟桩头的破坏;复合地基如果设计不当会破坏或削弱褥垫层隔震的效果,可在伴侣与桩之间预留缓冲空间.

  1. Prehistoric Packrats Piled Up Clues to Climate Change

    Science.gov (United States)

    Cole, Kenneth L.

    2008-01-01

    Scientists from the U.S. Geological Survey and Northern Arizona University studying climate change in the Southwestern United States are getting a helping hand?or would that be paw??from prehistoric packrats. By hoarding parts of animals and plants, including seeds and leaves, in garbage piles or ?middens,? these bushy-tailed rodents preserved crucial ecological and environmental information about the past. From these middens, scientists are able to reconstruct plant communities and natural systems from as long ago as 50,000 years. The contents of middens allow scientists to understand how ecosystems responded to rapid, large-scale climate changes of the past. The insights gained from midden research could offer clues to future changes driven by rapid climate shifts.

  2. Full Wave Solution for Hydrodynamic Behaviors of Pile Breakwater

    Institute of Scientific and Technical Information of China (English)

    ZHU Da-tong

    2013-01-01

    Rayleigh expansion is used to study the water-wave interaction with a row of pile breakwater in finite water depth.Evanescent waves,the wave energy dissipated on the fluid resistance and the thickness of the breakwater are totally included in the model.The formulae of wave reflection and transmission coefficients are obtained.The accuracy of the present model is verified by a comparison with existing results.It is found that the predicted wave reflection and transmission coefficients for the zero order are all highly consistent with the experimental data (Hagiwara,1984;Isaacson et al.,1998) and plane wave solutions (Zhu,2011).The losses of the wave energy for the fluid passing through slits play an important role,which removes the phenomena of enhanced wave transmission.

  3. Catalyse électro-microbienne dans les piles à combustible

    OpenAIRE

    Dumas, Claire

    2007-01-01

    Les piles à combustible microbiennes (PACM) sont des systèmes qui assurent la conversion directe de matières organiques en énergie électrique en utilisant des biofilms bactériens comme catalyseur des réactions électrochimiques. Cette étude vise à améliorer la compréhension des mécanismes de transfert électronique entre les bactéries adhérées et les électrodes, ainsi qu'à optimiser la production électrique des PACMs en explorant et caractérisant différents matériaux d'électrodes. Les expérienc...

  4. Field testing of stiffened deep cement mixing piles under lateral cyclic loading

    Science.gov (United States)

    Raongjant, Werasak; Jing, Meng

    2013-06-01

    Construction of seaside and underground wall bracing often uses stiffened deep cement mixed columns (SDCM). This research investigates methods used to improve the level of bearing capacity of these SDCM when subjected to cyclic lateral loading via various types of stiffer cores. Eight piles, two deep cement mixed piles and six stiffened deep cement mixing piles with three different types of cores, H shape cross section prestressed concrete, steel pipe, and H-beam steel, were embedded though soft clay into medium-hard clay on site in Thailand. Cyclic horizontal loading was gradually applied until pile failure and the hysteresis loops of lateral load vs. lateral deformation were recorded. The lateral carrying capacities of the SDCM piles with an H-beam steel core increased by 3-4 times that of the DCM piles. This field research clearly shows that using H-beam steel as a stiffer core for SDCM piles is the best method to improve its lateral carrying capacity, ductility and energy dissipation capacity.

  5. Refreezing of cast-in-place piles under various engineering conditions

    Institute of Scientific and Technical Information of China (English)

    Lei Guo; QiHao Yu; XiaoNing Li; XinBin Wang; YongYu Yue

    2015-01-01

    In the construction of the Qinghai-Tibet Power Transmission Line (QTPTL), cast-in-place piles (CIPPs) are widely applied in areas with unfavorable geological conditions. The thermal regime around piles in permafrost regions greatly affects the stability of the towers as well as the operation of the QTPTL. The casting of piles will markedly affect the thermal regime of the surrounding permafrost because of the casting temperature and the hydration heat of cement. Based on the typical geological and engineering conditions along the QTPTL, thermal disturbance of a CIPP to surrounding permafrost under different casting seasons, pile depths, and casting temperatures were simulated. The results show that the casting season (summer versus winter) can influence the refreezing process of CIPPs, within the first 6 m of pile depth. Sixty days after being cast, CIPPs greater than 6 m in depth can be frozen regardless of which season they were cast, and the foundation could be refrozen after a cold season. Comparing the refreezing characteristics of CIPPs cast in different seasons also showed that, without considering the ground surface conditions, warm seasons are more suitable for casting piles. With the increase of pile depth, the thermal effect of a CIPP on the surrounding soil mainly expands vertically, while the lateral heat disturbance changes little. Deeper, longer CIPPs have better stability. The casting temperature clearly affects the thermal disturbance, and the radius of the melting circle increases with rising casting temperature. The optimal casting temperature is between 2 °C and 9 °C.

  6. Analytical method of load-transfer of single pile under expansive soil swelling

    Institute of Scientific and Technical Information of China (English)

    FAN Zhen-hui; WANG Yong-he; XIAO Hong-bin; ZHANG Chun-shun

    2007-01-01

    The elastic differential equations of load-transfer of single pile either with applied loads on pile-top or only under the soil swelling were established, respectively, based on the theory of pile-soil interaction and the shear-deformation method. The derivation of analytic solution to load-transfer for single pile in expansive soil could hereby be obtained by means of superposition principle under expansive soils swelling. The comparison of two engineering examples was made to prove the credibility of the suggested method. The analyzed results show that this analytic solution can achieve high precision with few parameters required, indicating its' simplicity and practicability in engineering application. The employed method can contribute to determining the greatest tension along pile shaft resulting from expansive soils swelling and provide reliable bases for engineering design. The method can be employed to obtain various distributive curves of axial force, settlements and skin friction along the pile shaft with the changes of active depth, vertical movements of the surface and loads of pile-top.

  7. Postmortem analysis of sand grain crushing from pile interface using X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Silva, I. Matias; Combe, Gaeel; Foray, Pierre; Flin, Frederic; Lesaffre, Bernard [Universite de Grenoble, 3SR Lab, UMR 5521 Grenoble-INP, UJF-Grenoble 1, CNRS, Grenoble, France CEN, CNRM-GAME UMR 3589, Meteo France - CNRS, Grenoble (France)

    2013-06-18

    Pile foundations of offshore platforms, wind and water turbines are typically subjected to a variety of cyclic loading paths due to their complex environment. While many studies focus on global pile behaviour, the soil-pile interface is explored here by a micromechanical study of the soil layer in contact with the pile surface. This work is devoted to the analysis of frozen post-mortem silica sand samples recovered at the pile interface following installation and cyclic loading tests in a calibration chamber using x-ray tomography. An experimental procedure developed for three dimensional (3D) snow imaging was adapted for the recovery of the in-situ sand samples to preserve their structure during tomography scans. 3D images at a pixel size of 7 {mu}m were then obtained using a cryogenic cell. Results confirm the presence of a shear band at the pile surface as well as void ratios changes in the direction of the pile's radius.

  8. Nonlinear Behavior of Single Piles in Jacket Type Offshore Platforms Using Incremental Dynamic Analysis

    Directory of Open Access Journals (Sweden)

    Mohammad A. Assareh

    2008-01-01

    Full Text Available The operation for offshore oil has become an important issue in the recent years. Offshore platforms are some of those structures which are built to withstand environmental and accidental loads during oil exploitation operation. One of the most usual types of these platforms is the Jacket Type Offshore Platform (JTOP which can be divided into three important parts, which are Deck, Jacket and piles. In order to increase the safety, particular attention should be paid to earthquake excitations which are directly applied to the piles of these structures. Nonlinearity in piles and buckling of the struts are important issues which have to be considered by the designers of offshore platforms. The case of nonlinearity in piles and failure capture in these members has not effectively been covered by researchers. Incremental Dynamic Analysis (IDA is a powerful tool to assess the capacity of a structure upon seismic loads. In this paper incremental dynamic analysis has been implemented on single piles considering soil-pile interactions and free field site response. The use of nonlinear materials and lateral load resisting elements in the incremental dynamic analysis done in this paper has made it possible to get promising insights for incorporation of appropriate limit states and applications of performance based engineering. Special Engineering Demand Parameters (EDP and Intensity Measures (IM have been introduced for the single pile dynamic analysis in jacket type offshore platforms.

  9. Regressive approach for predicting bearing capacity of bored piles from cone penetration test data

    Directory of Open Access Journals (Sweden)

    Iyad S. Alkroosh

    2015-10-01

    Full Text Available In this study, the least square support vector machine (LSSVM algorithm was applied to predicting the bearing capacity of bored piles embedded in sand and mixed soils. Pile geometry and cone penetration test (CPT results were used as input variables for prediction of pile bearing capacity. The data used were collected from the existing literature and consisted of 50 case records. The application of LSSVM was carried out by dividing the data into three sets: a training set for learning the problem and obtaining a relationship between input variables and pile bearing capacity, and testing and validation sets for evaluation of the predictive and generalization ability of the obtained relationship. The predictions of pile bearing capacity by LSSVM were evaluated by comparing with experimental data and with those by traditional CPT-based methods and the gene expression programming (GEP model. It was found that the LSSVM performs well with coefficient of determination, mean, and standard deviation equivalent to 0.99, 1.03, and 0.08, respectively, for the testing set, and 1, 1.04, and 0.11, respectively, for the validation set. The low values of the calculated mean squared error and mean absolute error indicated that the LSSVM was accurate in predicting the pile bearing capacity. The results of comparison also showed that the proposed algorithm predicted the pile bearing capacity more accurately than the traditional methods including the GEP model.

  10. Simulating pile load-settlement behavior from CPT data using intelligent computing

    Science.gov (United States)

    Alkroosh, I.; Nikraz, H.

    2011-09-01

    Analysis of pile load-settlement behavior is a complex problem due to the participation of many factors involved. This paper presents a new procedure based on artificial neural networks (ANNs) for simulating the load-settlement behavior of pile foundations embedded in sand and mixed soils (subjected to axial loads). Three ANN models have been developed, a model for bored piles and two other models for driven piles (a model for each of concrete and steel piles). The data used for development of the ANN models is collected from the literature and comprise a series of in-situ piles load tests as well as cone penetration test (CPT) results. The data of each model is divided into two subsets: Training set for model calibration and independent validation set for model verification. Predictions from the ANN models are compared with the results of experimental data and with predictions of number of currently adopted load-transfer methods. Statistical analysis is used to verify the performance of the models. The results indicate that the ANN model performs very well and able to predict the pile load-settlement behaviour accurately.

  11. Effects of Cohesion On the Dynamic Response of A Conical Bead Pile

    Science.gov (United States)

    Palchoudhuri, Paroma; Lehman, Susan; Jacobs, D. T.

    2014-03-01

    We investigate the critical behavior of a 3D conical bead pile built from uniform 3 mm steel spheres. The pile is initially built on a circular base and is subsequently slowly driven through the addition of one bead at a time to the apex of the pile. We investigate the dynamic response of the pile by recording avalanches from the pile over the course of tens of thousands of bead drops, and determining the resulting distribution of avalanche size. In previous work, we have shown that dropping the beads onto the pile from a greater height causes the distribution to deviate from a simple power law due to a stark reduction in number of the largest avalanches. By placing the pile in a uniform magnetic field, we are now observing changes in the avalanche size distribution due to cohesion. When there is cohesion between beads, we find an increase in probability for the largest avalanches and a strong decrease in the probability of medium-sized avalanches. We also observe an increase in the time between avalanches as the cohesion of the system increases. Preliminary results on the effect of simultaneously increasing cohesion, which tends to make large avalanches more probable, and increasing drop height, which tends to make large avalanches less probable, will also be presented.

  12. Multivariate adaptive regression splines and neural network models for prediction of pile drivability

    Institute of Scientific and Technical Information of China (English)

    Wengang Zhang; Anthony T.C. Goh

    2016-01-01

    Piles are long, slender structural elements used to transfer the loads from the superstructure through weak strata onto stiffer soils or rocks. For driven piles, the impact of the piling hammer induces compression and tension stresses in the piles. Hence, an important design consideration is to check that the strength of the pile is sufficient to resist the stresses caused by the impact of the pile hammer. Due to its complexity, pile drivability lacks a precise analytical solution with regard to the phenomena involved. In situations where measured data or numerical hypothetical results are available, neural networks stand out in mapping the nonlinear interactions and relationships between the system’s predictors and dependent responses. In addition, unlike most computational tools, no mathematical relationship assumption between the dependent and independent variables has to be made. Nevertheless, neural networks have been criticized for their long trial-and-error training process since the optimal configu-ration is not known a priori. This paper investigates the use of a fairly simple nonparametric regression algorithm known as multivariate adaptive regression splines (MARS), as an alternative to neural net-works, to approximate the relationship between the inputs and dependent response, and to mathe-matically interpret the relationship between the various parameters. In this paper, the Back propagation neural network (BPNN) and MARS models are developed for assessing pile drivability in relation to the prediction of the Maximum compressive stresses (MCS), Maximum tensile stresses (MTS), and Blow per foot (BPF). A database of more than four thousand piles is utilized for model development and comparative performance between BPNN and MARS predictions.

