WorldWideScience

Sample records for rock tunnel boring

  1. New Rock Abrasivity Test Method for Tool Life Assessments on Hard Rock Tunnel Boring: The Rolling Indentation Abrasion Test (RIAT)

    Science.gov (United States)

    Macias, F. J.; Dahl, F.; Bruland, A.

    2016-05-01

    The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.

  2. Hard rock tunnel boring machine penetration test as an indicator of chipping process efficiency

    Directory of Open Access Journals (Sweden)

    M.C. Villeneuve

    2017-08-01

    Full Text Available The transition from grinding to chipping can be observed in tunnel boring machine (TBM penetration test data by plotting the penetration rate (distance/revolution against the net cutter thrust (force per cutter over the full range of penetration rates in the test. Correlating penetration test data to the geological and geomechanical characteristics of rock masses through which a penetration test is conducted provides the ability to reveal the efficiency of the chipping process in response to changing geological conditions. Penetration test data can also be used to identify stress-induced tunnel face instability. This research shows that the strength of the rock is an important parameter for controlling how much net cutter thrust is required to transition from grinding to chipping. It also shows that the geological characteristics of a rock will determine how efficient chipping occurs once it has begun. In particular, geological characteristics that lead to efficient fracture propagation, such as fabric and mica contents, will lead to efficient chipping. These findings will enable a better correlation between TBM performance and geological conditions for use in TBM design, as a basis for contractual payments where penetration rate dominates the excavation cycle and in further academic investigations into the TBM excavation process.

  3. Simulation of rock fragmentation induced by a tunnel boring machine disk cutter

    Directory of Open Access Journals (Sweden)

    Huiyun Li

    2016-05-01

    Full Text Available A constitutive model based on the Johnson–Cook material model and the extended Drucker–Prager strength criterion was implemented in LS-DYNA to simulate the rock failure process induced by a single disk cutter of a tunnel boring machine. The normal, rolling, and side forces were determined by numerical tests. The simulation results showed that the normal and rolling forces increased with increasing penetration while the side force changed little. The normal force also increased under the conditions of confining pressures. The damage region of rock and cutting forces were also obtained by simulation of two disk cutters acting in tandem with different cutting spacings. The optimum ratio of cutter spacing to penetration depth determined from numerical modeling agrees well with that obtained by linear cutting machine tests. The average normal and rolling forces acting on the first cutter are slightly greater than those acting on the second when the cutting disk spacing is relatively small. The numerical modeling was verified to accurately capture the fragmentation of rock induced by disk cutter.

  4. Performance characteristics of tunnel boring machine in basalt and pyroclastic rocks of Deccan traps – A case study

    Directory of Open Access Journals (Sweden)

    Prasnna Jain

    2014-02-01

    Full Text Available A 12.24 km long tunnel between Maroshi and Ruparel College is being excavated by tunnel boring machine (TBM to improve the water supply system of Greater Mumbai, India. In this paper, attempt has been made to establish the relationship between various litho-units of Deccan traps, stability of tunnel and TBM performances during the construction of 5.83 km long tunnel between Maroshi and Vakola. The Maroshi–Vakola tunnel passes under the Mumbai Airport and crosses both runways with an overburden cover of around 70 m. The tunneling work was carried out without disturbance to the ground. The rock types encountered during excavation are fine compacted basalt, porphyritic basalt, amygdaloidal basalt, pyroclastic rocks with layers of red boles and intertrappean beds consisting of various types of shales. Relations between rock mass properties, physico-mechanical properties, TBM specifications and the corresponding TBM performance were established. A number of support systems installed in the tunnel during excavation were also discussed. The aim of this paper is to establish, with appropriate accuracy, the nature of subsurface rock mass condition and to study how it will react to or behave during underground excavation by TBM. The experiences gained from this project will increase the ability to cope with unexpected ground conditions during tunneling using TBM.

  5. Free-face-Assisted Rock Breaking Method Based on the Multi-stage Tunnel Boring Machine (TBM) Cutterhead

    Science.gov (United States)

    Geng, Qi; Wei, Zhengying; Meng, Hao; Macias, Francisco Javier; Bruland, Amund

    2016-11-01

    In order to improve the rock breaking efficiency of hard rock tunnel boring, many innovative rock breaking methods have been proposed (e.g., the water jet cutting, the high-power laser cutting, the impact-rotary drilling, and the undercutting method). However, most of the methods are not applicable to TBMs due to some structural reasons. Aiming on this problem, a free-face-assisted rock breaking method based on the multi-stage TBM cutterhead has been proposed. Series of proof-of-concept tests includes (1) the static compression test with vertical free face and (2) the rotary cutting tests in different free surface conditions were designed and carried out. The results show that the rock breaking force and efficiency can be significantly reduced and improved, respectively, with the assistance of the free face, due to the failure of the rock close to the free face is tensile-dominated failure. The influencing distance of the free face in the radial direction is at least 330 mm which covers about 5 disk cutters. Finally, the general structure of a small two-stage cutterhead (4 m in diameter) was tentatively designed in order to provide a possible approach to apply the free-face effect to TBMs.

  6. Superconducting Super Collider Laboratory : tunnel boring

    CERN Multimedia

    SSC Media Production

    1999-01-01

    This film will take you down into the tunnel, show you the technology involved in boring the tunnel, and show what the SSC fmeans to the U.S. in terms of scientific discovery, innovative collaborations with industry and stimulating the job base nation-wide.

  7. Seismic source characterisation of a Tunnel Boring Machine (TBM)

    Science.gov (United States)

    Kreutzer, Ingrid; Brückl, Ewald; Radinger, Alexander

    2015-04-01

    The Tunnel Seismic While Drilling (TSWD) method aims at predicting continuously the geological situation ahead of the tunnel without disturbing the construction work. Thereby the Tunnel Boring Machine (TBM) itself is used as seismic source. The cutting process generates seismic waves radiating into the rock mass and vibrations propagating to the main bearing of the cutter head. These vibrations are monitored and used as pilot signal. For the processing and interpretation it was hypothesized so far that the TBM acts like a single force. To prove this assumption the radiation pattern of several TBM's under construction were investigated. Therefore 3-components geophones were installed at the surface, which were situated directly above the tunnel axes and also with lateral offset. Additional, borehole geophones were placed in the wall of one tube of a two-tube tunnel. The geophones collected the forward and backward radiated wave field, as the TBM, operating in the other tube, passed their positions. The obtained seismic data contains continuous records over a range of 600 m of the TBM position. The offsets vary from 25 m to 400 m and the frequency ranges from 20-250 Hertz. The polarisation of the p-wave and the s-wave and their amplitude ratio were determined and compared with modelled seismograms with different source mechanism. The results show that the description of the source mechanism by a single force can be used as a first order approximation. More complex radiation pattern including tensile forces and several source locations like the transmission of reaction forces over the gripper to the tunnel wall are further tested and addressed.

  8. Acoustic Monitoring for Tunnel Boring in Soft Soils

    NARCIS (Netherlands)

    Swinnen, G.

    2003-01-01

    The TBM, not a blind mole! This thesis deals with some aspects of seismic imaging of the soft soil in front of a Tunnel Boring Machine to help tunnel constructors ``see'' the subsurface they are approaching, instead of steering the TBM forward like a ``blind mole''. The Dutch shallow subsurface has

  9. Study on influence of ground settlement in bored metro tunnel

    Institute of Scientific and Technical Information of China (English)

    FANG Jiang-hua; ZHANG Zhi-hong

    2006-01-01

    At present the bored construction method is one of the main construction methods of metro and tunnel construction in China. The empirical estimated formulas of tunnel ground surface settlement using the bored construction method were obtained,combining the mechanical stimulant calculated result of tunnel model of different embedded depth, different cross section and different construction method and the actual measurement data of Beijing metro construction. According to the regressed analysis of calculated data, the calculated equations of ground surface settlement value and settlement range of tunnel section under the condition of different embedded depth, different cross section and different construction method were gained. Among them there are some empirical formulas can apply to the construction design ofmetro tunnel directly.

  10. 3D Finite Element Simulation of Tunnel Boring Machine Construction Processes in Deep Water Conveyance Tunnel

    Institute of Scientific and Technical Information of China (English)

    ZHONG Denghua; TONG Dawei

    2009-01-01

    Applying stiffness migration method, a 3D finite element mechanical model is established to simulate the excavation and advance processes. By using 3D nonlinear finite element method, the tunnel boring machine (TBM) excavation process is dynamically simulated to analyze the stress and strain field status of surrounding rock and segment. The maximum tensile stress of segment ring caused by tunnel construction mainly lies in arch bottom and presents zonal distribution. The stress increases slightly and limitedly in the course of excavation. The maxi-mum and minimum displacements of segment, manifesting as zonal distribution, distribute in arch bottom and vault respectively. The displacements slightly increase with the advance of TBM and gradually tend to stability.

  11. Boring of full scale deposition holes at the Aespoe Hard Rock Laboratory. Operational experiences including boring performance and a work time analysis

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Johansson, Aasa [SWECO, Stockholm (Sweden)

    2002-12-01

    Thirteen experimental deposition holes similar to those in the present KBS-3 design have been bored at the Aespoe Hard Rock Laboratory, Oskarshamn, Sweden. The objective with the boring program was to test and demonstrate the current technique for boring of large vertical holes in granitic rock. Conclusions and results from this project is used in the planning process for the deposition holes that will be bored in the real repository for spent nuclear fuel. The boreholes are also important for three major projects. The Prototype Repository, the Canister Retrieval Test and the Demonstration project will all need full-scale deposition holes for their commissioning. The holes are bored in full scale and have a radius of 1.75 m and a depth of 8.5 m. To bore the holes an existing TBM design was modified to produce a novel type Shaft Boring Machine (SBM) suitable for boring 1.75 m diameter holes from a relatively small tunnel. The cutter head was equipped with two types of roller cutters: two row carbide button cutters and disc cutters. Removal of the cuttings was made with a vacuum suction system. The boring was monitored and boring parameters recorded by a computerised system for the evaluation of the boring performance. During boring of four of the holes temperature, stress and strain measurements were performed. Acoustic emission measurements were also performed during boring of these four holes. The results of these activities will not be discussed in this report since they are reported separately. Criteria regarding nominal borehole diameter, deviation of start and end centre point, surface roughness and performance of the machine were set up according to the KBS-3 design and were fulfilled with a fair margin. The average total time for boring one deposition hole during this project was 105 hours.

  12. Performance model for Micro Tunnelling Boring Machines (MTBM

    Directory of Open Access Journals (Sweden)

    J. Gallo

    2017-06-01

    Full Text Available From the last decades of the XX century, various formulae have been proposed to estimate the performance in tunnelling of disc cutters, mainly employed in Tunnelling Boring Machines (TBM. Nevertheless, their suitability has not been verified in Micro Tunnelling Boring Machines (MTBM, with smaller diameter of excavation, between 1,000 and 2,500 mm and smaller cutter tools, where parameters like joint spacing may have a different influence. This paper analyzes those models proposed for TBM. After having observed very low correlation with data obtained in 15 microtunnels, a new performance model is developed, adapted to the geomechanical data available in this type of works. Moreover, a method to calculate the total amount of hours that are necessary to carry out microtunnels, including all the tasks of the excavation cycle and installation and uninstallation.

  13. Ten Years of bored tunnels in the Netherlands: Part I: Geotechnical issues

    NARCIS (Netherlands)

    Bakker, K.J.; Bezuijen, A.

    2008-01-01

    Ten years have passed since in 1997 for the first time construction of bored tunnels in the Netherlands soft soil was undertaken. Before that date essentially only immersed tunnels and cut-and-cover tunnels were constructed in the Netherlands. The first two bored tunnels were Pilot Projects, the 2nd

  14. Rocks Are Boring--Aren't They?

    Science.gov (United States)

    Lievesley, Tara

    2014-01-01

    The new English Curriculum requiring not only the study of sedimentary and igneous rocks but also understanding of fossil formation, is a great opportunity to make this one of the most exciting units any science teacher can present. When an animal or plant dies, it "disappears" completely as it is degraded by a range of organisms. It may…

  15. An introduction to RAM analysis of EPB tunnel boring machine

    Directory of Open Access Journals (Sweden)

    Hasel Amini Khoshalan

    2014-03-01

    Full Text Available Earth pressure balance tunnel boring machines (EPB - TBMs are favorably used in construction of tunnels in urban areas. These more expensive machines with high operational costs require an exclusive study and knowledge on these machine components and subsystems and their failure and downtimes for time planning, cost control and performance prediction with a high accuracy. Thus guidelines for reliability, availability and maintainability (RAM analysis of an EPB machine are completely expressed. Gathering and recording all daily failure and repair times and other maintenance tasks, dividing the machine into subsystems (including mechanical subsystem, electrical subsystem, hydraulic subsystem, pneumatic subsystem and water subsystem, graphical tests (trend test and correlation test, statistical tests and analysis are discussed in detail.

  16. A tunnel boring system for the Yucca Mountain Project

    Energy Technology Data Exchange (ETDEWEB)

    Short, S.N. [Construction & Tunneling Services, Inc., Kent, WA (United States)

    1994-12-31

    Design of the Yucca Mountain Project (YMP) tunnel boring machine (TBM) and backup began in June of 1993, with fabrication, machining and light assembly proceeding through to the end of the year. The original specifications for the project were contained in the request for quote for the YMP TBM and in Construction & Tunneling Services proposal document. As with all complex custom assignments, much of the finer details of the definition of the final scope of delivery was concurrent with the design effort itself. The summation of this effort is described in this paper. The major technical scope of the machine delivery is defined by the parameters listed in TABLE 1. Within the confines of the installed power and design excavation rates, the final product has been tailored to suit the particular needs of the project.

  17. The Time and Cost Prediction of Tunnel Boring Machine in Tunnelling

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Making use of microsoft visual studio. net platform, the assistant decision-making system of tunnel boring machine in tunnelling has been built to predict the time and cost. Computation methods of the performance parameters have been discussed. New time and cost prediction models have been depicted. The multivariate linear regression has been used to make the parameters more precise, which are the key factor to affect the prediction near to the reality.

  18. ZEDEX - A study of damage and disturbance from tunnel excavation by blasting and tunnel boring

    Energy Technology Data Exchange (ETDEWEB)

    Emsley, S. [Golder Associates, Maidenhead (United Kingdom); Olsson, Olle; Stenberg, L. [Swedish Nuclear Fuel and Waste Co., Figeholm (Sweden); Alheid, H.J. [Federal Inst. for Geosciences and Natural Resources, Hannover (Germany); Falls, S. [Queens Univ., Kingston, ON (Canada)

    1997-12-01

    The objectives of the ZEDEX project were to understand the mechanical behaviour of the excavation disturbed zone (EDZ) with respect to its origin, character, magnitude of property change, extent and its dependence on excavation method. Excavation with normal smooth blasting, blasting with low shock explosives and tunnel boring were studied. The drifts are located at Aespoe at a depth of 420 m, the profiles are circular and 5 m in diameter. The results have shown that there is a damaged zone, close to the drift wall dominated by changes in rock properties which are irreversible, and that there is a disturbed zone beyond the damaged zone that is dominated by changes in stress state and mainly reversible. There is no distinct boundary between the two zones. The results from ZEDEX indicate that the role of the EDZ as a preferential pathway to radionuclide transport is limited to the damaged zone. The extent of the damaged zone can be limited through application of appropriate excavation methods. By limiting the extent of the damaged zone it should also be feasible to block pathways in the damaged zone by plugs placed at strategic locations 68 refs, 92 figs, 31 tabs

  19. An experimental and computational investigation of electrical resistivity imaging for prediction ahead of tunnel boring machines

    Science.gov (United States)

    Schaeffer, Kevin P.

    Tunnel boring machines (TBMs) are routinely used for the excavation of tunnels across a range of ground conditions, from hard rock to soft ground. In complex ground conditions and in urban environments, the TBM susceptible to damage due to uncertainty of what lies ahead of the tunnel face. The research presented here explores the application of electrical resistivity theory for use in the TBM tunneling environment to detect changing conditions ahead of the machine. Electrical resistivity offers a real-time and continuous imaging solution to increase the resolution of information along the tunnel alignment and may even unveil previously unknown geologic or man-made features ahead of the TBM. The studies presented herein, break down the tunneling environment and the electrical system to understand how its fundamental parameters can be isolated and tested, identifying how they influence the ability to predict changes ahead of the tunnel face. A proof-of-concept, scaled experimental model was constructed in order assess the ability of the model to predict a metal pipe (or rod) ahead of face as the TBM excavates through a saturated sand. The model shows that a prediction of up to three tunnel diameters could be achieved, but the unique presence of the pipe (or rod) could not be concluded with certainty. Full scale finite element models were developed in order evaluate the various influences on the ability to detect changing conditions ahead of the face. Results show that TBM/tunnel geometry, TBM type, and electrode geometry can drastically influence prediction ahead of the face by tens of meters. In certain conditions (i.e., small TBM diameter, low cover depth, large material contrasts), changes can be detected over 100 meters in front of the TBM. Various electrode arrays were considered and show that in order to better detect more finite differences (e.g., boulder, lens, pipe), the use of individual cutting tools as electrodes is highly advantageous to increase spatial

  20. The relationship of geophysical measurements to engineering and construction parameters in the Straight Creek Tunnel pilot bore, Colorado

    Science.gov (United States)

    Scott, J.H.; Lee, F.T.; Carroll, R.D.; Robinson, C.S.

    1968-01-01

    Seismic-refraction and electrical-resistivity measurements made along the walls of the Straight Creek Tunnel pilot bore indicate that both a low-velocity and a high-resistivity layer exist in the disturbed rock surrounding the excavation. Seismic measurements were analyzed to obtain the thickness and seismic velocity of rock in the low-velocity layer, the velocity of rock behind the layer and the amplitude of seismic energy received at the detectors. Electrical-resistivity measurements were analyzed to obtain the thickness and electrical resistivity of the high-resistivity layer and the resistivity of rock behind the layer. The electrical resistivity and the seismic velocity of rock at depth, the thickness of rock in the low-velocity layer, and the relative amplitude of seismic energy were correlated against the following parameters, all of which are important in tunnel construction: height of the tension arch, stable vertical rock load, rock quality, rate of construction and cost per foot, percentage of lagging and blocking, set spacing, and type and amount of steel support required, The correlations were statistically meaningful, having correlation coefficients ranging in absolute value from about 0??7 to nearly 1??0. This finding suggests the possibility of predicting parameters of interest in tunnel construction from geophysical measurements made in feeler holes drilled ahead of a working face. Predictions might be based on correlations established either during the early stages of construction or from geophysical surveys in other tunnels of similar design in similar geologic environments. ?? 1968.

  1. Looking ahead of a tunnel boring machine with 2-D SH full waveform inversion

    NARCIS (Netherlands)

    Pisupati, P.B.; Mulder, W.A.; Drijkoningen, G.G.; Reijnen, R.

    2015-01-01

    In the near-surface with unconsolidated soils, shear properties can be well imaged, sometimes better than P-wave properties. To facilitate ground prediction ahead of a tunnel boring machine (TBM), active ‘surveys’ with shear-wave vibrators are carried out during boring. In such surveys, only a few s

  2. The use of a Tunnel Boring Machine (TBM) as a seismic source

    Science.gov (United States)

    Kreutzer, Ingrid; Chwatal, Werner; Radinger, Alexander; Brückl, Ewald

    2014-05-01

    The Tunnel Seismic While Drilling (TSWD) method uses the Tunnel Boring Machine (TBM) as the seismic source. The method has been developed to predict the geological situation from reflections ahead of the tunnel face without disturbing the tunneling. The vibrations of the TBM are continuously monitored near the drilling head (pilot signal) as well as the direct and reflected seismic wave field at borehole geophones (geophone signal) situated in the tunnel wall behind the TBM. During the processing these signals are correlated and result in excellent seismic traces comparable to conventional seismic methods. The interpretation of the reflections leads to a nearly daily prognosis about 100 m ahead of the TBM. This system was successfully implemented at three different construction sites in Austria and is currently operating at one further. The cutters on front of the TBM head are pressed against the tunnel face and split the rock during rotating which is called the chipping process. This cutting process generates seismic waves radiated into the rock mass and results also in vibrations of the TBM itself. On the one hand it is important to know the source mechanism of the TBM and the radiation pattern of the seismic waves in all directions. Until now this is not well understood. To investigate this 3C-geophones were installed at the surface above the tunnel axis at different construction sites. The obtained seismograms show the forward and backward radiated seismic wave field of the TBM, for the present without consideration of the influence of the free surface. We compare this data with modelled seismograms in which we use different possible source mechanism, like single force or force due to tensile cracks. First results are shown in the scope of this work. On the other hand it is essential to know how good the recorded pilot signal represents the entire chipping process. Due to technically reasons the pilot signal has been registered so far on the non-rotating part

  3. A bayesian nework based risk model for volume loss in soft soils in mechanized bored tunnels

    NARCIS (Netherlands)

    Chivatá Cárdenas, Ibsen; Al-Jibouri, Saad H.S.; Halman, Johannes I.M.

    2012-01-01

    Volume loss is one of the most important risks when boring a tunnel. This is particularly true when a tunnel is being constructed in soft soils. The risk of excessive volume loss, if materialised can lead to large consequences such as damage in buildings on the surface. This paper describes the

  4. Caldecott 4th bore tunnel project: influence of ground water flows and inflows triggered by tectonic fault zones?

    Science.gov (United States)

    Neuhuber, G.; G. Neuhuber1, W. Klary1, A. Nitschke1, B. Thapa2, Chris Risden3, T. Crampton4, D. Zerga5

    2011-12-01

    The 4th Bore is a highway tunnel on California State Route 24 currently under construction. The 4th Bore is undertaken by the California State Department of Transportation (CALTRANS) and the Contra Costa County Transportation Commission (CCTC) to alleviate traffic congestion on SR24 connecting the cities of Oakland and Orinda in the San Francisco East Bay Area. The cost for the 4th Bore is estimated at $ 390.8 Mill. The 3,249 ft long 4th Bore tunnel will have excavated dimensions of approximately 40 ft height and 49 ft width. A total of 7 cross passages will run between the 3rd and the new 4th bore. Geology and Hydrogeology: The project is located in the Oakland Berkeley Hills of the SF Bay Area. The Caldecott Tunnels lie within the easterly assemblage of the Hayward fault zone province which consists of a sequence of sedimentary and volcanic rocks that accumulated in the interval between about 16 and 8.4 Ma (Miocene). The basal rocks of these Tertiary deposits consist of deep marine basin sediments of the Monterey Group. These rocks are overlain uncomfortably by an interbedded sequence of terrestrial sediments (Orinda Formation) and volcanic rocks (Moraga Formation). The Tertiary rocks have been folded into large amplitude, NW trending folds that are cut by N trending strike and slip faults. The SF Bay Region, which is crossed by 4 major faults (San Gregorio, San Andreas, Hayward, and Calaveras), is considered one of the more seismically active regions of the world. The active Hayward fault lies 0.9mi to the west of the Caldecott Tunnels and is the closest major fault to the project area. The tunnel is at the moment under top heading construction: West Portal (360ft) and East Portal (1,968.5ft). While major faults typically influence groundwater flow, characterization of such influences is extremely difficult because of the heterogeneity of the hydraulic systems and the different lithological parameters and influences. Four major inactive fault zones striking

  5. 盾构机姿态的人工测量原理%Manual measurement principle of tunnel boring machine attitude

    Institute of Scientific and Technical Information of China (English)

    黄小斌; 区兆铭; 张永超; 蒋样明

    2011-01-01

    The paper put forward the manual measurement principle of tunnel boring machine attitude for the oriented approach of the tunnel boring machine in Metro tunnel shield construction. It used the shield attitude solver in Excel to calculate the real-time tunnel boring machine attitude. It could be the timely guidance for correcting tunnel boring machine, and ensure the tunnel boring machine tunneling along the designed circuit.%本文针对地铁隧道盾构法施工中盾构机的导向方法,提出盾构机姿态的人工测量原理,通过在Excel中编辑的盾构掘进姿态解算程序来计算盾构机的实时掘进姿态,及时指导盾构机纠偏,确保盾构机按照设计的线路进行掘进.

  6. 隧道掘进机技术的发展和研究现状%Application,Research and Future of Tunnel Boring Machine Technology

    Institute of Scientific and Technical Information of China (English)

    彭琦

    2013-01-01

    In this article,the classification of tunnel boring machines (TBM),the state-of-the-art of studies on tunnel boring machine technology,and the trend of study and development of tunnel boring machine technology are studied and discussed.Conclusions drawn are as follows:1) According to the strength of the rocks and soils bored,tunnel boring machines can be divided into rock tunnel boring machines and shield machines.2) The hot topics of studies on rock tunnel boring machines include the rock-breaking mechanism of disc cutters and the establishing of TBM performance prediction models.On the other hand,the hot topics of studies on shield machines include the stability of working face,the control of boring process and the study on ground surface settlement.3) Studies on tunnel boring machine technology will focus on the improving of the boring mechanism,the boring mechanism and the boring process control under complex geological conditions,and the development of composite boring technology.%通过对隧道掘进机的分类、隧道掘进机技术的研究现状以及隧道掘进机技术研究和发展趋势的调研和探讨,提出:1)根据掘进岩土体强度的不同,隧道掘进机大致可以分为岩石隧道掘进机和盾构;2)目前岩石隧道掘进机的研究热点问题主要包括滚刀破岩机制和施工预测模型的建立2个方面,而盾构主要研究内容集中在掌子面稳定、施工过程控制和地表沉降研究3个方面,虽然这些研究都取得了较大进展,并且部分已经有效地应用到实际工程建设中,但解决得不够透彻,还有待于进一步研究;3)隧道掘进机技术的研究发展趋势将集中在掘进力学机制的完善、复杂地质条件下掘进机制与施工过程控制研究和复合掘进机技术的发展等方面,这些会给隧道掘进机技术的研究和发展带来挑战和契机.

  7. Applications of NTNU/SINTEF Drillability Indices in Hard Rock Tunneling

    Science.gov (United States)

    Zare, S.; Bruland, A.

    2013-01-01

    Drillability indices, i.e., the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), Cutter Life Index™ (CLI), and Vickers Hardness Number Rock (VHNR), are indirect measures of rock drillability. These indices are recognized as providing practical characterization of rock properties used in the Norwegian University of Science and Technology (NTNU) time and cost prediction models available for hard rock tunneling and surface excavation. The tests form the foundation of various hard rock equipment capacity and performance prediction methods. In this paper, application of the tests for tunnel boring machine (TBM) and drill and blast (D&B) tunneling is investigated and the impact of the indices on excavation time and costs is presented.

  8. Analysis of the Tunnel Boring Machine Advancement on the Bologna-Florence Railway Link

    Directory of Open Access Journals (Sweden)

    M. Cardu

    2009-01-01

    Full Text Available Problem statement: The high-velocity railway link between Bologna and Firenze (Italy is today under construction and several tunnels have to be excavated for this purpose, some of these using TBMs. A small diameter tunnel, named Cunicolo ginori, was realized by TBM parallel to a large railway tunnel (Vaglia, at the distance of only 35 m. Approach: The Vaglia tunnel had been excavated by conventional methods and provided, thanks to a detailed survey and a systematic geotechnical monitoring (rock quality evaluation and convergence measurements the characterization data of the crossed rock mass; moreover the TBM performance data in Cunicolo ginori were continuously monitored. A tunnel stretch, 587 m long, was recorded and the analysis of the data from both surveys allowed to correlate the geomechanical parameters of the rock-mass to the TBM performances (net advancement rate, thrust, specific energy. Results: Based on this large amount of data a new system to predict the net TBM advancement rate for a tunnel in rock masses of known geological and geomechanical characteristics was then developed. Also the Utilization Coefficient (CU can be correlated to the rock quality Indices: The net advance rate and the utilization coefficient provide a mean to foresee the gross advancement rate and to evaluate the suitability of a machine for the excavation of a tunnel. Conclusion: In this study, an analysis had been carried out on about 587 m of a service tunnel, excavated by a TBM in a flysch formation.

  9. Boring and Sealing Rock with Directed Energy Millimeter-Waves

    Science.gov (United States)

    Woskov, P.; Einstein, H. H.; Oglesby, K.

    2015-12-01

    Millimeter-wave directed energy is being investigated to penetrate into deep crystalline basement rock formations to lower well costs and to melt rocks, metals, and other additives to seal wells for applications that include nuclear waste storage and geothermal energy. Laboratory tests have established that intense millimeter-wave (MMW) beams > 1 kW/cm2 can melt and/ or vaporize hard crystalline rocks. In principle this will make it possible to create open boreholes and a method to seal them with a glass/ceramic liner and plug formed from the original rock or with other materials. A 10 kW, 28 GHz commercial (CPI) gyrotron system with a launched beam diameter of about 32 mm was used to heat basalt, granite, limestone, and sandstone specimens to temperatures over 2500 °C to create melts and holes. A calibrated 137 GHz radiometer view, collinear with the heating beam, monitored real time peak rock temperature. A water load surrounding the rock test specimen primarily monitored unabsorbed power at 28 GHz. Power balance analysis of the laboratory observations shows that the temperature rise is limited by radiative heat loss, which would be expected to be trapped in a borehole. The analysis also indicates that the emissivity (absorption efficiency) in the radiated infrared range is lower than the emissivity at 28 GHz, giving the MMW frequency range an important advantage for rock melting. Strength tests on one granite type indicated that heating the rock initially weakens it, but with exposure to higher temperatures the resolidified black glassy product regains strength. Basalt was the easiest to melt and penetrate, if a melt leak path was provided, because of its low viscosity. Full beam holes up to about 50 mm diameter (diffraction increased beam size) were achieved through 30 mm thick basalt and granite specimens. Laboratory experiments to form a seal in an existing hole have also been carried out by melting rock and a simulated steel casing.

  10. EVALUATION OF RESERVOIR ROCK AND WELL BORE CEMENT ALTERATION WITH SUPERCRITICAL CO2

    Energy Technology Data Exchange (ETDEWEB)

    William k. O' Connor; Gilbert E Rush

    2009-01-01

    An evaluation of the alteration of reservoir rock and well bore cement at their interface, under supercritical CO{sub 2} (SCCO{sub 2}), was conducted at the laboratory-scale using simulated brine solutions at down-hole conditions. These studies were intended to identify potential leakage pathways for injected CO{sub 2} due to degradation of the well bore. Two distinct test series were conducted on core samples of the Mt. Simon sandstone from the Illinois Basin, IL, and the Grand Ronde basalt from the Pasco Basin, WA. LaFarge Class H well bore cement was used for both series. Reservoir rock/cement cores were immersed within a CO{sub 2}-saturated brine for up to 2000 hours at 35 degrees C and 100 atm CO{sub 2}. Results suggest that the impact of SCCO{sub 2} injection is reservoir-specific, being highly dependent on the reservoir brine and rock type. Brine pH can be significantly altered by CO{sub 2} injection, which in turn can dramatically impact the dissolution characteristics of the reservoir rock. Finally, well bore cement alteration was identified, particularly for fresh cast cement allowed to cure at SCCO{sub 2} conditions. However, this alteration was generally limited to an outer rind of carbonate and Ca-depleted cement which appeared to protect the majority of the cement core from further attack. These studies indicate that at the cement-rock interface, the annular space may be filled by carbonate which could act as an effective barrier against further CO{sub 2} migration along the well bore.

  11. Study on calculation of rock pressure for ultra-shallow tunnel in poor surrounding rock and its tunneling procedure

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Zhou; Jinghe Wang; Bentao Lin

    2014-01-01

    A computational method of rock pressure applied to an ultra-shallow tunnel is presented by key block theory, and its mathematical formula is proposed according to a mechanical tunnel model with super-shallow depth. Theoretical analysis shows that the tunnel is subject to asymmetric rock pressure due to oblique topography. The rock pressure applied to the tunnel crown and sidewall is closely related to the surrounding rock bulk density, tunnel size, depth and angle of oblique ground slope. The rock pressure applied to the tunnel crown is much greater than that to the sidewalls, and the load applied to the left side-wall is also greater than that to the right sidewall. Mean-while, the safety of the lining for an ultra-shallow tunnel in strata with inclined surface is affected by rock pressure and tunnel support parameters. Steel pipe grouting from ground surface is used to consolidate the unfavorable surrounding rock before tunnel excavation, and the reinforcing scope is proposed according to the analysis of the asymmetric load induced by tunnel excavation in weak rock with inclined ground surface. The tunneling procedure of bench cut method with pipe roof protection is still discussed and carried out in this paper according to the special geological condition. The method and tunneling procedure have been successfully utilized to design and drive a real expressway tunnel. The practice in building the super-shallow tunnel has proved the feasibility of the calculation method and tunneling procedure presented in this paper.