  13. Laboratory testing of cyclic laterally loaded pile in cohesionless soil. [MONOPILES

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Mette; Kirk Wolf, T. [COWI, Kgs. Lyngby (Denmark); Lange Rasmussen, K. [Niras, Aalborg (Denmark); Ravn Roesen, H.; Ibsen, L.B. [Aalborg Univ.. Dept. of Civil Engineering, Aalborg (Denmark)

    2013-06-15

    Offshore wind turbines are placed in a rough environment, subjected to variable lateral loads, mostly from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the soil-pile system which is critical in the serviceability limit state. The accumulated rotation due to long-term lateral loading is therefore a current issue of interest as today's design guidances have little knowledge in this area. The cost of large-scale testing is extensive which make small-scale testing desirable as a tool for describing the behaviour of a soil-pile system subjected to lateral load. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test pile has a diameter of 100 mm and is 600 mm high, making the slenderness ratio 6, which resembles the ratio of offshore wind turbines today. The test pile is placed in saturated dense sand. A monotonic test is conducted to define the ultimate lateral capacity. Afterwards a cyclic test is conducted to investigate the accumulation of rotation when the pile is subjected to cyclic lateral load. Force and displacement during both tests are recorded to determine the deformation of the pile. Comparing the responses of the monotonic and the cyclic test, the cyclic test shows a stiffer response. During the cyclic test, the rotation of the pile accumulates with decreasing rotation increments. However, no stabilised situation occurs. The measured data is compared to theories on degradation, agreeing that the accumulated rotation as an estimate can be express by both a logarithmic and exponential expression. Comparing the results from the cyclic test with results from other recent small-scale tests shows agreement in the accumulation of rotation with decreasing rotation increments with no stabilising situation. (Author)

  14. The single pile classification: a new tool for the classification of haemorrhoidal disease and the comparison of treatment results.

    Science.gov (United States)

    Elbetti, C; Giani, I; Novelli, E; Fucini, C; Martellucci, Jacopo

    2015-12-01

    The purpose of the paper is to compare Goligher Classification with the Single Pile Hemorrhoid Classification (SPHC) to show the possible bias and limits of Goligher's use and the possible advantage with the employment of the new classification. SPHC considers the number of pathological piles(N), the characteristics of each internal pile and the characteristics of each external pile, reporting the presence of a fibrous inelastic redundant pile(F), the presence of the subversion of dentate line or the congestion of the external pile(E) and the presence of not tolerated skin tags(S). From September 2010 to December 2012, 197 consecutive patients were analysed according to both classifications. Considering pathological piles, I and II Goligher patients showed a complete agreement between pathological pile and grade, III Goligher patients had 80.5 % of pathological piles of III grade while IV Goligher patients had only 44.3 % of IV grade pathological piles (p < 0.001). Regarding the distribution of the other anatomical variables: F, E, S described in SPHC, the results showed that F was present in 18.3 % while ES was present in 46.2 %. Goligher's Classification has showed to be an inadequate tool to overview surgical outcome or to compare surgical procedure, particularly for high grades, while SPHC showed to be a feasible instrument both to describe and to compare patients affected by hemorrhoid disease.

  15. CENTRIFUGAL MODEL TEST OF SLOPE REINFORCED BY SMALL-DIAMETER STEEL PIPE ROW PILES%小直径钢管排桩加固边坡的离心模型试验

    Institute of Scientific and Technical Information of China (English)

    向波; 马建林; 何云勇; 朱林; 张正义

    2012-01-01

    As a new retaining structure, the small-diameter steel pipe anti-sliding pile is used extensively for slope reinforcement and landslide control, but its some behaviors, such as anti-sliding characteristics, force mechanism and failure mode, etc., need to be further studied. Combining with a specific engineering, centrifugal model tests of small- diameter steel pipe row piles are used to investigate the effects of slope failure mode, stress condition, pile spacing and connection beams on slope anti-sliding capacity. The results show that the model slope in each group suffers overall structure failure, and sliding surface can be observed clearly only in slopes without reinforcement. The anti-sliding mechanism of this kind of structures represents the geological improvement by high-pressure grouting and cooperative anti-sliding activity by piles and rock-soil composite structure. The main failure mode of this kind of structure is overall instability caused by axial tension and compression. The anti-sliding capacity of row piles is affected dramatically by pile spacing. The relationship between the ratio of pile spacing to pile diameter(L/φ) and factor of safety of slope is apower function, and the value of L/φ of this type of row piles is recommended to be 6 - 12. Soil pressures behind piles increase with the increasing depth first and then decrease, and they approximately present a triangular distribution above the sliding surface. For the triple-row pile structure with connection beams, the bearing capacity of pile B decreases with the increase of acceleration, while that of pile C is on the contrary. The factor of safety of slope increases by 38.3% under the action of connection beams.%小直径钢管抗滑桩作为一种新型支挡结构广泛应用于边坡加固和滑坡治理中,但其抗滑特性、受力机制及破坏模式等还有待于深入研究.结合工程背景,开展小直径钢管排桩离心模型试验,研究排桩加固边坡破坏模式、

  16. Methods for Predicting Potential Impacts of Pile-Driving Noise on Endangered Sturgeon During Bridge Construction.

    Science.gov (United States)

    Krebs, Justin; Jacobs, Fred; Conway, Robert; Popper, Arthur N; Moese, Mark; Rollino, John; Racca, Roberto; Martin, Bruce; MacGillivray, Alexander

    2016-01-01

    The potential impacts of pile-driving noise on Hudson River sturgeon during construction of the New NY Bridge were predicted. Abundance data for shortnose and Atlantic sturgeon derived from fisheries sampling were combined with data about the spatial extent of pile-driving noise. This approach was used to calculate the number of sturgeon that could occur within sound level isopleths exceeding peak and cumulative noise criteria used by the National Marine Fisheries Service to determine the incidental take of sturgeon. The number of sturgeon subject to the potential onset of physiological effects during pile driving was predicted to be 35-41 fish for each species.

  17. Backfilling of a Scour Hole around a Pile in Waves and Current

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Petersen, Thor Ugelvig; Locatelli, Luca;

    2013-01-01

    This paper presents the results of an experimental investigation of the backfilling of scour holes around circular piles. Scour holes around a pile are generated either by a current or a wave. Subsequently, the flow climate is changed from current to wave, combined waves and current, or wave...... around the pile for the same wave (or combined waves and current) climate. The time scale of backfilling has been determined as a function of three parameters, namely, (1) the Keulegan-Carpenter number of the initial wave or current (which generates the initial scour hole); (2) that of the subsequent...

  18. Study on the squeezing effect of open-ended pipe piles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    During the installation of a pipe pile,the soil around the pile will be squeezed out. This paper deals with this squeezing effect of open-ended pipe piles using the cylindrical cavity expansion theory. The characteristics of soil with different tension and compression moduli and dilation are involved by applying the elastic theory with different moduli and logarithmic strain. The closed-form solutions of the radius of the plastic region,the displacement of the boundary between the plastic region and the ela...

  19. Comparison of Design Methods for Axially Loaded Driven Piles in Cohesionless Soil

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2012-01-01

    For offshore wind turbines on deeper waters, a jacket sub-structure supported by axially loaded piles is thought to be the most suitable solution. The design method recommended by API and two CPT-based design methods are compared for two uniform sand profiles. The analysis show great difference...... in the predictions of bearing capacities calculated by means of the three methods for piles loaded in both tension and compression. This implies that further analysis of the bearing capacity of axially loaded piles in sand should be conducted....

  20. Treating jet correlations in high pile-up at hadron colliders

    Directory of Open Access Journals (Sweden)

    F. Hautmann

    2016-03-01

    Full Text Available Experiments in the high-luminosity runs at the Large Hadron Collider face the challenges of very large pile-up. Primary techniques to deal with this are based on precise vertex and track reconstruction. Outside tracker acceptances, however, lie regions of interest for many aspects of the LHC physics program. We explore complementary approaches to pile-up treatment and propose a data-driven jet-mixing method which can be used outside tracker acceptances without depending on Monte Carlo generators. The method can be applied to treat correlation observables and take into account, besides the jet transverse momentum pedestal, effects of hard jets from pile-up.

  1. Evaluation of the Load-Displacement Relationships for Large-Diameter Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Brodbaek, K. T.; Moller, M.;

    2009-01-01

    was developed for slender piles with diameters much less than 6 m and it is based on a limited number of tests. The aim of the present work is to extend the p-y curve method to large-diameter non-slender piles by considering the effects of the pile diameter on the soil response. The main focus is the initial...... stiffness of the p-y curves. The evaluation is based on experimental work as well as three-dimensional numerical analyses in the commercial programme FLAC3D....

  2. Bacterial diversity in soil samples from two uranium waste piles as determined by rep-APD, RISA and 16S rDNA retrieval.

    Science.gov (United States)

    Selenska-Pobell, S; Kampf, G; Hemming, K; Radeva, G; Satchanska, G

    2001-06-01

    The bacterial diversity in two uranium waste piles was studied. Total DNA was recovered from a large number of soil samples collected from different sites and depths in the piles using two procedures for direct lysis. Significant differences in the bacterial composition of the samples were revealed by the use of rep-APD, RISA and 16S ARDREA. The 16S rDNA analyses showed that the uranium wastes were dominated by Acidithiobacillusferrooxidans and by several Pseudomonas species classified in the gamma-subdivision of the Proteobacteria. The three kinds of A. ferrooxidans 16S and IGS rDNA specific fragments that were found corresponded to the three phylogenetic groups recognised in this species. This microdiversity probably reflects the genetic adaptation of the uranium waste strains to different concentrations of heavy metals.

  3. 桥梁高桩承台基础抗震性能研究%Study of earthquake-resistant performance of high pile cap foundation of bridge

    Institute of Scientific and Technical Information of China (English)

    韩振峰; 叶爱君

    2016-01-01

    文章通过3个钢筋混凝土群桩试件在低周反复荷载作用下的受力性能试验研究 ,讨论了群桩基础破坏形态及滞回特征 ,解释了其破坏机理 ,分析了土体参数、密实度及桩身自由段长度等对其延性的影响.结果表明 ,极限状态时 ,群桩结构受力模式会由地基梁模型转变为悬臂柱模型 ;减小自由长度和提高土体含水率都会增加其抗震性能.在OpenSees有限元框架中建立了群桩基础有限元模型 ,使用弹塑性纤维梁柱单元模拟桩体 ,采用非线性p-y单元模拟桩土相互作用 ;对模型进行了单调 Pushover分析 ,并且对分析结果与试验结果进行了比较 ,结果表明该模型能很好地模拟试验数据.%Firstly ,based on an experimental research on three reinforced concrete pile foundation specimens tested under low cyclic loads ,the destroy pattern and hysteretic characteristic of pile group foundation were discussed ,the destroy mechanism was explained ,and the effect of soil parameters ,compactness ,and free length of the pile on the foundation ductility was analyzed .The results show that the mechanical pattern of the foundation may change from the foundation beam model to the cantilever column model at the ultimate state ,and reducing free length of the pile and raising the moisture content of the soil can improve the earth-quake-resistant performance of the foundation .Secondly ,a finite element model of this foundation was built in the OpenSees framework .In the model ,the fiber element was used to simulate the pile shaft ,and the non-linear p-y element was used to simulate the soil-pile interaction .Thirdly ,the monotonic Pushover analysis was performed on the model ,and the results were compared with the test results .The results show good co-herence with the experimental data .

  4. 上海中心大厦桩基础变刚度调平设计%Variable rigidity design in the pile foundation of Shanghai Tower

    Institute of Scientific and Technical Information of China (English)

    姜文辉; 巢斯

    2012-01-01

    How to control the settlement and differential settlements of buildings in Shanghai is important. Variable rigidity design is based on the settlement control and is efficient in differential-settlement control of high-rise buildings with piles group and soft bed. Large-diameter post-grouting bored piles are adopted in the foundation of Shanghai Tower. The foundation of Shanghai Tower was designed according to the variable rigidity conception. By selecting length and distance of piles properly, the differential settlements of plate at centre and edges were controlled within the reasonable range, which can optimize the plate design. Pile tests show that post-grouting technique can increase the bearing capacity of the single pile as well as decrease differences among bearing capacities of different piles.%对于上海地区的超厚软弱土层,如何控制建筑沉降和差异沉降是设计的重点。变刚度调平设计是基于沉降控制的基础设计方法,对于群桩基础和软土地基的高层建筑沉降差异控制有显著的效果。介绍了上海中心大厦大直径后注浆钻孔灌注桩基础设计中按照变刚度调平概念,通过合理选择桩长和桩距,使得主楼底板中心和边缘的计算差异沉降控制在合理的范围,优化了底板的设计。经过试桩,认为后注浆的桩端注浆方法能有效提高单桩承载力和减小不同桩承载力间的变异值。

  5. Vertical Equilibrium of Sheet Pile Walls with Emphasis on Toe Capacity and Plugging

    DEFF Research Database (Denmark)

    Iversen, Kirsten Malte; Augustesen, Anders Hust; Nielsen, Benjaminn Nordahl

    Constructions including retaining walls are normally established in areas where it is impossible to conduct an excavation with inclined sides. Due to large excavation depths and due to restrictions on the deformations of the wall, it is often necessary to anchor the wall. The limited space makes...... at the pile toe to fulfil vertical equilibrium. The paper describes a case study of sheet pile walls in Aalborg Clay, and the amount of loads transferred as point loads at the pile toe for free and anchored walls is estimated. A parametric study is made for the free wall with regards to the height...... and the roughness of the wall. Due to limitations of the calculation method, the study of the anchored wall only includes variation of the roughness. For the case study, it is found that the vertical equilibrium is fulfilled for the considered free wall. An anchored wall needs a plug forming at the pile toe...

  6. Numerical analysis of energy piles under different boundary conditions and thermal loading cycles

    Directory of Open Access Journals (Sweden)

    Khosravi Ali

    2016-01-01

    Full Text Available The thermo- mechanical behavior of energy piles has been studied extensively in recent years. In the present study, a numerical model was adapted to study the effect of various parameters (e.g. heating/cooling temperature, head loading condition and soil stiffness on the thermo-mechanical behavior of an energy pile installed in unsaturated sandstone. The results from the simulations were compared with measurements from a thermal response test on a prototype energy pile installed beneath a 1-story building at the US Air Force Academy (USAFA in Colorado Springs, CO. A good agreement was achieved between the results obtained from the prototype and the numerical models. A parametric evaluation were also carried out which indicated the significance of the stiffness of the unsaturated sandstone and pile’s head loading condition on stress-strain response of the energy pile during heating/cooling cycles.

  7. Torsional vibration of a pipe pile in transversely isotropic saturated soil

    Science.gov (United States)

    Zheng, Changjie; Hua, Jianmin; Ding, Xuanming

    2016-09-01

    This study considers the torsional vibration of a pipe pile in a transversely isotropic saturated soil layer. Based on Biot's poroelastic theory and the constitutive relations of the transversely isotropic medium, the dynamic governing equations of the outer and inner transversely isotropic saturated soil layers are derived. The Laplace transform is used to solve the governing equations of the outer and inner soil layers. The dynamic torsional response of the pipe pile in the frequency domain is derived utilizing 1D elastic theory and the continuous conditions at the interfaces between the pipe pile and the soils. The time domain solution is obtained by Fourier inverse transform. A parametric study is conducted to demonstrate the influence of the anisotropies of the outer and inner soil on the torsional dynamic response of the pipe pile.

  8. Numerical Modelling of Large-Diameter Steel Piles at Horns Rev

    DEFF Research Database (Denmark)

    Augustesen, Anders Hust; Brødbæk, K. T.; Møller, M.;

    2009-01-01

    Today large-diameter monopiles are the most common foundation type used for large offshore wind farms. This paper aims to investigate the behaviour of monopiles under monotonic loading taking the interaction between the pile and the subsoil into account. Focus is paid to a monopile used as founda......Today large-diameter monopiles are the most common foundation type used for large offshore wind farms. This paper aims to investigate the behaviour of monopiles under monotonic loading taking the interaction between the pile and the subsoil into account. Focus is paid to a monopile used...... as foundation for a wind turbine at Horns Rev located in the Danish sector of the North Sea. The outer diameter of the pile is 4 m and the subsoil at the location consists primarily of sand. The behaviour of the pile is investigated under realistic loading conditions by means of a traditional Winkler...

  9. On construction scheme of bored piles%谈灌注桩施工方案

    Institute of Scientific and Technical Information of China (English)

    刘立创

    2012-01-01

    The paper points out the bored pile is the common foundation treatment,and fully introduces the craft procedure and craft methods of the bored pile construction by taking the engineering example of the bored pile construction,so as to enhance the application of the bored pile.%指出灌注桩是常用的一种地基处理方法,通过灌注桩施工的一个工程实例,较全面地介绍了灌注桩施工的工艺流程、工艺方法,从而促进灌注桩的推广应用。

  10. Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector

    Science.gov (United States)

    Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adelman, J.; Adersberger, M.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agheorghiesei, C.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akatsuka, S.; Akerstedt, H.; Åkesson, T. P. A.; Akilli, E.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albicocco, P.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Gonzalez, B. Alvarez; Piqueras, D. Álvarez; Alviggi, M. G.; Amadio, B. T.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Angerami, A.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antel, C.; Antonelli, M.; Antonov, A.; Antrim, D. J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Arabidze, G.; Arai, Y.; Araque, J. P.; Ferraz, V. Araujo; Arce, A. T. H.; Ardell, R. E.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagnaia, P.; Bahrasemani, H.; Baines, J. T.; Bajic, M.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisits, M.-S.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska-Blenessy, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Navarro, L. Barranco; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beermann, T. A.; Begalli, M.; Begel, M.; Behr, J. K.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Benitez, J.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernardi, G.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bylund, O. Bessidskaia; Bessner, M.; Besson, N.; Betancourt, C.; Bethani, A.; Bethke, S.; Bevan, A. J.; Beyer, J.; Bianchi, R. M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; De Mendizabal, J. Bilbao; Billoud, T. R. V.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biondi, S.; Bisanz, T.; Bittrich, C.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blair, R. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blue, A.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogavac, D.; Bogdanchikov, A. 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C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spieker, T. M.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Denis, R. D. St.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanitzki, M. M.; Stapf, B. S.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Stark, S. H.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultan, DMS; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Suruliz, K.; Suster, C. J. E.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Swift, S. P.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takasugi, E. H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tanaka, J.; Tanaka, M.; Tanaka, R.; Tanaka, S.; Tanioka, R.; Tannenwald, B. B.; Araya, S. Tapia; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Delgado, A. Tavares; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teixeira-Dias, P.; Temple, D.; Kate, H. Ten; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Tibbetts, M. J.; Torres, R. E. Ticse; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Pastor, E. Torró; Toth, J.; Touchard, F.; Tovey, D. R.; Treado, C. J.; Trefzger, T.; Tresoldi, F.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsang, K. W.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Cakir, I. Turk; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Vaidya, A.; Valderanis, C.; Santurio, E. Valdes; Valentinetti, S.; Valero, A.; Valéry, L.; Valkar, S.; Vallier, A.; Ferrer, J. A. Valls; Van Den Wollenberg, W.; van der Graaf, H.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varni, C.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, A. T.; Vermeulen, J. C.; Vetterli, M. C.; Maira, N. Viaux; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Perez, M. Villaplana; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vishwakarma, A.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wagner-Kuhr, J.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, Q.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wang, W.; Wang, Z.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, A. F.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weirich, M.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A. S.; White, A.; White, M. J.; White, R.; Whiteson, D.; Whitmore, B. W.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winkels, E.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wobisch, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Wong, V. W. S.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Wozniak, K. W.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xia, L.; Xu, D.; Xu, L.; Xu, T.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamatani, M.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Wong, K. H. Yau; Ye, J.; Ye, S.; Yeletskikh, I.; Yigitbasi, E.; Yildirim, E.; Yorita, K.; Yoshihara, K.; Young, C.; Young, C. J. S.; Yu, J.; Yu, J.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zacharis, G.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanzi, D.; Zeitnitz, C.; Zemaityte, G.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, P.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Y.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Zou, R.; Nedden, M. zur; Zwalinski, L.

    2017-09-01

    The rejection of forward jets originating from additional proton-proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range |η |>2.5. This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb^{-1} of proton-proton collisions at a centre-of-mass energy of 13 {TeV} collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5growth due to additional proton-proton interactions, thus enhancing the reach for such signatures.

  11. Os 200 anos da pilha elétrica The 200 years of the electric pile

    Directory of Open Access Journals (Sweden)

    Aécio Pereira Chagas

    2000-06-01

    Full Text Available In celebration of the 200th anniversary of the electric pile, invented by Alessandro Volta, a synopsis of his letter to The Royal Society (London and of his biography is presented.

  12. Numerical study of pile-up in bulk metallic glass during spherical indentation

    Institute of Scientific and Technical Information of China (English)

    Al Ke; DAI LanHong

    2008-01-01

    Pile-up around indenter is usually observed during instrumented indentation tests on bulk metallic glass. Neglecting the pile-up effect may lead to errors in evaluating hardness, Young's modulus, stress-strain response, etc. Finite element analysis was employed to implement numerical simulation of spherical indentation tests on bulk metallic glass. A new model was proposed to describe the pile-up effect. By using this new model, the contact radius and hardness of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass were obtained under several different indenter loads with pile-up, and the results agree well with the data generated by numerical simulation.

  13. Numerical study of pile-up in bulk metallic glass during spherical indentation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pile-up around indenter is usually observed during instrumented indentation tests on bulk metallic glass. Neglecting the pile-up effect may lead to errors in evaluating hardness,Young’s modulus,stress-strain response,etc. Finite element analysis was employed to implement numerical simulation of spherical indentation tests on bulk metallic glass. A new model was proposed to describe the pile-up effect. By using this new model,the contact radius and hardness of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass were obtained under several different indenter loads with pile-up,and the results agree well with the data generated by numerical simulation.

  14. RCP 劲性复合桩的应用%The application of RCP composite pile

    Institute of Scientific and Technical Information of China (English)

    宋阳

    2016-01-01

    介绍了 RCP 劲性复合桩的技术原理,结合工程案例,从定点放线、搅拌钻进、水泥浆制作、桩芯植入等方面,阐述了 RCP 劲性复合桩的施工工艺流程及要点,并介绍了该技术的优点,可为其他项目桩基工程提供参考。%This paper introduced the technology principle of RCP composite piles,combining with the engineering case,starting from aspects of fixed-point sampling,mixing drilling,cement slurry prefabrication and inside pile planting,describes the construction process and points of RCP composite pile,and introduces the advantages of the technology,can provide a reference for other projects pile works.

  15. Numerical prediction of underwater noise reduction during offshore pile driving by a Small Bubble Curtain

    DEFF Research Database (Denmark)

    Göttsche, Klaus Marco; Juhl, Peter Møller; Steinhagen, Ulrich

    2013-01-01

    Small Bubble Curtains are an effective technique to reduce the underwater noise being emitted during offshore pile driving. In order to protect the marine fauna, noise reduction becomes even more important, since the increasing contribution of offshore wind energy leads to a rising number...... of offshore construction sites in order to cover the need for clean energy. Within the Bubble Curtain air bubbles are injected into the water surrounding the pile. When these are driven by the pressure wave being emitted from the pile, reflection, scattering and absorption effects occur. Within this paper......, a method is presented in order to predict the rate of noise attenuation achieved by a Small Bubble Curtain. For this purpose, the bubble distribution is determined with Computational Fluid Dynamics. The noise radiation during pile driving is simulated by Finite Element Analysis and an Effective Medium...

  16. Internal force analysis of steel sheet pile cofferdam by considering the construction "path" effect

    Directory of Open Access Journals (Sweden)

    Dong LIANG

    2016-04-01

    Full Text Available In the process of installing inner support, the force loaded on the steel sheet pile is continuous, that is, the installation of inner support always happens after the accumulative deformation caused by inside and outside pressure difference of the steel sheet pile cofferdam. Taking the steel sheet pile cofferdam construction of a specially long span bridge as example, the paper puts forwards a spatial model of steel sheet pile cofferdam considering the construction “path” based on ANSYS. The model calculation result and the actual measurement result are compared. The results show that the model based on considering the “path” effects has a more similar calculating result with the measured value.

  17. Seismic Performance Research of Transmission Tower in Consideration of the Pile-soil-structure System

    Science.gov (United States)

    Liu, Chuncheng; Mao, Long; Wang, Chongyang; Zha, Chuanming

    2016-11-01

    The seismic performance of transmission tower in consideration of pile-soil- structure dynamic interaction is researched through numerical simulation. Based on a transmission tower of a specific project, pile-soil-transmission tower coupled system is established. By using the method of time history, the pile-soil- transmission tower system dynamic response under seismic load were calculated, and comparing with the results without considering interaction system. Results show that, after considering interaction of the system, the period of the structure have extended and the mode of the structure lagged. On soft sites, compare with no considering the interaction, the results have a big difference, the relative increment of the maximum displacement at the top of the tower is 39.82%, respectively. Therefore it is suggested that the pile-soil-structure dynamic interaction should be fully considered in aseismic design of transmission tower on soft sites and medium soft sites.

  18. 大直径微型钢管桩桩基托换技术在地铁施工中的应用%Application of Large-diameter Micro Steel Pipe Pile Underpinning Technology in Construction of Metro Works

    Institute of Scientific and Technical Information of China (English)

    谢永盛

    2012-01-01

    广州地铁二、八号线延长线洛溪站—南洲站盾构区间从彩虹花园密集桩群中通过,大量桩基侵入盾构掘进区域,需对彩虹花园进行加固处理,但加固施工空间狭小。为了解决彩虹花园加固处理难题,采用350 mm大直径微型钢管桩进行桩基托换,盾构到达原桩位置时采取停机截桩方案进行加固处理。加固过程中建筑物沉降稳定,未出现任何裂缝,结构完好,达到预期加固效果,可供相似工程进行参考。%Luoxi stationNanzhou station shield tunneling section on the extended section of No. 2 and No. 8 line of Guangzhou Metro passes through the pile group of Caihong Garden. Many piles intrude into the clearance of the shield bored tunnel, therefore Caihong Garden should be reinforced. Furthermore, the operation space for the reinforcement is small. Micro steel pipe piles with 350 mm diameter are adopted to underpin the pile foundation. When the shield arrives at the position of the existing piles, the piles are cut and reinforcement is made. During the reinforcement, the settle ment of the buildings is stable and expected reinforcement effect is achieved.

  19. 3D mathematical modelling of scour around a circular pile in current

    DEFF Research Database (Denmark)

    Roulund, Andreas; Sumer, B. Mutlu; Fredsøe, Jørgen;

    1999-01-01

    This paper deals with scour around a circular pile exposed to a steady current. A 3D numerical model incorporated with the k-w,SST closure coupled with the sediment-continuity equation and a bedload sediment transport formula has been used to predict the scour. 3D calculations have also been...... to scour depth of 0.6-0.7 times the pile diameter. Calculations that describe the entire scour process (including the equilibrium stage) are underway....