  12. Characterization of the excavation disturbance caused by boring of the experimental full scale deposition holes in the Research Tunnel of Olkiluoto

    Energy Technology Data Exchange (ETDEWEB)

    Autio, J. [Saanio and Riekkola Oy, Helsinki (Finland)

    1997-09-01

    Three holes, the size of deposition holes, were bored in the Research Tunnel using a novel full-face boring technique. During the boring test, procedures were carried out in order to determine the effect of changes in operating parameters on the performance of the boring machine and the quality of the hole. Evaluation of the quality of the hole included studies of the geometry of the holes, measurements of surface roughness using a laser profilometer, rock mechanical determinations and study of excavation disturbances in the zone adjacent to the surface of the holes using two novel methods, the He-gas method and the {sup 14}C-polymethylmethacrylate ({sup 14}C-PMMA) method. It was found that there is a distinct disturbed zone adjacent to the surface of the full scale deposition holes which can be divided into three different zones. The zones are as follows: a crushed zone penetrating to a depth of about 3 mm from the surface, a fractured zone extending to a depth of 6 - 10 mm from the crushed zone and a micro fractured zone extending to a depth of 15 - 31 mm from the fractured zone. The porosity of the rock in the disturbed zone measured using the {sup 14}C-PMMA method was clearly greater than the porosity of undisturbed rock to a depth of about 11 mm. The values of permeability and effective diffusion coefficient in the disturbed zone measured in a direction perpendicular to the disturbed surface were found to be approximately one order of magnitude larger than those of undisturbed rock. The degree of disturbance was found to be greater where higher levels of thrust had been employed during the boring process. The results obtained also suggest that the disturbance caused by using 4- and 5-row cutters in the cutter head is more pronounced than the disturbance caused when using 5- and 6-row cutters 31 refs, 118 figs, 15 tabs

  13. Research on Mechanism of Rock Burst Generation and Development for High Stress Rock Tunnels

    Institute of Scientific and Technical Information of China (English)

    高全臣; 赫建明; 王代华

    2001-01-01

    Through the investigation and analysis of high stress distribution in surrounding rock during the excavation of rock tunnels,the key factors to cause rock burst and the mechanism of rock burst generation and development are researched. The result shows that the scale and range of rock burst are related with elastic deformation energy storied in rock mass and the characteristics of unloading stress waves. The measures of preventing from rock burst for high stress rock tunnels are put forward.

  14. Arrival of the Robbins machine in LSS1 after completing the boring of the SPS tunnel.

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A few months after the signature of the agreement giving the go-ahead for the expansion of CERN into French territory (see Bulletin no.24/2004), work began on the Super Proton Synchrotron (SPS). Two years later, on 31 July 1974, the Robbins tunnel-boring machine excavating the SPS tunnel returned to its starting point (see photograph). It had excavated a tunnel with a circumference of 7 kilometres, at an average depth of 40 metres below the surface. The tunnel straddled the Franco-Swiss border, making the SPS the first cross-border accelerator. More than a thousand magnets were needed to equip the ring. The civil engineering and installation work was completed in record time after only four years. The SPS was equipped with a control system which was ahead of its time, consisting of 24 small control computers distributed in the tunnel and the control room and communicating by means of a high-rate data transmission system. The main control room housed only four consoles as opposed to the banks of electronic eq...

  15. Dynamic Instability of Tunnel in Blocky Rock Mass

    Institute of Scientific and Technical Information of China (English)

    QI Chengzhi; CHEN Canshou; QIAN Qihu; LUO Jian

    2008-01-01

    The displacements and geometry of the rock blocks and the properties of the rock structure play an important role in the stability of tunnels.Based on the key block model, the dynamic instability analysis of underground tunnel subjected to intensive short-time compressional wave was conducted.The instability of the tunnel caused by the spallation and the inertial effect was distinguished.And the influence of the roof contour curvature of tunnel was also determined.

  16. Identification of rock mass characteristics using microtremor in the boring hole

    Science.gov (United States)

    Che, Ailan; Wang, Huan; Feng, Shaokong; Siguyama, Takeshi

    2014-05-01

    An identification analysis method of the rock mass characteristics is proposed using microtremor measurements in the boring hole. The method is based on the assumption that the epicenter of incident waves of each observation point in the same boring hole almost agrees. And the calculations are deconvoluted by the multiple reflection theory. The procedure applicable to the identification of the average elastic characteristics of in situ rock masses is presented. It is based on the minimization of an error function representing the difference between microtremor measurements performed on the rock mass and the corresponding data obtained by a numerical analysis subjected to known external actions. The method requires the formulation of the elasticity inverse problem and is based on the least square minimization procedure. As an example the approach has been applied to the identification of the dynamic properties and the predominant characteristics of the rock mass underlying a deep excavated quarry in west of Shanghai city. The inverted rock mass characteristics are compared with the PS logs at the sites and show consistency, confirming that the proposed inversion is promising.

  17. ROCK MASS DAMAGED ZONE CAUSED BY BLASTING DURING TUNNEL EXCAVATION

    OpenAIRE

    Hrvoje Antičević; Mario Dobrilović; Hrvoje Perković

    2012-01-01

    Design of underground spaces, including tunnels, and repositories for radioactive waste include the application of the same or similar technologies. Tunnel excavation by blasting inevitably results in the damage in the rock mass around the excavation profile. The damage in the rock mass immediately next to the tunnel profile emerges as the expanding of the existing cracks and the appearance of new cracks, i.e. as the change of the physical and-mechanical properties of the rock mass. Concernin...

  18. Load-sharing characteristic of multiple pinions driving in tunneling boring machine

    Science.gov (United States)

    Wei, Jing; Sun, Qinchao; Sun, Wei; Ding, Xin; Tu, Wenping; Wang, Qingguo

    2013-05-01

    The failure of the key parts, such as gears, in cutter head driving system of tunneling boring machine has not been properly solved under the interaction of driving motors asynchronously and wave tunneling torque load. A dynamic model of multi-gear driving system is established considering the inertia effects of driving mechanism and cutter head as well as the bending-torsional coupling. By taking into account the nonlinear coupling factors between ring gear and multiple pinions, the influence for meshing angle by bending-torsional coupling and the dynamic load-sharing characteristic of multiple pinions driving are analyzed. Load-sharing coefficients at different rotating cutter head speeds and input torques are presented. Numerical results indicate that the load-sharing coefficients can reach up to 1.2-1.3. A simulated experimental platform of the multiple pinions driving is carried out and the torque distributions under the step load in driving shaft of pinions are measured. The imbalance of torque distribution of pinions is verified and the load-sharing coefficients in each pinion can reach 1.262. The results of simulation and test are similar, which shows the correctness of theoretical model. A loop coupling control method is put forward based on current torque master slave control method. The imbalance of the multiple pinions driving in cutter head driving system of tunneling boring machine can be greatly decreased and the load-sharing coefficients can be reduced to 1.051 by using the loop coupling control method. The proposed research provides an effective solution to the imbalance of torque distribution and synchronous control method for multiple pinions driving of TBM.

  19. Modelling of tunnelling processes and rock cutting tool wear with the particle finite element method

    Science.gov (United States)

    Carbonell, Josep Maria; Oñate, Eugenio; Suárez, Benjamín

    2013-09-01

    Underground construction involves all sort of challenges in analysis, design, project and execution phases. The dimension of tunnels and their structural requirements are growing, and so safety and security demands do. New engineering tools are needed to perform a safer planning and design. This work presents the advances in the particle finite element method (PFEM) for the modelling and the analysis of tunneling processes including the wear of the cutting tools. The PFEM has its foundation on the Lagrangian description of the motion of a continuum built from a set of particles with known physical properties. The method uses a remeshing process combined with the alpha-shape technique to detect the contacting surfaces and a finite element method for the mechanical computations. A contact procedure has been developed for the PFEM which is combined with a constitutive model for predicting the excavation front and the wear of cutting tools. The material parameters govern the coupling of frictional contact and wear between the interacting domains at the excavation front. The PFEM allows predicting several parameters which are relevant for estimating the performance of a tunnelling boring machine such as wear in the cutting tools, the pressure distribution on the face of the boring machine and the vibrations produced in the machinery and the adjacent soil/rock. The final aim is to help in the design of the excavating tools and in the planning of the tunnelling operations. The applications presented show that the PFEM is a promising technique for the analysis of tunnelling problems.

  20. 双模式全断面掘进机探讨%Discussion on Dual-mode Full-face Tunnel Boring Machines

    Institute of Scientific and Technical Information of China (English)

    张宁川; 李光

    2013-01-01

    为适应地质的复杂性以及中国国情,探讨双模式全断面掘进机的未来发展趋势,并举例说明双模式全断面掘进机的设计理念,详述其主要结构及适用范围.与单模式掘进机相比,双模式全断面掘进机地质适应性广、设备利用率高、施工成本低,是隧道掘进设备技术发展的主要方向之一,具有良好的发展前景.%The development trend of dual-mode full-face tunnel boring machines is discussed,the design concept of dual-mode full-face tunnel boring machines is presented and the main structure and applicability scope of dual-mode fullface tunnel boring machines are described in detail.The study shows that,compared to single-mode tunnel boring machines,the applicability scope of dual-mode full-face tunnel boring machines is more extensive,the availability of dualmode full-face tunnel boring machines is higher and the tunneling cost of dual-mode full-face tunnel boring machines is lower.Conclusion is drawn that the dual-mode full-face tunnel boring machine,which is the main development trend of tunnel boring machines,has a splendid future.

  1. NEW THEORY IN TUNNEL STABLILITY CONTROL OF SOFT ROCK ——MECHANICS OF SOFT ROCK ENGINEERING

    Institute of Scientific and Technical Information of China (English)

    何满朝

    1996-01-01

    Tunnel stability control is a world-wide difficult problem. For the sake of solving it,the new theory of soft rock engineering mechanics has been estabilished. Some key points,such as the definition and classification of soft rock, mechanical deformation mechanism of a soft rock tunnel, the critical support technique of soft rock tunnel and the new theory of the soft rock tunnel stability control are proposed in this paper.

  2. Modeling and Dynamic Analysis of Cutterhead Driving System in Tunnel Boring Machine

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2017-01-01

    Full Text Available Failure of cutterhead driving system (CDS of tunnel boring machine (TBM often occurs under shock and vibration conditions. To investigate the dynamic characteristics and reduce system vibration further, an electromechanical coupling model of CDS is established which includes the model of direct torque control (DTC system for three-phase asynchronous motor and purely torsional dynamic model of multistage gear transmission system. The proposed DTC model can provide driving torque just as the practical inverter motor operates so that the influence of motor operating behavior will not be erroneously estimated. Moreover, nonlinear gear meshing factors, such as time-variant mesh stiffness and transmission error, are involved in the dynamic model. Based on the established nonlinear model of CDS, vibration modes can be classified into three types, that is, rigid motion mode, rotational vibration mode, and planet vibration mode. Moreover, dynamic responses under actual driving torque and idealized equivalent torque are compared, which reveals that the ripple of actual driving torque would aggravate vibration of gear transmission system. Influence index of torque ripple is proposed to show that vibration of system increases with torque ripple. This study provides useful guideline for antivibration design and motor control of CDS in TBM.

  3. YUCCA MOUNTAIN SITE CHARACTERIZATIONS PROJECT TUNNEL BORING MACHINE (TBM) SYSTEM SAFETY ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    1997-02-19

    The purpose of this analysis is to systematically identify and evaluate hazards related to the tunnel boring machine (TBM) used in the Exploratory Studies Facility (ESF) at the Yucca Mountain Site Characterization Project. This process is an integral part of the systems engineering process; whereby safety is considered during planning, design, testing, and construction. Since the TBM is an ''as built'' system, the M&O is conducting the System Safety Analysis during the construction or assembly phase of the TBM. A largely qualitative approach was used since a radiological System Safety Analysis is not required. The risk assessment in this analysis characterizes the accident scenarios associated with the TBM in terms of relative risk and includes recommendations for mitigating all identified risks. The priority for recommending and implementing mitigation control features is: (1) Incorporate measures to reduce risks and hazards into the system/subsystem/component design, (2) add safety features and capabilities to existing designs, and (3) develop procedures and conduct training to increase worker awareness of potential hazards, on methods to reduce exposure to hazards, and on the actions required to avoid accidents or correct hazardous conditions. The scope of this analysis is limited to the TBM during normal operations, excluding hazards occurring during assembly and test of the TBM or maintenance of the TBM equipment.

  4. Research on Dynamic Models and Performances of Shield Tunnel Boring Machine Cutterhead Driving System

    Directory of Open Access Journals (Sweden)

    Xianhong Li

    2013-01-01

    Full Text Available A general nonlinear time-varying (NLTV dynamic model and linear time-varying (LTV dynamic model are presented for shield tunnel boring machine (TBM cutterhead driving system, respectively. Different gear backlashes and mesh damped and transmission errors are considered in the NLTV dynamic model. The corresponding multiple-input and multiple-output (MIMO state space models are also presented. Through analyzing the linear dynamic model, the optimal reducer ratio (ORR and optimal transmission ratio (OTR are obtained for the shield TBM cutterhead driving system, respectively. The NLTV and LTV dynamic models are numerically simulated, and the effects of physical parameters under various conditions of NLTV dynamic model are analyzed. Physical parameters such as the load torque, gear backlash and transmission error, gear mesh stiffness and damped, pinions inertia and damped, large gear inertia and damped, and motor rotor inertia and damped are investigated in detail to analyze their effects on dynamic response and performances of the shield TBM cutterhead driving system. Some preliminary approaches are proposed to improve dynamic performances of the cutterhead driving system, and dynamic models will provide a foundation for shield TBM cutterhead driving system's cutterhead fault diagnosis, motion control, and torque synchronous control.

  5. Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

    Energy Technology Data Exchange (ETDEWEB)

    Hardenby, Carljohan (Vattenfall Power Consultant AB (Sweden)); Sigurdsson, Oskar (HAskGeokonsult AB (Sweden))

    2010-12-15

    The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m2. As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories (&apos

  6. Prediction of swelling rocks strain in tunneling

    Science.gov (United States)

    Parsapour, D.; Fahimifar, A.

    2016-05-01

    Swelling deformations leading to convergence of tunnels may result in significant difficulties during the construction, in particular for long term use of tunnels. By extracting an experimental based explicit analytical solution for formulating swelling strains as a function of time and stress, swelling strains are predicted from the beginning of excavation and during the service life of tunnel. Results obtained from the analytical model show a proper agreement with experimental results. This closed-form solution has been implemented within a numerical program using the finite element method for predicting time-dependent swelling strain around tunnels. Evaluating effects of swelling parameters on time-dependent strains and tunnel shape on swelling behavior around the tunnel according to this analytical solution is considered. The ground-support interaction and consequent swelling effect on the induced forces in tunnel lining is considered too. Effect of delay in lining installation on swelling pressure which acting on the lining and its structural integrity, is also evaluated. A MATLAB code of " SRAP" is prepared and applied to calculate all swelling analysis around tunnels based on analytical solution.

  7. ROCK MASS DAMAGED ZONE CAUSED BY BLASTING DURING TUNNEL EXCAVATION

    Directory of Open Access Journals (Sweden)

    Hrvoje Antičević

    2012-07-01

    Full Text Available Design of underground spaces, including tunnels, and repositories for radioactive waste include the application of the same or similar technologies. Tunnel excavation by blasting inevitably results in the damage in the rock mass around the excavation profile. The damage in the rock mass immediately next to the tunnel profile emerges as the expanding of the existing cracks and the appearance of new cracks, i.e. as the change of the physical and-mechanical properties of the rock mass. Concerning the design of deep geological repositories, requirements in terms of damaged rock are the same or more rigorous than for the design of tunnel. The aforementioned research is directed towards determining the depth of damage zone caused by blasting. The depth of the damage zone is determined by measuring the changes of physical and-mechanical properties of the rock mass around the tunnel excavation profile. By this research the drilling and blasting parameters were correlated with the depth and size of the damage zone (the paper is published in Croatian.

  8. Zonal disintegration phenomenon in rock mass surrounding deep tunnels

    Institute of Scientific and Technical Information of China (English)

    WU Hao; FANG Qin; GUO Zhi-kun

    2008-01-01

    Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.

  9. Rock mass characterization for tunnels in the Copenhagen limestone

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Jakobsen, Lisa; Jackson, Peter

    2007-01-01

    Tunnels in Copenhagen are drilled through highly anisotropic limestone comprising alternating strongly lithified and less lithified parts. The mass quality of the limestone is usually defined from fracture spacing registered in core samples. The deposit is, however, affected destructively by dril...... by drilling activity yielding a low Rock Quality Designation RQD. In-situ observations of the limestone in excavations or televiewer logs reveal only few natural discontinuities compared to core logging, indicating a very good suitability for tunneling....

  10. Rock mass characterization for tunnels in the Copenhagen limestone

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Jakobsen, Lisa; Jackson, Peter;

    2007-01-01

    Tunnels in Copenhagen are drilled through highly anisotropic limestone comprising alternating strongly lithified and less lithified parts. The mass quality of the limestone is usually defined from fracture spacing registered in core samples. The deposit is, however, affected destructively by dril...... by drilling activity yielding a low Rock Quality Designation RQD. In-situ observations of the limestone in excavations or televiewer logs reveal only few natural discontinuities compared to core logging, indicating a very good suitability for tunneling....

  11. Tunnelling through weak and fragile rocks of Himalayas

    Institute of Scientific and Technical Information of China (English)

    Goel R.K.

    2014-01-01

    A considerable amount of tunnelling has been going on in India for various projects such as hydroelectric power, irrigation, roads and railways. Most of these projects are located in Himalayas, far away from the urban areas. Tunnelling through weak and jointed rock masses such as the one in the Himalayas is a challenging task for the planners, designers, engineers and geologists because of high overburden, thickly vegetated surface, weak, poor and fragile rocks and highly varying geology with the presence of numerous small and big shear zones, faults, etc. Due to these reasons, various tunnelling problems have been faced in the past and are still being encountered. Failures and the problems may be regarded as challenges and opportunities for generating new knowledge base and thereby increasing self-reliance in tunnelling. The experiences of Himalayan tunnelling through weak and fragile rocks covering varying and mixed geology, understanding on tunnelling in squeezing ground conditions and applicability of TBM in Himalayas are presented. It has also been highlighted that the probe holes planning, drilling and mon-itoring shall be followed seriously to reduce the geological surprises.

  12. Tunnel Design by Rock Mass Classifications

    Science.gov (United States)

    1990-01-01

    fact, rock mass classifications have been successfully applied throughout the world : in the United States,2 - Canada,7 8 Western Europe, 9 -12 South...gneiss. Very high strength >30000 >200 Quartzite, dolerite, gabbro , basalt. Table 10 3 Classification for Discontinuity Spacing Spacing of Rock Mass

  13. Control of rock joint parameters on deformation of tunnel opening

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

    Tunneling in complex rock mass conditions is a challenging task, especially in the Himalayan terrain, where a number of unpredicted conditions are reported. Rock joint parameters such as persistence, spacing and shear strength are the factors which significantly modify the working environments in the vicinity of the openings. Therefore, a detailed tunnel stability assessment is critically important based on the field data collection on the excavated tunnel’s face. In this context, intact as well as rock mass strength and defor-mation modulus is obtained from laboratory tests for each rock type encountered in the study area. Finite element method (FEM) is used for stability analysis purpose by parametrically varying rock joint persis-tence, spacing and shear strength parameters, until the condition of overbreak is reached. Another case of marginally stable condition is also obtained based on the same parameters. The results show that stability of tunnels is highly influenced by these parameters and the size of overbreak is controlled by joint persistence and spacing. Garnetiferous schist and slate characterized using high persistence show the development of large plastic zones but small block size, depending upon joint spacing; whereas low persistence, low spacing and low shear strength in marble and quartzite create rock block fall condition.

  14. Application of steel fibre reinforced sprayed concrete to a deep tunnel in weak rocks

    Institute of Scientific and Technical Information of China (English)

    周宏伟; 彭瑞东; 李振东; 董正亮; 陈文伟; 王健

    2002-01-01

    Based on an engineering background of a deep tunneling in weak rocks, the numerical modeling is used to compare different support schemes of tunnel at great depth in this paper. Focused on the general behaviors of weak rocks at great depth, a tunneling scheme with rock bolting and steel fibre reinforced sprayed concrete is proposed. This scheme is practiced successfully at a deep tunnel in weak rocks in Coal Mine No.10 of Hebi Coal Mining Administration.

  15. Prediction of rock brittleness using nondestructive methods for hard rock tunneling

    Institute of Scientific and Technical Information of China (English)

    Rennie B. Kaunda; Brian Asbury

    2016-01-01

    The material and elastic properties of rocks are utilized for predicting and evaluating hard rock brit-tleness using artificial neural networks (ANN). Herein hard rock brittleness is defined using Yagiz’ method. A predictive model is developed using a comprehensive database compiled from 30 years’ worth of rock tests at the Earth Mechanics Institute (EMI), Colorado School of Mines. The model is sensitive to density, elastic properties, and P-and S-wave velocities. The results show that the model is a better predictor of rock brittleness than conventional destructive strength-test based models and mul-tiple regression techniques. While the findings have direct implications on intact rock, the methodology can be extrapolated to rock mass problems in both tunneling and underground mining where rock brittleness is an important control.

  16. Prediction of rock brittleness using nondestructive methods for hard rock tunneling

    Directory of Open Access Journals (Sweden)

    Rennie B. Kaunda

    2016-08-01

    Full Text Available The material and elastic properties of rocks are utilized for predicting and evaluating hard rock brittleness using artificial neural networks (ANN. Herein hard rock brittleness is defined using Yagiz' method. A predictive model is developed using a comprehensive database compiled from 30 years' worth of rock tests at the Earth Mechanics Institute (EMI, Colorado School of Mines. The model is sensitive to density, elastic properties, and P- and S-wave velocities. The results show that the model is a better predictor of rock brittleness than conventional destructive strength-test based models and multiple regression techniques. While the findings have direct implications on intact rock, the methodology can be extrapolated to rock mass problems in both tunneling and underground mining where rock brittleness is an important control.

  17. Tunnel Boring Machine Technology for a Deeply Based Missile System. Volume I, Application Feasibility. Part 2.

    Science.gov (United States)

    1980-08-01

    Air Force Weapons Laboratory (NTESG) August 1980 Kirtland AFB, NM 87117 NUMBER OF PAGES 14. MONITORING AGENCY NAME & ADDRESS(il different from...incorporate in selected initial tunnel sections, trial sunport systems lighter than those calculated by existing RSP methods. These could be monitored as part...a pair of steel, 156 lA wide-flanqe (1F) beams, shaped to fit the tunnel opening and bolted toqether at the tunnel crown set on kicker foot blocks

  18. Numerical analysis of tunnel reinforcing influences on failure process of surrounding rock under explosive stress waves

    Institute of Scientific and Technical Information of China (English)

    ZUO Yu-jun; TANG Chun-an; ZHU Wan-cheng; LI Di-yuan; LI Shu-cai

    2008-01-01

    Based on mesoscopic damage mechanics, numerical code RFPA2D (dynamic edition) was developed to analyze the influence of tunnel reinforcing on failure process of surrounding rock under explosive stress waves. The results show that the propagation phenomenon of stress wave in the surrounding rock of tunnel and the failure process of surrounding rock under explosive stress waves are reproduced realistically by using numerical code RFPAED; from the failure process of surrounding rock,the place at which surrounding rock fractures is transferred because of tunnel reinforcing, and the rockfall and collapse caused by failure of surrounding rock are restrained by tunnel reinforcing; furthermore, the absolute values of peak values of major principal stress, and the minimal principal stress and shear stress at center point of tunnel roof are reduced because of tunnel reinforcing, and the displacement at center point of tunnel roof is reduced as well, consequently the stability of tunnel increases.

  19. Rock Cracking Indices for Improved Tunnel Support Design: A Case Study for Columnar Jointed Rock Masses

    Science.gov (United States)

    Feng, Xia-Ting; Hao, Xian-Jie; Jiang, Quan; Li, Shao-jun; Hudson, John A.

    2016-06-01

    Measurements indicate that the development of cracking is a key feature relating to the strength and collapse of a columnar jointed rock mass. In this context, a new support design method utilising rock cracking indices for columnar jointed rock mass under high stress is proposed to restrain the development of cracking in the surrounding rock mass. The method involves limiting the cracking evolution of the surrounding rock mass by designing the appropriate parameters and time of installation of the support system. Two indices are suggested: the allowable depth of the excavation damaged zone (EDZ); and the allowable damage extent of the rock mass in the EDZ. The method involves limiting the evolution of cracking in the surrounding rock mass by designing the parameters and time of installation of the support system. The support system should have a suitable stiffness and installation time so as to restrain the evolution of the depth and damage extent of the EDZ within the surrounding rock. Therefore, the depth and damage extent of the EDZ, as well as the axial stress in the anchor bolts, are calculated at different distances between the support location and the tunnel working face to find the appropriate stiffness and installation time of the support system. The method has been successfully adopted to determine the thickness of shotcrete, the arrangement and installation time of rockbolts, and other parameters, for five large diversion tunnels at the Baihetan hydropower station, China, which were excavated in columnar jointed rock masses.

  20. Deep Tunnel in Transversely Anisotropic Rock with Groundwater Flow

    Science.gov (United States)

    Bobet, Antonio

    2016-12-01

    Closed-form solutions for the stresses and deformations induced in the ground and tunnel liner are provided for a deep tunnel in a transversely anisotropic elastic rock, with anisotropic permeability, when subjected to groundwater seepage. Complex variable theory and conformal mapping are used to obtain the solutions; additional complex functions, necessary to prevent multiple solutions of the displacements, are included. The analytical solutions are verified by comparing their results from those of a finite element method. Simplified formulations are presented for tunnels with a perfectly flexible and completely incompressible liner. A spreadsheet is included that can be used to obtain stresses and displacements of the liner due to groundwater flow and far-field geostatic stresses.

  1. Effects of Rock Bolting on Stress Distribution around Tunnel Using the Elastoplastic Model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To ensure the stability of a tunnel during construction, rock bolts are usually installed, which affects the stress distribution around the tunnel.Therefore, it is necessary to study the effects of rock bolting on the stress distribution around the tunnel.In this article, the effects of rock bolting on the stress distribution around the tunnel, including the position and orientation of bolts, the overburden depths, and the bolt lengths, are simulated using the ANSYS software with an elastoplastic model.The effect of multiple bolts of 2 m and 1 m lengths on the stress distribution in the roof and on the lateral sides of a tunnel and at different overburden depths is considered.An important finding is that the tensile stress region that is very dangerous for rock in the bottom of the tunnel grows rapidly with increasing overburden depths when rock bolts are installed only in the roof or on the lateral sides of a tunnel.The determination of the length of the rock bolt used around a tunnel is dependent on the loads and the integrity of the rock mass around the tunnel.In addition, rock bolting around the tunnel can obviously reduce the coefficients and the size of the region of stress concentration, especially when installed in high-stress areas.This fact is very important and essential for the design of tunnels and ensures engineering safety in tunnel engineering.

  2. Cutting system arrangement method of hard rock boring machine%硬岩掘进机破碎机构布置方法

    Institute of Scientific and Technical Information of China (English)

    毛君; 谢春雪; 梁晗; 黄华

    2013-01-01

      Hard rock roadheader is the key equipment in laneway constructions. In view of the traditional point-attack picks sever loss while breaking rocks, this paper put forward a shock and rolling breaking method which utilizes impact mechanism and a rolling mechanism to break rocks. This study analyzed the duration, the reliability and the driving efficiency on the cutter of the hard rock tunnel boring machine, and optimized the relations between the hard rock crushers using multi-disciplinary optimization method. In addition, this paper researched on factors that influence the layout of crushers which include global coordinating optimization as main factor, coordinating the optimization of parameters, the impact parameter, cutting force, cutting parameters and rock properties matching. The results of study show that the arrangement of the hard rock crusher was feasible, and it is optimal in energy consumption, tool wearing, driving efficiency and overall performance.%  针对传统镐齿破碎岩石的损耗严重,提出一种冲击滚压破碎方式。其结构采用冲击机构和滚压机构配合破碎岩石,考虑影响硬岩掘进机刀具的寿命、可靠性、掘进效率因素,采用多学科优化方法构建硬岩掘进机破碎机构布置关系,并以全局协调优化为主导,总体协调优化参数,对破碎机构的布置进行冲击参数、刀具受力、切削参数、围岩属性的匹配研究。研究结果表明:该硬岩掘进机破碎机构布置方法可行,降低了硬岩掘进机能量消耗、刀具的磨损,提高了掘进效率,使整机性能达到最优。

  3. Asymmetric Rock Pressure on Shallow Tunnel in Strata with Inclined Ground Surface

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-jun; YANG Chang-yu

    2007-01-01

    By building a tunnel model with a semi-circular crown, the asymmetric rock pressure applied to the shallow tunnel in strata with inclined ground surface is analyzed. Formulae, which not only include the parameters related to both tunnel structure and surrounding rock mass, but the overburden depth, are developed. The computation for four tunnel models show that the method presented is feasible and convenient. Furthermore, the influence of the overburden depth on the rock pressure is elaborated, and the criterion to identify the deep or shallow tunnels is formulated as well.

  4. Evaluating safety of tunneled small bore central venous catheters in chronic kidney disease population: A quality improvement initiative.

    Science.gov (United States)

    Bhutani, Gauri; El Ters, Mireille; Kremers, Walter K; Klunder, Joe L; Taler, Sandra J; Williams, Amy W; Stockland, Andrew H; Hogan, Marie C

    2016-09-20

    Introduction Peripherally inserted central venous catheters (PICCs) may adversely impact future successful arteriovenous fistulae (AVF). As part of a quality improvement project, the performance of tunneled small bore tunneled central venous catheters (TSB-CVCs), as alternatives to PICCs, was evaluated. Methods A retrospective observational study, involving individuals ≥18 years of age who underwent TSB-CVC placement by Interventional Radiology at Mayo Clinic, Rochester, MN between 1/1/2010 and 8/30/2013. Findings The study cohort included 92 patients with a median age of 55 (46-67) years, who underwent 108 TSB-CVC placements. Baseline renal disease was present in 71% (77/108). Most TSB-CVCs were placed in hospitalized patients (94%; 102/108); five French in diameter (61%; 66/108) and located in an internal jugular vein (84%; 91/108). Median catheter indwelling time was 20 (11-43) days (n = 84). TSB-CVC-related bloodstream infection, deep venous thrombosis (DVT), and superficial venous thrombosis (SpVT) rates per line were 0.009 (1/108), 0.018 (2/108), and 0.009 (1/108), respectively. Venous outcomes in a subgroup of 54 patients, who had documented PICC placements (n = 161) in addition to TSB-CVC (n = 58) were compared. TSB-CVC-DVT rate was lower than the PICC-DVT rate (0.017 [1/58] vs. 0.106 per line [17/161]; P = 0.04). The TSB-CVC-SpVT rate was not different from the PICC-SpVT rate (0 [0/58] vs. 0.037 [6/161] per line; P = 0.14). Discussion TSB-CVCs demonstrated an excellent safety profile in our study. These catheters should be preferentially utilized for arm vein preservation in advanced kidney disease. Their impact on future AVF success needs further evaluation.

  5. Predator-prey interactions between shell-boring beetle larvae and rock-dwelling land snails.

    Science.gov (United States)

    Baalbergen, Els; Helwerda, Renate; Schelfhorst, Rense; Castillo Cajas, Ruth F; van Moorsel, Coline H M; Kundrata, Robin; Welter-Schultes, Francisco W; Giokas, Sinos; Schilthuizen, Menno

    2014-01-01

    Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies.

  6. Predator-prey interactions between shell-boring beetle larvae and rock-dwelling land snails.

    Directory of Open Access Journals (Sweden)

    Els Baalbergen

    Full Text Available Drilus beetle larvae (Coleoptera: Elateridae are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies.

  7. Rheological properties of surrounding rock in deep hard rock tunnels and its reasonable support form

    Institute of Scientific and Technical Information of China (English)

    王辉; 陈卫忠; 王清标; 郑朋强

    2016-01-01

    Second lining stability, which is the last protection in tunnel engineering, is critically important. The rheological properties of the surrounding rock heavily affect second lining stability. In this work, we used laboratory triaxial compressive rheological limestone tests to study nonlinear creep damage characteristics of surrounding rock mass in construction projects. We established a nonlinear creep damage constitutive model for the rock mass, as well as a constitutive model numerical implementation made by programming. Second, we introduced a new foam concrete with higher compression performance and good ductility and studied its mechanical properties through uniaxial and triaxial tests. This concrete was used as the filling material for the reserved deformation layer between the primary support and second lining. Finally, we proposed a high efficiency and accuracy staged optimization method. The minimum reserved deformation layer thickness was established as the optimization goal, and the presence of plastic strain in the second lining after 100 years of surrounding rock creep was used as an evaluation index. Reserved deformation layer thickness optimization analysis reveals no plastic strain in the second lining when the reserved deformation minimum thickness layer is 28.50 cm. The results show that the new foam concrete used as a reserved deformation layer filling material can absorb creep deformation of surrounding rock mass, reduce second lining deformation that leads to plastic strain, and ensure long-term second lining stability.

  8. Classification of Soft-rock Tunnels and the Corresponding Large-section Construction Methods

    Directory of Open Access Journals (Sweden)

    Huang Mingli

    2014-03-01

    Full Text Available This study is concerned with the classification of soft-rock tunnels which could instruct the tunnel construction more efficiently and effectively. It is difficult for NATM which is based on the geological classification to adapt to soft-rock tunnel construction. Through comparative study of the numerical models with different surrounding rock and different cross-sectional dimensions, the deformation characteristics of the soft-rock tunnel is put forward. Soft-rock tunnel is divided into four classes: A, B1, B2 and C. The classification is based on the proportion of the advanced displacement in the total radial displacement and the value of tunnel face extrusion. According to the different characteristics of these four classes of soft-rock tunnel, a high-speed construction with reinforcements of the surrounding rock in front of the face is put forward. The characteristics of the four classes of soft-rock tunnels are: In the general initial support conditions, the proportion of the advanced displacement in the total radial displacement of Class-A tunnels is low, which enables them to achieve self-stabilization. The corresponding proportions of Class-B1 and Class-B2 tunnels are beyond the limit, which can only enable them to achieve short-term stability. The extrusion of Class-B2 tunnel’s face is larger but it does not break the limit. The extrusion of Class-C tunnels breaks the limit which cannot maintain stability if without face reinforcements.

  9. EBZ-220型掘进机回油冷却器的改造设计%Retrofit Design of Oil Return Cooler in EBZ-220 Tunnel-Boring Machines

    Institute of Scientific and Technical Information of China (English)

    闫品

    2015-01-01

    Through the transformation design of the cooler of EBZ-220 type tunnel-boring machines, the cooling effect of the tunnel-boring machines is greatly improved, the efficiency of boring machine is increased, the failure rate of the tunnel-boring machines is reduced, longer service life is obtained.%通过对EBZ-220型掘进机冷却器的改造设计,大大改善了掘进机的冷却效果,提高了掘进机的使用效率,降低了掘进机故障率,使其效率更高,寿命更长。

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

    Institute of Scientific and Technical Information of China (English)

    XI Jia-mi; YANG Geng-she

    2008-01-01

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

  11. Research on the stability analysis and design of soil tunnel surrounding rock

    Institute of Scientific and Technical Information of China (English)

    Zheng Yingren; Qiu Chenyu; Xiao Qiang

    2010-01-01

    The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel and the size of the plastic zone of surrounding rock as the criterion of stability.So the writers put forward the idea that the safety factor of surrounding rock calculated through strength reduction FEM(finit element method)should be regarded as the criterion of stability,which has strict mechanical basis and unified standard and would not be influenced by other factors.The paper also studies the safety factors of tunnel surrounding rock(safety factors of shear and tension failure)and lining and some methods of designing and calculating tunnels.At last,the writers take the loess tunnel for instance and show the design and calculation results of two-lane railway tunnel.

  12. Rock Pressure on Tunnel with Shallow Depth in Geologically Inclined Bedding Strata

    Institute of Scientific and Technical Information of China (English)

    Zhou Xiaojun; Li Zelong; Yang Changyu; Gao Yang

    2006-01-01

    The method to calculate rock pressure to which the lining structure of tunnel with shallow depth is subjected in geologically inclined bedding strata is analyzed and put forward. Both the inclination angle of bedding strata as well as the internal friction angle of bedding plane and its cohesion all exert an influence upon the magnitude of the asymmetric rock pressure applied to tunnel. The feature that rock pressure applied to tunnel structure varies with the inclination angle of bedding strata is discussed. At last, the safety factor, which is utilized to evaluate the working state of tunnel lining structure, is calculated for both symmetric and asymmetric lining structures. The calculation results elucidate that the asymmetric tunnel structure can be more superior to bear rock pressure in comparison with the symmetric one and should be adopted in engineering as far as possible.

  13. Effects of tunneling on groundwater flow and swelling of clay-sulfate rocks

    Science.gov (United States)

    Butscher, Christoph; Einstein, Herbert H.; Huggenberger, Peter

    2011-11-01

    Swelling of clay-sulfate rocks is a major threat in tunneling. It is triggered by the transformation of the sulfate mineral anhydrite into gypsum as a result of water inflow in anhydrite-containing layers after tunnel excavation. The present study investigates the hydraulic effects of tunneling on groundwater flow and analyzes how hydraulic changes caused by excavation lead to water inflow into anhydrite-containing layers in the tunnel area. Numerical groundwater models are used to conduct scenario simulations that allow one to relate hydrogeological conditions to rock swelling. The influence of the topographic setting, the excavation-damaged zone around the tunnel, the sealing effect of the tunnel liner, and the geological configuration are analyzed separately. The analysis is performed for synthetic situations and is complemented by a case study from a tunnel in Switzerland. The results illustrate the importance of geological and hydraulic information when assessing the risk of swelling at an actual site.

  14. Analysis of potential cave-in from fault zones in hard rock subsea tunnels

    Science.gov (United States)

    Nilsen, B.

    1994-04-01

    As a part of a research program on the rock engineering aspects of hard rock subsea tunnelling, analyses of potential cave-in from fault zones have been carried out at the Norwegian Institute of Technology. This is a topic of great importance for the planning of future subsea tunnels, and particularly for the selection of the minimum rock cover of such projects. The paper is divided into three main parts: a) review of cases of instability in Norwegian subsea tunnels, b) evaluation of theoretical maximum sliding, and c) discussion of cases of cave-in in tunnels under land. In theory, a cave-in during subsea tunnelling may propagate far higher than the normal minimum rock cover. Taking into consideration the comprehensive geo-investigations that are always carried out for subsea tunnel projects today, it would, however, be unrealistic to base the dimensioning of rock cover for future projects on worst-case scenarios. Consequently, the main result of this study is to emphasize the importance of comprehensive geo-investigations, detailed tunnel mapping, a high degree of readiness during tunnelling and a thorough quality control.

  15. Boring of full scale deposition holes using a novel dry blind boring method

    Energy Technology Data Exchange (ETDEWEB)

    Autio, J.; Kirkkomaeki, T. [Saanio and Riekkola Oy, Helsinki (Finland)

    1996-10-01

    Three holes the size of deposition holes (depth 7.5 m and diameter 1.5 m) were bored in the Research Tunnel at Olkiluoto, Finland. A novel full-face boring technique was used based on rotary crushing of rock and removal of crushed rock by vacuum flushing through the drill string. The purpose of the work was to demonstrate the feasibility of the technique. During the boring test procedures were carried out in order to determine the effect of changes in operating parameters on the performance of the boring machine and the quality of the hole. The boring method was found to be technically feasible and efficient. Evaluation of the quality of the hole included studies of the geometry of the hole, measurements of the surface roughness using a laser profilometer and study of excavation disturbances in the zone adjacent to the surface of the holes using two novel methods, He-gas diffusion and the {sup 14}C-polymethylmethacrylate methods. 43 refs.

  16. Stresses and Shear Fracture Zone of Jinshazhou Tunnel Surrounding Rock in Rich Water Region

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jun-jie; LOU Xiao-ming

    2008-01-01

    Field evidence has shown that large-scale and unstable discontinuous planes in the rock mass surrounding tunnels in rich water region are probably generated after excavation. The tunnel surrounding rock was divided into three zones, including elastic zone, plastic damage zone and shear fracture zone fof assessing the stability of the tunnel surrounding rock. By local hydrogeology, the stresses of surrounding rock of Jinshazhou circular tunnel was analyzed and the stress solutions on the elastic and plastic damage zones were obtained by applying the theories of fluid-solid coupling and elasto-plastic damage mechanics. The shear fracture zone generated by joints was studied and its range was determined by using Mohr-Coulomb strength criterion. Finally, the correctness of the theoretical results was validated by comparing the scopes of shear fracture zones calculated in this paper with those from literature.

  17. Numerical Analysis of Advanced Displacement in Construction Progress of Tunnel Excavation with Weak Surrounding Rock

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2013-07-01

    Full Text Available Analysis of advanced displacement in construction progress of tunnel excavation with weak surrounding rock is carried out by numerical method and comparison of model test result. In allusion to the problems of regional landslides and extruded large-deformation seriously impacting the stability of rock mass in construction process of large-section tunnel with weak surrounding rock, the elastic-plastic numerical simulation relying on Liangshui tunnel of Lan-Yu railroad is conducted on mechanical behaviors and deformation steric effect of tunnel construction and the calculation results are compared with the modeling data. The research results show that: the steric effect of excavation face is the dominant factor in the incidence of working face and the stress of surrounding rocks gradually releases from excavation face; the range of 0.5~1 times the cave diameter around rock mass in front of working face is the disturbance range and the key area of stabilization and reinforcement for wake surrounding rock. According to the analysis and construction practice, the supporting structure of large-section tunnel with weak surrounding rock should be established as soon as possible to control the displacement change of surrounding rock in the range of load-bearing ring, reduce disturbance and improve the self-bearing capability of surrounding rock. Because of the distinct excavation steric effect of weak surrounding rock, the secondary lining structure must be established in time to bear the later pressure and restrict the large displacement of surrounding rock. The research results can provide reliable basis for engineering stability control of analogous tunnels.

  18. Dynamic design method for deep hard rock tunnels and its application

    Institute of Scientific and Technical Information of China (English)

    Xia-Ting Feng; Chuanqing Zhang; Shili Qiu; Hui Zhou; Quan Jiang; Shaojun Li

    2016-01-01

    Numerous deep underground projects have been designed and constructed in China, which are beyond the current specifications in terms of scale and construction difficulty. The severe failure problems induced by high in situ stress, such as rockburst, spalling, damage of deep surrounding rocks, and time-dependent damage, were observed during construction of these projects. To address these problems, the dynamic design method for deep hard rock tunnels is proposed based on the disintegration process of surrounding rocks using associated dynamic control theories and technologies. Seven steps are basically employed: (i) determination of design objective, (ii) characteristics of site, rock mass and project, and identification of constraint conditions, (iii) selection or development of global design strategy, (iv) determination of modeling method and software, (v) preliminary design, (vi) comprehensive integrated method and dynamic feedback analysis, and (vii) final design. This dynamic method was applied to the construction of the headrace tunnels at Jinping II hydropower station. The key technical issues encountered during the construction of deep hard rock tunnels, such as in situ stress distribution along the tunnels, mechanical properties and constitutive model of deep hard rocks, determination of me-chanical parameters of surrounding rocks, stability evaluation of surrounding rocks, and optimization design of rock support and lining, have been adequately addressed. The proposed method and its application can provide guidance for deep underground projects characterized with similar geological conditions.

  19. Numerical analysis and field monitoring tests on shallow tunnels under weak surrounding rock

    Institute of Scientific and Technical Information of China (English)

    刘建华; 刘晓明; 张永杰; 肖庭

    2015-01-01

    The Jianpudong No. 4 tunnel is a shallow tunnel, which belongs to Shaoshan County scenic highway in Hunan province, China and whose surrounding rock is weak. According to its characteristics, the field monitoring tests and numerical analysis were done. The mechanical characteristics of shallow tunnels under weak surrounding rock and the stress−strain rule of surrounding rock and support were analyzed. The numerical analysis results show that the settlement caused by upper bench excavating accounts for 44% of the total settlement, and the settlement caused by tunnel upper bench supporting accounts for 56% of the total settlement. The maximum axial force of shotcrete lining is 177.2 kN, which locates in hance under the secondary lining. The maximum moment of shotcrete lining is 5.08 kN·m, which locates in the arch foot. The stress curve of steel arch has three obvious stages during the tunnel construction. The maximum axial force of steel arch is 297.4 kN, which locates in tunnel vault. The axial forces of steel arch are respectively 23.5 kN and−21.8 kN, which is influenced by eccentric compression of shallow tunnel and locates in hance. The results show that there is larger earth pressure in tunnel vault which is most unfavorable position of steel arch. Therefore, the advance support should be strengthened in tunnel vault during construction process.

  20. Why are some microorganisms boring?

    Science.gov (United States)

    Cockell, Charles S; Herrera, Aude

    2008-03-01

    Microorganisms from diverse environments actively bore into rocks, contributing significantly to rock weathering. Carbonates are the most common substrate into which they bore, although there are also reports of microbial borings into volcanic glass. One of the most intriguing questions in microbial evolutionary biology is why some microorganisms bore. A variety of possible selection pressures, including nutrient acquisition, protection from UV radiation and predatory grazing could promote boring. None of these pressures is mutually exclusive and many of them could have acted in concert with varying strengths in different environments to favour the development of microorganisms that bore. We suggest that microbial boring might have begun in some environments as a mechanism against entombment by mineralization.

  1. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2014-06-01

    Full Text Available Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  2. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Institute of Scientific and Technical Information of China (English)

    Hui Zhou; Chuanqing Zhang; Zhen Li; Dawei Hu; Jing Hou

    2014-01-01

    Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  3. Stability of Large Parallel Tunnels Excavated in Weak Rocks: A Case Study

    Science.gov (United States)

    Ding, Xiuli; Weng, Yonghong; Zhang, Yuting; Xu, Tangjin; Wang, Tuanle; Rao, Zhiwen; Qi, Zufang

    2017-09-01

    Diversion tunnels are important structures for hydropower projects but are always placed in locations with less favorable geological conditions than those in which other structures are placed. Because diversion tunnels are usually large and closely spaced, the rock pillar between adjacent tunnels in weak rocks is affected on both sides, and conventional support measures may not be adequate to achieve the required stability. Thus, appropriate reinforcement support measures are needed, and the design philosophy regarding large parallel tunnels in weak rocks should be updated. This paper reports a recent case in which two large parallel diversion tunnels are excavated. The rock masses are thin- to ultra-thin-layered strata coated with phyllitic films, which significantly decrease the soundness and strength of the strata and weaken the rocks. The behaviors of the surrounding rock masses under original (and conventional) support measures are detailed in terms of rock mass deformation, anchor bolt stress, and the extent of the excavation disturbed zone (EDZ), as obtained from safety monitoring and field testing. In situ observed phenomena and their interpretation are also included. The sidewall deformations exhibit significant time-dependent characteristics, and large magnitudes are recorded. The stresses in the anchor bolts are small, but the extents of the EDZs are large. The stability condition under the original support measures is evaluated as poor. To enhance rock mass stability, attempts are made to reinforce support design and improve safety monitoring programs. The main feature of these attempts is the use of prestressed cables that run through the rock pillar between the parallel tunnels. The efficacy of reinforcement support measures is verified by further safety monitoring data and field test results. Numerical analysis is constantly performed during the construction process to provide a useful reference for decision making. The calculated deformations are in

  4. Study on visualization simulation of temperature distributions in surrounding rock of tunnels in a deep mine

    Institute of Scientific and Technical Information of China (English)

    SUN Pei-de

    2006-01-01

    Based on the mathematical model for rock temperature distribution in a geothermal field, the properties of rock temperature distribution in geothermal field for four kinds of surrounding rock cross-sections of tunnels in a deep mine were simulated by using finite element method. It is shown that the relationship for rock temperature distribution varied with the geothermal parameters, time and space. Namely, 2-dimensional time-dependent isograms clearly showed the process for rock temperature variation and distribution in a geothermal field which has been redisplayed with visualization numerical simulation.

  5. Rapid Construction Technology for a Shallow-buried Bored Tunnel in Sandy Pebble Stratum%砂卵石地层浅埋暗挖法快速施工技术

    Institute of Scientific and Technical Information of China (English)

    刘魁刚; 王文正; 裴书锋

    2011-01-01

    The running tunnel of phase three of the Beijing Subway Line 4 passes through a sandy pebble stratum, which creates construction risks of surrounding rock collapse, tunnel bottom swell, sand outflow and soil settlement above the roof. It also affects the road and bridge safety and results in difficult drilling and grouting. This paper addresses the optimization of the design and grouting parameters of small conduits and discusses the construction principles of "early covering, fine short tube, less disturbance, quick setting, abutment reinforcing and middle slotting" regarding the bored tunnel with a shallow overburden at the sandy pebble stratum. The construction technology of the bench method is introduced, which includes the key points of counter core soil excavation, small conduit grouting and locking anchor pipe, with a monthly advance rate of 60~70 m.%北京地铁四号线三期区间隧道穿越砂卵石地层,存在围岩易塌落、隧道底部起鼓和涌砂、顶板上方土体沉降,影响道路和桥梁安全等施工风险,并且不易钻孔注浆,工效较低.针对以上问题,改进了小导管设计参数和注浆参数,提出了砂卵石地层浅埋暗挖法“早封面、管细短、少扰动、快凝固、固拱脚、中拉槽”施工原则,施工效果较好,月进度达60~70 m.文章介绍了砂卵石地层台阶法施工工艺,提出了下台阶反核心土开挖,以及小导管注浆和锁脚锚管施工要点.

  6. Prediction of Brittle Failure for TBM Tunnels in Anisotropic Rock: A Case Study from Northern Norway

    Science.gov (United States)

    Dammyr, Øyvind

    2016-06-01

    Prediction of spalling and rock burst is especially important for hard rock TBM tunneling, because failure can have larger impact than in a drill and blast tunnel and ultimately threaten excavation feasibility. The majority of research on brittle failure has focused on rock types with isotropic behavior. This paper gives a review of existing theory and its application before a 3.5-m-diameter TBM tunnel in foliated granitic gneiss is used as a case to study brittle failure characteristics of anisotropic rock. Important aspects that should be considered in order to predict brittle failure in anisotropic rock are highlighted. Foliation is responsible for considerable strength anisotropy and is believed to influence the preferred side of v-shaped notch development in the investigated tunnel. Prediction methods such as the semi- empirical criterion, the Hoek- Brown brittle parameters, and the non-linear damage initiation and spalling limit method give reliable results; but only as long as the angle between compression axis and foliation in uniaxial compressive tests is relevant, dependent on the relation between tunnel trend/plunge, strike/dip of foliation, and tunnel boundary stresses. It is further demonstrated that local in situ stress variations, for example, due to the presence of discontinuities, can have profound impact on failure predictions. Other carefully documented case studies into the brittle failure nature of rock, in particular anisotropic rock, are encouraged in order to expand the existing and relatively small database. This will be valuable for future TBM planning and construction stages in highly stressed brittle anisotropic rock.

  7. Numerical Analysis of Effect of Water on Explosive Wave Propagation in Tunnels and Surrounding Rock

    Institute of Scientific and Technical Information of China (English)

    XIA Chang-jing; SONG Zhen-duo; TIAN Lu-lu; LIU Hong-bin; WANG Lu; WU Xiao-fang

    2007-01-01

    Based on the application of practical engineering, propagation processes of explosive waves in rock with water well and tunnel are simulated by ANSYS/LS-DYNA software. The evolution of damage in rock is presented. The effect of water on the damage of the concrete slab in a tunnel is compared with damage inflicted without water. The numerical simulation illustrates that water plays an important role in the evolution of damage of the concrete slab in a mine tunnel. In the presence of water in the rock the concrete slab is damaged more severely than without water in rock. The effect of water location in the rock is also considered. It is found that the concrete slab in the tunnel shows various degrees of damage as a function of the different locations of water. Attenuation laws of stress waves over time-space in rock with water are also obtained. Numerical results indicate that, under blast loading, there are three zones in the rock: a crushed zone nearby the explosive charge, a damaged zone and an elastic zone. The conclusions of numerical analysis may provide references for blasting designs and structure protection.

  8. Numerical Simulation of Rock Burst in Circular Tunnels Under Unloading Conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Rock burst in a circular tunnel under high in-situ stress conditions was investigated with a numerical method coupled the rock failure process theory (RFPA) and discontinuous deformation theory (DDA).Some numerical tests were carraied out to investigate the failuer patterns of circular tunnel under unloading conditions.Compared the results under loading conditions, the shapes of failure zones are more regular under the unloading conditions.The failure patterns in the same type of rock mass are clearly different because of non-homogeneity of the rock material.The extension of cracks shows some predictability with an increasing of in-situ stress.When the homogeneity index of rocks (m) is either relatively high or low and lateral pressure coefficients (λ) is high, the number of regular shear slide cracks decreases and the probability of a rock burst also becomes lower.Our numerical simulation results show that the stability of surface rock and the natural bedding stratification of rock material greatly affect rock bursts.Installing bolts with due diligence and suitably can effectively prevent rock bursts.However, it is not effective to control rock bursts by releasing the strain energy with normal pre-boreholes.

  9. A new technology for hard-rock tunneling based on drilling and hydraulic impact breaking

    Institute of Scientific and Technical Information of China (English)

    Long Risheng; Sun Shaoni; Lian Zisheng; Liao Yaoyao; Qin Xiaofeng

    2015-01-01

    In order to realize the safety, high efficiency and rapidity of hard rock tunneling, we propose the drilling&hydraulic impact hard-rock tunneling (DHIHT) technology and method. Based on the LS-DYNA explicit module and APDL programming, the key parameters of DHIHT, including drilling spacing and drilling radius, were investigated. The simulation results show that: the drilling spacing should not exceed 0.20 m-larger distances weaken the actual breaking effect;the best drilling radius is about 0.035 m, lar-ger or smaller distances would both decrease the effect of drilling-hole free surfaces. The field impact breaking experiments were conducted in Baitaizi township granite quarry, Jinzhou, Liaoning province, China. The experiment results indicate that DHIHT is a feasible method for hard-rock tunneling, but its efficiency still needs to be further optimized and improved.

  10. Tunnel behaviour and support associated with the weak rock masses of flysch

    Institute of Scientific and Technical Information of China (English)

    V.Marinos

    2014-01-01

    Flysch formations are generally characterised by evident heterogeneity in the presence of low strength and tectonically disturbed structures. The complexity of these geological materials demands a more specialized geoengineering characterisation. In this regard, the paper tries to discuss the standardization of the engineering geological characteristics, the assessment of the behaviour in underground excava-tions, and the instructionseguidelines for the primary support measures for flysch layer qualitatively. In order to investigate the properties of flysch rock mass, 12 tunnels of Egnatia Highway, constructed in Northern Greece, were examined considering the data obtained from the design and construction records. Flysch formations are classified thereafter in 11 rock mass types (IeXI), according to the siltstone esandstone proportion and their tectonic disturbance. A special geological strength index (GSI) chart for heterogeneous rock masses is used and a range of geotechnical parameters for every flysch type is presented. Standardization tunnel behaviour for every rock mass type of flysch is also presented, based on its site-specific geotechnical characteristics such as structure, intact rock strength, persistence and complexity of discontinuities. Flysch, depending on its types, can be stable even under noticeable overburden depth, and exhibit wedge sliding and wider chimney type failures or cause serious defor-mation even under thin cover. Squeezing can be observed under high overburden depth. The magnitude of squeezing and tunnel support requirements are also discussed for various flysch rock mass types under different overburdens. Detailed principles and guidelines for selecting immediate support mea-sures are proposed based on the principal tunnel behaviour mode and the experiences obtained from these 12 tunnels. Finally, the cost for tunnel support from these experiences is also presented.

  11. Tunnel behaviour and support associated with the weak rock masses of flysch

    Directory of Open Access Journals (Sweden)

    V. Marinos

    2014-06-01

    Full Text Available Flysch formations are generally characterised by evident heterogeneity in the presence of low strength and tectonically disturbed structures. The complexity of these geological materials demands a more specialized geoengineering characterisation. In this regard, the paper tries to discuss the standardization of the engineering geological characteristics, the assessment of the behaviour in underground excavations, and the instructions–guidelines for the primary support measures for flysch layer qualitatively. In order to investigate the properties of flysch rock mass, 12 tunnels of Egnatia Highway, constructed in Northern Greece, were examined considering the data obtained from the design and construction records. Flysch formations are classified thereafter in 11 rock mass types (I–XI, according to the siltstone–sandstone proportion and their tectonic disturbance. A special geological strength index (GSI chart for heterogeneous rock masses is used and a range of geotechnical parameters for every flysch type is presented. Standardization tunnel behaviour for every rock mass type of flysch is also presented, based on its site-specific geotechnical characteristics such as structure, intact rock strength, persistence and complexity of discontinuities. Flysch, depending on its types, can be stable even under noticeable overburden depth, and exhibit wedge sliding and wider chimney type failures or cause serious deformation even under thin cover. Squeezing can be observed under high overburden depth. The magnitude of squeezing and tunnel support requirements are also discussed for various flysch rock mass types under different overburdens. Detailed principles and guidelines for selecting immediate support measures are proposed based on the principal tunnel behaviour mode and the experiences obtained from these 12 tunnels. Finally, the cost for tunnel support from these experiences is also presented.

  12. Estimating large-scale fractured rock properties from radon data collected in a ventilated tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Unger, Andre; Finsterle, Stefan; Bodvarsson, Gudmundur S.

    2003-05-12

    To address regulatory issues regarding worker safety, radon gas concentrations have been monitored as part of the operation of a deep tunnel excavated from a highly fractured tuff formation. The objective of this study was to examine the potential use of the radon data to estimate large-scale formation properties of fractured rock. An iTOUGH2 model was developed to predict radon concentrations for prescribed ventilation rates. The numerical model was used (1) to estimate the permeability and porosity of the fractured formation at the length scale of the tunnel and extending tens of meters into the surrounding rock, and (2) to understand the mechanism leading to radon concentrations that potentially exceed the regulatory limit. The mechanism controlling radon concentrations in the tunnel is a function of atmospheric barometric fluctuations propagated down the tunnel. In addition, a slight suction is induced by the ventilation system. The pressure fluctuations are dampened in the fractured formation according to its permeability and porosity. Consequently, as the barometric pressure in the tunnel drops, formation gases from the rock are pulled into the opening, resulting in high radon concentrations. Model calibration to both radon concentration data measured in the tunnel and gas phase pressure fluctuations observed in the formation yielded independent estimates of effective, large-scale fracture permeability and porosity. The calibrated model was then used as a design tool to predict the effect of adjusting the ventilation-system operation strategy for reducing the probability that radon gas concentrations will exceed the regulatory limit.

  13. Upper bound analytical solution for surrounding rock pressure of shallow unsymmetrical loading tunnels

    Institute of Scientific and Technical Information of China (English)

    雷明锋; 彭立敏; 施成华; 谢友均; 谭立新

    2015-01-01

    By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing “code method” and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.

  14. Study on Fluid-Lining-Rock Coupling Interaction of Diversion Tunnel under Seismic Load

    Directory of Open Access Journals (Sweden)

    Jian Deng

    2015-01-01

    Full Text Available Fluid-lining-rock coupling interaction of diversion tunnel under seismic load is a critical problem in seismic research which should be solved urgently. Based on the explicit finite element method for dynamic analysis of single-phase fluid and solid medium and combining with the boundary conditions of coupling interface, a dynamic explicit finite element solving format of diversion tunnel considering fluid-lining coupling interaction is established. In light of the basic theory of dynamic contact force method and applying the nonlinear hyperbolic constitutive model of contact surface, a dynamic explicit finite element time-domain integral equation of combined bearing of lining and surrounding rocks, which takes the bond-slip behavior of the contact surface into account, is put forward. Meanwhile, considering the dynamic interaction process of inner water and lining, lining and surrounding rocks, an explicit finite element numerical simulation analysis method of fluid-lining-rock coupling interaction of diversion tunnel under seismic load is presented. The calculation results of case study reasonably reflect the seismic response characteristics of diversion tunnel, and an effective analysis method is provided for the aseismic design of hydraulic tunnel.

  15. Dynamic Analysis of Tunnel in Weathered Rock Subjected to Internal Blast Loading

    Science.gov (United States)

    Tiwari, Rohit; Chakraborty, Tanusree; Matsagar, Vasant

    2016-11-01

    The present study deals with three-dimensional nonlinear finite element (FE) analyses of a tunnel in rock with reinforced concrete (RC) lining subjected to internal blast loading. The analyses have been performed using the coupled Eulerian-Lagrangian analysis tool available in FE software Abaqus/Explicit. Rock and RC lining are modeled using three-dimensional Lagrangian elements. Beam elements have been used to model reinforcement in RC lining. Three different rock types with different weathering conditions have been used to understand the response of rock when subjected to blast load. The trinitrotoluene (TNT) explosive and surrounding air have been modeled using the Eulerian elements. The Drucker-Prager plasticity model with strain rate-dependent material properties has been used to simulate the stress-strain response of rock. The concrete damaged plasticity model and Johnson-Cook plasticity model have been used for the simulation of stress-strain response of concrete and steel, respectively. The explosive (TNT) has been modeled using Jones-Wilkins-Lee (JWL) equation of state. The analysis results have been studied for stresses, deformation and damage of RC lining and the surrounding rock. It is observed that damage in RC lining results in higher stress in rock. Rocks with low modulus and high weathering conditions show higher attenuation of shock wave. Higher amount of ground shock wave propagation is observed in case of less weathered rock. Ground heave is observed under blast loading for tunnel close to ground surface.

  16. Zonal disintegration mechanism of isotropic rock masses around a deep spherical tunnel

    Institute of Scientific and Technical Information of China (English)

    谷新保; 毕靖; 许明

    2015-01-01

    In order to investigate zonal disintegration mechanism of isotropic rock masses around a deep spherical tunnel, a new mechanical model subjected to dynamic unloading under hydrostatic pressure condition is proposed. The total elastic stress-field distributions is determined using the elastodynamic equation. The effects of unloading rate and dynamic mechanical parameters of isotropic deep rock masses on the zonal disintegration phenomenon of the surrounding rock masses around a deep spherical tunnel as well as the total elastic stress field distributions are considered. The number and size of fractured and non-fractured zones are determined by using the Hoek-Brown criterion. Numerical computation is carried out. It is found from numerical results that the number of fractured zones increases with increasing the disturbance coefficient, in-situ stress, unloading time and unloading rate, and it decreases with increasing parameter geological strength index, the strength parameter and the uniaxial compressive strength of intact rock.

  17. Water flow in fractured rock masses: numerical modeling for tunnel inflow assessment

    Science.gov (United States)

    Gattinoni, P.; Scesi, L.; Terrana, S.

    2009-04-01

    Water circulation in rocks represents a very important element to solve many problems linked with civil, environmental and mining engineering. In particular, the interaction of tunnelling with groundwater has become a very relevant problem not only due to the need to safeguard water resources from impoverishment and from the pollution risk, but also to guarantee the safety of workers and to assure the efficiency of the tunnel drainage systems. The evaluation of the hydrogeological risk linked to the underground excavation is very complex, either for the large number of variables involved or for the lack of data available during the planning stage. The study is aimed to quantify the influence of some geo-structural parameters (i.e. discontinuities dip and dip direction) on the tunnel drainage process, comparing the traditional analytical method to the modeling approach, with specific reference to the case of anisotropic rock masses. To forecast the tunnel inflows, a few Authors suggest analytic formulations (Goodman et al., 1965; Knutsson et al., 1996; Ribacchi et al., 2002; Park et al., 2008; Perrochet et al., 2007; Cesano et al., 2003; Hwang et al., 2007), valid for infinite, homogeneous and isotropic aquifer, in which the permeability value is given as a modulus of equivalent hydraulic conductivity Keq. On the contrary, in discontinuous rock masses the water flow is strongly controlled by joints orientation, by their hydraulic characteristics and by rocks fracturing conditions. The analytic equations found in the technical literature could be very useful, but often they don't reflect the real phenomena of the tunnel inflow in rock masses. Actually, these equations are based on the hypothesis of homogeneous aquifer, and then they don't give good agreement for an heterogeneous fractured medium. In this latter case, the numerical modelling could provide the best results, but only with a detailed conceptual model of the water circulation, high costs and long

  18. Vibrations due to a test train at variable speeds in a deep bored tunnel embedded in London clay

    Science.gov (United States)

    Degrande, G.; Schevenels, M.; Chatterjee, P.; Van de Velde, W.; Hölscher, P.; Hopman, V.; Wang, A.; Dadkah, N.

    2006-06-01

    This paper reports on the results of in situ vibration measurements that have been performed within the frame of the CONVURT project at a site in Regent's Park on the Bakerloo line of London Underground during 35 passages of a test train at a speed between 20 and 50 km/h. Vibration measurements have been performed on the axle boxes of the test train, on the rails, on the tunnel invert and tunnel wall, and in the free field, both at the surface and at a depth of 15 m. Measurements have also been made on floors and columns of two buildings in a row of Regency houses at a distance of 70 m from the tunnel. Prior to these vibration measurements, the dynamic soil characteristics have been determined by in situ and laboratory testing. Rail and wheel roughness have been measured and the track characteristics have been determined by rail receptance and wave decay measurements. Time histories and one-third octave band RMS spectra of the measured velocities are discussed and the variation of the peak particle velocity and the frequency content as a function of the train speed and the distance to the tunnel are elaborated.

  19. ALTERNATING METHOD STUDY ON STRESS ANALYSIS OF SURROUNDING ROCK FOR TWO RANDOM GEOMETRY TUNNELS

    Institute of Scientific and Technical Information of China (English)

    吕爱钟; 张路青

    1997-01-01

    The stress analysis of surrounding rock for two random geometry tunnels is studied inthis paper by using Schwarz's alternating method. The simple and effective alternating algorithm is found, in which the surplus surface force is approximated by Fourier series, thus the iteration derivation can be conducted according to the precision required, finally, the stress results with high precision are obtained.

  20. Deterioration Mechanisms and Durability of Sprayed Concrete for Rock Support in Tunnels

    NARCIS (Netherlands)

    Hagelia, P.