  20. Effects of Pile Driving on the Residency and Movement of Tagged Reef Fish.

    Science.gov (United States)

    Iafrate, Joseph D; Watwood, Stephanie L; Reyier, Eric A; Scheidt, Douglas M; Dossot, Georges A; Crocker, Steven E

    2016-01-01

    The potential effects of pile driving on fish populations and commercial fisheries have received significant attention given the prevalence of pile driving occurring in coastal habitats throughout the world. Behavioral impacts of sound generated from these activities on fish typically have a greater area of influence than physical injury, and may therefore adversely affect a greater portion of the local population. This study used acoustic telemetry to assess the movement, residency, and survival of 15 sheepshead (Archosargus probatocephalus) and 10 grey snapper (Lutjanus griseus) in Port Canaveral, Florida, USA, in response to 35 days of pile driving at a wharf complex. No obvious signs of mortality or injury to tagged fish were evident from the data. Received sound pressure levels from pile strikes on the interior of the wharf, where reef fish primarily occur, were on average 152-157 dB re 1 μPa (peak). No significant decrease in sheepshead daytime residency was observed during pile driving within the central portion of the wharf and area of highest sound exposure, and no major indicators of displacement from the exposure wharf with the onset of pile driving were observed. There was evidence of potential displacement from the exposure wharf that coincided with the start of pile driving observed for 2 out of 4 grey snapper, along with a decrease in daytime residency for a subset of this species with high site fidelity prior to the event. Results indicate that snapper may be more likely to depart an area of pile driving disturbance more readily than sheepshead, but were less at risk for behavioral impact given the lower site fidelity of this species.

  1. Reliability of Foundation Pile Based on Settlement and a Parameter Sensitivity Analysis

    OpenAIRE

    Shujun Zhang; Luo Zhong; Zhijun Xu

    2016-01-01

    Based on the uncertainty analysis to calculation model of settlement, the formula of reliability index of foundation pile is derived. Based on this formula, the influence of coefficient of variation of the calculated settlement at pile head, coefficient of variation of the permissible limit of the settlement, coefficient of variation of the measured settlement, safety coefficient, and the mean value of calculation model coefficient on reliability is analyzed. The results indicate that (1) hig...

  2. Noise reduction by the application of an air-bubble curtain in offshore pile driving

    Science.gov (United States)

    Tsouvalas, A.; Metrikine, A. V.

    2016-06-01

    Underwater noise pollution is a by-product of marine industrial operations. In particular, the noise generated when a foundation pile is driven into the soil with an impact hammer is considered to be harmful for the aquatic species. In an attempt to reduce the ecological footprint, several noise mitigation techniques have been investigated. Among the various solutions proposed, the air-bubble curtain is often applied due to its efficacy in noise reduction. In this paper, a model is proposed for the investigation of the sound reduction during marine piling when an air-bubble curtain is placed around the pile. The model consists of the pile, the surrounding water and soil media, and the air-bubble curtain which is positioned at a certain distance from the pile surface. The solution approach is semi-analytical and is based on the dynamic sub-structuring technique and the modal decomposition method. Two main results of the paper can be distinguished. First, a new model is proposed that can be used for predictions of the noise levels in a computationally efficient manner. Second, an analysis is presented of the principal mechanisms that are responsible for the noise reduction due to the application of the air-bubble curtain in marine piling. The understanding of these mechanisms turns to be crucial for the exploitation of the maximum efficiency of the system. It is shown that the principal mechanism of noise reduction depends strongly on the frequency content of the radiated sound and the characteristics of the bubbly medium. For piles of large diameter which radiate most of the acoustic energy at relatively low frequencies, the noise reduction is mainly attributed to the mismatch of the acoustic impedances between the seawater and the bubbly layer. On the contrary, for smaller piles and when the radiated acoustic energy is concentrated at frequencies close to, or higher than, the resonance frequency of the air bubbles, the sound absorption within the bubbly layer

  3. Experimental and Analytical Investigations of Piles and Abutments of Integral Bridges

    OpenAIRE

    Arsoy, Sami

    2000-01-01

    Bridges without expansion joints are called "integral bridges." Eliminating joints from bridges crates concerns for the piles and the abutments of integral bridges because the abutments and the piles are subjected to temperature-induced cyclic lateral loads. As temperatures change daily and seasonally, the lengths of integral bridges increase and decrease, pushing the abutment against the approach fill and pulling it away. As a result the bridge superstructure, the abutment, the approach f...

  4. Timber vs. composite/plastic pile fender systems in Pearl Harbor maintenance cost comparison

    OpenAIRE

    Alling, Joseph

    1996-01-01

    CIVINS The Navy has traditionally used treated timber materials for fender systems for piers and wharves in Pearl Harbor. In recent years, the costs associated with the use of timber have escalated and the Navy has begun to use plastic piles at installations around the world to replace timber fender systems. Plastic fender systems are more expensive, but have greater energy absorption capabilities and are more resilient to environmental decay. To determine whether plastic piles are a cost ...

  5. The Method of Calculating the Settlement of Weak Ground Strengthened with the Reinforced Sandy Piles

    Directory of Open Access Journals (Sweden)

    Maltseva Tatyana

    2016-01-01

    Full Text Available The paper presents an engineering method for calculating the weak clay base, strengthened with sandy piles reinforced along the contour. The method is based on the principle of layer-by-layer summation, which is used when designing the bases and foundations. The novelty of the suggested method lies in the taking account of the soil reaction along the pile lateral surface and the impact of external vertical loads on the vertical displacement of the base.

  6. Anomalous Scaling Behaviors in a Rice-Pile Model with Two Different Driving Mechanisms

    Institute of Scientific and Technical Information of China (English)

    ZHANGDuan-Ming; SUNHong-Zhang; LIZhi-Hua; PANGui-Jun; YUBo-Ming; LIRui; YINYan-Ping

    2005-01-01

    The moment analysis is applied to perform large scale simulations of the rice-pile model. We find that this model shows different scaling behavior depending on the driving mechanism used. With the noisy driving, the rice-pile model violates the finite-size scaling hypothesis, whereas, with fixed driving, it shows well defined avalanche exponents and displays good finite size scaling behavior for the avalanche size and time duration distributions.

  7. EVALUATION OF EFFECTS OF YAVAKSHAR OINTMENT ON ABHYANTAR ARSHA (INTERNAL PILES

    Directory of Open Access Journals (Sweden)

    Ukhalkar V. P.

    2013-08-01

    Full Text Available A disease which anguishes patient’s vital force or prana is called as Arsha according to Ayurveda. ‘Arsha’ is the gift of sedentary life style. One of its prime etiological factors is poor dietary habit which is unavoidable due to busy lifestyle. According to Sushruta the management of Arsha involves Aushadhi Chikitsa (conservative, Ksharkarma, Agnikarma and Shastrakarma (surgical. The ‘Dhatuvaigunya’ (Organic pathology local deformity of anal structures requires local treatment. Ksharkarma is the treatment having more effect but needed intervention of another person for therapy. Concept of application of Kshar by patient himself was presumed and for this purpose the ointment of Kshar was used. The study was carried out in eight groups i.e. A, B, C, D, E, F, G, H and each group consists of about 25 to 30 patients. The patients of I II and III degree piles and P/R bleeding were included in this study. At the end of trial it was found that the application of Yava Kshar ointment of 10% having base Siktha Tailam was more effective than other ointments (i.e. Yava Kshar ointment 5% base Siktha Tailam, Yava Kshar ointment 5% base petroleum jelly, Yava Kshar ointment 10% base petroleum jelly, Faktu ointment, Trifgol powder, plane Siktha Tailam and plane Petroleum jelly to reduced the P/R bleeding markedly in minimal period and to reduced the degree of haemorrhoids up to certain extent.

  8. Loop structures in the 5' untranslated region and antisense RNA mediate pilE gene expression in Neisseria gonorrhoeae.

    Science.gov (United States)

    Masters, Thao L; Wachter, Jenny; Hill, Stuart A

    2016-11-01

    Regulation of the Neisseria gonorrhoeae pilE gene is ill-defined. In this study, post-transcriptional effects on expression were assessed. In silico analysis predicts the formation of three putative stable stem-loop structures with favourable free energies within the 5' untranslated region of the pilE message. Using quantitative reverse transcriptase PCR analyses, we show that each loop structure forms, with introduced destabilizing stem-loop mutations diminishing loop stability. Utilizing a series of pilE translational fusions, deletion of either loop 1 or loop 2 caused a significant reduction of pilE mRNA resulting in reduced expression of the reporter gene. Consequently, the formation of the loops apparently protects the pilE transcript from degradation. Putative loop 3 contains the pilE ribosomal binding site. Consequently, its formation may influence translation. Analysis of a small RNA transcriptome revealed an antisense RNA being produced upstream of the pilE promoter that is predicted to hybridize across the 5' untranslated region loops. Insertional mutants were created where the antisense RNA is not transcribed. In these mutants, pilE transcript levels are greatly diminished, with any residual message apparently not being translated. Complementation of these insertion mutants in trans with the antisense RNA gene facilitates pilE translation yielding a pilus + phenotype. Overall, this study demonstrates a complex relationship between loop-dependent transcript protection and antisense RNA in modulating pilE expression levels.

  9. Development of In-pile Plug Assembly and Primary Shutter for Cold Neutron Guide System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jin Won; Cho, Yeong Garp; Ryu, Jeong Soo; Lee, Jung Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    The HANARO, a 30 MW multi-purpose research reactor in Korea, will be equipped with a neutron guide system, in order to transport cold neutrons from the neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly with in-pile guides, the primary shutter with in-shutter guides, the neutron guides in the guide shielding room with dedicated secondary shutters, and the neutron guides connected to the instruments in the neutron guide hall. The functions of the in-pile plug assembly are to shield the reactor environment from a nuclear radiation and to support the neutron guides and maintain them precisely oriented. The primary shutter is a mechanical device to be installed just after the in-pile plug assembly, which stops neutron flux on demand. This report describes the mechanical design, fabrication, and installation procedure of the in-pile plug assembly and the primary shutter for the neutron guide system at HANARO. A special tool and procedure for a replacement of in-pile plug and guide cassette is also presented with the interface condition in the reactor hall.

  10. Vertical Dynamic Response of Pile Embedded in Layered Transversely Isotropic Soil

    Directory of Open Access Journals (Sweden)

    Wenbing Wu

    2014-01-01

    Full Text Available The dynamic response of pile embedded in layered transversely isotropic soil and subjected to arbitrary vertical harmonic force is investigated. Based on the viscoelastic constitutive relations for a transversely isotropic medium, the dynamic governing equation of the transversely isotropic soil is obtained in cylindrical coordinates. By introducing the fictitious soil pile model and the distributed Voigt model, the governing equations of soil-pile system are also derived. Firstly, the vertical response of the soil layer is solved by using the Laplace transform technique and the separation of variables technique. Secondly, the analytical solution of velocity response in the frequency domain and its corresponding semianalytical solution of velocity response in the time domain are derived by means of inverse Fourier transform and convolution theorem. Finally, based on the obtained solutions, a parametric study has been conducted to investigate the influence of the soil anisotropy on the vertical dynamic response of pile. It can be seen that the influence of the shear modulus of soil in the vertical plane on the dynamic response of pile is more notable than the influence of the shear modulus of soil in the horizontal plane on the dynamic response of pile.

  11. Fiber Bragg Grating-Based Performance Monitoring of Piles Fiber in a Geotechnical Centrifugal Model Test

    Directory of Open Access Journals (Sweden)

    Xiaolin Weng

    2014-01-01

    Full Text Available In centrifugal tests, conventional sensors can hardly capture the performance of reinforcement in small-scale models. However, recent advances in fiber optic sensing technologies enable the accurate and reliable monitoring of strain and temperature in laboratory geotechnical tests. This paper outlines a centrifugal model test, performed using a 60 g ton geocentrifuge, to investigate the performance of pipe piles used to reinforce the loess foundation below a widened embankment. Prior to the test, quasidistributed fiber Bragg grating (FBG strain sensors were attached to the surface of the pipe piles to measure the lateral friction resistance in real time. Via the centrifuge actuator, the driving of pipe piles was simulated. During testing, the variations of skin friction distribution along the pipe piles were measured automatically using an optical fiber interrogator. This paper represents the presentation and detailed analysis of monitoring results. Herein, we verify the reliability of the fiber optic sensors in monitoring the model piles without affecting the integrity of the centrifugal model. This paper, furthermore, shows that lateral friction resistance developed in stages with the pipe piles being pressed in and that this sometimes may become negative.

  12. Study of vibrating foundations considering soil-pile-structure interaction for practical applications

    Institute of Scientific and Technical Information of China (English)

    Hart Yingcai

    2008-01-01

    An investigation of soil-pile-structure interaction is carried out, based on a large reciprocating compressor installed on an elevated concrete foundation (table top structure). A practical method is described for the dynamic analysis, and compared with a 3D finite element (FE) model. Two commercial software packages are used for dynamic analysis considering the soil-pile-structure interaction (SPSI). Stiffness and damping of the pile foundation are generated fi-om a computer program, and then input into the FE model. To examine the SPSI thoroughly, three cases for the soil, piles and superstructure are considered and compared. In the first case, the interaction is fully taken into account, that is, both the superstructure and soil-pile system are flexible. In the second case, the superstructure is flexible but fixed to a rigid base, with no deformation in the base (no SSI). In the third case, the dynamic soil-pile interaction is taken into account, but the table top structure is assumed to be rigid. From the comparison beteen the results of these three cases some conclusions are made, which could be helpful for engineering practice.