    2011-01-01

    Steel fibre reinforced sprayed concretes used for rock support in tunnels are subjected to variable and complex exposure conditions. Structurally weakened concretes (5 to 35 years old) were investigated with respect to deterioration mechanisms, sources of aggressive agents and related engineering as

  1. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    Directory of Open Access Journals (Sweden)

    Zhengzhao Liang

    2013-01-01

    Full Text Available To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE and far infrared (FIR techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE was calculated to predict the tunnel rock burst. The results showed that the vertical stress enhanced the stability of the tunnel, and the tunnels with higher confining pressure demonstrated a more abrupt and strong rock burst. Abnormal temperature changes around the wall were observed prior to the rock burst of the tunnel. Analysis of the AE events showed that a sudden drop and then a quiet period could be considered as the precursors to forecast the rock burst hazard. Statistical analysis indicated that rock fragment spalling occurred earlier than the abnormal temperature changes, and the abnormal temperature occurred earlier than the descent of the AE b-value. The analysis indicated that the temperature changes were more sensitive than the AE b-value changes to predict the tunnel rock bursts.

  2. Rock blasting and explosives engineering

    Energy Technology Data Exchange (ETDEWEB)

    Persson, P.-A.; Holmberg, R.; Lee, J. (New Mexico Institute of Mining and Technology, Socorro, NM (United States). Research Center for Energetic Materials)

    1994-01-01

    The book covers the practical engineering aspects of different kinds of rock blasting. It includes a thorough analysis of the cost of the entire process of tunneling by drilling and blasting compared with full-face boring. It covers the economics of the entire rock blasting operation and its dependence on the size of excavation. The book highlights the fundamentals of rock mechanics, shock waves and detonation, initiation and mechanics of rock motion. It describes the engineering design principles and computational techniques for many separate mining methods and rock blasting operations. 274 refs.

  3. Zonal disintegration phenomenon in enclosing rock mass surrounding deep tunnels Elasto-plastic analysis of stress field of enclosing rock mass

    Institute of Scientific and Technical Information of China (English)

    WU Hao; FANG Qin; ZHANG Ya-dong; GONG Zi-ming

    2009-01-01

    The zonal disintegration phenomenon (ZDP) is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constitutive model of rock mass were used to analyze the elasto-plastic stress field of the enclosing rock mass around a deep round tunnel. The radius of the plastic region and stress of the enclosing rock mass were obtained by introducing dimensionless parameters of radial distance. The results show that tunneling in deep rock mass causes a maximum stress zone to appear in the vicinity of the boundary of the elastic and the plas-tic zone in the surrounding rock mass. Under the compression of a large tangential force and a small radial force, the rock mass in the maximum stress zone was in an approximate uniaxial loading state, which could lead to a split failure in the rock mass.

  4. Rock mechanical conditions at the Aespoe HRL. A study of the correlation between geology, tunnel maintenance and tunnel shape

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Soederhaell, Joergen [SWECO VBB VIAK AB, Stockholm (Sweden)

    2001-12-01

    Maintenance records including scaling, shotcreting and bolting have been kept since the excavation start of Aespoe HRL 1990 together with records of groundwater flow and all other activities taking place in the tunnels. When the facility was constructed one objective was to limit the rock support as much as possible. The reason for this was that it should be possible to go back and easily study the exposed rock surface. Support during the operational phase has only been carried out where and when necessary. This type of maintenance and its location is documented in the digital database each time. The maintenance records have been compiled and areas requiring more maintenance than average noted. An interview has also been held with one of the miners conducting scaling and bolting in the tunnel. His experiences together with the study of the database maintenance records led to the selection of certain areas in the tunnel to be studied by numerical modelling. The probable reason for the need of additional maintenance in all areas, not only these numerically modelled, has been investigated. Almost all maintenance in the main tunnel both during construction and the operational phase has been located in the widened curves of the access tunnel. The maintenance is also located in areas containing veins or intrusions of Smaaland granite or fine-grained granite. These areas are often located in fracture zones of different sizes or show an increasing fracture frequency. The areas numerically modelled indicate stress concentrations or unloaded stress conditions. The stress concentrations are created by the geometry of the niches and side-tunnels in relation to the in situ stress field. The angle between the tunnel and the major principal stress has an impact on the need for maintenance. The areas with the largest angles towards the principal stress direction need more maintenance than the areas almost parallel to the major principal stress direction. The maintenance work in

  5. Numerical simulation on deformation character of surrounding rock masses of Changjiashan tunnel through the gob of coalmine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-pei

    2006-01-01

    Based on the construction project of the Changjiashan tunnel of the freeway,the variety rule of surrounding rock masses of the tunnel through the gob of coalmine was studied by using of finite element methed(FEM). The status of the stress and strain, the variety of the plastic area were simulated in the whole rock mass before and after the tunnel was excavated. The characters of stress and deformation of surrounding rock masses were analyzed when the tunnel was built. It concluded from the numerical simulation that the influence on the tunneling is great when the tunnel passing through the gob of coalmine is excavated, and the relative measures should be taken.

  6. Elasto-plastic analysis of the surrounding rock mass in circular tunnel based on the generalized nonlinear unified strength theory

    Institute of Scientific and Technical Information of China (English)

    Huang Xiujie; Zhang Jixun; Yang Ling; Yang Shikou; Wang Xingli

    2016-01-01

    The present paper aims to establish a versatile strength theory suitable for elasto-plastic analysis of underground tunnel surrounding rock. In order to analyze the effects of intermediate principal stress and the rock properties on its deformation and failure of rock mass, the generalized nonlinear unified strength theory and elasto-plastic mechanics are used to deduce analytic solution of the radius and stress of tunnel plastic zone and the periphery displacement of tunnel under uniform ground stress field. The results show that: intermediate principal stress coefficient b has significant effect on the plastic range, the magnitude of stress and surrounding rock pressure. Then, the results are compared with the unified strength criterion solution and Mohr–Coulomb criterion solution, and concluded that the generalized nonlinear unified strength criterion is more applicable to elasto-plastic analysis of underground tunnel surrounding rock.

  7. Rational Design of Tunnel Supports: Tunnel Support Loading Caused by Rock Failure

    Science.gov (United States)

    1975-05-01

    Minerale , Vol. 41; No. 1, Janvier, pp. 78-92, No. 4, Avril, pp. 313-315, 1959. Translation by C, Pairhurst, University of Nottingham Mining...G,: "Calcul du revetement des tunnels creuses dans des terrains presentant des deformations differees," Industrie Minerale , pp. 13-18

  8. Specification of rock abrasiveness for the purposes of tunnel driving using TBM

    Directory of Open Access Journals (Sweden)

    Miklúšová Viera

    2000-09-01

    Full Text Available This article analyses rock abrasiveness that causes attrition (wearing down of the disintegration indentors. In the case of drilling machines equipped with disc chipper tools it is the attrition of the discs. The attrition of the discs results in the reduction of the drilling rate and the increase in the specific disintegration energy, thus directly affecting the total economic outcome of the mining site (tunnel.Abrasiveness of the rock is the rock’s ability to wear down the working tool during the mutual interaction between the working indentor and the rock in the mechanic rock disintegration process. The disintegration indentor wears down during the interaction, that changes its geometric dimensions, causing the increase in the contact area between the tool and the surface of the rock. The changes in these dimensions consequently alter the rate of advance of the drilling machine and the specific disintegration energy.Abrasiveness is therefore an overall result of physical and mechanical characteristics of the rock during the interaction between the disintegration indentor and the rock. In the present time there is no method that would formulate the rock’s abrasiveness at the hands of physical-mechanical characteristics of the rock. Because the interaction between the tool and the rock depends on the characteristics of the tool, abrasiveness is at present a relative quantity, dependent also on the quality of the disintegration indentors. With the progress in the quality of disintegration tools, the abrasiveness and the attrition of the tool during mechanic rock disintegration changes. From this standpoint it is, in the course of determining the rock’s abrasiveness in the laboratory procedures, needed to eliminate the impact of the disintegration indentor characteristics. By choosing one disintegration indentor type with predetermined physical-mechanical characteristics for the laboratory measurements, we can obtain abrasiveness that

  9. Reactive loading function on tunnel excavation contour in rock mass

    Directory of Open Access Journals (Sweden)

    Lukić Dragan

    2003-01-01

    Full Text Available Investigation of the stress field around the cavity that is loaded or partially loaded at the inner surface by the rotationally symmetric loading is still the contemporary problem in the theory of elasticity. As the contribution to the similar investigations, the paper introduces the new function of loading in the form of the infinite sine series. Besides the definition of the mentioned loading function as the boundary condition on inner surface of the cavity, the paper presents the comparative analysis of the new function with the previously used ones. The said loading function at the inner surface of a cavity is internal loading between rock mass and supporting structure, for the case of homogeneous isotropic elastic medium as the first approximation of the real situation.

  10. Propagation simulation and attenuation law analysis of seismic wave in elastoplastic tunnel rock medium

    Institute of Scientific and Technical Information of China (English)

    ZHAO Tong-bin; LI Jian-gong; XIAO Ya-xun; CHENG Guo-qiang

    2007-01-01

    The energy caused by the dynamic impact in mining engineering forth release and spread by the way of seismic waves, monitoring is an effective way for forecasting mine dynamical disasters, such as rockburst and coal and gas outburst. Three-dimensional dynamic model was built to simulate the propagating progress of seismic waves in the elastoplastic tunnel rock and analyzed the propagating law of perturbation acceleration around tunnel, based on the finite element dynamic analysis software ANSYS/LS-DYNA.The simulation results indicate that: (1) The propagation attenuation of seismic wave is a negative index relationship; (2) The acceleration amplitude of seismic wave decays rapidly in near-field and decays slowly in far-field; (3) When the perturbation is generated in the dead ahead of tunnel, the acceleration of seismic wave become smaller and smaller away from the roadway-rib;(4) The elastic and plastic stress state of tunnel rock is also an important factor for propagation process of wave, the energy of seismic wave is mainly consumed for geometric spreading and plastic deformation in propagation in the elastoplastic medium model.

  11. Influence of underground water seepage flow on surrounding rock deformation of multi-arch tunnel

    Institute of Scientific and Technical Information of China (English)

    LI Xi-bing; ZHANG Wei; LI Di-yuan; WANG Qi-sheng

    2008-01-01

    Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm).Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.

  12. Experimental study on similarity materials for soft rock of deep-buried tunnels

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yu; PENG Hai-you

    2011-01-01

    When every parameter is properly scaled down in accordance with some similarity coefficients, it is possible to study the physical-mechanical properties of rock mass with a scale model. To identify the key mechanisms of soft rock in deep buried tunnels, the proper sand, binder and ratio were selected. During the process, the model manufacture technology was introduced and typical tests were done and the results were presented. The physical and mechanical properties effects caused by each composition were discussed. It is shown that the physical and mechanical properties of chosen ratio material such as uniaxial compressive strength tests, elasticity modulus, tensile strength, internal frictional angle, and Poisson's ratio meet with similarity relationship well. The physical and mechanical properties of deep soft rock are simulated successfully.

  13. Characteristics, causes and control measures of disasters for the soft-rock tunnels in the Wenchuan seismic regions

    Science.gov (United States)

    Wang, Bo; Li, Tianbin; He, Chuan; Zhou, Yi

    2016-08-01

    The Guang(yuan)-Gan(su) Expressway is located in the core areas where the Wenchuan earthquake occurred. The surrounding soft-rocks of several tunnels in this region, such as the Dujiashan and Yangjiashan tunnels, are mainly broken into phyllites due to the severe action of the earthquake. Through analyzing the effects of large deformations, lining damage and collapses, which happen frequently in the soft-rock tunnels in the Guang-Gan Expressway, the characteristics and causes of such geological disasters are obtained. It is demonstrated that the large deformation and collapse occur near the vault and tunnel face. The poor mechanical properties and weak self-bearing capacity of the surrounding rock and the softening caused by groundwater are important contributing factors to these disasters. The lack of experience in the design and construction of tunnels in the meizoseismal area, as well as the aftershocks are other important factors to consider. Field test results indicate that the three-bench and the reserved core soil construction method should be applied to control the stability of broken phyllite tunnels, and that this key technology should be strictly controlled during its construction. In particular, increasing the stiffness of the supporting structure and enclosing of the lining in time are efficient methods to control large deformations and collapses in soft-rock tunnels in the meizoseismal area.

  14. Preliminary evaluation of the rock-mass disturbance resulting from shaft, tunnel, or borehole excavation

    Energy Technology Data Exchange (ETDEWEB)

    Kelsall, P.C.; Case, J.B.; Chabannes, C.R.

    1982-11-01

    The isolation of nuclear wastes in deep, mined repositories will require the sealing of all penetrations such as shafts, tunnels, or boreholes, into or nearby the repository. An important consideration in penetration sealing is the disturbed zone, or zone of increased permeability, which may be created in the rock mass adjacent to the penetration as a result of excavation. Disturbed zone characteristics for shafts, tunnels, and boreholes are evaluated by analysis and by review of previous laboratory and field tests. Consideration is given also to test methods for characterizing the disturbed zone in situ, and to methods for treating the disturbed zone in seal construction. Laboratory tests indicate that the disturbed zone associated with small-diameter boreholes is probably insignificant. In contrast, the disturbed zone is potentially a significant pathway for flow through seals placed in shafts and tunnels. Because a major mechanism for disturbance is believed to be stress relief acting across fractures, much of the disturbance occurs regardless of the excavation method used. Various test methods are proposed for disturbed zone characterization in shafts and tunnels, with seismic refraction identified as a promising index test. A proposed method for treating the disturbed zone uses cutoffs constructed as a series of overlapping boreholes. Each hole is filled with concrete which is allowed to cure before the adjacent holes are drilled.

  15. Energy analysis of face stability of deep rock tunnels using nonlinear Hoek-Brown failure criterion

    Institute of Scientific and Technical Information of China (English)

    张佳华; 李永鑫; 许敬叔

    2015-01-01

    The nonlinear Hoek-Brown failure criterion was introduced to limit analysis by applying the tangent method. Based on the failure mechanism of double-logarithmic spiral curves on the face of deep rock tunnels, the analytical solutions of collapse pressure were derived through utilizing the virtual power principle in the case of pore water, and the optimal solutions of collapse pressure were obtained by using the optimization programs of mathematical model with regard of a maximum problem. In comparison with existing research with the same parameters, the consistency of change rule shows the validity of the proposed method. Moreover, parametric study indicates that nonlinear Hoek-Brown failure criterion and pore water pressure have great influence on collapse pressure and failure shape of tunnel faces in deep rock masses, particularly when the surrounding rock is too weak or under the condition of great disturbance and abundant ground water, and in this case, supporting measures should be intensified so as to prevent the occurrence of collapse.

  16. Evaluation of Spalling Fallout on Excavation Disturbed Zone under Deep Hard Rock Tunnel

    Science.gov (United States)

    Azit, Romziah; Ashraf Mohamaed Ismail, Mohd; You Jiang, Thang

    2017-08-01

    The prediction of compressive stress-induced failures is of concern when designing and constructing facilities in rock for deep underground excavation. The purpose of this study is to model compressive stress-induced failure and fallouts with appropriate material models and strength parameters for deep hard rock tunnel excavation. Three method of numerical modelling are used, which are Generalised Hoek-Brown; Mohr-Coulomb; and Mohr-Coulomb with Cohesion Softening Friction Hardening (CSFH) material models for capturing the observed rock behaviour. A parametric study was also carried out to verify that the peak friction angle of 10° used in CSFH model. The results show that numerical models used only Generalised Hoek-Brown and Mohr Coulomb strength parameters does not show a good agreement with the observed fallout. The comparison revealed that the numerical models using the Mohr-Coulomb with CSFH provides most realistic to the observation fallout length. This model is valid for prediction of failure and fallouts in hard rock masses with high quality (GSI >65 MPa; intact rock compressive strength >70MPa).

  17. Effect Blasting Excavation of Yujiapeng Tunnel on Stability of Nearby Giant Dangerous Rock Masses (DRM)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of the interpretation of engineering geology of the tunnel and of its adjacent dangerous rock masses (DRM), this paper presents the energy and vibration parameters of the explosion that propagates in different blasting modes according to the experimental formulas now usually employed. Then the stability checking computation of T8-T12 area, the most dangerous area of DRM, is conducted under the limited blasting condition and with the limited equilibrium method. The result shows that the effect on the stability is only 5.5 % and that this area also contains certain safety reserves.

  18. Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Ittner, Henrik (Chalmers Univ. of Technology, Goeteborg (Sweden))

    2009-07-01

    This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

  19. Effects of statistical distribution of joint trace length on the stability of tunnel excavated in jointed rock mass

    Directory of Open Access Journals (Sweden)

    Kayvan Ghorbani

    2015-12-01

    Full Text Available The rock masses in a construction site of underground cavern are generally not continuous, due to the presence of discontinuities, such as bedding, joints, faults, and fractures. The performance of an underground cavern is principally ruled by the mechanical behaviors of the discontinuities in the vicinity of the cavern. During underground excavation, many surrounding rock failures have close relationship with joints. The stability study on tunnel in jointed rock mass is of importance to rock engineering, especially tunneling and underground space development. In this study, using the probability density distribution functions of negative exponential, log-normal and normal, we investigated the effect of joint trace length on the stability parameters such as stress and displacement of tunnel constructed in rock mass using UDEC (Universal Distinct Element Code. It was obtained that normal distribution function of joint trace length is more critical on the stability of tunnel, and exponential distribution function has less effect on the tunnel stability compared to the two other distribution functions.

  20. The Delft Sand, Clay and Rock Cutting Model

    NARCIS (Netherlands)

    Miedema, S.A.

    2014-01-01

    Sand, clay and rock have to be excavated for a variety of purposes, such as dredging, trenching, mining (including deep sea mining), drilling, tunnel boring and many other applications. Many excavations take place on dry land, but they are also frequently required in completely saturated conditions,

  1. Numerical simulation and analysis of moisture-heat coupling of soft rock tunnels in the cold regions

    Institute of Scientific and Technical Information of China (English)

    YANG Geng-she; ZHOU Chun-hua; TIAN Ying-guo; LIU Hui

    2006-01-01

    With the western development in China, more problems with rock and soil engineering in cold regions will be encountered. To study the stability of rock mass under the frost and thaw condition is of far significance. We attempt to simulate and analyze the temperature and moisture field in the surrounding rock of Dabanshan tunnel at its exit KI06+025 in the cold region by software Femlab. First, introduced the common numerical solution to the moisture and heat coupled about the soft rock in tunnels of cold region. Then gave emphasis on simulation of the law of temperature distribution coupled temperature-moisture field and draw a parallel between temperature fields with different coefficient of percolation. In the course of simulation we considered the problem of caloric receptivity, thermal conductivity and critical heat varying with temperature.

  2. Numerical Simulation of Rock Mass Damage Evolution During Deep-Buried Tunnel Excavation by Drill and Blast

    Science.gov (United States)

    Yang, Jianhua; Lu, Wenbo; Hu, Yingguo; Chen, Ming; Yan, Peng

    2015-09-01

    Presence of an excavation damage zone (EDZ) around a tunnel perimeter is of significant concern with regard to safety, stability, costs and overall performance of the tunnel. For deep-buried tunnel excavation by drill and blast, it is generally accepted that a combination of effects of stress redistribution and blasting is mainly responsible for development of the EDZ. However, few open literatures can be found to use numerical methods to investigate the behavior of rock damage induced by the combined effects, and it is still far from full understanding how, when and to what degree the blasting affects the behavior of the EDZ during excavation. By implementing a statistical damage evolution law based on stress criterion into the commercial software LS-DYNA through its user-subroutines, this paper presents a 3D numerical simulation of the rock damage evolution of a deep-buried tunnel excavation, with a special emphasis on the combined effects of the stress redistribution of surrounding rock masses and the blasting-induced damage. Influence of repeated blast loadings on the damage extension for practical millisecond delay blasting is investigated in the present analysis. Accompanying explosive detonation and secession of rock fragments from their initial locations, in situ stress in the immediate vicinity of the excavation face is suddenly released. The transient characteristics of the in situ stress release and induced dynamic responses in the surrounding rock masses are also highlighted. From the simulation results, some instructive conclusions are drawn with respect to the rock damage mechanism and evolution during deep-buried tunnel excavation by drill and blast.

  3. Discussion on Tunnel Boring by Laser Beam%一种用于隧道断面脆性硬岩的激光破岩原理探讨

    Institute of Scientific and Technical Information of China (English)

    顿苗苗; 宋宏伟; 王春苗

    2011-01-01

    As a new rock spallation technology, the application of advanced high power laser to rock tunnel drilling has been significantly improved recently. The research advances of laser rock spallation technology at home and abroad are summarized. Based on our studies and laser beam characteristics, the authors propose a new rock breaking technology called "laser-water spray method" which can be used to large-scale hard rock tunnel drilling. It is solved that the scale problem between tiny laser beam point and large tunnel cross-section. The feasibility and effectiveness of the prposed method are proved further by numerical simulation.%激光作为一种新型破岩技术,在用于岩石隧道开挖技术的研究中已经取得了较大进展.本文在总结国内外激光破岩技术研究进展的基础之上,结合现有激光光束的特点,提出了适用于大断面脆性硬岩隧道的激光-喷水破岩方法,并通过数值模拟进一步分析了这种方法的破岩效果.该方法解决了激光光点小而隧道工程开挖断面大的矛盾,具有很强的实用性.

  4. Drip Sealing Grouting of Tunnels in Crystalline Rock: Conceptualisation and Technical Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Butron, Christian

    2012-07-01

    A conceptual model of the groundwater hydraulic conditions around the tunnel contour in ancient brittle crystalline rocks has been developed and verified. The general aim has been to reach an understanding of the groundwater conditions in and close to the tunnel roof where dripping takes place and to propose technical and practical strategies for waterproofing. Dripping is accompanied by ice growth and icicle formation in cold regions, creating additional problems such as shotcrete fall-outs, icicle fall-outs, damage to vehicles, damage to trains, etc. The methodology for the development of the conceptual model is based mainly on transmissivity determinations from short-duration hydraulic tests and analyses of the connectivity of the fracture structure by means of semi-variogram analysis. The determination of the dimensionality of the flow in the fractures has also been found to be essential in order to describe the conductive system. This conceptual model describes the fracture systems as a combination of transmissive patches (2D-flow fractures) connected by less pervious channels (1D-flow fractures). It provides an understanding of the heterogeneity and connectivity of the fracture network and thus the groundwater conditions, not only in the roof but also around the tunnel contour. The pre-excavation grouting design process used in the tunnelling projects followed a structured approach and the evaluation showed that the grouting design reduced the inflow and fulfilled the environmental demands. However, dripping remained, making its characterisation very important when proposing a possible solution for its control. It is proposed that the remaining dripping comes from a channelised system that has been left unsealed and which would be extremely difficult to intersect with future boreholes, as well as from some ungrouted fractures with inconvenient orientations. Geomembrane lining and post-excavation grouting are possible solutions, although particular attention

  5. Tunnel Face Stability & New CPT Applications

    NARCIS (Netherlands)

    Broere, W.

    2001-01-01

    Nearly all tunnels bored in soft soils have encountered problems with the stability of the tunnel face. In several cases these problems led to an extended stand-still of the boring process. A better understanding of the face stability, and of the soil conditions around the tunnel boring machine, can

  6. Improved response surface method and its application in stability reliability degree analysis of tunnel surrounding rock

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An approach of limit state equation for surrounding rock was put forward based on deformation criterion. A method of symmetrical sampling of basic random variables adopted by classical response surface method was mended, and peak value and deflection degree of basic random variables distribution curve were took into account in the mended sampling method. A calculation way of probability moment, based on mended Rosenbluth method, suitable for non-explicit performance function was put forward.The first, second, third and fourth order moments of functional function value were calculated by mended Rosenbluth method through the first, second, third and fourth order moments of basic random variable. A probability density the function(PDF) of functional function was deduced through its first, second, third and fourth moments, the PDF in the new method took the place of the method of quadratic polynomial to approximate real functional function and reliability probability was calculated through integral by the PDF for random variable of functional function value in the new method. The result shows that the improved response surface method can adapt to various statistic distribution types of basic random variables, its calculation process is legible and need not iterative circulation. In addition, a stability probability of surrounding rock for a tunnel was calculated by the improved method,whose workload is only 30% of classical method and its accuracy is comparative.

  7. Research on sustenance of soft rock tunnel in Hongmiao Mine of Pingzhuang Mine Area

    Institute of Scientific and Technical Information of China (English)

    KONG Xiang-yi; ZHANG Bao-an

    2008-01-01

    The return airway tunnel of bank 6 is an important tunnel for air return and auxiliary transportation. While under construction, the tunnel was seriously deformed, and the bottom was heavily squeezed. When completed, the bottom was smoothed out several times and a lot of maintenance were done. But about half year later, the tunnel collapsed. To counter the problems mentioned above, we systematically expounded our ideas and designed for solving the problem of the sustenance of the return airway tunnel of section 6.

  8. On bore collapse

    Science.gov (United States)

    Yeh, Harry H.; Ghazali, A.

    1988-06-01

    Using the laser-induced fluorescent method, the transition process from bore to runup mode, i.e., "bore collapse," is investigated experimentally. The observed process appears to be different from both previous analytical and numerical predictions. The results indicate that momentum exchange takes place between the incident bore and the quiescent water body along the shoreline. Turbulence generated in a bore nearshore is highly three-dimensional and sporadic. Very close to the shore, turbulence is advected with the bore front, and consequently, the bore collapse process involves strong turbulent action onto the dry beach bed.

  9. 氯化物环境暗挖海底隧道支护结构的耐久性设计%The Durability Design of Subsea Bored Tunnel Support Structures under Chloride Corrosion

    Institute of Scientific and Technical Information of China (English)

    宋超业; 贺维国

    2016-01-01

    A subsea tunnel suffers the long-term impact of chloride corrosion, and with a required design service life of 100 years or more, many more studies of durability design are needed than for normal tunnels. Current study of subsea tunnel durability focuses on material selection and the mix proportion of reinforced concrete structures. This paper gives a detailed analysis of environmental conditions, relevant code specifications and durability design principles for subsea bored tunnels in chloride environments and proposes the concept of paying equal attention to the durability design and bearing capacity design as well as reserving enough space for later restoration. The analy-sis shows that high-strength high-performance concrete should be adopted for subsea tunnel linings in order to im-prove concrete density and to resist seawater corrosion, and the limited groundwater drainage principle should be ad-opted for mined subsea tunnels to ensure effectiveness of their drainage systems.%海底隧道长期受海水氯化物环境的影响,而隧道的设计使用年限为100年甚至更长,这就要求设计中对于其耐久性要比常规隧道做出更多的研究.目前海底隧道耐久性研究主要集中在钢筋混凝土结构的材料选择和配合比设计.文章针对氯化物环境下的矿山法海底隧道,对其环境条件、规范要求和耐久性设计原则等进行了详细分析,提出了耐久性设计应与结构承载力设计并重、预留空间满足后期可修复要求的理念.隧道衬砌结构应采用高强高性能混凝土,提高其密实性抵抗海水侵蚀;矿山法隧道采用限量排放地下水处理,保证排水系统通畅可靠.

  10. Boring and excavation technologies for Opalinus clay in the rock laboratories at Mont Terri; Techniques de forages et d'excavations dans les argiles à Opalinus, laboratoire souterrain du Mont Terri

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, P.; Nussbaum, Ch. [Swiss Federal Office of Topography swisstopo, Wabern (Switzerland); Burrus, F. [Groupe Grands Travaux GGT, Porrentruy (Switzerland)

    2012-07-01

    This comprehensive article discusses the work done since 1996 at the rock laboratories at Mont Terri in the Swiss Jura Mountains. The work being done by fifteen international partners on the characterisation of the Opalinus clay with regard to its geological, hydro-geological, geochemical and geotechnical characteristics is reported on. Various methods of drilling are described that are able to preserve any tectonic crevices in the rock. Drilling under special conditions, including the use of nitrogen and argon atmospheres to prevent bacterial contamination, is looked at, as are the methods used in tunnelling without having to use water.

  11. Intelligent direct analysis of physical and mechanical parameters of tunnel surrounding rock based on adaptive immunity algorithm and BP neural network

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Because of complexity and non-predictability of the tunnel surrounding rock, the problem with the determination of the physical and mechanical parameters of the surrounding rock has become a main obstacle to theoretical research and numerical analysis in tunnel engineering. During design, it is a frequent practice, therefore, to give recommended values by analog based on experience. It is a key point in current research to make use of the displacement back analytic method to comparatively accurately determi...

  12. The Interplay of In Situ Stress Ratio and Transverse Isotropy in the Rock Mass on Prestressed Concrete-Lined Pressure Tunnels

    Science.gov (United States)

    Simanjuntak, T. D. Y. F.; Marence, M.; Schleiss, A. J.; Mynett, A. E.

    2016-11-01

    This paper presents the mechanical and hydraulic behaviour of passively prestressed concrete-lined pressure tunnels embedded in elastic transversely isotropic rocks subjected to non-uniform in situ stresses. Two cases are distinguished based on whether the in situ vertical stress in the rock mass is higher, or lower than the in situ horizontal stress. A two-dimensional finite element model was used to study the influence of dip angle, α, and horizontal-to-vertical stress ratio, k, on the bearing capacity of prestressed concrete-lined pressure tunnels. The study reveals that the in situ stress ratio and the orientation of stratifications in the rock mass significantly affect the load sharing between the rock mass and the lining. The distribution of stresses and deformations as a result of tunnel construction processes exhibits a symmetrical pattern for tunnels embedded in a rock mass with either horizontal or vertical stratification planes, whereas it demonstrates an unsymmetrical pattern for tunnels embedded in a rock mass with inclined stratification planes. The results obtained for a specific value α with coefficient k are identical to that for α + 90° with coefficient 1/ k by rotating the tunnel axis by 90°. The maximum internal water pressure was determined by offsetting the prestress-induced hoop strains at the final lining intrados against the seepage-induced hoop strains. As well as assessing the internal water pressure, this approach is capable of identifying potential locations where longitudinal cracks may occur in the final lining.

  13. Research on sustenance of soft rock tunnel in Hongmiao Mine of Pingzhuang Mine Area

    Institute of Scientific and Technical Information of China (English)

    KONG Xiang-yi; ZHANG Bao-an

    2008-01-01

    The return airway tunnel of bank 6 is an important tunnel for air return and auxiliary transportation.While under construction,the tunnel was seriously deformed,and the bottom was heavily squeezed.When completed,the bottom was smoothed out several times and a lot of maintenance were done.But about half year later,the tunnel collapsed.To counter the problems mentioned above,we systematically expounded our ideas and designed for solving the problem of the sustenance of the return airway tunnel of section 6.

  14. A Top Pilot Tunnel Preconditioning Method for the Prevention of Extremely Intense Rockbursts in Deep Tunnels Excavated by TBMs

    Science.gov (United States)

    Zhang, Chuanqing; Feng, Xiating; Zhou, Hui; Qiu, Shili; Wu, Wenping

    2012-05-01

    The headrace tunnels at the Jinping II Hydropower Station cross the Jinping Mountain with a maximum overburden depth of 2,525 m, where 80% of the strata along the tunnels consist of marble. A number of extremely intense rockbursts occurred during the excavation of the auxiliary tunnels and the drainage tunnel. In particular, a tunnel boring machine (TBM) was destroyed by an extremely intense rockburst in a 7.2-m-diameter drainage tunnel. Two of the four subsequent 12.4-m-diameter headrace tunnels will be excavated with larger size TBMs, where a high risk of extremely intense rockbursts exists. Herein, a top pilot tunnel preconditioning method is proposed to minimize this risk, in which a drilling and blasting method is first recommended for the top pilot tunnel excavation and support, and then the TBM excavation of the main tunnel is conducted. In order to evaluate the mechanical effectiveness of this method, numerical simulation analyses using the failure approaching index, energy release rate, and excess shear stress indices are carried out. Its construction feasibility is discussed as well. Moreover, a microseismic monitoring technique is used in the experimental tunnel section for the real-time monitoring of the microseismic activities of the rock mass in TBM excavation and for assessing the effect of the top pilot tunnel excavation in reducing the risk of rockbursts. This method is applied to two tunnel sections prone to extremely intense rockbursts and leads to a reduction in the risk of rockbursts in TBM excavation.

  15. Simulation of groundwater drainage into a tunnel in fractured rock and numerical analysis of leakage remediation, Romeriksporten tunnel, Norway

    Science.gov (United States)

    Kitterød, N.-O.; Colleuille, H.; Wong, W. K.; Pedersen, T. S.

    2000-09-01

    Standard geostatistical methods for simulation of heterogeneity were applied to the Romeriksporten tunnel in Norway, where water was leaking through high-permeable fracture zones into the tunnel while it was under construction, causing drainage problems on the surface. After the tunnel was completed, artificial infiltration of water into wells drilled from the tunnel was implemented to control the leakage. Synthetic heterogeneity was generated at a scale sufficiently small to simulate the effects of remedial actions that were proposed to control the leakage. The flow field depends on the variance of permeabilities and the covariance model used to generate the heterogeneity. Flow channeling is the most important flow mechanism if the variance of the permeability field is large compared to the expected value. This condition makes the tunnel leakage difficult to control. The main effects of permeability changes due to sealing injection are simulated by a simple perturbation of the log-normal probability density function of the permeability. If flow channeling is the major transport mechanism of water into the tunnel, implementation of artificial infiltration of water to control the leakage requires previous chemical-sealing injection to be successful. Résumé. Des méthodes géostatistiques standard ont été employées pour simuler l'hétérogénéité des zones de fractures à fortes perméabilitées dans lesquelles, au cours de la construction du tunnel ferroviaire de Romeriksporten (Norvège), l'eau s'est écoulée, causant des problèmes de drainage en surface. Quand les travaux ont été terminés, l'injection d'eau dans des puits forés à partir du tunnel a été réalisée pour contrôler ces infiltrations. Une hétérogénéité synthétique a été créée à une échelle suffisamment petite pour simuler les effets de l'injection d'eau. Le champ des écoulements dépend de la variance des perméabilités et de la covariance du modèle utilisé pour g

  16. Stresses and Displacements in Steel-Lined Pressure Tunnels and Shafts in Anisotropic Rock Under Quasi-Static Internal Water Pressure

    Science.gov (United States)

    Pachoud, Alexandre J.; Schleiss, Anton J.

    2016-04-01

    Steel-lined pressure tunnels and shafts are constructed to convey water from reservoirs to hydroelectric power plants. They are multilayer structures made of a steel liner, a cracked backfill concrete layer, a cracked or loosened near-field rock zone and a sound far-field rock zone. Designers often assume isotropic behavior of the far-field rock, considering the most unfavorable rock mass elastic modulus measured in situ, and a quasi-static internal water pressure. Such a conventional model is thus axisymmetrical and has an analytical solution for stresses and displacements. However, rock masses often have an anisotropic behavior and such isotropic assumption is usually conservative in terms of quasi-static maximum stresses in the steel liner. In this work, the stresses and displacements in steel-lined pressure tunnels and shafts in anisotropic rock mass are studied by means of the finite element method. A quasi-static internal water pressure is considered. The materials are considered linear elastic, and tied contact is assumed between the layers. The constitutive models used for the rock mass and the cracked layers are presented and the practical ranges of variation of the parameters are discussed. An extensive systematic parametric study is performed and stresses and displacements in the steel liner and in the far-field rock mass are presented. Finally, correction factors are derived to be included in the axisymmetrical solution which allow a rapid estimate of the maximum stresses in the steel liners of pressure tunnels and shafts in anisotropic rock.

  17. VALIDITY OF THE HIGH-TENSILE-STRENG TH BOLT FOR THE SOFT ROCK WITH LARGE CROSS SECTIONAL TUNNEL

    Science.gov (United States)

    Yagi, Hiroshi; Tamamura, Kouji; Uneda, Atsushi; Domon, Tsuyoshi; Nishimura, Kazuo

    This paper reports the experiential result about the applications of the high tensile strength bolts as a countermeasure for the displacement, considered about the denaturalization of the large cross sectional tunnel in mudstone layer. In Kanaya Tunnel of the New Tomei Expressway, the soft rock section appeared where we cannot restrain support denaturizi ng and internal displacement by materials of the standard design. Then fore, we adopted the high tensile strength bolts (748kN) replacing with of the standard design, and improved the support proof for stress. As the result, we got possible to control the displacement and execute the work safety and economi cally. We compared the analysis result (FEM) by the limited element method with the measure result on the spot, and inspected the supportability effect of the higt tensile strength bolts.

  18. TBM tunneling in mixed-face ground:Problems and solutions

    Institute of Scientific and Technical Information of China (English)

    Ma Hongsu; Yin Lijun; Gong Qiuming; Wang Ju

    2015-01-01

    Mixed-face ground encountered in Tunnel Boring Machine (TBM) tunneling presents great challenges and may trigger potential hazards without warning. A detailed understanding of such unfavorable con-ditions is therefore critical to a successful bored tunnel. In this paper, we firstly present a brief review of the definition, classification and the factors related to mixed-face conditions. Secondly, for a better understanding of this topic, we investigate the main difficulties and problems involved in TBM tun-nelling under mixed-face ground with detailed cases. Thirdly, from the viewpoint of rock-machine interaction, we give some suggestions on the corresponding mitigation measurements from three cat-egories: (i) selection of TBM type and modification of TBM, (ii) condition of ground and (iii) optimiza-tion of TBM operation.

  19. Tunneling methods used at the railway tunnels construction in Slovak republic

    Directory of Open Access Journals (Sweden)

    Jozef Čížik

    2007-10-01

    Full Text Available Rail transport is an energy-efficient and capital-intensive means of mechanized land transport. Methods of tunneling vary with the nature of the material to be cut through. When soft earth is encountered, the excavation is timbered for support as the work advances; the timbers are sometimes left as a permanent lining for the tunnel. Another method is to cut two parallel excavations in which the side walls are constructed first. Arches connecting them are then built as the material between them is extracted. Portions of the unexcavated center, left temporarily for support, may be removed later. A tunnel cut through rock frequently requires no lining. Often, to speed construction, work is started at both ends. This poses no problem with the cut-and-cover method, but when the tunnel is bored from within, it must be assured that the tubes will actually meet in the center. Modern methods accomplish this with high precision.

  20. 量度及預測隧道鑽機的土傳噪音及震動%Measurement and prediction of groundborne noise and vibration from a tunnel boring machine

    Institute of Scientific and Technical Information of China (English)

    何偉麟

    2006-01-01

    在市區進行夜間隧道鑽挖工程所産生的土傳噪音及震動,容易引起投訴.現時的技術難以準確預測噪音及震動的級數,而隧道工程的進度也常因進行隧道鑽挖工程時產生過大的土傳噪音及震動而延誤.本文所提述的新技術,可以更準確地量度及預測鑽機震動强度及土壤傳震的特性.這個技術包括測量單位衝擊力及隧道鑽機摩擦力所産生的震動級數.其實早於80於代,美國政府運輸部門(U.S.Dept of Transportation Federal Transit Administrative)已研發相關的技術,並將該技術應用於鐵路土傳噪音量度及預測上.本文報告隧道鑽機所產生的土傳噪音及震動級數1/3倍频帶數值的量度及預測.比較地面震動峰值速度(PPV)、最高(Lmax)噪聲和振動級數按快速和緩慢的時間常數和整體百分比(Percentile)數值列出.%A new empirical method for prediction of groundborne noise and vibration (GBN&V) induced by tunnel boring machine (TBM) has been developed. The method is based on empirical determination of ground vibration transmissibility and TBM vibration source strength. The method includes measurements of ground vibration levels caused by unit force impacts and TBM operation at various setbacks. With these measured data, the ground vibration transfer mobility and TBM vibration source strength are determined separately. Prediction of TBM-induced GBN&V is performed by combining the determined TBM vibration source strength and the further measurement data of ground vibration transfer mobility by impacting in boreholes along the proposed tunnel alignment. Predicted GBN&V levels are presented in 1/3 octave spectrum at various setbacks from the tunnel alignment.Comparisons are given in predicted peak particle velocity (PPV), maximum noise and vibration levels in fast and slow time constant and overall percentile values (cumulative probability distributions).

  1. Experimental investigation on the infrared refraction and extinction properties of rock dust in tunneling face of coal mine.

    Science.gov (United States)

    Wang, Wenzheng; Wang, Yanming; Shi, Guoqing

    2015-12-10

    Comprehensive experimental research on the fundamental optical properties of dust pollution in a coal mine is presented. Rock dust generated in a tunneling roadway was sampled and the spectral complex refractive index within an infrared range of 2.5-25 μm was obtained by Fourier transform infrared spectroscopy measurement and Kramers-Kronig relation. Experimental results were validated to be consistent with equivalent optical constants simulated by effective medium theory based on component analysis of x-ray fluorescence, which illustrates that the top three mineral components are SiO2 (62.06%), Al2O3 (21.26%), and Fe2O3 (4.27%). The complex refractive index and the spatial distribution tested by a filter dust and particle size analyzer were involved in the simulation of extinction properties of rock dust along the tunneling roadway solved by the discrete ordinates method and Mie scattering model. The compared results illustrate that transmission is obviously enhanced with the increase of height from the floor but weakened with increasing horizontal distance from the air duct.

  2. Mind where you bore!

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    With renewable energies on the up and up, geothermal heating is becoming increasingly popular. An ardent supporter of sustainable development, CERN welcomes this trend, even though it has certain risks for the Laboratory.   More and more people in Switzerland and France are switching to geothermal heating, with the result that more and more bore holes are being sunk for geothermal probes. Since, on average, such bore holes go down to depths of 100 m they can have an impact on CERN’s underground facilities, which are also located at approximately that depth. In the Canton of Geneva, all bore holes, whatever their depth, are subject to planning permission. Applications for planning permission are granted – or refused – only after consultation with the Ground survey department (GESDEC). In France, only bore holes below a depth of 100 m require planning permission. In theory, bore holes to lesser depths simply need to be declared to the DREAL (Dire...

  3. On the use of Li isotopes as a proxy for water-rock interaction in fractured crystalline rocks: A case study from the Gotthard rail base tunnel

    Science.gov (United States)

    Wanner, Christoph; Bucher, Kurt; Pogge von Strandmann, Philip A. E.; Waber, H. Niklaus; Pettke, Thomas

    2017-02-01

    We present Li isotope measurements of groundwater samples collected during drilling of the 57 km long Gotthard rail base tunnel in Switzerland, to explore the use of Li isotope measurements for tracking water-rock interactions in fractured crystalline rocks at temperatures of up to 43 °C. The 17 groundwater samples originate from water-conducting fractures within two specific crystalline rock units, which are characterized by a similar rock mineralogy, but significantly different fluid composition. In particular, the aqueous Li concentrations observed in samples from the two units vary from 1-4 mg/L to 0.01-0.02 mg/L. Whereas δ7Li values from the unit with high Li concentrations are basically constant (δ7Li = 8.5-9.1‰), prominent variations are recorded for the samples from the unit with low Li concentrations (δ7Li = 10-41‰). This observation demonstrates that Li isotope fractionation can be highly sensitive to aqueous Li concentrations. Moreover, δ7Li values from the unit with low Li concentrations correlate well with reaction progress parameters such as pH and [Li]/[Na] ratios, suggesting that δ7Li values are mainly controlled by the residence time of the fracture groundwater. Consequently, 1D reactive transport modeling was performed to simulate mineral reactions and associated Li isotope fractionation along a water-conducting fracture system using the code TOUGHREACT. Modeling results confirm the residence time hypothesis and demonstrate that the absence of δ7Li variation at high Li concentrations can be well explained by limitation of the amount of Li that is incorporated into secondary minerals. Modeling results also suggest that Li uptake by kaolinite forms the key process to cause Li isotope fractionation in the investigated alkaline system (pH >9), and that under slow flow conditions (mineral reaction rates if more thermodynamic data about the temperature-dependent incorporation of Li in secondary minerals as well as corresponding fractionation

  4. Time-Dependent Damage Investigation of Rock Mass in an In Situ Experimental Tunnel

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2012-08-01

    Full Text Available In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, etc., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an in situ experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, i.e., nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.

  5. Key technologies of drilling process with raise boring method

    Directory of Open Access Journals (Sweden)

    Zhiqiang Liu

    2015-08-01

    Full Text Available This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are described. The components of a raise boring machine including the drill rig, the drill string and the auxiliary system are also presented. Based on the analysis of the raise boring method, the rock mechanics problems during the raise boring process are put forward, including rock fragmentation, removal of cuttings, shaft wall stability, and borehole deviation control. Finally, the development trends of raise boring technology are described as follows: (i improvement of rock-breaking modes to raise drilling efficiency, (ii development of an intelligent control technique, and (iii development of technology and equipment for nonlinear raise boring.

  6. Key technologies of drilling process with raise boring method

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Liu; Yiping Meng

    2015-01-01

    This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are described. The components of a raise boring machine including the drill rig, the drill string and the auxiliary system are also presented. Based on the analysis of the raise boring method, the rock mechanics problems during the raise boring process are put forward, including rock fragmentation, removal of cuttings, shaft wall stability, and borehole deviation control. Finally, the development trends of raise boring technology are described as follows:(i) improve-ment of rock-breaking modes to raise drilling efficiency, (ii) development of an intelligent control tech-nique, and (iii) development of technology and equipment for nonlinear raise boring.

  7. Based on B/S structure of the tunnel boring machine operation simulation and fault diagnosis system%基于B/S架构的掘进机运行仿真与故障诊断系统研究

    Institute of Scientific and Technical Information of China (English)

    汤其建

    2015-01-01

    Yongcheng Vocational College developed to run the simulation and fault diagnosis system based on In‐ternet technology roadheader .The system uses advanced computer simulation technology virtual Tunneling sud‐den disposal and roadheader typical faults to troubleshoot .Teachers can set a variety of unexpected situations and failures on a server or superuser machine;Students can be performed on the brow ser side virtual training to deal with unexpected situations , troubleshooting , the status process and troubleshooting process , you can choose a variety of simulation tools and test equipment ,process automatic record .The system was applied to the teaching and training ,so that students can not only deepen the Tunneling relevant expertise to understand ,and can exercise their ability to handle emergencies and Diagnostics boring machine failure .The system is to improve student interest in learning and learning efficiency w hile reducing costs and time costs of teaching in schools and training institutions .%永城职业学院开发了基于网络技术的掘进机运行仿真与故障诊断系统。该系统利用先进的计算机虚拟仿真技术实现巷道掘进突发状况处置和掘进机典型故障诊断排除。教师可以在服务器或超级用户机上设置各种突发状况和故障;学生可以在浏览器端上进行虚拟实训,应对突发状况、排除故障,在状况处理和排除故障过程中,可选用各种仿真工具和检测仪器,过程自动记录。将该系统运用到教学和培训中,不但可以使学员加深对巷道掘进相关专业知识的理解,而且可以锻炼其处置突发状况和诊断掘进机故障的能力。该系统在提高学员学习兴趣和学习效率的同时,还能降低学校和培训机构的教学成本和时间成本。

  8. 基于互联网的隧道掘进机故障筛选及预警系统开发%The Development of Tunnel Boring Machine Malfunction Screening and Early Warning System Based on Internet

    Institute of Scientific and Technical Information of China (English)

    张迅博

    2015-01-01

    国内盾构机在施工时,在盾构机掘进过程中时常会遇到各种突发情况,然而报警信息无法及时传递到技术专家手中,这为盾构施工埋下了安全隐患。为解决这一困难,文章设计了一套基于互联网的隧道掘进机故障筛选及预警系统,能实现实时搜集多台盾构机施工中的报警信息,通过因特网汇集到远端服务器,利用故障筛选及预警系统,实时向技术专家,业主,监理发出预警短信。系统保障了施工人员及机械的安全,提高了管理效率节约了项目成本。%Domestic Shield in the construction,in the course of the shield tunneling machine often encounter a variety of emergency situations,but the alarms information can not be delivered in time to the hands of technical experts,which buried a security risk for the shield construction.To address this problem,design a tunnel boring machine malfunction screening and early warning system based on the Internet,can achieve real-time collection of multiple shield machine construction alarm information collection to the remote server through the Internet, the use of screening and early warning failure system, real-time early warning messages to technical experts,owners, supervision.The system protects the safety of construction workers and machinery,and the same time the system improves the management efifciency savings in project costs.

  9. Double diameter boring tool

    Science.gov (United States)

    Ashbaugh, Fred N.; Murry, Kenneth R.

    1988-12-27

    A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation. The method includes the step of inserting the boring tool into the boring head, adjusting the distance between the tool centerline and the tool axis of rotation as described above and boring the two concentric holes.

  10. Differentiation and analysis on rock breaking characteristics of TBM disc cutter at different rock temperatures

    Institute of Scientific and Technical Information of China (English)

    谭青; 张桂菊; 夏毅敏; 李建芳

    2015-01-01

    In order to study rock breaking characteristics of tunnel boring machine (TBM) disc cutter at different rock temperatures, thermodynamic rock breaking mathematical model of TBM disc cutter was established on the basis of rock temperature change by using particle flow code theory and the influence law of interaction mechanism between disc cutter and rock was also numerically simulated. Furthermore, by using the linear cutting experiment platform, rock breaking process of TBM disc cutter at different rock temperatures was well verified by the experiments. Finally, rock breaking characteristics of TBM disc cutter were differentiated and analyzed from microscale perspective. The results indicate the follows. 1) When rock temperature increases, the mechanical properties of rock such as hardness, and strength, were greatly reduced, simultaneously the microcracks rapidly grow with the cracks number increasing, which leads to rock breaking load decreasing and improves rock breaking efficiency for TBM disc cutter. 2) The higher the rock temperature, the lower the rock internal stress. The stress distribution rules coincide with the Buzin Neske stress circle rules: the maximum stress value is below the cutting edge region and then gradually decreases radiant around; stress distribution is symmetrical and the total stress of rock becomes smaller. 3) The higher the rock temperature is, the more the numbers of micro, tensile and shear cracks produced are by rock as well as the easier the rock intrusion, along with shear failure mode mainly showing. 4) With rock temperature increasing, the resistance intrusive coefficients of rock and intrusion power decrease obviously, so the specific energy consumption that TBM disc cutter achieves leaping broken also decreases subsequently. 5) The acoustic emission frequency remarkably increases along with the temperature increasing, which improves the rock breaking efficiency.

  11. Effect of temperature on deep lined circular tunnels in transversely anisotropic elastic rock

    Directory of Open Access Journals (Sweden)

    Fei Tao

    2016-12-01

    Full Text Available Considerably less attention has been given to thermal stresses in a tunnel. Temperature changes in the ground or inside the tunnel, e.g. due to fire, can cause cracking and damage to the liner and surrounding ground. This study derived analytical solutions for stresses and displacements caused by thermal load for a lined circular tunnel under a transversely anisotropic ground where the ground anisotropy axis coincides with the stacking direction. The FEM code ABAQUS was used to study a lined deep tunnel when the ground anisotropy axis is perpendicular to the stacking direction. A parametric study was performed to investigate the effects of Young’s modulus, Poisson’s ratio, thermal conductivity and the coefficient of thermal expansion on the behavior of the liner and ground. The results show that the Young’s modulus and the coefficient of thermal expansion are the most important parameters that determine the stresses and displacements of the liner and ground. The analysis also shows that the thermal conductivity has a significant effect on the temperature distribution in the ground.

  12. Measurement of the stress field of a tunnel through its rock EMR

    Science.gov (United States)

    Qiu, Liming; Wang, Enyuan; Song, Dazhao; Liu, Zhentang; Shen, Rongxi; Lv, Ganggang; Xu, Zhaoyong

    2017-08-01

    In order to quantitatively study the relationship between the disturbance stress of coal mine roadways and the electromagnetic radiation (EMR) of rocks, and further evaluate their internal stress distributions, we first examined the characteristics of EMR signals emitted from rock mass under uniaxial compression, analyzed the relationship between the stress inside the rock mass and its emitted EMR intensity, and put forward a new disturbance stress testing method by monitoring the EMR from the rock mass to retrieve its surrounding stress field. Then, we applied the method to monitor EMR intensity from the no.11803 rock roadway of the Nuodong coal mine, China, and inversely retrieved its stress field. Lastly, we analyzed the causes of local stress anomalies in the Nuodong area by testing the EMR intensity of its nearby areas, and we examined the geology of the whole region. The results showed that: (1) in the rock roadway and the surrounding area of the Nuodong coal mine, the disturbance stress was in the range of 4.8 ∼ 9.1 MPa, the angle between the direction of the stress field and the horizontal plane of the roadway was 35 ± 2.5°, the lateral pressure coefficient was 1.30 ∼ 1.57 (2) the Laoguishan and Yulong anticlines in the vicinity of the Nuodong coal mine caused great horizontal tectonic stress in the region, and the existence of the auxiliary roadway and F12 normal fault resulted in the formation of two high stress zones in the no.11803 rock roadway. Overall, monitoring the EMR from rock mass could ascertain the state, direction, size and distribution of disturbance stress in a roadway and further obtain the distribution of the stress field of an underground structure.

  13. A Hybrid Monte Carlo Method Based Artificial Neural Networks Approach for Rock Boundaries Identification: A Case Study from the KTB Bore Hole

    Science.gov (United States)

    Maiti, Saumen; Tiwari, R. K.

    2009-11-01

    Identification of rock boundaries and structural features from well log response is a fundamental problem in geological field studies. However, in a complex geologic situation, such as in the presence of crystalline rocks where metamorphisms lead to facies changes, it is not easy to discern accurate information from well log data using conventional artificial neural network (ANN) methods. Moreover inferences drawn by such methods are also found to be ambiguous because of the strong overlapping of well log signals, which are generally tainted with deceptive noise. Here, we have developed an alternative ANN approach based on Bayesian statistics using the concept of Hybrid Monte Carlo (HMC)/Markov Chain Monte Carlo (MCMC) inversion scheme for modeling the German Continental Deep Drilling Program (KTB) well log data. MCMC algorithm draws an independent and identically distributed (i.i.d) sample by Markov Chain simulation technique from posterior probability distribution using the principle of statistical mechanics in Hamiltonian dynamics. In this algorithm, each trajectory is updated by approximating the Hamiltonian differential equations through a leapfrog discrimination scheme. We examined the stability and efficiency of the HMC-based approach on “noisy” data assorted with different levels of colored noise. We also perform uncertainty analysis by estimating standard deviation (STD) error map of a posteriori covariance matrix at the network output of three types of lithofacies over the entire length of the litho section of KTB. Our analyses demonstrate that the HMC-based approach renders robust means for classification of complex lithofacies successions from the KTB borehole noisy signals, and hence may provide a useful guide for understanding the crustal inhomogeneity and structural discontinuity in many other tectonically critical and complex regions.

  14. Changes of ecological conditions induced by rock tunneling in Laoshan Mountain area

    Institute of Scientific and Technical Information of China (English)

    Xiaozhao LI; Xiaobao ZHAO; Zhongsheng WANG

    2008-01-01

    Through field investigation, this paper exam-ined the changes of ecological conditions induced by tun-nel construction in Laoshan Mountain area, Nanjing, Jiangsu Province, P. R. China. The effects of habitat frag-mentation and edge effect are examined and discussed. It is found that the environmental factors and vegetation situation have been influenced by the tunneling activity, and the disturbed area is approaching the sampling patch centre. The changed ecological conditions are beneficial for the settlement and growth of some herb and shrub species, and are unfavorable for the existence and growth of saplings, especially for the predominant species (e.g., robur) in this area. If the time of habitat fragmentation is long enough and there is no supplement from external areas, some vegetation species in the engineering influ-encing area will deteriorate, or even diminish in the future. The results can be used as a reference for the long-term ecological study in this area.

  15. Plugs for deposition tunnels in a deep geologic repository in granitic rock. Concepts and experience

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D.A. (AECL, Chalk River (Canada)); Boergesson, L. (Clay Technology, Lund (Sweden)); Gunnarsson, D. (Swedish Nuclear Fuel and Waste Management Co, Stockholm (Sweden)); Hansen, J. (Posiva Oy, Eurajoki (Finland))

    2009-11-15

    Regardless of the emplacement geometry selected in a geological repository for spent nuclear fuel, there will be a requirement for the access tunnels to remain open while repository operations are ongoing. The period of repository operation will stretch for many years (decades to more than a century depending on disposal concept and number of canisters to be installed). Requirements for extended monitoring of the repository before final closure may further extend the period over which the tunnels must remain open. The intersection of the emplacement rooms/drifts and the access tunnels needs to be physically closed in order to ensure that the canisters remain undisturbed and that no undesirable hydraulic conditions are allowed to develop within the backfilled volume. As a result of these requirements, generic guidelines and design concepts have been developed for 'Plugs' that are intended to provide mechanical restraint, physical security and hydraulic control functions over the short-term (repository operational and pre-closure monitoring periods). This report focuses on the role and requirements of plugs to be installed at emplacement room/ tunnel/drift entrances or in other locations within the repository that may require installation of temporary mechanical or hydraulic control structures. These plugs are not necessarily a permanent feature of the repository and may, if required, be removed for later installation of a permanent seal. Room/Drift plugs are also by their defined function, physically accessible during repository operation so their performance can be monitored and remedial actions taken if necessary (e.g. increased seepage past the plug). A considerable number of sealing demonstrations have been undertaken at several research laboratories that are focussed on development of technologies and materials for use in isolation of spent nuclear fuel and these are briefly reviewed in this report. Additionally, technologies developed for non

  16. Study on the Reinforcement Measures and Control Effect of the Surrounding Rock Stability Based on the Shield Tunneling Under Overpass Structure

    Directory of Open Access Journals (Sweden)

    Qian-cheng Fang

    2016-04-01

    Full Text Available To study the stability of surrounding rocks for shield tunneling under overpass structures and the safety of existing bridge structures, a practical example of the method was cited through a shield tunneling project under the overpass structure between K1+110 and K1+700 on Line 2 of Shenyang Subway, China. The sub-area reinforcement was proposed according to surrounding rock deformation characteristics during shield tunnel excavation. The bridge foundation (i.e., the clear spacing to the shield tunnel is less than 2 m was reinforced by steel support, the bridge foundation (the clear spacing is about 2~7m used “jet grouting pile” reinforcement, whereas the bridge foundation (the clear spacing is greater than 7 m did not adopt any reinforcement measures for the moment. For this study, the mean value and material heterogeneity models were established to evaluate the reinforcement effect from several aspects, such as surrounding rock deformation, plastic zone development, and safety factor. The simulation results were consistent with those of field monitoring. After reinforcement, the maximum deformation values of the surrounding rock were reduced by 4.9%, 12.2%, and 48.46%, and the maximum values of surface subsidence were decreased by 5.6%, 72.2%, and 88.64%. By contrast, the overall safety factor was increased by 4.1%, 55.46%, and 55.46%. This study posited that this reinforcement method can be adopted to solve tunnel construction problems in engineering-geological conditions effectively. References for evaluating similar projects are provided.

  17. Energetic aspects of boring tools wear

    Directory of Open Access Journals (Sweden)

    Lazarová Edita

    2002-03-01

    Full Text Available In the process of rock desintegration a boring tool is subjected to the wear. From a viewpoint of the bit wear, changes on the contact of operating tool with rock at its one-shot and rerun load or overload by external forces are technically significant. Theis change results in the degradation of bit working properties and the output of desintegration also decreases. In the major part of cases, together with the bit wear, the contact area of a tool with a rock massifs enhanced and this fact causes an increase of fines (dust creation during the desintegration. The wear is always connected with a friction, forces action, deformation, damage, and the increased mechanical work consumption. As to energetic aspects of bit wear, the wear was observed as a function of bore length and in the most of cases as a dependence of the operating time. A linear dependence between the wear intensity (bit wear per unit of bore length and the specific energy of desintegration (energy consumed per volume unit of desintegrated rock was experimentally verified. Thus, the changes of bit wear can be implicitly observed by monitoring the specific energy. At the same time, the specific energy is a function of input parameters of the desintegration process and in the field of applicable external forces it shows an extreme (minimum. Therefore, the specific energy is useful for the extreme optimisation of the rock desintegration process from the viewpoint of the bit wear. It was mathematically proven that the tool output at the desintegration exponentially decreases with the amount of work consumed in the rock desintegration. The derivation of this knowledge comes out from the Krendelev equation.

  18. Techniques for the Construction of Tunnels in Areas of Strong Rock Burst%强岩爆隧道施工技术

    Institute of Scientific and Technical Information of China (English)

    李方利

    2012-01-01

    The embedded depth of the 3# auxiliary tunnel of the Jinping Power Station is more than 2,200m,with very high in-situ stress.The tunnel is located in an area of strong rock burst.The microseismic monitoring method of rock burst is used for the prediction of rock burst in the process of construction,with the techniques of spraying high-pressure water and injecting water deep into the body of rocks,smooth-face blasting,stress-relieving blasting and timely providing anchor bolts,shotcreting supporting concrete,etc.adopted in collaboration.The above-mentioned techniques and measures help greatly reduce the probability of rock burst and the risks of serious consequences of rock burst,and ensure the successful completion of the excavation of the tunnel.%锦屏电站辅引3#隧洞埋深超过2 200m,地应力极高,属于强岩爆洞段。施工中采用微震监测方法进行岩爆预测,结合喷洒高压水和岩体深部注水技术、光面爆破及应力解除爆破技术和及时施作锚杆、喷砼等支护措施,大大降低岩爆发生概率和产生严重后果的风险,顺利完成隧洞的开挖施工。

  19. 2D DEM analyses for T-M coupling effects of extreme temperatures on surrounding rock-supporting system of a tunnel in cold region

    Institute of Scientific and Technical Information of China (English)

    张玉军; 杨朝帅; 王永刚

    2013-01-01

    Taking the Kunlunshan Tunnel on Qinghai Tibet Railway as an engineering background, the curved wall-inverted arch lining of the tunnel was simplified into the straight wall-umbrella arch one, and the fractured rock mass with developed joints was treated as a discrete medium in the calculation. Using the UDEC code, the numerical simulations for thermo-mechanical coupling processes in the surrounding rock mass-supporting system were carried out aiming at the conditions of mean temperature, extreme highest temperature and extreme lowest temperature in one year. The distributions and changes of stresses, displacements, plastic zones, temperatures in the rock mass of near field, as well as the loading states in the model-building concrete and bolting were investigated and compared for these three computation cases. The results show that compared with the case of mean temperature, the ranges, where the temperatures of surrounding rock mass change obviously, are 6.0 m and 6.5 m, respectively, for the cases of extreme highest temperature and extreme lowest temperature; the displacements of tunnel are raised by 3.2 9.3 and 5.7 12.7 times, and the thicknesses of plastic zones reach 1.5 2.5 m and 2.0 4.5 m for case 2 and 3, respectively; the extreme temperatures of air have strong effects on the stress, deformation and failure states of supporting structure of tunnel in cold region, and the influence degree of extreme lowest temperature is the highest.

  20. 公路隧道围岩变形破坏理论研究%Deformation Damage Theory of Highway Tunnel Surrounding Rock

    Institute of Scientific and Technical Information of China (English)

    尚峰利

    2014-01-01

    this paper uses the methods of theoretic analysis, simulation, field monitoring and measuring to deeply study deformation damage theory of highway tunnel surrounding rock. This paper gets the relation-ship between damage variable and surrounding material parameter by analyzing the evolution of surround-ing damage in the course of excavation and proposes the method of predicting mechanical parameters of surrounding rocks;by studying rock damage mechanism, the influence scope of surrounding rock damage stress and all of the factors influencing surrounding rock stability, this paper establishes constitutive rela-tionship of surrounding rock damage in unloading condition and damage constitutive model based on ener-gy dissipation. Based on the elastoplastic numerical analysis mechanism, this paper establishes the analy-sis method of tunnel surrounding rock damage evolution in consideration of deterioration course of sur-rounding rock parameters and analyzes the elastoplastic damage evolution mechanism of tunnel surround-ing rock in excavation stress condition;establishes the model of highway tunnel surrounding rock pressure evolution trend and prediction based on experience formula and progressive surrounding rock damage the-ory, and proposes the predicting method of highway tunnel surrounding rock pressure evolution trend.%采用理论分析、数值模拟以及现场监控量测等手段对公路隧道围岩变形破坏理论进行较深入的研究。通过分析开挖过程中围岩损伤演化,获得了损伤变量与围岩材料参数之间的关系,提出了围岩力学参数的预测方法。通过岩体破坏机理、围岩损伤应力影响范围以及影响围岩稳定性的各个因素综合研究,建立了卸荷状态下的围岩损伤本构关系和基于能量耗散的损伤本构模型。基于一般弹塑性数值分析原理,建立了考虑围岩参数劣化过程的隧道围岩损伤演化分析方法,分析了开挖应力状态下隧道围

  1. Application of Geostatistical Modelling to Study the Exploration Adequacy of Uniaxial Compressive Strength of Intact Rock alongthe Behesht-Abad Tunnel Route

    Directory of Open Access Journals (Sweden)

    Mohammad Doustmohammadi

    2014-12-01

    Full Text Available Uniaxial compressive strength (UCS is one of the most significant factors on the stability of underground excavation projects. Most of the time, this factor can be obtained by exploratory boreholes evaluation. Due to the large distance between exploratory boreholes in the majority of geotechnical projects, the application of geostatistical methods has increased as an estimator of rock mass properties. The present paper ties the estimation of UCS values of intact rock to the distance between boreholes of the Behesht-Abad tunnel in central Iran, using SGEMS geostatistical program. Variography showed that UCS estimation of intact rock using geostatistical methods is reasonable. The model establishment and validation was done after assessment that the model was trustworthy. Cross validation proved the high accuracy (98% and reliability of the model to estimate uniaxial compressive strength. The UCS values were then estimated along the tunnel axis. Moreover, using geostatistical estimation led to better identification of the pros and cons of geotechnical explorations in each location of tunnel route.

  2. Discussion of the Rock Classification and Selection of Support Parameters for a Soft Rock Tunnel with Large Deformation%软岩大变形隧道围岩分级及支护参数适宜性探讨

    Institute of Scientific and Technical Information of China (English)

    武建广; 朱洪莹

    2012-01-01

    Tunnels located in soft rock such as slate and carbonaceous slate are susceptible to large deformations, and this is true of the Lanzhou-Guangyuan section of the Lanzhou-Chongqing railway. Based on site practice and experiments, this paper analyzes the specific geological characteristics of this section and introduces the classification of the tunnel'surrounding rock and design alternatives during construction, with a focus on the standard for classification and support parameter selection process of tunnels in soft rock with large deformation.%兰渝线兰广段通过板岩、碳质板岩等软岩区段的隧道极易发生大变形.在现场工程实践和试验的基础上,文章对该区段地质条件的特殊性进行了分析,并对目前隧道围岩基本分级及在施工过程中的设计变更修正进行了阐述,着重对软岩大变形隧道的围岩分级标准和选用支护参数的适宜性进行了探讨,以期能为今后同类工程提供参考和借鉴.