  13. Physical modelling of pipe piles under oblique pullout loads using transparent soil and particle image velocimetry

    Institute of Scientific and Technical Information of China (English)

    曹兆虎; 刘汉龙; 孔纲强; 周航

    2015-01-01

    A small-scale physical modelling method was developed to investigate the pile bearing capacity and the soil displacement around the pile using transparent soil and particle image velocimetry(PIV) technique. Transparent sand was made of baked quartz and a pore fluid with a matching refractive index. The physical modelling system consists of a loading system, a laser light, a CCD camera, an optical platform and a computer for image analyzing. A distinctive laser speckle was generated by the interaction between the laser light and transparent soil. Two laser speckle images before and after deformation were used to calculate the soil displacement field using PIV. Two pipe piles with different diameters under oblique pullout loads at angles of 0°, 30°, 45°, 60° and 90° were used in tests. The load-displacement response, oblique pullout ultimate resistances and soil displacement fields were then studied. The test results show that the developed physical modelling method and transparent soil are suitable for pile-soil interaction problems. The soil displacements around the pipe piles will improve the understanding on the capacity of pipe piles under oblique pullout loads.

  14. Survival of plant pathogens in static piles of ground green waste.

    Science.gov (United States)

    Downer, A J; Crohn, D; Faber, B; Daugovish, O; Becker, J O; Menge, J A; Mochizuki, M J

    2008-05-01

    Ground green waste is used as mulch in ornamental landscapes and for tree crops such as avocados. Survival of Armillaria mellea, Phytophthora cinnamomi, Sclerotinia sclerotiorum, and Tylenchulus semipenetrans was assessed for 8 weeks within unturned piles of either recently ground or partially composted green waste. S. sclerotiorum survived at the pile surface and at 10, 30, and 100 cm within the pile for the entire 8 weeks in both fresh green waste (FGW) and aged green waste (AGW). A. mellea and T. semipenetrans did not survive more than 2 days in FGW, while P. cinnamomi persisted for over 21 days in FGW. AGW was less effective in reducing pathogen viability than FGW, most likely because temperatures in AGW peaked at 45 degrees C compared with 70 degrees C in FGW. Survival modeling curves based on pile temperatures indicate the time to inactivate 10 propagules of pathogens was 11, 30, 363, and 50 days for A. mellea, P. cinnamomi, S. sclerotiorum, and T. semipenetrans, respectively. Sclerotia-forming pathogens pose the greatest risk for escape; to ensure eradication of persistent fungi, green waste stockpiles should be turned intermittently to mix pile contents and move pathogen propagules to a location within the pile where they are more likely to be killed by heat, microbial attack, or chemical degradation.

  15. A destructive field study on the behavior of piles under tension and compression

    Institute of Scientific and Technical Information of China (English)

    Zhong-miao ZHANG; Qian-qing ZHANG; Feng YU

    2011-01-01

    This paper involves a series of destructive full-scale load tests on long bored piles instrumented with strain gauges along the shafts, including two compression and two tension loading tests. The load-displacement response, axial force, skin friction, and the thresholds of the slip displacement for fully mobilizing the skin resistances in different soils are discussed.Moreover, the theoretical solution for estimating the pile tip settlement under compression was adopted to analyze the test results.It was found that the measured skin frictions for the piles under compression were about 6% to 42% higher than the estimated values of the cone penetration tests (CPTs), whereas the measured skin frictions in the uplift cases were about 16% to 50% smaller than the estimated values. In addition, the average limited skin frictions for the tension piles were about 0.36 to 0.78 times the average ultimate skin frictions for the piles under compression. It also can be indicated that the skin friction along the pile depth approached the limited state, and decreased from a peak value with increasing loads.

  16. Analysis of inter-event times for avalanches on a conical bead pile with cohesion

    Science.gov (United States)

    Lehman, Susan; Johnson, Nathan; Tieman, Catherine; Wainwright, Elliot

    2015-03-01

    We investigate the critical behavior of a 3D conical bead pile built from uniform 3 mm steel spheres. Beads are added to the pile by dropping them onto the apex one at a time; avalanches are measured through changes in pile mass. We investigate the dynamic response of the pile by recording avalanches from the pile over tens of thousands of bead drops. We have previously shown that the avalanche size distribution follows a power law for beads dropped onto the pile apex from a low drop height. We are now tuning the critical behavior of the system by adding cohesion from a uniform magnetic field and find an increase in both size and number for very large avalanches and decreases in the mid-size avalanches. The resulting bump in the avalanche distribution moves to larger avalanche size as the cohesion in the system is increased. We compare the experimental inter-event time distribution to both the Brownian passage-time and Weibull distributions, and observe a shift from the Weibull to Brownian passage-time as we raise the threshold from measuring time between events of all sizes to time between only the largest system-spanning events. These results are both consistent with those from a mean-field model of slip avalanches in a shear system [Dahmen, Nat Phys 7, 554 (2011)].

  17. 遮帘式板桩码头的工作机理%Mechanism of sheet-pile wharf with barrier piles

    Institute of Scientific and Technical Information of China (English)

    蔡正银; 侯伟; 关云飞

    2015-01-01

    板桩码头结构深水化过程中遇到的主要问题是如何克服作用于前墙上的随开挖深度剧增的土压力.遮帘式板桩结构的设计思路是在传统的板桩码头前墙陆侧增加一排遮帘桩,利用其遮帘效应来分担一部分作用于前墙上的土压力,从而达到建设大型深水板桩码头的条件.通过前期开发的基于ABAQUS有限元平台的土和结构相互作用分析软件,采用"南水双屈服面弹塑性本构模型"来模拟地基土的应力应变关系,通过基于接触力学的本构模型来模拟土和码头结构的相互作用,研究了遮帘桩的工作机理和遮帘效应,探讨了遮帘式板桩码头前墙两侧的土压力分布规律,以及码头结构的变形和弯矩分布规律.通过与单锚板桩码头结构的比较,验证了遮帘式板桩码头对于板桩码头深水化的作用.%The main problem for deep-water sheet-pile wharf is how to deal with the earth pressures acting on the front wall, which dramatically increase with the excavation depth. The design idea of the barrier-pile structure is as follows: a row of barrier piles are constructed in front of the traditional sheep-pile wharf, and part of the earth pressures acting on the front wall are shared owing to their barrio effects so as to reach the condition for building large deep-water sheet-pile wharf. Using the developed analysis software for soil-structure interaction based on ABAQUS, the NHRI double-yield face elastoplastic constitutive model is employed to simulate stress-strain relation of soils. The constitutive model based on contact mechanics is used to simulate soil-wharf interaction. The mechanism and effect of barrier piles are studied, the distribution rules of earth pressures at the two sides of the front wall of the sheet-pile wharf with barrier piles are discussed as well as its deformation and distribution of bending moment. By comparing with the sheet-pile wharf with single anchorage, the deep

  18. Precision physics with pile-up insensitive observables

    CERN Document Server

    Frye, Christopher; Schwartz, Matthew D; Yan, Kai

    2016-01-01

    To deepen the search for beyond the Standard Model physics, the Large Hadron Collider is pushing to higher and higher luminosity. At high luminosity, precision physics becomes increasingly difficult due to contamination from additional proton collisions per bunch crossing called pile-up. In recent years, many methods have been developed to cull this excess mostly low-energy radiation away from important signal regions, but it has been unclear if these methods were amenable to systematically-improvable theoretical understanding. In this paper, it is shown that one such method, soft drop jet grooming, has excellent theoretical properties: it is ultra-local, depending on only radiation within a jet, and it is free of non-global logarithms. Calculations of the soft drop jet mass and related observables are presented at next-to-next-to-leading logarithmic accuracy matched to next-to-next-to-leading fixed-order in perturbative Quantum Chromodynamics. Once measured at the Large Hadron Collider, precision comparisons...

  19. Stability of binaries. Part II: Rubble-pile binaries

    Science.gov (United States)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  20. A preliminary metagenomic study of puer tea during pile fermentation.

    Science.gov (United States)

    Lyu, Changyong; Chen, Chaoyin; Ge, Feng; Liu, Diqiu; Zhao, Shenglan; Chen, Dan

    2013-10-01

    Up to now, there has been no report on the taxonomic and functional analysis of the microbial community in fermenting puer tea by pyrosequencing. In this study, metagenomic pyrosequencing was first used in fermenting puer tea to delineate a relatively comprehensive overview of the microbial taxonomy while also preliminarily characterising the functional ontologies of microbial genes present in puer tea pile fermentation. A total of 251 738 pyrosequencing reads (9197 contigs and 145 402 singletons) were generated by pyrosequencing. Taxonomic analysis revealed three dominant bacterial phyla, Actinobacteria (30.08%), Proteobacteria (24.47%) and Firmicutes (20.23%), and one dominant eukaryotic phylum, Ascomycota (15.21%) [corrected]. A total of 58 664 hits were categorised into 28 functional subsystems based on the SEED database. Moreover, two categories, 'metabolism of terpenoids and polyketides' and 'biosynthesis of other secondary metabolites', were selectively analysed and 69 enzyme genes were presented in 16 pathways. The dominant microbes of puer tea fermentation were bacteria in the present study, and yeasts rather than moulds accounted for the overwhelming majority of Eukaryota. The analysis of functional genes and metabolic pathways will be helpful for further study of the mechanism of puer tea fermentation at molecular level. © 2013 Society of Chemical Industry.

  1. The Supercritical Pile GRB Model: The Prompt to Afterglow Evolution

    Science.gov (United States)

    Mastichiadis, A.; Kazanas, D.

    2009-01-01

    The "Supercritical Pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a Relativistic Blast Wave (RBW) into radiation and at the same time produces - in the prompt GRB phase, even in the absence of any particle acceleration - a spectral peak at energy approx. 1 MeV. We extend this model to include the evolution of the RBW Lorentz factor Gamma and thus follow its spectral and temporal features into the early GRB afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Gamma with radius. This feedback and the presence of kinematic and dynamic thresholds in the model can be the sources of rich time evolution which we have began to explore. In particular. one can this may obtain afterglow light curves with steep decays followed by the more conventional flatter afterglow slopes, while at the same time preserving the desirable features of the model, i.e. the well defined relativistic electron source and radiative processes that produce the proper peak in the (nu)F(sub nu), spectra. In this note we present the results of a specific set of parameters of this model with emphasis on the multiwavelength prompt emission and transition to the early afterglow.

  2. Early corrosion monitoring of prestressed concrete piles using acoustic emission

    Science.gov (United States)

    Vélez, William; Matta, Fabio; Ziehl, Paul H.

    2013-04-01

    The depassivation and corrosion of bonded prestressing steel strands in concrete bridge members may lead to major damage or collapse before visual inspections uncover evident signs of damage, and well before the end of the design life. Recognizing corrosion in its early stage is desirable to plan and prioritize remediation strategies. The Acoustic Emission (AE) technique is a rational means to develop structural health monitoring and prognosis systems for the early detection and location of corrosion in concrete. Compelling features are the sensitivity to events related to micro- and macrodamage, non-intrusiveness, and suitability for remote and wireless applications. There is little understanding of the correlation between AE and the morphology and extent of early damage on the steel surface. In this paper, the evidence collected from prestressed concrete (PC) specimens that are exposed to salt water is discussed vis-à-vis AE data from continuous monitoring. The specimens consist of PC strips that are subjected to wet/dry salt water cycles, representing portions of bridge piles that are exposed to tidal action. Evidence collected from the specimens includes: (a) values of half-cell potential and linear polarization resistance to recognize active corrosion in its early stage; and (b) scanning electron microscopy micrographs of steel areas from two specimens that were decommissioned once the electrochemical measurements indicated a high probability of active corrosion. These results are used to evaluate the AE activity resulting from early corrosion.

  3. 水平荷载下导管架平台桩基础的非线性有限元分析%Nonlinear finite element analysis of jacket platform pile foundations under lateral loads

    Institute of Scientific and Technical Information of China (English)

    袁志林; 段梦兰; 陈祥余; 钟超; 王建国

    2012-01-01

    导管架平台桩基础的控制荷载主要为风荷载、波浪荷载、地震荷载等水平荷载,为研究水平荷载下导管架平台桩基础的承载特性,采用非线性有限元分析方法对水平荷载下桩-土之间的相互作用进行研究,提出了有效模拟桩基水平承载特性的有限元模型,分析了模型桩的刚度、直径、土质参数中水平土压力系数、剪胀角对桩基承载特性的影响及水平荷载下群桩承载特性,并将有限元计算结果与API规范及模型试验结果进行对比.研究结果表明,非线性有限元分析方法分析水平荷载下桩-土相互作用是可行的,计算结果可为导管架平台的桩基设计提供参考.%The control loads of jacket platform pile foundations are the wind load, wave load, seismic load and other lateral loads. A fundamental study of the soil response of piles subjected to lateral loads is conducted using the nonlinear finite element analysis. A finite element model is established to simulate the response of a pile subjected to lateral loads effectively. The effects of pile properties, i.e. stiffness and diameter and soil properties, i.e., coefficient of horizontal earth pressure, dilation angle on the response of a pile subjected to lateral loads are investigated. In addition, the response of pile groups under lateral loads is also analyzed. Finally, the results of finite element analysis are compared with API recommendations and the model test results. The results of the study show that the nonlinear finite element analysis is accurate in analyzing soil response of piles subjected to lateral loads. The calculation results can provide reference for the pile foundation design of jacket platform.