  3. The three-dimension model for the rock-breaking mechanism of disc cutter and analysis of rock-breaking forces

    Institute of Scientific and Technical Information of China (English)

    Zhao-Huang Zhang; Fei Sun

    2012-01-01

    To study the rock deformation with three-dimensional model under rolling forces of disc cutter,by carrying out the circular-grooving test with disc cutter rolling around on the rock,the rock mechanical behavior under rolling disc cutter is studied,the mechanical model of disc cutter rolling around the groove is established,and the theory of single-point and double-angle variables is proposed.Based on this theory,the physics equations and geometric equations of rock mechanical behavior under disc cutters of tunnel boring machine (TBM) are studied,and then the balance equations of interactive forces between disc cutter and rock are established.Accordingly,formulas about normal force,rolling force and side force of a disc cutter are derived,and their validity is studied by tests.Therefore,a new method and theory is proposed to study rock- breaking mechanism of disc cutters.

  4. Breaking through the tranfer tunnel

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    This image shows the tunnel boring machine breaking through the transfer tunnel into the LHC tunnel. Proton beams will be transferred from the SPS pre-accelerator to the LHC at 450 GeV through two specially constructed transfer tunnels. From left to right: LHC Project Director, Lyn Evans; CERN Director-General (at the time), Luciano Maiani, and Director for Accelerators, Kurt Hubner.

  5. Report Tunneling Cost Reduction Study prepared for Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    1999-07-16

    Fermi National Accelerator Laboratories has a need to review the costs of constructing the very long tunnels which would be required for housing the equipment for the proposed Very Large Hadron Collider (VLHC) project. Current tunneling costs are high, and the identification of potential means of significantly reducing them, and thereby helping to keep overall project costs within an acceptable budget, has assumed great importance. Fermilab has contracted with The Robbins Company to provide an up-to-date appraisal of tunneling technology, and to review the potential for substantially improving currently the state-of-practice performance and construction costs in particular. The Robbins Company was chosen for this task because of its long and successful experience in hard rock mechanical tunnel boring. In the past 40 years, Robbins has manufactured over 250 tunneling machines, the vast majority for hard rock applications. In addition to also supplying back-up equipment, Robbins has recently established a division dedicated to the manufacture of continuous conveying equipment for the efficient support of tunneling operations. The study extends beyond the tunnel boring machine (TBM) itself, and into the critical area of the logistics of the support of the machine as it advances, including manpower. It is restricted to proven methods using conventional technology, and its potential for incremental but meaningful improvement, rather than examining exotic and undeveloped means of rock excavation that have been proposed from time to time by the technical community. This is the first phase of what is expected to be a number of studies in increasing depth of technical detail, and as such has been restricted to the issues connected with the initial 34 kilometer circumference booster tunnel, and not the proposed 500 kilometer circumference tunnel housing the VLHC itself. The booster tunnel is entirely sited within low to medium strength limestone and dolomite formations

  6. Intelligent direct analysis of physical and mechanical parameters of tunnel surrounding rock based on adaptive immunity algorithm and BP neural network

    Institute of Scientific and Technical Information of China (English)

    Xiao-rui Wang; Yuan-han Wang; Xiao-feng Jia

    2009-01-01

    Because of complexity and non-predictability of the tunnel surrounding rock, the problem with the determination of the physical and, mechanical parameters of the surrounding rock has become a main obstacle to theoretical research and numerical analysis in tunnel engineering. During design, it is a frequent practice, therefore, to give recommended values by analog based on experience. It is a key point in current research to make use of the displacement back analytic method to comparatively accurately determine the parameters of the surrounding rock whereas artificial intelligence possesses an exceptionally strong capability of identifying, expressing and coping with such complex non-linear relationships. The parameters can be verified by searching the optimal network structure, using back analysis on measured data to search optimal parameters and performing direct computation of the obtained results. In the current paper, the direct analysis is performed with the biological emulation system and the software of Fast Lagrangian Analysis of Continua (FLAC3D. The high non-linearity, network reasoning and coupling ability of the neural network are employed. The output vector required of the training of the neural network is obtained with the numerical analysis software. And the overall space search is conducted by employing the Adaptive Immunity Algorithm. As a result, we are able to avoid the shortcoming that multiple parameters and optimized parameters are easy to fall into a local extremum. At the same time, the computing speed and efficiency are increased as well. Further, in the paper satisfactory conclusions are arrived at through the intelligent direct-back analysis on the monitored and measured data at the Erdaoya tunneling project. The results show that the physical and mechanical parameters obtained by the intelligent direct-back analysis proposed in the current paper have effectively unproved the recommended values in the original prospecting data. This is of

  7. Seismic monitoring experiment of raise boring in 2014

    Energy Technology Data Exchange (ETDEWEB)

    Saari, J.; Malm, M. [AaF-Consult Oy, Espoo (Finland)

    2015-01-15

    In Olkiluoto, Posiva Oy has operated a local seismic network since February 2002. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of ONKALO. The possibility to excavate an illegal access to ONKALO has been concerned when the safeguards are discussed. Therefore all recorded explosions in the Olkiluoto area and in ONKALO are located. If a concentration of explosions is observed, the origin of that is found out. Also a concept of hidden illegal explosions, detonated at the same time as the real excavation blasts, has been examined. According to the experience gained in Olkiluoto, it can be concluded that, as long the seismic network is in operation and the results are analysed by a skilled person, it is practically impossible to do illegal undetected excavation by blasting within the Olkiluoto seismic network area. In this report a possibility of seismic monitoring of undeclared excavation done by tunnel boring machine (TBM) has been investigated. In the earlier investigations the instruments were at the ground surface and the sensors were triaxial short period (1 Hz) geophones or broadband geophones. The characteristics (frequency content, polarity and amplitude) of the continuous seismic vibration generated by TMB were studied. The onset time of the seismic signal were not distinguished. Altogether 16 new 10 kHz accelerometers were installed in boreholes inside ONKALO March 2012. The sensors comprised a new subnetwork that monitored the raise boring of two shafts done 2014, from the level -455 m to the level -290 m. The aim was to record the seismic signal generated when the drill bit hits the rock at the moment the tunnel boring begins. Altogether 113 seismic signals generated by the drill bit were located during the

  8. Rock stability considerations for siting and constructing a KBS-3 repository. Based on experiences from Aespoe HRL, AECL's URL, tunnelling and mining

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C.D. [Univ. of Alberta, Edmonton (Canada); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Soederhaell, J. [VBB VIAK AB, Stockholm (Sweden)

    2001-12-01

    mapping of the borehole walls. Two major tasks must be accomplished during this period: 1. an assessment of the quality of the rock mass and 2. an assessment of the state of stress within the volume of rock containing the repository. Empirical methods such as the Q system can be used to establish the domains of rock mass quality and to assess tunnel support requirements during the preliminary design phase. The laboratory testing should be carried out to determine the crack initiation stress, the long-term strength, peak strength and post-peak response. The determination of these parameters should be determined from stress-strain data, as well acoustic emission testing techniques, using testing methods based on accepted national standards, such as the ISRM suggested methods or ASTM. The in-situ stress state must be measured with confidence. The number of measurements and the method(s) used will be a function of the geology of the site. Practical experience indicates that stress-induced failure (spalling) will occur on the boundary of an underground opening in hard rocks when the maximum tangential stresses on the boundary of the opening exceed approximately 0.3 to 0.4 of the laboratory uniaxial compressive strength. Hence to assess the potential for spalling, numerical analysis will be required for the various shaped openings planned for the repository. These numerical analysis can be used to optimize the shape of the tunnels, the orientation of the tunnels relative to the far-field stress state, intersection support, and deposition tunnel/borehole spacing. The support for the tunnels in a repository is expected to range from light support pressure equivalent to standard spot-bolting to local bolts with mesh and fibre-reinforced shotcrete. At major intersections medium to heavy support pressure may be required. The layout of a repository will be similar to a mine using a room-and-pillar mining method but the extraction ratio will be of the order of <30%. A drill

  9. Maneuvering impact boring head

    Science.gov (United States)

    Zollinger, W. Thor; Reutzel, Edward W.

    1998-01-01

    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

  10. Boring sponges (Porifera, Clionidae) collected during the "Tydeman" Canary Islands expedition Cancap-II, 1977

    NARCIS (Netherlands)

    Groot, de R.A.

    1980-01-01

    INTRODUCTION AND MATERIAL The boring sponges of the Canary Islands have never been studied in any detail, but the boring fauna of this archipelago cannot be expected to be very rich. All islands are volcanic and calcareous rocks are not common. Consequently, in most areas large shells and rhodophyte

  11. Rock stability considerations for siting and constructing a KBS-3 repository. Based on experiences from Aespoe HRL, AECL's URL, tunnelling and mining

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C.D. [Univ. of Alberta, Edmonton (Canada); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Soederhaell, J. [VBB VIAK AB, Stockholm (Sweden)

    2001-12-01

    mapping of the borehole walls. Two major tasks must be accomplished during this period: 1. an assessment of the quality of the rock mass and 2. an assessment of the state of stress within the volume of rock containing the repository. Empirical methods such as the Q system can be used to establish the domains of rock mass quality and to assess tunnel support requirements during the preliminary design phase. The laboratory testing should be carried out to determine the crack initiation stress, the long-term strength, peak strength and post-peak response. The determination of these parameters should be determined from stress-strain data, as well acoustic emission testing techniques, using testing methods based on accepted national standards, such as the ISRM suggested methods or ASTM. The in-situ stress state must be measured with confidence. The number of measurements and the method(s) used will be a function of the geology of the site. Practical experience indicates that stress-induced failure (spalling) will occur on the boundary of an underground opening in hard rocks when the maximum tangential stresses on the boundary of the opening exceed approximately 0.3 to 0.4 of the laboratory uniaxial compressive strength. Hence to assess the potential for spalling, numerical analysis will be required for the various shaped openings planned for the repository. These numerical analysis can be used to optimize the shape of the tunnels, the orientation of the tunnels relative to the far-field stress state, intersection support, and deposition tunnel/borehole spacing. The support for the tunnels in a repository is expected to range from light support pressure equivalent to standard spot-bolting to local bolts with mesh and fibre-reinforced shotcrete. At major intersections medium to heavy support pressure may be required. The layout of a repository will be similar to a mine using a room-and-pillar mining method but the extraction ratio will be of the order of <30%. A drill

  12. Study on Soft Rock Tunnel Construction Technology%浅埋偏压软岩隧道施工技术研究

    Institute of Scientific and Technical Information of China (English)

    邵大鹏; 李廷春

    2012-01-01

    Xinzhai Tunnel is located in the fold system of western Qinling Mountains, and the jointed and fractured sur-rounding rock, characterized by rock crushing, consists mainly of the Silurian carbonaceous phyllite. Import section is loca-ted at the left edge of the landslide, gully is formed at the portal with the minimum buried depth of 13 - 18m. The bias, shallow buried depth and weak surrounding rock causes great difficulties for construction, especially high security risk for tunneling. Based on the Xinzhai Tunnel under construction, the paper introduces the construction scheme and construction techniques and makes a summary of experience in dealing with similar issues.%新寨隧道位于西秦岭褶皱系中,节理裂隙发育,岩体破碎,围岩主要以志留系碳质千枚岩为主。进口段位于滑坡左侧边缘,洞门左侧发育冲沟一条,最小埋深13~18 m,在此偏压、浅埋、软弱围岩的条件下施工难度大,特别是进洞施工安全风险高。以在建新寨隧道施工为依托,介绍了该隧道的施工方案及施工技术措施,总结得出一些处理类似问题的经验。

  13. 西南地区某隧道围岩岩爆预测研究%PREDICTION OF ROCKBURST AT WALL ROCKS OF TUNNELS IN SOUTHWEST

    Institute of Scientific and Technical Information of China (English)

    王开洋; 肖鸿; 尚彦军; 苏开敏; 何万通

    2014-01-01

    The prediction of rockburst is a great challenge for the construction of underground engineering.We take a tunnel in southwest China as a case study.We consider the three conditions inducing rockburst as:rockburst occurring probability of rock mass,the integrity of rock mass and the high in-situ stress.We take the maximum stored elastic strain energy(Es)and the rock brittleness modulus(B)as the indicators.We then analyze the rockburst occurring probability of quartz sandstone and limestone in the deep tunnel.Based on the collected in-situ stress data we collected,with the assistance of finite element method which immediately simulates the geological process,we launch a back analysis on the stress field of the rock mass in the tunnel area and consequently obtain the high in-situ stress-section in the area.Utilizing field sampling tests,we study the physical and mechanical properties of the wall rocks like the uniaxial compressive strength of intact rock.We summarize the previous rockburst predicting methods,employ the comprehensive engineering geological analysis,elaborate the conditions causing tunnel rockburst.Then,we use the theory of rock mass mechanics,the non-linear science as guidance,the geological comprehensive analysis method and the stress intensity ratio method to predict the location and intensity of rockburst that may occur in the tunnel area.%岩爆预测一直是地下工程领域中的世界性难题。本文以西南某隧道工程为例,从岩爆形成的3个条件:岩石岩爆倾向性、岩体完整性和高地应力环境3个方面着手,应用最大储存弹性应变能指标Es和岩石脆性系数B,对深埋隧道区段内可能发生岩爆的石英砂岩、灰岩岩体进行岩爆倾向性分析预测;基于地应力测量数据资料,采用地质过程动态模拟的有限元分析方法,反演分析隧道工程区岩体地应力场,对隧道高应力区段作出判断;根据现场所取样品试验结果综合分析隧

  14. Photoelectric Inspecting of Artillery Bore

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; MA Hong; BAI Su-ping; YAN Yu-feng

    2008-01-01

    A photoelectric equipment for inspecting artillery bore is composed of digital display grating sensor and data processing with computer. It can replace the traditional mechanical measurer and realize the automatic inspection of artillery bore. Introduced are briefly the working principles and analysis of this device.

  15. Modeling of Damage, Permeability Changes and Pressure Responses during Excavation of the TSX Tunnel in Granitic Rock at URL, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, Jonny; Borgesson, Lennart; Chijimatsu, Masakazu; Hernelind, Jan; Jing, Lanru; Kobayashi, Akira; Nguyen, Son

    2008-08-01

    This paper presents numerical modeling of excavation-induced damage, permeability changes, and fluid-pressure responses during excavation of the TSX tunnel at the underground research laboratory (URL) in Canada. Four different numerical models were applied, using a wide range of approaches to model damage and permeability changes in the excavation disturbed zone (EDZ) around the tunnel. Using in situ calibration of model parameters the modeling could reproduce observed spatial distribution of damage and permeability changes around the tunnel, as a combination of disturbance induced by stress redistribution around the tunnel and by the drill-and-blast operation. The modeling showed that stress-induced permeability increase above the tunnel is a result of micro and macrofracturing under high deviatoric (shear) stress, whereas permeability increases alongside the tunnel as a result of opening of existing microfractures under decreased mean stress. The remaining observed fracturing and permeability changes around the periphery of the tunnel were attributed to damage from the drill-and-blast operation. Moreover, a reasonably good agreement was achieved between simulated and observed excavation-induced pressure responses around the TSX tunnel for 1 year following its excavation. The simulations showed that these pressure responses are caused by poroelastic effects as a result of increasing or decreasing mean stress, with corresponding contraction or expansion of the pore volume. The simulation results for pressure evolution were consistent with previous studies, indicating that the observed pressure responses could be captured in a Biot model using a relatively low Biot-Willis coefficient, {alpha} {approx} 0.2, a porosity of n {approx} 0.007, and a relatively low permeability of k {approx} 2 x 10{sup -22} m{sup 2}, which is consistent with the very tight, unfractured granite at the site.

  16. 铁路松散破碎围岩隧道防塌控制技术%Collapse Control Technology in Incompact and Fractured Surrounding Rock Railway Tunnel

    Institute of Scientific and Technical Information of China (English)

    柴跃进

    2013-01-01

    隧道施工中经常遇到破碎围岩而发生塌方及掌子面涌出、坍塌的事故.一旦塌方灾害发生,不仅影响工程进度,而且影响施工企业形象;若处理不当,将遭受更大损失,如塌方频繁发生,或留下隐患.提出一种新型隧道防塌控制技术-“双曲拱”耦合支护技术,支护效果表明该技术可靠性强,能有效控制隧道顶板坍塌,具有很好的经济效益和社会效益.%Often fractured surrounding rock in tunnel construction and face the collapse and gushing, collapse accident.Once the landslide disaster, not only the project, but construction corporate image;If not handled properly, will suffer more losses, such as landslides are frequent, hidden or left.Made a new tunnel collapse prevention control technologies - "double -curved arch" coupling supporting technology, supporting effect indicates that the technical reliability, can effectively control the tunnel roof collapsed, with good economic and social benefits.

  17. 贵广线天平山隧道软岩变形分析%Analysis of Soft Rock Deformation of Tianpingshan Tunnel of Guiyang - Guangzhou Railway

    Institute of Scientific and Technical Information of China (English)

    付开隆; 蔡家鹏; 冯涛

    2011-01-01

    Research purposes: Predicting and monitoring the soft rock deformation is a complex and important work in railway engineering, and searching an effective method for predicting and monitoring the soft rock deformation is of significance.Research conclusions: For the soft rock deformation of the Tianpingshan Tunnel, the comprehensive survey was conducted and the analysis of the deformation range and deformation level caused by the excavation was made from the lithology characters,structure and ground stress.It can be seen from the current excavation that the prediction of the deformation of the the incline shaft 2 and the main tunnel that under- passes the Chaotang Fault Zone is rather reasonable and whether the prediction of the deformation of carbonaceous shale area is correct or not, it needs waiting for comparing it with the excavation result..%研究目的:软岩变形预测及监测是铁路工程地质中一项复杂而又重要的工作,寻求一种有效的预测及监测方法具有重要的意义.研究结论:针对天平山隧道的软岩变形问题,勘察阶段已经有了较为充分的认识,并为此开展了综合勘探,从岩性、构造、地应力等方面对隧道开挖所经受的变形范围及程度进行了详细的分析.从目前开挖情况看,2号斜井及相应正洞穿过下朝塘断裂带变形预测较为合理,而页岩为主夹炭质页岩段的变形预测还有待开挖对比.

  18. Performance Assessment of Hard Rock TBM and Rock Boreability Using Punch Penetration Test

    Science.gov (United States)

    Jeong, Ho-Young; Cho, Jung-Woo; Jeon, Seokwon; Rostami, Jamal

    2016-04-01

    Rock indentation tests are often called punch penetration tests and are known to be related to penetration rates of drilling equipment and hard rock tunnel boring machines (TBMs). Various indices determined from analysis of the force-penetration plot generated from indentation tests have been used to represent the drillability, boreability, and brittleness of rocks. However, no standard for the punch penetration test procedure or method for calculating the related indices has been suggested or adopted in the rock mechanics community. This paper introduces new indices based on the punch test to predict the performance of hard rock TBMs. A series of punch tests was performed on rock specimens representing six rock formations in Korea with different dimensions, i.e., the core specimens had different lengths and diameters. Of the indices obtained from the punch tests, the peak load index and mean load index showed good correlations with the cutting forces measured in full-scale linear cutting machine tests on the same rock types. The indices also showed good linear correlations with the ratio of uniaxial strength to Brazilian tensile strength, which indicates the brittleness of rock. The scale effect of using core specimens was investigated, and a preferred dimension for the punch test specimens is proposed. This paper also discusses the results of the punch test and full-scale rock cutting tests using LCM. The results of this study confirm that the proposed indices from the punch tests can be used to provide a reliable prediction of the cutting forces that act on a disc cutter. The estimated cutting forces can then be used for optimization of cutter-head design and performance prediction of hard rock TBMs.

  19. Microseismic Monitoring of Strainburst Activities in Deep Tunnels at the Jinping II Hydropower Station, China

    Science.gov (United States)

    Xu, N. W.; Li, T. B.; Dai, F.; Zhang, R.; Tang, C. A.; Tang, L. X.

    2016-03-01

    Rockbursts were frequently encountered during the construction of deep tunnels at the Jinping II hydropower station, Southwest China. Investigations of the possibility of rockbursts during tunnel boring machine (TBM) and drilling and blasting (D&B) advancement are necessary to guide the construction of tunnels and to protect personnel and TBM equipment from strainburst-related accidents. A real-time, movable microseismic monitoring system was installed to forecast strainburst locations ahead of the tunnel faces. The spatiotemporal distribution evolution of microseismic events prior to and during strainbursts was recorded and analysed. The concentration of microseismic events prior to the occurrence of strainbursts was found to be a significant precursor to strainbursts in deep rock tunnelling. During a 2-year microseismic investigation of strainbursts in the deep tunnels at the Jinping II hydropower station, a total of 2240 strainburst location forecasts were issued, with 63 % correctly forecasting the locations of strainbursts. The successful forecasting of strainburst locations proved that microseismic monitoring is essential for the assessment and mitigation of strainburst hazards, and can be used to minimise damage to equipment and personnel. The results of the current study may be valuable for the construction management and safety assessment of similar underground rock structures under high in situ stress.

  20. 3D Finite Element Analysis of TBM Water Diversion Tunnel Segment Coupled with Seepage Field

    Institute of Scientific and Technical Information of China (English)

    钟登华; 胡能明; 程正飞; 吕鹏; 佟大威

    2016-01-01

    In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not consid-ered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly oc-curs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BReP hybrid data structure in this paper. Then the seepage field of the surrounding rock con-sidering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is stud-ied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.

  1. Cicatrization of the damaged zone around a tunnel in low permeable rocks; Cicatrisation de la zone endommagee autour du tunnel dans des roches peu permeables

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, R.O

    2005-12-15

    Three types of clays have been studied in this work: the Mol clay (plastic clay), the Mont Terri clay (opalinus clay) and the East clay (stiff clay). This work is divided into three parts: an experimental part which has allowed to identify the cicatrization phenomenon and the cracks closing. Through several tests has been determined the evolution of the permeability of the clayey samples which are undamaged or damaged with time and according to the different applied hydro-mechanical loadings. In order to describe the cicatrization phenomenon, a rheological law has been developed from the experimental observations and under some hypotheses. The parameters of the cicatrization model have been determined by numerical simulation. In order to take into account the structures effects at a large scale, the modelling of a tunnel has allowed to better identify the cicatrization phenomenon and to analyze the long term stability of this work. (O.M.)

  2. 核心土对黄土隧道稳定性影响的有限元分析%On finite elementary analysis of core rock on stability influence of loess tunnels

    Institute of Scientific and Technical Information of China (English)

    王锋波

    2012-01-01

    Based on Zhongtiaoshan tunnel,the paper undertakes the finite element simulation on the differences in the step length and the length of the remained core rock in the excavation by adopting the remained core rock step method in the road tunnels,analyzes the influence of the step length and the length of the core rock on the longitudinal displacement of the tunnel face and the longitudinal depth of plastic zones,maximum and minimum principal stresses of tunnel face,and concludes the reasonable step length and the designed the length of the core rock.%依托中条山公路隧道,对公路隧道在黄土段采用预留核心土台阶法开挖时,对台阶长度、预留核心土长度的不同进行了有限元模拟,分析了台阶长度和核心土长度对隧道掌子面的纵向位移、塑性区的纵向深度的影响以及掌子面最大最小主应力,得出了合理的台阶长度及留设核心土的长度。

  3. Study on Tianpingshan Tunnel Soft Rock Construction Control Technology%天平山隧道软岩施工控制技术研究

    Institute of Scientific and Technical Information of China (English)

    李兴军

    2014-01-01

    天平山隧道部分地段为炭质页岩或砂岩夹炭质页岩,围岩极其破碎、有大量渗水,易掉块和变形,变形过大造成隧道坍塌,通过试验在保证安全的前提下,提出经济合理的支护参数,既有利于控制成本,同时也加快了施工进度。%Some sections of Tianpingshan tunnel are carbonaceous shale or sandstone with carbonaceous shale. The surrounding rock is broken with a lot of water seepage, causing easy chipping and deformation and excessive deformation can lead to tunnel collapse. On the premise of security, economic and reasonable support parameters are put forward through test, which can control the cost and accelerates the construction progress.

  4. Application of unconventional geoelectrical methods to the hydrogeological examination of the Mt. S. Croce rock formations (Umbria, Italy involved in a railway tunnel project

    Directory of Open Access Journals (Sweden)

    D. Patella

    1994-06-01

    Full Text Available he project of doubling and developing of the railway line Orte-Falconara, committed by the Italian State Railway Company to the COMAVI Consortium (Rome, Italy, envisaged building the Mt. S. Croce tunnel, about 3200 m long between the stations of Narni and Nera Montoro (Umbria, ltaly. During the last phase of the feasibility project, a geophysical research based on geoelectrical prospecting methods was carried out to complement other geognostic investigations with the following goals: a to outline the complex geotectonic model of the rock system, which will be affected by the new railway layout; b to gain information on the hydrogeologic features of the survey area, in relation to the existing geologic situation and the consequent effects on the digging conditions of the tunnel and on the operation conditions of the railway layout. The geophysical work was thus organized according to the following scheme: a execution of dipole electrical sounding pro-files, to depict a series of significant tomographic pseudosections, both across and along the new railway layout; b execution of self-potential measurements, to draw an anomaly map over the whole hydrogeological network system in the survey area. The research provided information which has helped to improve the geological-structural model of the area and disclosed the hydrogelogic network, conforming to the classified field surface manifestations. At present, further detailed field investigations are being carried out, which confirm all the results obtained by the geoelectrical survey.

  5. Risk of shear failure and extensional failure around over-stressed excavations in brittle rock

    Directory of Open Access Journals (Sweden)

    Nick Barton

    2017-04-01

    Full Text Available The authors investigate the failure modes surrounding over-stressed tunnels in rock. Three lines of investigation are employed: failure in over-stressed three-dimensional (3D models of tunnels bored under 3D stress, failure modes in two-dimensional (2D numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD, both in intact rock and in rock masses with one or two joint sets, and finally, observations in TBM (tunnel boring machine tunnels in hard and medium hard massive rocks. The reason for ‘stress-induced’ failure to initiate, when the assumed maximum tangential stress is approximately (0.4–0.5σc (UCS, uniaxial compressive strength in massive rock, is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect. However, because similar ‘stress/strength’ failure limits are found in mining, nuclear waste research excavations, and deep road tunnels in Norway, one is easily misled into thinking of compressive stress induced failure. Because of this, the empirical SRF (stress reduction factor in the Q-system is set to accelerate as the estimated ratio σθmax/σc >> 0.4. In mining, similar ‘stress/strength’ ratios are used to suggest depth of break-out. The reality behind the fracture initiation stress/strength ratio of ‘0.4’ is actually because of combinations of familiar tensile and compressive strength ratios (such as 10 with Poisson's ratio (say 0.25. We exceed the extensional strain limits and start to see acoustic emission (AE when tangential stress σθ ≈ 0.4σc, due to simple arithmetic. The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by ‘stable’ extensional strain fracturing, but propagation in ‘unstable’ and therefore dynamic shearing. In the case of very deep tunnels (and 3D physical simulations, compressive stresses may be too high for extensional strain fracturing, and

  6. In situ stresses in rock masses: methodology for its study in tunnel projects in Spain; Metodologia de estudio y obtencion de las tensiones in situ en los proyectos de obra subterranea realizados en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Madirolas Perez, G.; Perucho Martinez, A.

    2014-07-01

    In situ stress is one of the main factors to be taken into account in the design of tunnels, as it can cause inadmissible stresses and strains leading to high deviations in the budgets. For that reason, the stress state is directly introduced into the numerical models used for the design of tunnels. In Spain, although several tunnels have been carried out with an important overburden in tectonically relevant zones, a quantitative determination of the stresses has not been usually included in civil work projects. Therefore, it is considered necessary to implement a routine procedure of study of civil work projects involving tunnels excavated in rock, and a new detailed methodology is proposed. The challenge is that project managers, who face works in which stresses may play a determinant role, may have a practical reference enabling them to optimize available resources and to include the real stress information in the design of underground works. (Author)

  7. Aespoe HRL. Experiences of blasting of the TASQ tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Mats [Swebrec, Luleaa (Sweden); Niklasson, Bengt [Skanska Teknik, Stockholm (Sweden); Wilson, Lasse [Skanska Stora Projekt, Stockholm (Sweden); Andersson, Christer; Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2004-11-01

    A new tunnel was developed at the Aespoe Hard Rock Laboratory (AHRL) during the spring and summer 2003. The tunnel was specially designed for a rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). In this pillar experiment there was a high demand to initiate high in-situ stresses and therefore the tunnel was designed with a large height/ width ratio and with a circular floor. There were high requirements on bore hole precision and of a minimized EDZ (Excavation damaged zone) in the pillar area. This included a maximum borehole deviation of 10 mm/m, a maximum overbreak due to the lookout angle of 0.3 m and an EDZ of 0.3 m. To make a charge control feasible cartridged explosives was prescribed. The initiation was made with Nonel. The last three rounds used electronic initiation to enable studies of possibility to further reduce the EDZ. The collar of the tunnel was very close to installations and shaft and it was very important to avoid fly-rock and vibrations. Special types of stemming were used as well as steel plates and rubber mats. The excavation works was divided in three different phases. The first phase of the tunnel was an ordinary 26 m{sup 2} tunnel. After approximately 30 m a ramp separated the tunnel section into a top heading and a bench, total 33 m{sup 2}. After the last top heading round was excavated and the roof had been reinforced with fibre reinforced shotcrete the bench was taken out with horizontal holes as the third phase. The drilling precision was very good and 95% of all half-pipes fulfilled the demands. The total amount of visible half-pipes in the APSE-tunnel was high and indicated a successful smooth blasting. The EDZ was examined further by cutting slots in the wall and roof. Existing cracks appear very clearly when a dye penetrant is sprayed on the cleaned surface. A typical crack pattern consists of blast cracks, induced cracks (cracks from the distressing caused by blasting) and natural cracks. The maximum crack

  8. 某水工隧洞围岩稳定及支护结构分析%ANALYSIS ON SURROUNDING ROCK STABILITY AND SUPPORTING STRUCTURE OF DIVERSION SPILLWAY TUNNEL

    Institute of Scientific and Technical Information of China (English)

    秦雷; 郭德发; 王庆

    2012-01-01

    隧洞的围岩稳定及支护结构安全是保证隧洞安全、实现隧洞功能的关键因素.由围岩加固圈承担主要的外水压力是优化支护结构设计、保证围岩稳定的一种有效方法.建立肯斯瓦特导流泄洪洞三维有限元模型,并进行非线性有限元分析.分析结果表明,设计的支护措施能明显减少围岩变形、改善应力分布,为类似工程设计提供参考.%The stability of surrounding rock tunnel and the safe of support structure is the key factor to ensure tunnels safe and to achieve tunnel function. It is a optimized design to exert major external water pressure at reinforce circle also it is an effective method for the stability of surrounding rock. The author did the nonlinear finite element analysis by creating three-dimensional finite element model of Kensi-wate diversion spillway tunnel. The results show that the designed support measures can significantly reduce the rock deformation and improve the stress distribution,and it can provide a reference for the design of similar projects.

  9. Study on temporal and spatial distribution model of ground settlement induced by metro tunnels construction with bored method%地铁暗挖施工引起的地表沉降时空分布模型研究

    Institute of Scientific and Technical Information of China (English)

    张波; 马雪梅; 任雪峰; 孙建勋

    2014-01-01

    Taking the ground settlements analysis caused by tunnel excavation construction in one Beijing subway as an example,this paper carried out regress analysis of ground settlements distribution based on Peck formula by a large number of measured data,and got Gaussian curves which can include the measured data to the maximal degree and the forecast range of ground settlements through modifying. The regress analysis of ground settlements with time changing based on Logistic function is also implemented and the distribution law of ground settlements with time and velocity distribution law with time are also obtained. The space-time predicting curves calculated by this method are closely associated with the construction method and tunnel soil condition,and the calculated parameters such as settlement trough width coefficient,ground loss rate,time parameter can establish the database,which could predict the space-time distribution of ground settlement well.%以北京一地铁区间隧道暗挖施工引起的地表沉降分析为例,研究地表沉降分布规律及其时程分布规律。在大量实测数据的基础上,基于Peck公式进行地表沉降分布的回归分析,并通过修正,得到最大程度包络实测数据的高斯曲线,从而得到地表沉降的范围;基于Logistic函数模型,进行地表沉降随时间变化的回归分析,得到地表沉降时程分布规律和沉降速度时程分布规律。通过该方法得到的地表沉降时空预测曲线与隧道的土层性质、施工方法等密切相关。计算得到的沉降槽宽度系数、地层损失率、时间参数等可为预测沉降的时空分布提供参考数据。

  10. Research on The Surrounding Rock Deformation Law of Carbon Shale Small Interval Tunnel%炭质页岩小净距隧道围岩变形规律研究

    Institute of Scientific and Technical Information of China (English)

    段宝福; 翁现合

    2012-01-01

    以湖北宴家隧道工程为例,结合现场施工监测,采用有限元程序对节理围岩隧道施工进行模拟,对节理围岩隧道的开挖对地层扰动的范围进行定量确定.对小间距双线隧道在炭质页岩条件下节理面上游隧道先行施工进行数值模拟,将实测数据与数值模拟进行对比,总结出炭质页岩小间距隧道左右洞有施工差别时围岩变形规律.%Taking the Hubei Yanjia tunnel project as an example, the construction of jointed surrounding rock tunnels was simulated using finite element software and the range of disturbance caused by the excavation was quantatively determined. Numerical simulations were also performed for the upper tunnel under carbonaceous shale in small interval tunnel and simulation results were compared against site measurement.Conclusions were drawn regarding the principles of tunnel surrounding rock deformation when the two holes are constructed differently.

  11. Tsunami Bores in Kitakami River

    Science.gov (United States)

    Tolkova, Elena; Tanaka, Hitoshi

    2016-07-01

    The 2011 Tohoku tsunami entered the Kitakami river and propagated there as a train of shock waves, recorded with a 1-min interval at water level stations at Fukuchi, Iino, and the weir 17.2 km from the mouth, where the bulk of the wave was reflected back. The records showed that each bore kept its shape and identity as it traveled a 10.9-km-path Fukuchi-Iino-weir-Iino. Shock handling based on the cross-river integrated classical shock conditions was applied to reconstruct the flow velocity time histories at the measurement sites, to estimate inflow into the river at each site, to evaluate the wave heights of incident and reflected tsunami bores near the weir, and to estimate propagation speed of the individual bores. Theoretical predictions are verified against the measurements. We discuss experiences of exercising the shock conditions with actual tsunami measurements in the Kitakami river, and test applicability of the shallow-water approximation for describing tsunami bores with heights ranging from 0.3 to 4 m in a river segment with a depth of 3-4 m.

  12. Tsunami Bores in Kitakami River

    Science.gov (United States)

    Tolkova, Elena; Tanaka, Hitoshi

    2016-12-01

    The 2011 Tohoku tsunami entered the Kitakami river and propagated there as a train of shock waves, recorded with a 1-min interval at water level stations at Fukuchi, Iino, and the weir 17.2 km from the mouth, where the bulk of the wave was reflected back. The records showed that each bore kept its shape and identity as it traveled a 10.9-km-path Fukuchi-Iino-weir-Iino. Shock handling based on the cross-river integrated classical shock conditions was applied to reconstruct the flow velocity time histories at the measurement sites, to estimate inflow into the river at each site, to evaluate the wave heights of incident and reflected tsunami bores near the weir, and to estimate propagation speed of the individual bores. Theoretical predictions are verified against the measurements. We discuss experiences of exercising the shock conditions with actual tsunami measurements in the Kitakami river, and test applicability of the shallow-water approximation for describing tsunami bores with heights ranging from 0.3 to 4 m in a river segment with a depth of 3-4 m.

  13. Can tasks be inherently boring?

    Science.gov (United States)

    Charney, Evan

    2013-12-01

    Kurzban et al. argue that the experiences of "effort," "boredom," and "fatigue" are indications that the costs of a task outweigh its benefits. Reducing the costs of tasks to "opportunity costs" has the effect of rendering tasks costless and of denying that they can be inherently boring or tedious, something that "vigilance tasks" were intentionally designed to be.

  14. Microbial control of wood-boring insects attacking forest and shade trees

    Science.gov (United States)

    Ann E. Hajek; Leah S. Bauer

    2007-01-01

    Wood-boring insect pests that feed on the bark, phloem, or xylem (wood) of living trees pose unique management challenges because their immature stages live in cryptic, often inaccessible, habitats within host trees. The eggs of wood borers are laid in or on tree trunks, branches, terminal shoots, or roots. After the eggs hatch, neonates tunnel in and feed on internal...

  15. 节理岩体隧道围岩稳定性判定指标合理性研究%A Study of the Criterion for the Stability of a Tunnel in a Jointed Rock Mass

    Institute of Scientific and Technical Information of China (English)

    张志强; 何本国; 关宝树

    2012-01-01

    隧道围岩失稳模式和稳定性判据一直是工程界争论的焦点,迄今没有科学合理的标准,常以洞周位移或塑性区经验值作为稳定性判定指标.洞周位移受围岩弹模、隧道形状等因素影响,而且不同部位变形值差异很大,很难找到统一标准;以塑性区作为稳定性判据优于以位移作为判据,围岩塑性化反映连续介质宏观塑性流动力学动态,而不能用于量化判定由优势结构面控制节理岩体破坏的隧道稳定性.文章结合细观节理形态和变化,通过UDEC离散元程序,研究节理岩体隧道失稳模式及量化的稳定性判定指标,探讨了细观结构机制和宏观力学行为关系.结果表明:(1)结构面极大地削弱岩体力学性质及其稳定性,结构面变形与强度性质对于隧道稳定性起着关键控制性作用;(2)节理岩体隧道扰动区可划分为脱落区、张开区和剪切滑移区,其中脱落区表征围岩失稳模式,张开区围岩处于脱落临界状态,即塌方潜在区域;(3)剪切滑移区是诱发围岩发生渐进性破坏主因,提出将剪切滑移区作为节理岩体隧道稳定性判定指标具有严格力学依据,可以定量化评价围岩稳定程度.最后,以在建兰渝铁路木寨岭隧道为例,对比了锚杆支护前后力学效应,验证了以剪切滑移区作为节理岩体隧道稳定性判定指标的可靠性、合理性和现实性.%The instability model and criterion for the stability of tunnels in jointed rock masses have been a subject of debate, and no scientific and reasonable standard has been reached for the subject so far. The empirical value of the displacement around the tunnel and plastic zone is deemed the criterion for stability of surrounding rock; elastic modulus and the shape of a tunnel have a great influence on the displacement around the tunnel. Additionally, displacements around a tunnel are unequal at different positions. For these reasons, it is difficult to

  16. Treatment measures for underground water leakage during construction of tunnel in metamorphic soft rock%变质软岩隧道施工中地下水渗漏处治措施

    Institute of Scientific and Technical Information of China (English)

    李皓晖; 左昌群; 唐霞; 丁少林; 刘代国

    2015-01-01

    Due to the metamorphic soft rock characteristics of water softening and disintegration,there is the phenomenon such as groundwater seepage and water inflow in tunnel construction,which could bring huge hidden danger to the tunnel construction safety. T aking the typical groundwater seepage zone of W udang group schist tunnel in Shiyan-fangxian expressway as research object,in this paper,the groundwater seepage effect in metamorphic soft rock tunnel construction w as analyzed from the aspects including groundw ater seepage characteristics of disaster section,water rationality of surrounding rock,physical mechanics function of groundwater,and put forward the specific control measures of groundwater. T he practice showed that the measures presented in this paper has good control effect on groundw ater leakage of soft rock tunnel,w hich could provide a reference for w atery section safe construction of similar soft rock tunnel.%由于变质软岩具有遇水软化、崩解的特征,在隧道施工过程中易出现地下水渗漏、涌水等,给隧道施工安全带来巨大隐患。以十堰至房县高速公路武当群片岩隧道中典型地下水渗漏区段为主要研究对象,从灾害段地下水渗漏特征、围岩的水理性、地下水的物理力学作用等方面阐述了变质软岩隧道施工中地下水渗漏的影响,并提出了有针对性的地下水控制措施。实践证明,该措施对软岩隧道地下水渗漏具有较好的控制作用,可为类似软岩隧道富水段安全施工提供参考。

  17. Discussion boards: boring no more!

    Science.gov (United States)

    Adelman, Deborah S; Nogueras, Debra J

    2013-01-01

    Creating discussion boards (DBs) that capture student imaginations and contain meaningful interactions can be a difficult process. Traditional DBs use a question-and-answer format that often is boring for both the student and instructor. The authors present creative approaches to DBs that result in lively debates and student-to-student and student-to-faculty interactions, including role playing, blogging, wikis, and the use of voice.

  18. Hydrogeological Prognosis with Regard to Realisation of the New Colle Di Tenda Road Tunnel

    Directory of Open Access Journals (Sweden)

    Cinzia Banzato

    2011-01-01

    Full Text Available Problem statement: The doubling of Tenda pass road tunnel jointing SW France to Piedmont (Italy was planned to penetrate a complicate rock structure in which several complex play an hydrogeologic role including carbonate-Karst aquifer between flysch impervious complexes. The main problem of the project is the presence of an hydraulic circulation feeding a spring of social and economic great importance discharging into a railroad tunnel below. Approach: The authors was charged by ANAS, Italian National Roads Authority, to execute a complete hydrogeologic prognosis of the situation that will be determinate by the excavation of the new tunnel and forecast as well as possible the hazard for the tapped spring. Results: Two years research have included a complete hydrogeologic and hydrochemical survey all the hypothesized structure feeding the spring, with several bore holes used as observation wells, the use of several monitoring device for the discharge and the chemical characters of spring, a lot of laboratory tests on cements and micro-cements and other materials used in waterproofing and sustain the rocks during the excavation and the concrete lining of the tunnel. Conclusion: The study ends with the evaluation of the vulnerability of the spring and the forecasting of contamination and depletion of the spring.

  19. Age, growth and mortality in four populations of the boring bivalve Lithophaga patagonica from Argentina

    Science.gov (United States)

    Bagur, María; Richardson, Christopher A.; Gutiérrez, Jorge L.; Arribas, Lorena P.; Doldan, M. Socorro; Palomo, M. Gabriela

    2013-08-01

    The boring bivalve Lithophaga patagonica (d'Orbigny, 1842) is a locally abundant inhabitant of hard substrata in the coastal waters of the Southwestern Atlantic. In this paper, we describe the growth, age and mortality of three intertidal rock-boring populations of L. patagonica and one subtidal oyster shell (Ostrea puelchana) boring population. An analysis of acetate peel replicas of shell sections showed that L. patagonica slows down its growth during autumn-winter, which leads to changes in the direction and rate of shell deposition and the formation of conspicuous annual (low temperature induced) clefts in the shell margin. Cleft counts and Von Bertalanffy growth analyses indicated that maximum age varies from 4 years in the oyster-boring population to 13 years in a rock-boring one (longevity estimates varied between 6.5 and 15 years, respectively). Maximum asymptotic length (L∞) and Von Bertalanffy growth constant (K) were also variable between populations (L∞ between 14.76 and 36.95 mm and K from 0.20 to 0.90 yr- 1 respectively). Mortality rates were higher at the two southernmost populations. Type (rock vs. oyster), composition and hardness of the substrata are likely the main factors controlling the observed differences between populations.

  20. Utilizing partial least square and support vector machine for TBM penetration rate prediction in hard rock conditions

    Institute of Scientific and Technical Information of China (English)

    高栗; 李夕兵

    2015-01-01

    Rate of penetration (ROP) of a tunnel boring machine (TBM) in a rock environment is generally a key parameter for the successful accomplishment of a tunneling project. The objectives of this work are to compare the accuracy of prediction models employing partial least squares (PLS) regression and support vector machine (SVM) regression technique for modeling the penetration rate of TBM. To develop the proposed models, the database that is composed of intact rock properties including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and peak slope index (PSI), and also rock mass properties including distance between planes of weakness (DPW) and the alpha angle (α) are input as dependent variables and the measured ROP is chosen as an independent variable. Two hundred sets of data are collected from Queens Water Tunnel and Karaj−Tehran water transfer tunnel TBM project. The accuracy of the prediction models is measured by the coefficient of determination (R2) and root mean squares error (RMSE) between predicted and observed yield employing 10-fold cross-validation schemes. The R2 and RMSE of prediction are 0.8183 and 0.1807 for SVMR method, and 0.9999 and 0.0011 for PLS method, respectively. Comparison between the values of statistical parameters reveals the superiority of the PLSR model over SVMR one.

  1. Research on Techniques for Construction of Half-wet Sprayed Concrete in ClassⅢ Hard Rock Tunnels%Ⅲ级硬质岩隧道半喷混凝土施工技术研究

    Institute of Scientific and Technical Information of China (English)

    李伟坚; 郭军; 宋从军

    2015-01-01

    就特长隧道而言,Ⅲ级围岩比例较大,其已成为制约工期、实现快速施工的关键。以广东省博深高速公路石鼓隧道为依托,探讨3车道大断面特长公路隧道独头掘进条件下Ⅲ级围岩快速施工方法,对半喷混凝土施工技术条件下的围岩稳定性、支护强度与承载力进行系统分析,并采用三维计算进行论证。研究表明:Ⅲ级围岩采用半喷混凝土施工技术完全可行。%As for extralong tunnels,class III wall rock accounts for large proportion and has become the key to restrict construction period and achieve rapid construction. Dependent on Shigu Tunnel on Guangdong Boluo -Shenzhen Expressway,this paper probes into the methods for rapid construction of class III wall rock of 3-lane large-section extralong highway tunnels under the blind heading conditions, systematically analyzes stability,support strength and bearing capacity of wall rock under the technical condition of construction with half-wet sprayed concrete,and demonstrates with 3D calculation.The research shows that the half-wet sprayed concrete construction technique adopted for class III wall rock is fully feasible.

  2. 基于黏弹塑性的云岭隧道软弱围岩参数反演与稳定性分析%Visco-Elasto-Plastic Back Analysis on Yunling Tunnel in Weak Rock

    Institute of Scientific and Technical Information of China (English)

    王晓睿; 南冬梅; 朱学峰

    2011-01-01

    Weak rock tunnel in the engineering practice and experiment research have shown strong, easy to cause the rheologicai properties of rock deformation caused by excessive instability. We established ani-analysis system based on viscoelastic finite element method theory by monitoring the weak surrounding rock excavation process of Yunling left cave entrance according to the New Austria Tunneling Method and analyzing the initial value of surrounding rock displacement convergence and secondary support and lining of the pressure changes. By using ANSYS finite element program, the excavation process was simulated, and the actual field measured values were compared with the calculated data. The study provides a scientific basis and technical guidance for support design and construction of tunnel with safety and reliability.%软弱隧道围岩在工程实际和试验研究中都表现出较强的流变性质,容易造成围岩的过大变形而导致失稳.按新奥法施工原则对云岭隧道左洞进口段的软弱围岩段开挖过程进行监测,分析初期围岩位移收敛值以及二次支护和衬砌的压力变化情况,通过黏弹性有限元反分析理论,建立基于黏弹塑性的反分析体系,对围岩参数进行反演和优化.通过采用ANSYS有限元程序模拟开挖过程,并将现场实际量测值与计算数据进行比较,为隧道支护设计和施工的安全可靠性提供科学依据和技术指导.

  3. Cam-controlled boring bar

    Science.gov (United States)

    Glatthorn, Raymond H.

    1986-01-01

    A cam-controlled boring bar system (100) includes a first housing (152) which is rotatable about its longitudinal axis (154), and a second housing in the form of a cam-controlled slide (158) which is also rotatable about the axis (154) as well as being translatable therealong. A tool-holder (180) is mounted within the slide (158) for holding a single point cutting tool. Slide (158) has a rectangular configuration and is disposed within a rectangularly configured portion of the first housing (152). Arcuate cam slots (192) are defined within a side plate (172) of the housing (152), while cam followers (194) are mounted upon the cam slide (158) for cooperative engagement with the cam slots (192). In this manner, as the housing (152) and slide (158) rotate, and as the slide (158) also translates, a through-bore (14) having an hourglass configuration will be formed within a workpiece (16) which may be, for example, a nuclear reactor steam generator tube support plate.

  4. A convection-conduction model for analysis of the freeze-thaw conditions in the surrounding rock wall of a tunnel in permafrost regions

    Institute of Scientific and Technical Information of China (English)

    何春雄; 吴紫汪; 朱林楠

    1999-01-01

    Based on the analyses of fundamental meteorological and hydrogeological conditions at the site of a tunnel in the cold regions, a combined convection-conduction model for air flow in the tunnel and temperature field in the surrounding has been constructed. Using the model, the air temperature distribution in the Xiluoqi No. 2 Tunnel has been simulated numerically. The simulated results are in agreement with the data observed. Then, based on the in situ conditions of air temperature, atmospheric pressure, wind force, hydrogeology and engineering geology, the air-temperature relationship between the temperature on the surface of the tunnel wall and the air temperature at the entry and exit of the tunnel has been obtained, and the freeze-thaw conditions at the Dabanshan Tunnel which is now under construction is predicted.

  5. 不衬砌水工隧洞围岩稳定性数值模拟分析%Numerical simulation analysis for surrounding rock stability of unlined high pressure hydraulic tunnels

    Institute of Scientific and Technical Information of China (English)

    刘新颖; 曹平; 刘涛影; 梅慧浩; 宁果果

    2012-01-01

    Aiming at the phenomena that hyperosmolar role will not only change the stress state of rock and soil, but also cause the rock splitting , destroy the original structure of the rock. Based on the coupled fluid - solid theorem, numerical analysis for the stability of tunnel surrounding rock was done with fast Lagrangian analysis of continua in three - dimension (FLAC3D). Based on the surrounding rock stability considering percolation and the surrounding rock characteristics with the internal water fluid as main research aspects, the stress field and displacement field feature after rock excavation, feedback of excavation on seepage field, evolution trend of failure characteristics and hydraulic characteristics of the tunnel under the role of internal water was achieved. The research results can provide a theoretical basis for corresponding safety measurement in construction process and waterproofing of tunnel in aquifer condition.%针对高渗压作用不仅会改变岩土体的应力状态,同时可能会使岩体劈裂、破坏岩体的原有结构的现象,基于流固耦合分析理论,利用快速拉格朗日有限差分法对隧洞围岩稳定性进行分析.从考虑渗流效应时围岩开挖稳定性、内水作用下围岩力学特性方面开展研究,得到围岩开挖后应力场、位移场分布特征,开挖卸载对渗流场的反馈,内水作用下隧洞的破坏特征和水力特性演变趋势.研究结果表明:对隧洞施工过程中采取安全措施,富水条件下的隧洞工程防排水提供一定的理论参考.

  6. 黄土连拱隧道动态施工围岩损伤局部化研究%Study of damage localization of loess multi-arch tunnel's surrounding rock under dynamic construction

    Institute of Scientific and Technical Information of China (English)

    钟祖良; 刘新荣; 刘元雪; 李鹏; 王吉明

    2012-01-01

    In order to study the damage distribution of tunnel's surrounding rock, firstly, an elastoplastic damage constitutive model of Q2 loess is deduced based on triaxial shear tests and compiled as a user-defined damage model( UDM ) of FLAC3D. Then the conception of surrounding rock damage degree (SRDD) is put forward and compiled into a post-processing module. Based on the first loess multi-arch tunnel of road-Lishi tunnel, the damage position of tunnel's surrounding rock of two construction schemes is numerically simulated. The research results show that the SRDD and damage localization rules can be simulated well at every excavation step; and it also provides reference for the optimization of tunnel construction scheme. The research results provide a new method for the optimization of tunnel construction scheme and choice of construction scheme.%为了研究黄土连拱隧道动态施工时围岩的损伤情况和损伤分布规律,在室内试验的基础上推导了Q2黄土的弹塑性损伤本构模型,并基于FLAC3D平台编制了自定义本构模型,提出了损伤度概念并编制了损伤度后处理模块.以国内首条高速公路黄土连拱隧道-离石隧道为依托工程,对两种开挖方案施工时围岩损伤情况进行数值分析.研究表明,该成果可以较好地掌握隧道每一开挖步后围岩损伤度的分布情况和损伤区的演化规律,为施工方案优化选择提供依据.该研究成果为地下工程支护参数优化和方案的选择开辟了一个新的方向.

  7. The Attenuation Law of Vibrations in Highway Tunnel Surrounding Rocks Caused by Smooth Blasting%公路隧道光面爆破围岩振动衰减规律

    Institute of Scientific and Technical Information of China (English)

    陆瑜; 李超

    2014-01-01

    为了获得隧道围岩在爆破荷载作用下的振动效应,运用有限元软件 ADINA 建立隧道计算模型,通过加载简化的三角形等效爆破荷载,模拟了青山隧道Ⅲ类围岩段在单循环进尺为2 m 、2.5 m 和3 m 三种情况下的爆破振动效应,得到了隧道拱顶、拱脚和边墙部位围岩的振动衰减规律。计算结果表明:围岩质点的峰值振速随着与开挖轮廓面距离的增大先急剧衰减后平缓衰减,开挖进尺越大,围岩受到的扰动越大。最后通过满足规范的安全质点振动速度来确定三种开挖进尺条件下的最大段药量大小,为类似隧道钻爆设计的合理性提供参考。%In order to obtain vibration effect of tunnel surrounding rocks under blasting load ,the tunnel calculation model was established by using the finite element software ADINA .Under simplified triangle equivalent blast loading ,the blast-ing vibration effect of class Ⅲ surrounding rock section of Qingshan tunnel with the single footage driving cycle being 2 m ,2 .5 m and 3 m was simulated .And then the vibration attenuation law for adjacent rocks at the arch vault ,spring and side walls of the tunnel under blasting load action was obtained .As shown by the calculation results ,the peak particle velocity showed abrupt attenuation first and then flat attenuation with the increase of excavation profile distance .The larg-er the footage ,the more vibrations the rock was subject to .Lastly ,safety particle vibration velocity in compliance with specifications was used to determine the maximum charge under these three excavation footage conditions .This study will provide reference to the rationality of blasting and drilling design of similar tunnels .

  8. Engineering geology and geomechanics in dam and tunnel construction

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, L. (ed.)

    1981-01-01

    Papers presented at this conference included planning of road tunnels, geological and geotechnical exploration for tunnels, determination of rock mass strength of sedimentary rocks, geomechanical assessment and foundation problems of dams, excavation of mine roadways, movement and stress phenomena in rock strata resulting from hard coal mining, effects of rock bolts and thin linings as tunnel supports, system bolting in deep underground rock excavations, highly stressed areas in tunnels and damage in tunnelling. Papers are either in German or in English. Two papers have been previously abstracted.

  9. Large-bore pipe decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  10. Number of Producible and Service Well Bores on Federal Lands

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — This table contains the total number of producible well bores by state as of the end of each fiscal year. A well bore is considered producible if the well bore is...

  11. Use of the {sup 14}C-PMMA and He-gas methods to characterise excavation disturbance in crystalline rock

    Energy Technology Data Exchange (ETDEWEB)

    Autio, J.; Kirkkomaeki, T. [Saanio and Riekkola Oy, Helsinki (Finland); Siitari-Kauppi, M. [University of Helsinki (Finland). Lab. of Radiochemistry; Timonen, J.; Laajalahti, M.; Aaltonen, T.; Maaranen, J. [University of Jyvaeskylae (Finland). Dept. of Physics

    1999-04-01

    Characterisation of the excavation disturbance caused by boring of experimental full-scale deposition holes in the Research Tunnel at Olkiluoto was carried out successfully by using two novel methods; the {sup 14}C-PMMA and He-gas methods, which were modified and applied for the first time in this type of study. The experience obtained implies that the techniques are feasible and can be used to study similar types of rock excavation disturbance such as that caused by boring with mini discs, a technique which will be used in the underground Hard Rock Laboratory at Aespoe during late 1998 and early 1999. Both of the measurement methods have been in continuous use and the work has included development of both the measuring and interpretation techniques. Use of the {sup 14}C-PMMA method is suggested for studies of rock structure and the spatial distribution of porosity. The {sup 14}C-PMMA method also provides quantitative information about nanometer-range porosity which is beyond the scope of most standard methods of microscopic investigation. The use of He-gas methods are proposed for determining the diffusion coefficient, permeability and complementary porosity of rock samples taken from the disturbed zone. (orig.) 23 refs.

  12. 等值地应力下岩质圆形隧道位移释放系数比较及应用%COMPARISONS AND APPLICATIONS OF DISPLACEMENT RELEASE COEFFICIENTS FOR A CIRCULAR ROCK TUNNEL SUBJECTED TO ISOTROPIC GEOSTRESSES

    Institute of Scientific and Technical Information of China (English)

    张常光; 曾开华

    2015-01-01

    The deformation of tunnel at early stage is of critical importance to determine the support pressure and stable deformation of rock mass using the convergence-confinement method. Some typical formulae of displacement release coefficient for deep circular rock tunnels were summarized,classified and compared in terms of the applicability and the spatial effect of tunnel face. The differences from the convergence-confinement analysis due to the different coefficients of displacement release,different positions of support installing and different control objectives were discussed. It was found that the coefficient of displacement release dependent on the ultimate plastic radius of rock mass was applicable to both the elastic and the elasto-plastic rocks and therefore had wide prospects of engineering applications. The coefficients of elastic displacement release were found to be only applicable to the elastic rock,while the commonly used coefficients of plastic displacement release were only suitable for the rock tunnel with a normalized radius of 2. The support designed according to the support pressure distant from the tunnel face could not be moved forward arbitrarily and a reasonable and timely support with different stiffness should be designed according to the properties of rock mass.%隧道前期变形是利用收敛约束法确定支护压力和围岩稳定变形的关键,在分析隧道开挖面空间效应机制的基础上,总结具有代表性的深埋岩质圆形隧道位移释放系数公式,对其进行分类、适用性及空间效应的比较,得到不同位移释放系数、不同支护施作距离和不同控制目标下的收敛约束差异。研究结果表明:以围岩塑性区最大半径为基础的位移释放系数对弹性围岩和各种弹塑性围岩均适用,具有广泛的工程应用前景;弹性位移释放系数仅适用于弹性围岩,常用塑性位移释放系数仅适用于相对半径为2的隧道围岩;不宜

  13. Displacement Monitoring and Analysis Platform for Highway Tunnel Surrounding Rock Based on Internet Technology%基于互联网技术的公路隧道围岩常规位移监测分析平台

    Institute of Scientific and Technical Information of China (English)

    姜锡宸; 孟陆波; 李天斌; 刘家民

    2015-01-01

    Informationization of tunnel construction management is a trend nowadays.A displacement monitoring and analysis platform for highway tunnel surrounding rocks based on internet technology is developed by using PHP (Personal Home Page)programming language and in conjunction with Mysql data storage function and analysis principles of the least square method and regression model,so as to meet the informationization requirement of highway tunnel monitoring.By using the mentioned platform,the recording and regression analysis of the monitoring data of the highway tunnel,the assessment of the stability of the surrounding rock and the estimation of the final displacement of the surrounding rock and the secondary lining time can be realized.Furthermore,by using the mentioned platform,the technical staffs that are not at the site can obtain the monitoring data and analysis results of the tunnel so that they can make timely adjustment on the lining structure.%信息化是当前隧道施工管理的必然趋势,针对公路隧道监控量测信息化建设要求,采用 PHP 编程语言,结合 Mysql 的数据存储功能、最小二乘法及回归模型的分析原理,研发基于互联网技术的公路隧道围岩常规位移监测分析平台。该平台实现了在网络上对公路隧道监测断面数据的录入存储、回归分析、围岩稳定性判别及隧道围岩最终位移变形量与二次衬砌时间预估等功能。通过网络访问该平台,可使不在现场的参建人员及时掌握隧道监测数据及分析结果,可为支护结构的调整和变更提供更有效率的依据,进而提高公路隧道的管理效率。

  14. INFLUENCE OF ROCK DAMAGE ON ZONAL DISINTEGRATION AROUND DEEP CIRCLE TUNNELS%深部岩体损伤对分区破裂化效应的影响

    Institute of Scientific and Technical Information of China (English)

    周小平; 周敏; 钱七虎

    2012-01-01

    The deep rock mass is discontinuous medium containing cracks and joints. The zonal disintegration in deep rock mass is sensitive to the nucleation,growth and coalescence of cracks. These evolutions of cracks may induce a transform from Euclidean geometry space in deep rock mass to Non-euclidean one. In this paper,a damage variable is introduced to describe the evolution of cracks and joints in the deep rock mass. The elastic stress fields around a deep circle tunnel under hydrostatic and non-hydrostatic pressure condition arc obtained using the non-Euclidean model, and then the influences of damage on the elastic stress field and the zonal disintegration around the deep tunnel are discussed in detail. The distributions of the fractured and non-fractured zones around the deep circle tunnel under hydrostatic and non-hydrostatic pressure condition arc determined using Hoek-Brown criterion. The present study is helpful to understand the zonal disintegration in deep rock mass.%深部岩体是一种具有初始损伤的非连续介质,其内部存在着大量节理和裂隙.深部岩体分区破裂化效应与节理、裂隙的扩展、连接和汇合密切相关.节理、裂隙的扩展、连接和汇合可能会导致深部岩体的内部空间由欧氏几何空间向非欧几何空间转化.论文利用损伤变量表示含节理和裂隙岩体的损伤,根据非欧几何模型,获得了静水压力和非静水压力情况下深部圆形洞室损伤围岩的应力场,确定了损伤变量对圆形洞室围岩的应力场和分区破裂化效应的影响.采用Mohr- Coulomb准则,获得了静水压力和非静水压力情况下深部损伤围岩的破裂区与非破裂区的分布规律.论文的研究结果为理解深部岩体分区破裂模式提供了有价值的参考.

  15. Self-contained instrument for measuring subterranean tunnel wall deflection

    Science.gov (United States)

    Rasmussen, Donald Edgar; Hof, Jr., Peter John

    1978-01-01

    The deflection of a subterranean tunnel is measured with a rod-like, self-contained instrument that is adapted to be inserted into a radially extending bore of the tunnel adjacent an end of the tunnel where the tunnel is being dug. One end of the instrument is anchored at the end of the bore remote from the tunnel wall, while the other end of the intrument is anchored adjacent the end of the wall in proximity to the tunnel wall. The two ends of the instrument are linearly displaceable relative to each other; the displacement is measured by a transducer means mounted on the instrument. Included in the instrument is a data storage means including a paper tape recorder periodically responsive to a parallel binary signal indicative of the measured displacement.

  16. Aespoe Hard Rock Laboratory. Annual report 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The Aespoe HRL has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. Geoscientific investigations on Aespoe and nearby islands began 1986. Since then, bedrock conditions have been investigated by several deep boreholes. The Aespoe research village has been built and extensive underground construction work has been undertaken in parallel with comprehensive research. This has resulted in a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The objective of the ZEDEX project is to compare the mechanical disturbance to the rock for excavation by tunnel boring and blasting. The results indicate that the role of the EDZ as a preferential pathway to radionuclide transport is limited to the damaged zone. The tracer retention understanding experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models. During 1996 a series of tracer experiments in radially converging and dipole flow configuration have been performed. A special borehole probe has been designed for different kinds of retention experiments where data can be obtained representative for the in situ properties of groundwater at repository depth. The prototype repository test is focused on testing and demonstrating repository system function, and includes backfill and plug tests and demonstration of methods for deposition and retrieval of canisters in a new tunnel at the 420 m level. The long term tests of buffer material aim to validate models of buffer performance and at quantifying clay buffer alteration processes at adverse conditions. 80 refs, 53 figs, 16 tabs.

  17. 砂性地层中盾构隧道掘进围岩变形特性%Deformation characteristics of the shield tunnelling surrounding rock in sandy stratum

    Institute of Scientific and Technical Information of China (English)

    张业炜; 杨新安

    2011-01-01

    Based on the geological conditions and construction data in the sandy stratum of Shiziyang tunnel, the numerical model was established. By the comparison on the displacement of monitoring points in different sections during the excavation, it concluded that; the surrounding rock of the antecedence tunnel shrink to the centre, and the deformation of the top & bottom rock is obviously larger than that of the two sides. The antecedence tunnel has applied external force on the later tunnel; however, it has applied little longitudinal force. By the comparison on the two conditions with seepage and without seepage, it concluded that the early effects of the seepage are limited, but the deformation of the surrounding rock is aggravated to a large extent eventually. The method was put forward to determine the cumulative effects and cumulative effect curves of the soil disturbance in front of the excavation face, and the disturbance scope and extent were determined by the cumulative effects curves. Finally two factors affect the soil displacement rate were obtained, there were the distance between the soil and the excavation face and shield thrust.%以狮子洋隧道砂性地层段地质条件和施工资料为基础,建立有限差分数值计算模型.通过比较不同断面监测点随开挖进程的位移值,结果表明:先掘隧道围岩向中心收缩,上下部围岩变形明显大于两侧;后掘隧道对先掘隧道有横向外挤的作用,但对纵向几乎没有影响.对有、无渗流作用的2种工况的比较分析说明,起初渗流对围岩变形影响不大,但最终加剧了围岩的变形程度.提出了开挖面前方土体扰动的累积效应和累积效应曲线的确定方法,通过该曲线可确定土体扰动范围和程度,经过理论分析,认为影响土体位移速率的2个因素是土体与开挖面间距和盾构推力.