  4. On Pile Foundation Construction Technology and Its Application%论桩基础施工技术和应用

    Institute of Scientific and Technical Information of China (English)

    肖蓓

    2014-01-01

    地基基础工程施工前,根据打(沉)桩方法的不同,钢筋混凝土预制桩基础施工有锤击沉桩法、静力压桩法及振动法等,以锤击沉桩法和静力压桩法应用最为普遍。钢筋混凝土灌注桩是一种直接在现场桩位上就地成孔,然后在孔内浇筑混凝土或安放钢筋笼再浇筑混凝土而成的桩。按其成孔方法不同,可分为钻孔灌注桩、沉管灌注桩、人工挖空和挖空扩底灌注桩。%Before foundation construction, depending on the piling method, the basic construction of precast reinforced concrete piles have hammer pile sinking method, static pressure piling method and the vibration method, in which hammer pile sinking method and static pressure piling method are most commonly used. Reinforced concrete pile is a pile directly in the field on the spot into the hole, and then pouring concrete reinforcement cage placed in the holes or pouring concrete from the pile again. According to different holing methods, it can be divided into cast-in-situ bored pile, tube-sinking cast-in-situ pile, artificial hollowed out and hollowed reamed pile.

  5. 桩帽设计中的厚板分析%THICK PLATE ANALYSIS WITH APPLICATION TO PILE CAP DESIGN

    Institute of Scientific and Technical Information of China (English)

    郑榕明; 张勇慧

    2004-01-01

    The thick plate is commonly used for the pile cap and the transfer plate, and a proper analysis of it can greatly affect the cost of the thick plate. In actual practice, soft support condition is sometimes adopted by engineers for modeling of thick plates. In this paper, the limitations of soft support in the determination of deflection and bending moment with very thick plates are studied. The distribution of superstructure loadings to pile caps and piles is also carefully investigated.

  6. Deformation Measurement of a Driven Pile Using Distributed Fibre-optic Sensing

    Science.gov (United States)

    Monsberger, Christoph; Woschitz, Helmut; Hayden, Martin

    2016-03-01

    New developments in distributed fibre-optic sensing allow the measurement of strain with a very high precision of about 1 µm / m and a spatial resolution of 10 millimetres or even better. Thus, novel applications in several scientific fields may be realised, e. g. in structural monitoring or soil and rock mechanics. Especially due to the embedding capability of fibre-optic sensors, fibre-optic systems provide a valuable extension to classical geodetic measurement methods, which are limited to the surface in most cases. In this paper, we report about the application of an optical backscatter reflectometer for deformation measurements along a driven pile. In general, pile systems are used in civil engineering as an efficient and economic foundation of buildings and other structures. Especially the length of the piles is crucial for the final loading capacity. For optimization purposes, the interaction between the driven pile and the subsurface material is investigated using pile testing methods. In a field trial, we used a distributed fibre-optic sensing system for measuring the strain below the surface of an excavation pit in order to derive completely new information. Prior to the field trial, the fibre-optic sensor was investigated in the laboratory. In addition to the results of these lab studies, we briefly describe the critical process of field installation and show the most significant results from the field trial, where the pile was artificially loaded up to 800 kN. As far as we know, this is the first time that the strain is monitored along a driven pile with such a high spatial resolution.

  7. Marine dock pilings foster diverse, native cryptobenthic fish assemblages across bioregions.

    Science.gov (United States)

    Brandl, Simon J; Casey, Jordan M; Knowlton, Nancy; Duffy, James Emmett

    2017-09-01

    Anthropogenic habitats are increasingly prevalent in coastal marine environments. Previous research on sessile epifauna suggests that artificial habitats act as a refuge for nonindigenous species, which results in highly homogenous communities across locations. However, vertebrate assemblages that live in association with artificial habitats are poorly understood. Here, we quantify the biodiversity of small, cryptic (henceforth "cryptobenthic") fishes from marine dock pilings across six locations over 35° of latitude from Maine to Panama. We also compare assemblages from dock pilings to natural habitats in the two southernmost locations (Panama and Belize). Our results suggest that the biodiversity patterns of cryptobenthic fishes from dock pilings follow a Latitudinal Diversity Gradient (LDG), with average local and regional diversity declining sharply with increasing latitude. Furthermore, a strong correlation between community composition and spatial distance suggests distinct regional assemblages of cryptobenthic fishes. Cryptobenthic fish assemblages from dock pilings in Belize and Panama were less diverse and had lower densities than nearby reef habitats. However, dock pilings harbored almost exclusively native species, including two species of conservation concern absent from nearby natural habitats. Our results suggest that, in contrast to sessile epifaunal assemblages on artificial substrates, artificial marine habitats can harbor diverse, regionally characteristic assemblages of vertebrates that follow macroecological patterns that are well documented for natural habitats. We therefore posit that, although dock pilings cannot function as a replacement for natural habitats, dock pilings may provide cost-effective means to preserve native vertebrate biodiversity, and provide a habitat that can be relatively easily monitored to track the status and trends of fish biodiversity in highly urbanized coastal marine environments.

  8. Study on the measures of tunnels side-crossing bridge based on sheltering effects of isolation piles

    Science.gov (United States)

    Tang, Jian; Liu, Jun yan; Liu, Yan

    2017-08-01

    Based on the transit line 3, we studied the effect of the bridge piles crossed closely from the side by the shield tunnel. Using the three-dimensional finite element numerical analysis software Midas GTS/NX, we analyzed the effect of shield tunnel on pile deformation, statistics are obtained that under the condition of pile, subgrade reinforcement and ground changes. The calculation results show that in the condition of reinforcement, the new tunnel shield crossing through the pile caused longitudinal disturbance of the tunnel surrounding strata along the tunnel, where the soil over the area is within a certain range of pile and settlement deformation of surface subsidence occurs, changing the surface roughly to the shape of “V”. The maximum value appears above the shield tunnel and the value is high. In combination with engineering geology, hydrogeology and environment factors, this paper adopted isolation pile reinforcement to the pile, and the simulated results show that, pile settlement was significantly reduced under the condition of pile reinforcement. The calculation results show the rationality of the reinforcement scheme to a certain extent, which provides a theoretical basis for the similar tunnel.

  9. Nonlinear dynamic characteristics of piles embedded in rock%嵌岩桩非线性动力学特性

    Institute of Scientific and Technical Information of China (English)

    胡春林; 程昌钧; 胡胜刚

    2007-01-01

    The nonlinear dynamic characteristics of a pile embedded in a rock were investigated.Suppose that both the materials of the pile and the soil around the pile obey nonlinear elastic and linear viscoelastic constitutive relations.The nonfinear partial differential equation governing the dynamm characteristics of the pile was first derived.The Galerkin method Wasusedto simplify the equation and to obtain a nonlinear ordinary differential equation.The methods in nonlinear dynamics were employed to solve the simplified dynamical system,and the time-path curves,phase-trajectory diagrams,power spectrum,the dynamic characteristics of the system were also considered in detail.

  10. Numerical simulation and validation on heat exchange performance of pile spiral coil ground heat exchanger%桩基螺旋型地埋管换热器换热性能的数值模拟与验证

    Institute of Scientific and Technical Information of China (English)

    杨卫波; 杨晶晶; 孔磊

    2016-01-01

    The new trends in energy savings and greenhouse gas reductions are expecting to explore the utilization of shallow geothermal energy. The most popular way to exploit shallow geothermal energy resources is the ground coupled heat pump (GCHP) system with using ground as a heat source. Because underground temperature is rather constant compared with ambient air temperature, the GCHP could achieve higher efficiency as well as more stable performance compared with traditional air source heat pumps. Thus the GCHP system becomes increasingly popular in commercial and institutional buildings. In general, a vertical borehole with ground heat exchanger (GHE) is used as the mainstream of GCHP system. However, the wide application of this type of GCHP technology has been limited by its higher initial cost and substantial land areas required to install the GHE. For this reason, the foundation piles of buildings have been used as part of GHE in recent years to reduce the cost of drilling borehole and save the required land area. This innovative idea of utilizing what are usually called “energy piles”, has led to notable progress in the field of GCHP systems. It has become particularly attractive because it lowers total cost and spatial requirements, and offers the higher renewable contribution. In this paper, a novel configuration of an energy pile with a spiral coil was proposed. In order to investigate the effects of various factors on heat exchange performance of the pile spiral coil GHE, a numerical model of the pile with a spiral coil was developed. Based on the numerical solution of the model, the effects of pile diameter, pile depth, spiral coil group number and soil type on the heat exchange rate and soil temperature distribution of the spiral pile GHE were analyzed. The results indicated that increasing foundation pile diameter can improve the thermal storage capacity and thus enhance heat exchange rate of pile. But increase in foundation pile diameter can also

  11. 桩侧热交换能量桩技术开发及应用%Technology Development and Application of Energy Pile with Heat Exchange at the Pile Side

    Institute of Scientific and Technical Information of China (English)

    黄吉永

    2014-01-01

    Combined with the local reality of pile foundation and the exploration on energy pile technology, a new kind of energy pile technology with heat exchange at the pile side is presented. The main feature of the technology is bundling the ground source heat pump pipe to a precast pile buried underground by pile ramming and hooks traction. Engineering practice shows that the new construction technology has some advantages,including no squeezing effect, no damage to the pile, low noise, long pile controllable and with convenient heat exchange tube on setting. Among them, the heat exchange tubes laid on the pile almost have no impact on the construction of precast piles, overcoming the major obstacles at the respects of the traditional pre-energy pile in construction.%结合本地区的桩基工程实际和对能量桩技术的摸索,提出了在桩侧实现热交换的新型能量桩技术。该技术的主要特点是将地源热泵管绑扎于预制桩的桩侧,并通过桩体的下沉和挂钩的牵引埋入地下。通过对一个工程案例的总结分析,发现新型能量桩技术在施工方面具有无挤土效应、对桩无损伤、低噪声、桩长可控、热交换管设置方便等优点。其中,热交换管的布设对预制桩的接桩几乎无影响,克服了传统预制能量桩在施工方面的主要障碍。

  12. Settlement of composite foundation with discrete material pile considering modulus change

    Institute of Scientific and Technical Information of China (English)

    曹文贵; 刘海涛; 李翔; 张永杰

    2008-01-01

    Based on deeply discussing the deformation mechanism of composite foundation with discrete material pile, firstly, the settlement of composite foundation in rigid foundation conditions was assumed to consist of two parts, an expanding part and an un-expanding part. Then, in view of the differences of deformation properties between the expanding part and the un-expanding part, the relationships between the pile modulus and the applied load in these two parts were respectively developed. Thirdly, by introducing the above relationships into settlement analysis, a new method to calculate displacement of composite foundation with discrete material pile was proposed by using the multi-stage loading theory and the layer-wise summation approach. This method is effective not only for accounting for the effect of variations of pores on deformation modulus of the pile body in different depths, but also for describing the characteristics of different deformation mechanisms of the pile body with varying depth. Finally, the proposed method was used to a practical composite foundation problem, whose theoretical results were presented and compared to those of other methods. The rationality and feasibility of this method are identified through comparative analysis.

  13. Synergism Analysis of Bedding Slope with Piles and Anchor Cable Support under Sine Wave Vehicle Load

    Directory of Open Access Journals (Sweden)

    Li Dan-Feng

    2016-01-01

    Full Text Available Slope instability under dynamic load is the technical difficulty in the engineering; the evaluation of slope stability under dynamic load and the control of dynamic load is particularly important. In this paper, taking the right side slope of K27+140 m~380 m typical section (K27 slope for short in Chongqing Fuling-Fengdu-Shizhu expresses highway as an example to calculate and analyze. The K27 slope is under sinusoidal vehicle load and supported by anchor cable and antislide pile to resist downslide strength; at the same time, the combined effect of them is studied. Three-dimensional finite element methodology (FEM is used to simulate the bedding slope with piles and anchor cable support; furthermore, the eigenvalue can be obtained. In order to reduce error of the elastic boundary conditions caused by the reflection effect of wavelengths, the combination of Lysmer surface viscous boundary and traditional ground support boundaries is utilized to analyze and calculate the time-histories during bedding slope under dynamic load. The dynamic response of pile anchor support to resist sliding force is obtained. The concept of the pile anchor supporting coordinate interval is put forward. Furthermore, it is verified that the pile anchor supporting coordinate interval can be used to evaluate the stability of the slope under dynamic load and provide a new method for the control of the dynamic load.

  14. Physical modelling of pipe piles under oblique pullout loads using transparent soil and particle image velocimetry

    Institute of Scientific and Technical Information of China (English)

    曹兆虎; 刘汉龙; 孔纲强; 周航

    2015-01-01

    A small-scale physical modelling method was developed to investigate the pile bearing capacity and the soil displacement around the pile using transparent soil and particle image velocimetry (PIV) technique. Transparent sand was made of baked quartz and a pore fluid with a matching refractive index. The physical modelling system consists of a loading system, a laser light, a CCD camera, an optical platform and a computer for image analyzing. A distinctive laser speckle was generated by the interaction between the laser light and transparent soil. Two laser speckle images before and after deformation were used to calculate the soil displacement field using PIV. Two pipe piles with different diameters under oblique pullout loads at angles of 0°, 30°, 45°, 60° and 90° were used in tests. The load−displacement response, oblique pullout ultimate resistances and soil displacement fields were then studied. The test results show that the developed physical modelling method and transparent soil are suitable for pile−soil interaction problems. The soil displacements around the pipe piles will improve the understanding on the capacity of pipe piles under oblique pullout loads.

  15. Numerical simulation of liquefaction susceptibility of soil interacting by single pile

    Directory of Open Access Journals (Sweden)

    Ahmad Asaadi

    2015-06-01

    Full Text Available Previous case histories have shown that soil liquefaction severely damaged many structures supported on pile foundations during earthquakes. As a result, evaluating the potential for instability is an important consideration for the safe and resistant design of deep foundation against earthquakes. In this study, the liquefaction susceptibility of saturated sand interacting by single concrete pile was simulated by means of finite difference method. A nonlinear effective stress analysis was used to evaluate soil liquefaction, and the soil-pile interaction was considered using interface elements. The parameter Ru was defined as the pore water pressure ratio to investigate liquefaction in the soil mass during time. A set of numerical models were carried out by three types of soil mass with various condensation (loose, semi-dense and dense under three ground motion with different predominant frequencies and peak accelerations. The effect of these parameters was studied using excess pore pressure, lateral movement and settlement time histories. It was found that the pile can affect the liquefaction susceptibility of soil by comparing the near pile and free field responses. However, for various soil and earthquake characteristics, it was found that the depth of soil liquefaction and triggering, varies.

  16. INTERACTION OF A LONG PILE OF FINITE STIFFNESS WITH SURROUNDING SOIL AND FOUNDATION CAP

    Directory of Open Access Journals (Sweden)

    Ter-Martirosyan Zaven Grigor’evich

    2015-09-01

    Full Text Available The article presents the formulation and analytical solution to a quantification of stress strain state of a two-layer soil cylinder enclosing a long pile, interacting with the cap. The solution of the problem is considered for two cases: with and without account for the settlement of the heel and the underlying soil. In the first case, the article is offering equations for determining the stresses of pile’s body and the surrounding soil according to their hardness and the ratio of radiuses of the pile and the surrounding soil cylinder, as well as formulating for determining equivalent deformation modulus of the system “cap-pile-surrounding soil” (the system. Assessing the carrying capacity of the soil under pile’s heel is of great necessity. In the second case, the article is solving a second-order differential equation. We gave the formulas for determining the stresses of the pile at its top and heel, as well as the variation of stresses along the pile’s body. The article is also formulating for determining the settlement of the foundation cap and equivalent deformation modulus of the system. It is shown that, pushing the pile into underlying layer results in the reducing of equivalent modulus of the system.

  17. Forest fuel piles as ecological traps for saproxylic beetles in oak

    Energy Technology Data Exchange (ETDEWEB)

    Hedin, Jonas (County Administration of Kronoberg, Vaexjoe (Sweden)); Isacsson, Gunnar (Swedish Forest Agency, Haessleholm (Sweden)); Jonsell, Mats; Komonen, Atte (Dept. of Ecology, SLU, Uppsala (Sweden))

    2008-08-15

    Biodiversity management in broadleaved forests includes partial cutting to improve conditions for species that benefit from semi-open stand structure. The harvested wood is usually used as fuel and, therefore, it is stockpiled in situ for months before further processing. If such forest fuel piles attract saproxylic insects, they are likely to be ecological traps, because the settling cost for insects is death as the wood is chipped and used for energy. This study investigated beetle species composition in piles of oak wood in southern Sweden. Species density and frequency of occurrence were compared in wood with different diameters and at the top, middle and bottom parts of piles. A total of 39 species (six red-listed) and 3528 individual beetles emerged. The highest density of both individuals and species was in the top layer. No species was significantly more frequent in the middle or bottom layers. Diameter had only a limited effect on species density and individual species reproduced in both coarse and fine wood. In conclusion, forest fuel piles can be ecological traps for several uncommon and red-listed saproxylic beetles. The negative effects can be mitigated by removing the piles before the insects colonize them. If this is not possible, then the top layer should be retained

  18. Dynamic Instability of Pile-Supported Structures in Liquefiable Soils during Earthquakes

    Directory of Open Access Journals (Sweden)

    S. Adhikari

    2008-01-01

    Full Text Available Piles are long slender columns installed deep into the ground to support heavy structures such as oil platforms, bridges, and tall buildings where the ground is not strong enough to support the structure on its own. In seismic prone zones, in the areas of soft soils (loose to medium dense soil which liquefies like a quick sand piles are routinely used to support structures (buildings/ bridges. The pile and the building vibrate, and often collapse, in liquefiable soils during major earthquakes. In this paper an experimental and analytical approach is taken to characterize this vibration. The emphasis has been given to the dynamic instability of piled foundations in liquefied soil. The first natural frequency of a piled-structure vibrating in liquefiable soil is obtained from centrifuge tests. The experimental system is modelled using a fixed-free Euler-Bernoulli beam resting against an elastic support with axial load and tip mass with rotary inertia. Natural frequencies obtained from the analytical method are compared with experimental results. It was observed that the effective natural frequency of the system can reduce significantly during an earthquake.

  19. Spontaneous vegetation on overburden piles in the Coal Basin of Santa Catarina, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    dos Santos, R.; Citadini-Zanette, V.; Leal-Filho, L.S.; Hennies, W.T. [University of Extremo Sul Catarinense, Criciuma (Brazil)

    2008-09-15

    The objective of this work was to select indigenous vegetal species for restoration programs aiming at the regeneration of ombrophilous dense forest. Thirty-five spoil piles located in the county of Sideropolis, Santa Catarina, that received overburden disposal for 39 years (1950-1989) were selected for study because they exhibited remarkable spontaneous regrowth of trees compared to surrounding spoil piles. Floristic inventory covered the whole area of the 35 piles, whereas survey on phytosociology and natural regeneration studies were conducted in 70 plots distributed along the 35 piles. Floristic inventory recorded 83 species from 28 botanical families. Herbaceous terricolous plants constituted the predominant species (47.0%), followed by shrubs (26.5%), trees (19.3%), and vines (7.2%). Severe chemical (acidic pH and lack of nutrients) and physical (coarse substrate and slope angle of 40-50{sup o} characteristics displayed by the overburden piles constituted limitations to floristic diversity and size of indigenous trees, indicating the need for substrate reclamation prior to forest restoration.

  20. Displacement of Pile-Reinforced Slopes with a Weak Layer Subjected to Seismic Loads

    Directory of Open Access Journals (Sweden)

    Haizuo Zhou

    2016-01-01

    Full Text Available The presence of a weak layer in a slope requires special attention because it has a negative impact on slope stability. However, limited insight into the seismic stability of slopes with a weak layer exists. In this study, the seismic stability of a pile-reinforced slope with a weak thin layer is investigated. Based on the limit analysis theory, a translational failure mechanism for an earth slope is developed. The rotational rigid blocks in the previous rotational-translational failure mechanism are replaced by continuous deformation regions, which consist of a sequence of n rigid triangles. The predicted static factor of safety and collapse mechanism in two typical examples of slopes with a weak layer compare well with the results obtained from the available literature and by using the Discontinuity Layout Optimization (DLO technique. The lateral forces provided by the stabilizing piles are evaluated using the theory of plastic deformation. An analytical solution for estimating the critical yield acceleration coefficient for the pile-reinforced slopes is derived. Based on the proposed translational failure mechanism and the corresponding critical yield acceleration coefficient, Newmark’s analytical procedure is employed to evaluate the cumulative displacement. Considering different real earthquake acceleration records as input motion, the effect of stabilizing piles and varying the spacing of piles on the cumulative displacement of slopes with a weak layer is investigated.

  1. Design and Preparation of Carbon Based Composite Phase Change Material for Energy Piles

    Directory of Open Access Journals (Sweden)

    Haibin Yang

    2017-04-01

    Full Text Available Energy piles—A fairly new renewable energy concept—Use a ground heat exchanger (GHE in the foundation piles to supply heating and cooling loads to the supported building. Applying phase change materials (PCMs to piles can help in maintaining a stable temperature within the piles and can then influence the axial load acting on the piles. In this study, two kinds of carbon-based composite PCMs (expanded graphite-based PCM and graphite nanoplatelet-based PCM were prepared by vacuum impregnation for potential application in energy piles. Thereafter, a systematic study was performed and different characterization tests were carried out on two composite PCMs. The composite PCMs retained up to 93.1% of paraffin and were chemically compatible, thermally stable and reliable. The latent heat of the composite PCM was up to 152.8 J/g while the compressive strength of cement paste containing 10 wt % GNP-PCM was found to be 37 MPa. Hence, the developed composite PCM has potential for thermal energy storage applications.

  2. Numerical simulation of the influence of soil core on the bearing capacity of pipe pile

    Directory of Open Access Journals (Sweden)

    G.Ya. Bulatov

    2010-03-01

    Full Text Available The cost of the foundation can be up to 20-30% of the total building cost. Reducing consumption of materials and quality selection of the required characteristics of the pile can reduce both the estimated cost and time of work.In terms of compact construction and the high land prices the most relevant is high-rise building. But it is hard to build in soft ground conditions (for example, in St. Petersburg. The situation is complicated by insufficiently explored methods of selection and design of piles (especially steel-tube piles for specific cases of construction, as well as by the absence of regulatory documents related to the high-performance technology.The article considers the clarification methods for calculating the bearing capacity of tubular steel piles. An additional contribution of soil core to the overall bearing capacity due to accounting an effect of its "natural" selflocking in the cavity of the steel pipe is considered.The conclusions about the effectiveness of the piles, depending on different initial parameters are made.

  3. Isotopically enriched ammonium shows high nitrogen transformation in the pile top zone of dairy manure compost

    Science.gov (United States)

    Maeda, Koki; Toyoda, Sakae; Yano, Midori; Hattori, Shohei; Fukasawa, Makoto; Nakajima, Keiichi; Yoshida, Naohiro

    2016-03-01

    Nitrogen isotope ratios (δ15N) of NH4+ in dairy manure compost piles with and without bulking agent (10 % w/w) were compared to understand the effects of the use of bulking agent on nitrogen conversion during manure composting. The δ15N-NH4+ values in each of three pile zones (top, side and core) were also compared. At the end of the process, piles with bulking agent showed significantly higher δ15N values (17.7 ± 1.3 ‰) than piles without bulking agent (11.8 ± 0.9 ‰), reflecting the significantly higher nitrogen conversion and NH3 loss in the former. The samples from the top zone, especially in the piles with bulking agent, showed very high NH4+ concentrations with significantly high 15N (δ15N: 12.7-29.8 ‰) values, indicating that extremely high nitrogen conversion, nitrification-denitrification activity of the microbes and NH3 volatilization occurred in this zone.

  4. Three-dimensional numerical simulation and earth pressure analysis on double-row piles with consideration of spatial effects

    Institute of Scientific and Technical Information of China (English)

    Zi-han WANG; Jian ZHOU

    2011-01-01

    As a new kind of technology in retaining structures,the characteristics of double-row piles are significantly affected by spatial effects.In this paper,double-row piles as a retaining structure are simulated numerically in three-dimension by finite element software PLAXIS 3D FOUNDATION.The behavior differences of piles in different positions around the foundation pit are analyzed.By changing the parameters,including the length-width ratio,the excavation depth,the distance between rows and the diameter of piles,the variations of the lateral deformation,the bending moment and the earth pressure around the piles are determined.The reasonable values of parameters and some suggestions with consideration of earth pressure are proposed for the design of double-row piles as a retaining structure.The results show that the lateral deformation and bending moment are the largest in the middle of long side of the foundation pit,which is identified as the most unfavorable position.It is indicated that the earth pressure between rows above pit bottom is close to active earth pressure,while the earth pressure between rows under pit bottom is close to static earth pressure.It is suggested that 1/2-2/3 of pile length,0.6-1.2 m,3d-6d,and 2d-2.5d be chosen as embedded depth of piles,diameter of piles,distance between rows,and distance between piles,respectively,where d is the pile diameter.

  5. Effect of heterogeneity and anisotropy related to the construction method on transfer processes in waste rock piles.

    Science.gov (United States)

    Lahmira, Belkacem; Lefebvre, René; Aubertin, Michel; Bussière, Bruno

    2016-01-01

    Waste rock piles producing acid mine drainage (AMD) are partially saturated systems involving multiphase (gas and liquid) flow and coupled transfer processes. Their internal structure and heterogeneous properties are inherited from their wide-ranging material grain sizes, their modes of deposition, and the underlying topography. This paper aims at assessing the effect of physical heterogeneity and anisotropy of waste rock piles on the physical processes involved in the generation of AMD. Generic waste rock pile conditions were represented with the numerical simulator TOUGH AMD based on those found at the Doyon mine waste rock pile (Canada). Models included four randomly distributed material types (coarse, intermediate, fine and very fine-grained). The term "randomly" as used in this study means that the vertical profile and spatial distribution of materials in waste rock piles (internal structure) defy stratigraphy principles applicable to natural sediments (superposition and continuity). The materials have different permeability and capillary properties, covering the typical range of materials found in waste rock piles. Anisotropy with a larger horizontal than vertical permeability was used to represent the effect of pile construction by benches, while the construction by end-dumping was presumed to induce a higher vertical than horizontal permeability. Results show that infiltrated precipitation preferentially flows in fine-grained materials, which remain almost saturated, whereas gas flows preferentially through the most permeable coarse materials, which have higher volumetric gas saturation. Anisotropy, which depends on pile construction methods, often controls global gas flow paths. Construction by benches favours lateral air entry close to the pile slope, whereas end-dumping leads to air entry from the surface to the interior of the pile by secondary gas convection cells. These results can be useful to construct and rehabilitate waste rock piles to minimize

  6. Investigation on the Effect of Drained Strength when Designing Sheet Pile Walls

    DEFF Research Database (Denmark)

    Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    Long sheet pile walls are constructed in the cities as an integrated part of deep excavations for e.g. parking lots, pumping stations, reservoirs, and cut and cover tunnels. To minimise costs, the strength of the soil needs to be determined in the best possible way. The drained strength of clay...... expressed by c and ϕ is often estimated as c 10% = 10%・cu, and found by estimations based on the soil describtion, respectively. However, due to possible slicken slides and tension cracks, c = 0 is used on the back side of the sheet pile wall. This reduces the strength significantly. A parametric study...... is made on the effective cohesion to investigate the influence of c when designing sheet pile walls. Aalborg Clay is used as a case material. The parametric study is made in both a commercial finite element program and by use of Brinch Hansen’s earth pressure theory. In both studies, the analyses are made...

  7. RESEARCH INFLUENCE OF BOUNDARY CONDITIONS ON THE MOVE OF CFA PILE UNDER STATIC LOADS

    Directory of Open Access Journals (Sweden)

    Eschenko O. Y.

    2013-12-01

    Full Text Available The article discusses the influence of boundary conditions on the numerical results of displacement CFA piles under static loads. Comparative evaluation of the results of calculation of single movements of CFA piles to the extent of the computational domain, the number of grid points, FEM convergence criterion calculation has been presented. The recommendations on the appointment of the size of the computational domain in the vertical and horizontal direction, the number of grid points, FEM numerical value and choice to apply the criteria of convergence have been listed. On the example of calculating the movements of a single CFA piles we have chosen the parameters of the numerical model, eliminating the influence of boundary conditions on the results of the calculation

  8. Analytical Model for the End-Bearing Capacity of Tapered Piles Using Cavity Expansion Theory

    Directory of Open Access Journals (Sweden)

    Suman Manandhar

    2012-01-01

    Full Text Available On the basis of evidence from model tests on increasing the end-bearing behavior of tapered piles at the load-settlement curve, this paper proposes an analytical spherical cavity expansion theory to evaluate the end-bearing capacity. The angle of tapering is inserted in the proposed model to evaluate the end-bearing capacity. The test results of the proposed model in different types of sands and different relative densities show good effects compared to conventional straight piles. The end-bearing capacity increases with increases in the tapering angle. The paper then propounds a model for prototypes and real-type pile tests which predicts and validates to evaluate the end-bearing capacity.

  9. Application of self-diagnosis FRP to concrete pile for health monitoring

    Science.gov (United States)

    Nishimura, Hitoshi; Sugiyama, Takeshi; Okuhara, Yoshiki; Shin, Soon-Gi; Matsubara, Hideaki; Yanagida, Hiroaki

    2000-06-01

    The function and performance of the self-diagnosis composites embedded in concrete blocks and piles were investigated by bending tests and electrical resistance measurements. Carbon powder (CP) and carbon fiber (CF) were introduced in glass fiber reinforced plastics composites to obtain electrical conductivity. The CP composite has commonly good performances in various bending tests of block and pile specimens, comparing to the CF composite. The electrical resistance of the CP composite increases in a small strain to response remarkably micro-crack formation at about 200 μ strain and to detect well to smaller deformations before the crack formation. The CP composite posses a continuous resistance change up to a large strain level near the final fracture of concrete structures reinforced by steel bars. It has been concluded that the self-diagnosis composite is fairly useful for the measurement of damage and fracture in concrete blocks and piles.

  10. Precision Timing in High Pile-Up and Time-Based Vertex Reconstruction

    CERN Document Server

    Flamant, Cedric Wen

    2014-01-01

    For the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), the Com- pact Muon Solenoid Experiment (CMS) is currently studying various upgrade options (CMS Phase II Upgrade). HL-LHC involves raising the rate of collisions (luminosity) by a factor of 10 beyond the LHC’s original design value, posing the challenge of an in- creased rate of collisions per bunch-crossing (pile-up). In high pile-up conditions, it is difficult to assign final state particles to individual collisions, and complicated to separate jets. Studies have been conducted on the use of time of flight measurements in the elec- tromagnetic calorimeter (ECAL) of CMS in regards to time cleaning of pile-up jets and vertexing through triangulation of rechits. This project verifies a few applications of ECAL timing within the recently updated timing portion of the CMSSW framework.

  11. System of submarine linking between the legs of a platform and the relating foundation piles

    Energy Technology Data Exchange (ETDEWEB)

    Aggradi, G.P.F.; Di Mugello, B.; Ferrante, C.M.

    1987-09-22

    This patent describes a system for submarine linking between anchoring cylinders affixed to a platform leg and a related foundation pile. The anchoring cylinders are composed of two coaxial cylinders, one of which is an outer cylinder having a substantial thickness of high yield strength steel, the other of which is an inner cylinder having a thickness of low yield strength steel. The thickness is less than the thickness of the outer cylinder, wherein the outer cylinder and the inner cylinder are butt-welded to each other at their ends so as to define an annular chamber between the cylinders. The chamber being radially inwardly expansible by the application of pressure. The related foundation pile is composed of high yield strength steel in a zone where the submarine linking is to be accomplished. The zone of the pile including an outer surface with alternating slots and toothing and an inner thickened surface.

  12. A performance case study of energy pile foundation at Rosborg Gymnasium (Denmark)

    DEFF Research Database (Denmark)

    Pagola, Maria Alberdi; Jensen, Rasmus Lund; Poulsen, Søren Erbs

    2016-01-01

    The Rosborg Gymnasium building in Vejle (Denmark) is partially founded on 200 foundation pile heat exchangers (energy piles). The thermo-active foundation has supplemented the heating and free cooling needs of the building since 2011 (4,000 m2 living area). Operational data from the ground source...... ground heat extraction/injection activity , this paper provides a performance study of the energy pile-based ground source heat pump installation utilising operational data. The study demonstrates that the measured seasonal performance factors so far are lower than expected: 2.7 in heating mode and 4.......2 in cooling mode. Nevertheless, there is room for improvement if novel energy management strategies are applied. This highlights the relevance of considering the daily heating/cooling requirements of the building during the design phase of the heating and cooling system. Moreover, this study demonstrates...

  13. Modelling temperature-dependent heat production over decades in High Arctic coal waste rock piles

    DEFF Research Database (Denmark)

    Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.

    2011-01-01

    controlling the internal build up of heat leading to potential self-incineration. However, site specific measurements of temperature-dependent heat production as well as simulation results show that the heat produced from pyrite oxidation alone cannot cause such a temperature increase and that processes......Subsurface heat production from oxidation of pyrite is an important process that may increase subsurface temperatures within coal waste rock piles and increase the release of acid mine drainage, AMD. Waste rock piles in the Arctic are especially vulnerable to changes in subsurface temperatures...... as the release of AMD normally is limited by permafrost. Here we show that temperatures within a 20 year old heat-producing waste rock pile in Svalbard (78°N) can be modelled by the one-dimensional heat and water flow model (CoupModel) with a new temperature-dependent heat-production module that includes both...

  14. A performance case study of energy pile foundation at Rosborg Gymnasium (Denmark)

    DEFF Research Database (Denmark)

    Pagola, Maria Alberdi; Jensen, Rasmus Lund; Poulsen, Søren Erbs

    2016-01-01

    ground heat extraction/injection activity , this paper provides a performance study of the energy pile-based ground source heat pump installation utilising operational data. The study demonstrates that the measured seasonal performance factors so far are lower than expected: 2.7 in heating mode and 4......The Rosborg Gymnasium building in Vejle (Denmark) is partially founded on 200 foundation pile heat exchangers (energy piles). The thermo-active foundation has supplemented the heating and free cooling needs of the building since 2011 (4,000 m2 living area). Operational data from the ground source.......2 in cooling mode. Nevertheless, there is room for improvement if novel energy management strategies are applied. This highlights the relevance of considering the daily heating/cooling requirements of the building during the design phase of the heating and cooling system. Moreover, this study demonstrates...

  15. Critical Behaviors in a Stochastic Local Limited One-Dimensional Rice-Pile Model

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-Zhang; TANG Zheng-Xin

    2008-01-01

    A stochastic local fimited one-dimensional rice-pile model is numerically investigated. The distributions for ayalanche sizes have a clear power-law behavior and it displays a simple finite size scaling. We obtain the avalanche exponents Ts = 1.54±0.10, βs = 2.17±0.10 and τT = 1.80±0.10, βT = 1.46±0.10. This self-organized critical model belongs to the same universality class with the Oslo rice-pile model studied by K. Christensen et al. [Phys. Rev. Lett. 77 (1996) 107], a rice-pile model studied by L.A.N. Amaral et al. [Phys. Rev. E 54 (1996) 4512], and a simple deterministic self-organized critical model studied by M.S. Vieira [Phys. Rev. E 61 (2000) 6056].

  16. Boundary Value Problem for Analysis of Portal Double-Row Stabilizing Piles

    Directory of Open Access Journals (Sweden)

    Cheng Huang

    2013-01-01

    Full Text Available This paper presents a new numerical approach for computing the internal force and displacement of portal double-row piles used to stabilize potential landslide. First, the new differential equations governing the mechanical behaviour of the stabilizing pile are formulated and the boundary conditions are mathematically specified. Then, the problem is numerically solved by the high-accuracy Runge-Kutta finite difference method. A program package has been developed in MATLAB depending on the proposed algorithm. Illustrative examples are presented to demonstrate the validity of the developed program. In short, the proposed approach is a practical new idea for analyzing the portal double-row stabilizing pile as a useful supplement to traditional methods such as FEM.

  17. Experimental Comparison of Statically and Cyclically Loaded Non-Slender Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    and hence the effective stresses in the soil have been increased homogeneously. The tests have been conducted in a pressure tank at Aalborg University. A total of 29 quasi-static tests and 14 cyclic tests have been conducted on laterally loaded piles situated in sand. Aluminium pipe piles instrumented...... the effective stresses in the soil will be low and vary linearly with depth. As a consequence of this the soil parameters will vary greatly with depth and the determination of soil parameters is subject to great uncertainties. To overcome these uncertainties an overburden pressure, P0, has been applied...... with strain gauges have been used for the test series. The outer pile diameter has been varied between 40 and 100 mm, the length to diameter ration is between three and six and the overburden pressure is between 0 and 100 kPa....

  18. Numerical prediction of underwater noise reduction during offshore pile driving by a Small Bubble Curtain

    DEFF Research Database (Denmark)

    Göttsche, Klaus Marco; Juhl, Peter Møller; Steinhagen, Ulrich

    2013-01-01

    Small Bubble Curtains are an effective technique to reduce the underwater noise being emitted during offshore pile driving. In order to protect the marine fauna, noise reduction becomes even more important, since the increasing contribution of offshore wind energy leads to a rising number......, a method is presented in order to predict the rate of noise attenuation achieved by a Small Bubble Curtain. For this purpose, the bubble distribution is determined with Computational Fluid Dynamics. The noise radiation during pile driving is simulated by Finite Element Analysis and an Effective Medium...... Approach considers the acoustic effects within the Bubble Curtain. The pressure level at an arbitrary distance from the pile is determined by a Parabolic Equation method. Furthermore, comparisons between simulations and offshore measurements are presented. This combination of four methods provides...

  19. Acoustic emission signal processing technique to characterize reactor in-pile phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek, E-mail: vivek.agarwal@inl.gov [Department of Human Factors, Controls, and Statistics, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Tawfik, Magdy S., E-mail: magdy.tawfik@inl.gov [Nuclear Science and Technology Directorate, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Smith, James A., E-mail: james.smith@inl.gov [Department of Fuel Performance and Design, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2015-03-31

    Existing and developing advanced sensor technologies and instrumentation will allow non-intrusive in-pile measurement of temperature, extension, and fission gases when coupled with advanced signal processing algorithms. The transmitted measured sensor signals from inside to the outside of containment structure are corrupted by noise and are attenuated, thereby reducing the signal strength and the signal-to-noise ratio. Identification and extraction of actual signal (representative of an in-pile phenomenon) is a challenging and complicated process. In the paper, empirical mode decomposition technique is utilized to reconstruct actual sensor signal by partially combining intrinsic mode functions. Reconstructed signal will correspond to phenomena and/or failure modes occurring inside the reactor. In addition, it allows accurate non-intrusive monitoring and trending of in-pile phenomena.

  20. Analysis of uplift loads of precast-concrete piles in porous soils

    Directory of Open Access Journals (Sweden)

    Stélio Maia Menezes

    2006-01-01

    Full Text Available This paper presents the analysis of uplift load tests in three precast-concrete piles carried out in a collapsible sandy soil. The piles with 12 meters (m length and 0.17 x 0.17 square meter (m2 cross section were instrumented with strain gauges, in order to know the load transfer in depth. Three tests performed in a slow maintained load way were conducted in a natural condition of moisture content soil. A fourth test was carried out after the previous soaking of the soil around the pile head. The tests were performed in the experimental research site at the Universidade Estadual Paulista “Júlio de Mesquita Filho” (Unesp. The results obtained were evaluated by analytical and empirical methods.