  18. Elastic-plastic analytical solutions for surrounding rocks of tunnels and its engineering applications%巷道围岩弹塑性解析解及工程应用

    Institute of Scientific and Technical Information of China (English)

    曾开华; 鞠海燕; 盛国君; 张常光

    2011-01-01

    Based on the unified strength theory and a non-associated flow rule, the elastic-plastic analytical solutions of stress and displacement for surrounding rocks of tunnels were presented. The effects of intermediate principal stress,elastic strains in the plastic zone and dilatancy properties were taken into account in the analytical solutions. The resuits show that the influences of intermediate principal stress and dilatancy properties on the ground reaction curve and support pressure are significant. The strength potentials of rock mass are better achieved due to considering the intermediate principal stress effect. The tunnel design with ignoring volume changes in the plastic zone is in danger, in that the corresponding support pressure is smaller. The effect of dilatancy is important for the tunnel support design.%基于统一强度理论和非关联流动法则,合理考虑中间主应力、围岩塑性区弹性应变和剪胀特性等影响,建立了巷道围岩弹塑性应力和位移解析解.研究结果表明:中间主应力和围岩剪胀特性对围岩特征曲线和支护压力的影响显著,考虑中间主应力的影响能充分发挥围岩的强度潜能;不考虑塑性区体积变化所得支护压力较小,设计偏危险;巷道支护设计应考虑围岩剪胀特性的重要影响.

  19. FAST CLASSIFICATION METHOD FOR ROCK MASS SURROUNDING HIGHWAY TUNNEL DURING CONSTRUCTION%公路隧道施工期围岩快速分级的一种新方法

    Institute of Scientific and Technical Information of China (English)

    方昱; 刘开云; 刘保国

    2013-01-01

    施工期围岩快速分级是保证隧道施工安全和工程质量的关键措施.结合绩黄、宁绩高速公路隧道群施工期围岩分级实践,在大量现场测试和室内试验的基础上,提出了一种基于国标BQ分级的新分级体系,并给出了每个分级指标的现场快速测试方法.用新分级体系进行隧道施工期围岩的快速分级工作,并以分级结果作为进化支持向量回归算法分级的训练样本,建立了隧道围岩分级的进化支持向量回归智能模型.为了方便现场使用,依据支持向量回归理论,将智能模型进一步转化为初等函数数学模型,经隧道围岩分级实例验证了该初等函数数学模型的准确性,为隧道施工期围岩快速分级提供了一种简便的新方法.%Fast classification of surrounding rock mass during construction period is the key measure for construction security and engineering quality. This paper combines the surrounding rock mass classification work during tunnel group construction in Jihuang and Ningji expressway. It proposes a new classification system as a kind of improved national standard BQ classification method. The system is based on many field tests and indoor experiments. The quick field testing method of each classification index is presented. Furthermore, the new classification system is used to cope with the surrounding rock classification in-situ. The classification results are served as the training samples of the evolutionary support vector regression ( SVR) algorithm in order to establish the intelligent classification model. Finally, the intelligent model is transferred to an elementary function mathematical model according to SVR theory for the purpose of convenience application. The accuracy of this mathematical classification model is verified by classification examples of tunnel group. Thus, the system offers a new simple fast classification method for surrounding rock mass during tunnel construction period.

  20. Surface settlements during the tunnel drivage in loose rock. Prognosis, measurement and impact; Oberflaechensetzungen beim Tunnelvortrieb im Lockergestein. Prognose, Messung und Beeinflussung

    Energy Technology Data Exchange (ETDEWEB)

    Fillibeck, Jochen [Technische Univ. Muenchen (Germany). Zentrum fuer Geotechnik

    2012-11-01

    The realistic prediction of supplement in tunnel construction is essential to secure the acceptance of the construction measure in the population. In addition to numerical calculations particularly empirical processes are suitable whose input variables are derived from previous experiences. Empirical methods use the Gaussian function for the description of the settlement trough arising from the tunnelling at the surface. The contribution under consideration describes the method of Fillibeck allowing the determination of the input parameters for shotcrete drivages and shield drivages. This empirical method was derived from a large number of carefully selected and inspected measuring cross-sections.

  1. Determination of ejection velocity of rock fragments during rock burst in consideration of damage

    Institute of Scientific and Technical Information of China (English)

    ZUO Yu-jun; LI Xi-bing; ZHOU Zi-long

    2005-01-01

    The ejection velocity of rock fragments during rock burst, one of the important indexes representing the rock burst strength, is used most conveniently in the supporting design of tunnel with rock burst tendency and is often determined by means of observation devices. In order to calculate the average ejection velocity of rock fragments theoretically, the energy of rock burst was divided into damage consuming energy and kinetic energy gained by unit volume of rock firstly, and then the rock burst kinetic proportional coefficient η was brought up which could be determined according to the rock-burst damage energy index WD , at last the expression of the average ejection velocity of rock fragments during rock burst was obtained and one deep level underground tunnel was researched using the mentioned method. The results show that the calculation method is valid with or without considering the tectonic stress of tunnels, and that the method can be a reference for supporting design of deep mining.

  2. Key Techniques for the Construction of the 3rd System Fine-Powdered Sandy Rock Section of the Humaling Tunnel%胡麻岭隧道第三系粉细砂岩段施工关键技术

    Institute of Scientific and Technical Information of China (English)

    徐长久

    2011-01-01

    胡麻岭隧道3#、4#斜井和隧道正洞区段穿越第三系弱胶结粉细砂岩,由于地层岩性软,地下水丰富,施工中涌水、流砂、掌子面泥化现象明显,施工难度极大。介绍了施工中所采用的降水、围岩加固、加强支护等措施和方法,有效保证了工期和施工质量。施工经验可供同类工程参考。%The third and fourth oblique shafts and the section of the main body of the Humaling Tunnel go through the third system under-cemented fine-powdered sandy rock stratum,where the rock of the stratum is soft and underground water is rich,owing to which gush of underground water and flowing sand arise here and there,and the slurrying phenomenon of the work face is obvious,which make the construction extremely difficult.Introduced in the paper are technical measures and methods related to draining underground water,solidifying the surrounding rock and strengthening the support,etc.,all of which help ensure the construction duration and quality.The experience of the project may serve as a useful reference for other projects of the same type.

  3. 基于广义粒子动力学的巷道围岩弹塑性分析%Elastoplastic analysis of surrounding rock masses around tunnels using general particle dynamics method

    Institute of Scientific and Technical Information of China (English)

    赵毅; 周小平; 钱七虎

    2016-01-01

    提出了广义粒子动力学数值分析方法,该方法是一种无网格数值分析方法,可以考虑关联塑性流动法则和非关联塑性流动法则对岩石材料塑性变形的影响。将广义粒子动力学数值分析方法应用于巷道围岩的弹塑性分析,确定了巷道围岩的应力场、位移场和塑性区。该数值模拟结果与有限元结果吻合较好,表明将考虑岩石材料剪胀特性的弹塑性本构理论引入到广义粒子动力学数值分析方法,不失为模拟岩石类材料弹塑性破坏的一种有效数值手段,研究结果为更好地理解岩石材料的屈服破坏过程提供重要的参考。%The novel meshless numerical method, which is known as general particle dynamics (GPD) method, is proposed. The non-associated flow law and the associated flow law can be employed to analyze the plastic deformation of the surrounding rock masses around tunnels using the GPD method. The stability of the surrounding rock masses around tunnels are also determined using the GPD method as well as the stress fields, displacement fields and plastic zone. The numerical results by the proposed method are in good agreement with the FEM results. It is proved that the GPD method is efficient to predict the elastic-plastic properties of the surrounding rock masses around tunnels.

  4. 基于水-力耦合理论的超深隧道围岩渗透性预测%PREDICTION OF WALL ROCK PERMEABILITY FOR TUNNELS WITH SUPERTHICK OVERBURDEN

    Institute of Scientific and Technical Information of China (English)

    徐则民; 黄润秋; 许模; 屈科; 苟定才

    2001-01-01

    To predict water-gushing is one of the principal problems faced in the surveying and designing extra-long tunnels. To obtain hydraulic conductivity(HC) is the basis to forecast water-gushing and HC can not be determined by pumping test on a large scale for tunnels with superthick overburden. According to the hydraulic-mechanical coupling theory, the paper puts forward a method to predict the wall rock permeability for tunnels with superthick overburden. Its main steps are as follows: (1) to determine the tensor of hydraulic conductivity of the rock mass near the ground; (2) to back-analyzing of stress field; (3) to predict the fissure aperture at different levels; (4) to suppose the structure of fissure network not to vary with depth and to calculate the tensor of hydraulic conductivity of the wall rock.%涌水预测是特长超深隧道勘测设计及施工中面临的重要问题之一。围岩渗透性是涌水预测的基础,对于超深隧道,不能通过大规模抽水试验来获得渗透性参数。以水力耦合理论为基础,该文提出了一种超深隧道围岩渗透性预测方法。其主要思想是,首先确定近地表岩体的渗透张量;根据地应力实测资料进行地应力场的量级反演;选择适当的裂隙开度-应力模型,预测不同深度的裂隙开度;在裂隙网络结构不随深度变化这一假定的基础上,计算隧道标高的围岩渗透性。

  5. Tunnelling Association of Canada. Fourth annual general meeting with technical program. Innovation and opportunity. Preprint volume

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    The following papers were presented: opportunities for Canadians in tunnelling; mining related underground construction - what's new in Canada; development in shotcrete for underground support; control of water in tunnelling; support - who needs it.; developments in extruded tunnel lining systems; recent developments in mechanical excavation; technical advancements in raise boring equipment and application; the world's largest- diameter soil tunnel; the ABC's of the Export Development Corporation.

  6. 隧道石膏质围岩溶蚀及溶出特性试验研究%Experimental Research on Corrosion and Leaching Characteristics of Gypsum Rock Surrounding Tunnels

    Institute of Scientific and Technical Information of China (English)

    祝艳波; 吴银亮; 余宏明

    2016-01-01

    石膏质岩的溶蚀对隧道工程的建设及运营极为不利,研究其溶蚀机理及其影响因素,可为此类隧道的建设提供参考。宜巴高速公路部分隧道通过的地层含有石膏质岩,为了研究其溶蚀及溶出特性,利用X-衍射试验仪、自制简易溶蚀装置、离子色谱分析仪从宏观角度研究其溶蚀、溶出现象及其规律,利用环境扫描电镜从微观上观察其溶蚀机理。结果表明,研究区石膏质岩在地下水的作用下易溶蚀,溶蚀后强度性质变差,同时溶出大量的硫酸根离子于环境水中。影响石膏质岩溶蚀的因素多而复杂,动态水环境将使其溶蚀作用更强烈,并且水流流速越大,溶蚀特征越明显。弱酸性环境的水溶液也会促进溶蚀作用的进行。温度通过影响石膏质岩在水中的溶解度,从而影响其溶蚀量及溶蚀速率。石膏质岩溶蚀后会降低隧道围岩的稳定性,溶出的酸根离子对混凝土衬砌结构产生中等腐蚀,在隧道建设中应注意采取相应防治措施,避免工程病害的发生。%Since the corrosion of gypsum rock has detrimental effects on tunnel construction and operation, the cor⁃rosion mechanism and its influencing factors were studied, providing a reference for tunnel construction in these con⁃ditions. In this paper, the gypsum rock surrounding tunnels on the Yichang-Badong expressway is studied, and a se⁃ries of experiments on the corrosion and leaching characteristics of gypsum rock are carried out to macroscopically study and analyze the law of corrosion and leaching phenomena by using X-ray diffraction tester, self-made corro⁃sion equipment and ion-chromatography analyzer. Additionally, the corrosion mechanism is microscopically ob⁃served with an environmental scanning electron microscope. The research results indicate that the corrosion of gyp⁃sum rock is obvious under the action of underground water and the gypsum

  7. Effects of in-plane magnetization orientation on magnetic and electronic properties in a Bcc Co (001)/rock salt MgO (001)/Bcc Co (001) magnetic tunnel junction system: ab initio calculations.

    Science.gov (United States)

    Yoo, Dong Su; Chae, Kisung; Chung, Yong-Chae

    2012-04-01

    Ab initio calculations were performed on a fully epitaxial bcc Co (001)/rock salt MgO (001)/bcc Co (001) magnetic tunnel junction system for two cases where the magnetization is parallel to bcc Co [100] and to bcc Co [110]. Structural optimization reveals that the two cases are equivalent systems and that the Co electrodes contract in the z-direction whereas the MgO insulating barrier expands. The magnetic moments of each monolayer vary slightly in each case; furthermore, only the magnetic moment at the surface of the Co atom shows any enhancement (12%). The layer decomposed density of states profiles reveals that the bonding character of the junction interface is derived mainly from the 2p-3d hybridization of the MgO and Co interfacial atoms.

  8. Study of Support Measures for Large Deformed Section of Muzhailing Tunnel in Soft Rocks%木寨岭隧道软岩大变形段支护措施研究

    Institute of Scientific and Technical Information of China (English)

    刘国庆

    2011-01-01

    Based on the construction practices of the Muzhailing tunnel on the Lanzhou-Chongqing railway and the understanding of deformation causes and mechanism of carbonaceous slate stratum, this paper analyzestechniques for controlling deformations of tunnels in soft rock with high ground stresses. It addresses control-based principles, relative support methods, and measures of deformation control used to guarantee rapid and safeconstruction.%文章结合新建兰渝线木寨岭隧道工程实践,在了解了碳质板岩地层发生大变形的原因和机理的基础上,对高地应力条件下软岩大变形的控制技术进行了分析研究,提出了处理隧道大变形应以控制为主的原则,以及确保隧道安全施工、快速通过的支护措施和变形控制对策.

  9. Study of dynamic damage of surrounding rocks for tunnels under high in-situ stress%高地应力下隧道围岩动力损伤分析

    Institute of Scientific and Technical Information of China (English)

    杨栋; 李海波; 夏祥; 罗超文; 李卫兵

    2013-01-01

    为预估和控制爆破荷载作用下围岩损伤范围,在赣龙铁路梅花山隧道工程现场进行岩体声波测试,得到围岩的损伤范围。根据爆破荷载作用下岩体损伤发展规律,采用基于概率形式的损伤变量定义,运用三维有限差分软件对不同地应力状态下爆破产生的围岩损伤范围进行数值模拟,并与现场岩体声波测试结果进行比较。计算结果表明,数值计算与实测结果有较好的一致性,随着地应力大小增大,围岩损伤范围呈现先减小后增大的趋势,且增大幅度较大,地应力较高时,局部部位如顶板、底板损伤更为明显,说明地应力大小对围岩损伤分布有着显著影响;随着侧压力系数增大,损伤范围先减小后增大,但增速逐渐减小。所得到的结论可为高地应力下隧道稳定性分析和支护设计提供依据。%In order to forecast and control the damage zone of surrounding rock under blasting load, sound wave tests have been conducted in the construction site of Meihuashan Tunnel in Jiangxi province dragon railway. Based on the change rate of sound wave speed, damage zone size of surrounding rock are obtained. On this basis, a statistics-based damage variable of rockmass has been proposed based on micromechanics. Damage zone size of surrounding rock under blasting load at different in-situ stresses is thus studied by using three-dimensional finite difference software. Calculations show that the numerical simulation results agree well with the site monitoring results. With the in-situ stress increasing, the size of damage zone decreases first, then increases, and increases by a large margin;when the in-situ stress is high, local parts such as tunnel roof, floor damage is more obvious; it is shown that the in-situ stress has significant impact on surrounding rock damage distribution. With the lateral pressure coefficient increasing, the size of damage zone decreases first

  10. Construction Technology of Hadapu Tunnel Soft PlasticⅥGrade Shallow Buried Adj oining Rock%哈达铺隧道软塑状Ⅵ级围岩浅埋段施工技术

    Institute of Scientific and Technical Information of China (English)

    朱洪莹; 武建广; 刘兴平; 王会军

    2014-01-01

    Crushing loose soft surrounding rock section,the ground settlement and level conver-gence value difficult to control,bench excavation difficult,is the difficulty of construction work. Lan yu railway Hadapu Tunnel exit is cross blacksmith ditch bottom shallow-buried section,geo-logical conditions complex.Through strata of geological studies revealed piecewise process of con-struction,comparative analysis the actual results and applicability of the horouchi horizontal rota-ry j et grouting piles,advanced tune shed,curtain grouting,surface chemical churning pile and oth-er programs.Finally,use surface vertical chemical churning pile scheme,accompanied by tunnel face advance strengthening and closed,to achieve effective control of soft plastic mucky Ⅵ grade shallow buried adjoining rock tunnel initial support deformation and surface settlement.%破碎松散的软弱围岩地段,地表沉降及水平收敛值难以控制,台阶开挖难度大、是施工作业的难点。兰渝铁路哈达铺隧道出口端穿越铁匠沟底浅埋段,地质条件复杂。通过对施工过程中逐段揭示的地层地质研究,对比分析了洞内水平旋喷桩、超前管棚+帷幕注浆、地表旋喷桩等施工工艺的实际效果及适用性,最终选择地表竖直旋喷桩方案并伴以掌子面超前加固及封闭,实现了对软塑淤泥质Ⅵ级围岩浅埋隧道的初期支护变形及地表沉降的有效控制。

  11. The possible forms of bore resistance

    Directory of Open Access Journals (Sweden)

    N. Balasubramanian

    1957-04-01

    Full Text Available A method is proposed for calculating the bore resistance of projectile by assuming as given the pressure-space curve. Applying this method to the Le Due and the isothermal systems of internal ballistics, it is shown that these systems imply certain physically in admissible features at the beginning of the motion.

  12. The Bored Self in Knowledge Work

    DEFF Research Database (Denmark)

    Costas, Jana; Kärreman, Dan

    2016-01-01

    of the bored self as a combination of unfilled aspirations and the sense of stagnation, leading to an arrested identity. Our contribution is to expand extant conceptualizations of employee interactions with identity regulation, in particular relating to identity work and identification. The findings provide...

  13. 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...

  14. Experimental hydrodynamic study of the Qiantang River tidal bore

    Institute of Scientific and Technical Information of China (English)

    HUANG Jing; PAN Cun-hong; KUANG Cui-ping; ZENG Jian; CHEN Gang

    2013-01-01

    To study the hydrodynamics of tidal bore,a physical modeling study is carried out in a rectangular flume with considerations of the tidal bore heights,the propagation speeds,the tidal current velocities,the front steepness,and the bore shapes.After the validation with the field observations,the experimental results are analyzed,and it is shown that:(1) the greater initial ebb velocity or the larger initial water depth impedes the tidal bore propagation,(2) the maximum bore height appears at an initial ebb velocity in the range of 0.5 m/s-1.5 m/s,(3) when the Froude number exceeds 1.2,an undular bore appears,after it exceeds 1.3,a breaking bore occurs,and after it exceeds 1.7,the bore is broken.

  15. Biomechanics of substrate boring by fig wasps.

    Science.gov (United States)

    Kundanati, Lakshminath; Gundiah, Namrata

    2014-06-01

    Female insects of diverse orders bore into substrates to deposit their eggs. Such insects must overcome several biomechanical challenges to successfully oviposit, which include the selection of suitable substrates through which the ovipositor can penetrate without itself fracturing. In many cases, the insect may also need to steer and manipulate the ovipositor within the substrate to deliver eggs at desired locations before rapidly retracting her ovipositor to avoid predation. In the case of female parasitoid ichneumonid wasps, this process is repeated multiple times during her lifetime, thus testing the ability of the ovipositioning apparatus to endure fracture and fatigue. What specific adaptations does the ovipositioning apparatus of a female ichneumonoid wasp possess to withstand these challenges? We addressed this question using a model system composed of parasitoid and pollinator fig wasps. First, we show that parasitoid ovipositor tips have teeth-like structures, preferentially enriched with zinc, unlike the smooth morphology of pollinator ovipositors. We describe sensillae present on the parasitoid ovipositor tip that are likely to aid in the detection of chemical species and mechanical deformations and sample microenvironments within the substrate. Second, using atomic force microscopy, we show that parasitoid tip regions have a higher modulus compared with regions proximal to the abdomen in parasitoid and pollinator ovipositors. Finally, we use videography to film wasps during substrate boring and analyse buckling of the ovipositor to estimate the forces required for substrate boring. Together, these results allow us to describe the biomechanical principles underlying substrate boring in parasitoid ichneumonid wasps. Such studies may be useful for the biomimetic design of surgical tools and in the use of novel mechanisms to bore through hard substrates.

  16. 基于Hoek-Brown准则的隧洞围岩变形研究%Study of deformations of surrounding rock of tunnel based on Hoek-Brown criterion

    Institute of Scientific and Technical Information of China (English)

    温森; 杨圣奇

    2011-01-01

    In many practical situations, for instance, in jointed rock mass, linear M-C yield criterion may not be justified and a nonlinear Hoek-Brown yield criterion would be more appropriate, so it is necessary to attempt to calculate deformation of tunnel by the criterion.The surrounding rock is divided into three zones: elastic zone, strain softening zone and plastic flow zone.Theoretical derivation on deformation is carried out by Hoek-Brown criterion and non-associated flow rule.Parameters of surrounding rock in strain softening zone are variable and they depend on the plastic deformation of this zone, so it's difficult to derive the analytical solution for stress in this zone.Runge-Kutta method is used to carry out numerical calculation and the radiuses of strain softening zone and plastic flow zone are calculated.Finally, the deformations of tunnel are calculated.It is demonstrated by an example that the results calculated by the method in this paper and Carranza-Torres's method are almost the same when strain softening zone and plastic flow zone are not be considered.Furthermore, it is demonstrated by the other example that dilation angle affects deformation more severely when in-situ stress becomes greater.%由于在许多实际条件下,比如节理岩体中,线性的M-C准则不太适用,非线性的Hoek-Brown比较适用,因此,可以尝试使用这一非线性屈服准则对洞室变形进行研究.研究隧洞变形时,将围岩分为弹性区、应变软化区、塑性流动区.采用Hoek-Brown准则和非关联流动法则对洞室变形进行了理论推导:软化区域围岩参数随着塑性变形增加而变化,解析法难以求得应力,采用龙格一库塔方法进行数值计算,求解得到塑性软化区和流动区半径,并最终求得洞室变形.通过算例计算表明,在不考虑软化区和流动区时,方法和Carranza-Torres计算结果相差甚小;随着原岩应力的增加,膨胀角对洞室变形的影响增大.

  17. RESEARCH ON MECHANISM OF LARGE DEFORMATION AND COUNTERMEASURES OF SURROUNDING ROCKS OF TUNNEL THROUGH COAL STRATA%穿越煤系地层隧道围岩大变形机制及处治研究

    Institute of Scientific and Technical Information of China (English)

    李生杰; 谢永利; 吴丹泽; 朱小明

    2013-01-01

    Surrounding rock of Anyuan highway tunnel through coal strata is made of carbonaceous shale,coal line and mudstone weak interlayer. The uniaxial compressive strength of the carbonaceous shale specimens are 3.9-4.8 MPa. The geostress measurement is carried out,and the results show that the maximum horizontal principal stress is 8-10 MPa,and the horizontal principal stress is dominant in the area of tunnel. Based on the on-site monitoring and numerical simulation,the characteristics of surrounding rock deformation are analyzed. The reasons for large deformation are summarized as follows:(1) The strength of surrounding rock is low and the rock swells easily;(2) The level of geostress is high as to the low strength of rockmass;(3) Water effect;(4) Improper construction. The mechanism of large deformation is discussed also. The countermeasures are proposed as follows:the tunnel face should be closed quickly after excavation,then the temporary support is set up,long bolts and grouting pipe are used to control the deformation,the arch is replaced after deformation become stable,the spacing of steel arch is reduced,and finally,invert and inner lining are applied timely. According to the measurement results,it is shown that the treatment measures are effective.%高速公路安远隧道穿越煤系地层,围岩主要由炭质页岩、煤线、泥岩夹层组成,炭质页岩试件单轴抗压强度为3.9~4.8 MPa。开展地应力测量,测量结果表明隧址区最大水平主应力为8~10 MPa,水平应力作用占主导。通过现场监测以及数值模拟分析,分析围岩大变形的特征,总结围岩大变形产生的原因,主要有:(1)围岩强度低且易膨胀;(2)相对岩体强度,地应力较高;(3)水理作用;(4)施工不当。在此基础上探讨变形机制。提出相应的处治措施:开挖后迅速封闭掌子面,设置临时支撑,施作长锚杆和注浆小导管控制变形,待变形稳定后适时进行拱圈

  18. 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

  19. 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

  20. Energy and material efficient non-circular bore Bitter magnets

    CERN Document Server

    Akhmeteli, A

    2015-01-01

    There exist a number of experiments/applications where the second dimension of the bore of Bitter magnets is not fully utilized. Using an analytical solution for elliptical bore coils, we show that reducing one of the dimensions of the bore can lead to considerable decrease in consumed power and/or coil material.

  1. Solution of Strain-Softening Surrounding Rock in Deep Tunnel Incorporating 3D Hoek-Brown Failure Criterion and Flow Rule

    Directory of Open Access Journals (Sweden)

    Jin-feng Zou

    2016-01-01

    Full Text Available In order to investigate the influence of the intermediate principal stress on the stress and displacement of surrounding rock, a novel approach based on 3D Hoek-Brown (H-B failure criterion was proposed. Taking the strain-softening characteristic of rock mass into account, the potential plastic zone is subdivided into a finite number of concentric annulus and a numerical procedure for calculating the stress and displacement of each annulus was presented. Strains were obtained based on the nonassociated and associated flow rule and 3D plastic potential function. Stresses were achieved by the stress equilibrium equation and generalized Hoek-Brown failure criterion. Using the proposed approach, we can get the solutions of the stress and displacement of the surrounding rock considering the intermediate principal stress. Moreover, the proposed approach was validated with the published results. Compared with the results based on generalized Hoek-Brown failure criterion, it is shown that the plastic radius calculated by 3D Hoek-Brown failure criterion is smaller than those solved by generalized H-B failure criterion, and the influences of dilatancy effect on the results based on the generalized H-B failure criterion are greater than those based on 3D H-B failure criterion. The displacements considering the nonassociated flow rule are smaller than those considering associated flow rules.

  2. Choice of rock excavation methods for the Swedish deep repository for spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Baeckblom, Goeran [Conrox, Stockholm (Sweden); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Lagerstedt, Leif [SwedPower AB, Stockholm (Sweden)

    2004-09-01

    Choice of rock excavation methods will or may have implications for a number of issues like repository layout, long term and operational safety, environmental impact, design of and operation of transport vehicles and methodology for backfilling the repository before closure as well as effects on costs and schedules. To fully analyse the issues at hand related to selection of excavation methods, SKB organized a project with the objectives: To investigate and compare principal technical solutions for rock excavation, both methods that are used at present but also methods that may be feasible 10 years from now; To assess how the selection of excavation method influences the design and operation of the deep repository; To present a definition of the Excavation Damaged/Disturbed Zone and practical methods for measurements of EDZ; To present advantages and disadvantages with different excavation methods for the various tunnels and underground openings as a basis for selection of preferred excavation methods; To present the Design Justification Statement for the selection of particular excavation methods for the different tunnels and openings in the deep repository to underpin a decision on excavation method; and To present background data that may be required for the evaluation of the long term safety of the deep repository. Main alternatives studied are very smooth blasting, excavation with a tunnel-boring machine (TBM) and excavation with horizontal pull-reaming using more or less conventional raise-boring equipment. The detailed studies were carried through in co-operation with major suppliers and end-users of the technology. An observation in this study is that all excavation technologies are mature; no major breakthroughs are foreseen within a 10 year period but it is likely that for any technology selected, SKB would specifically fine-tune the design of the equipment and work procedures in view of requirements and site specific conditions. Excavation methods have

  3. Probabilistic Reliability and Sensitivity of System Bolt in Soft Rock Highway Tunnel%软岩公路隧道系统锚杆概率可靠度及灵敏度分析

    Institute of Scientific and Technical Information of China (English)

    巩正玺; 杨建国; 陈明

    2011-01-01

    In order to understand the force in a system of rock bolts in bolt-shotcrete support, judge the stability of the tunnel lining structure and avoid loss resulting from instability of the support structure, the probabilistic reliability of the system of rock bolts is calculated based on the geological conditions of the discussed project with the elastic modulus of surrounding rock and thickness of the lining as the main random variables. Probabilistic sensitivity is analyzed using the Spearman rank correlation coefficient method. Prefabricated bolts were installed in random cross sections in the studied tunnel section, anchoring forces were monitored continually at different points within the surrounding rock, and a large number of data points were obtained. The magnitude, cross distribution and change of bolt axial forces over time are analyzed according to a curve of variation vs. Time and an axial force diagram. Bolt reliability is verified by bearing capacity and field test results are in accordance with the calculation of probabilistic reliability. It is concluded that physical property parameters of the surrounding rock and the thickness of shotcrete are the main factors affecting bolt reliability. The construction quality of system bolts should be guaranteed in order to improve safety and stability of bolt-shotcrete. Moreover, thickness of shotcrete and its construction quality should also be guaranteed.%为了解锚喷支护中系统锚杆受力情况,判断隧道衬砌结构稳定性,确保施工安全,避免支护结构失稳带来的损失,结合工点工程地质条件,选择围岩弹性模量、衬砌厚度等作为主要随机变量,计算得到锚杆概率可靠度.利用Spearman秩相关系数对锚杆概率灵敏度进行分析,认为围岩物性参数和喷混凝土厚度是影响锚杆可靠性的主要因素.要提高锚喷支护的安全和稳定性,除保证系统锚杆施工质量外,应确保喷混凝土厚度及其施工质量.在研究段

  4. Radar interferometry based settlement monitoring in tunnelling: visualisation and accuracy analyses

    OpenAIRE

    Schindler, Steffen; Hegemann, Felix; Koch, Christian; König, Markus; Mark, Peter

    2016-01-01

    Background The accurate, efficient and economical monitoring of settlements caused by tunnel boring machines, especially in regions of particular interest such as critical inner city areas, has become an important aspect of the tunnelling operation. Besides conventional terrestrial based methods to capture settlements, satellite based techniques that can accurately determine displacements remotely, are increasingly being used to augment standard terrestrial measurements. However, not much...

  5. Short tunnels.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1965-01-01

    Before dealing with the question of lighting short tunnels, it is necessary define what is meant by a tunnel and when it should be called 'short'. Confined to motorized road traffic the following is the most apt definition of a tunnel: every form of roofing-over a road section, irrespective of it le

  6. Engineering geology and geomechanics as fundamentals of rock engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, L. (ed.)

    1982-01-01

    Topics covered included modelling of flexural slip phenomena, statistical methods in engineering geology, design of tunnels, calculating strength properties of jointed clay, retaining measures and foundations in rock slopes, slope design for open pit mines, slopes of dams, use of convergency and workability of coal as indication of rock bursts, deformation in bearing rock mass mechanical drivage of tunnels, and control of water inflows during construction of tunnels. Two papers have previously been abstracted.

  7. Tunnel large deformation of surrounding rock research based on radar information and monitoring warning%基于雷达信息与监测预警的隧道围岩大变形研究

    Institute of Scientific and Technical Information of China (English)

    董辉; 陈家博; 杨珺博; 侯俊敏

    2012-01-01

    针对公路隧道溶洞和孔洞的存在给围岩的稳定性控制带来不同程度的困难且围岩大变形极易发生而造成工程事故,采用探地雷达超前探测和监控量测,归纳分析隧道围岩大变形的异常特征,并进一步通过贵州省晴兴高速公路登攀隧道出口围岩大变形预警的工程实例进行验算,获得黔西南区强风化多孔玄武岩及下伏灰岩溶洞雷达图像特征:有充填物时反射波振幅在洞腔范围内衰减强烈,强弱相间;无充填物时反射波基本无衰减,存在中断、起伏和错动现象。围岩大变形监测以拱顶下沉为主,21d最大累计沉降值达到89.40mm,变形速率最大波动范围为14.66~0.64mm/d。应用此结论可以在围岩出现大变形时及时预警并采取控制措施,更好地为后续工程服务。%Aiming at the existence of caves and holes in high.way tunnel will cause difficulty for surrounding rock' s stability in varying degrees and it is prone to result in large deformation of surrounding rock, cause accident, the paper summarizes and analyzes the abnormal characteristics of tunnel large deformation of surrounding rock by advanced detection of ground penetrating radar and monitoring. Meanwhile, with the project of Qingxing highway Dengpan tunnel exit surrounding rock' s large deformation and warning, we obtain radar images' characteristics to highly weathered porous basalt and underlying limestone caves in southwest of Guizhou province: reflection amplitude attenuates strongly and strength of the white in filling caves and there is almost no attenuation but with the phenomenon of disruption, ups and downs and dislocation in inanition. On the other side, when large deformation of surrounding rock is mainly vault sedimentation, its maximum cumulative settlement is 89.40mm during 21 days and deformation rate fluctuates from 14.66mm to 0.64mm per day. With the conclusion, it should be warned and take control measures timely

  8. Site Measurement of Surrounding Rock Pressure and Analysis of Structure Stress of Large-span Bias-pressured Shallow Tunnels%大跨浅埋偏压隧道围压实测及结构受力分析

    Institute of Scientific and Technical Information of China (English)

    江磊; 侯哲生; 吴海卫

    2015-01-01

    大跨浅埋偏压隧道由于其非对称的受力条件,易引发结构变形与开裂等突出问题,近年来越来越受工程技术界的重视。以邢汾高速公路邢台段后偏梁大跨度隧道浅埋偏压段为例,通过实测围岩压力,根据荷载结构法的基本原理,利用 ANSYS 软件对其结构受力特性进行数值分析,得到结论:实测的围岩压力分布和偏压的地形之间具有较为一致的对应性,即围岩压力受地形的影响显著;二衬总应力受轴力引起的应力影响较小,主要受弯矩引起的应力控制,整个拱圈范围内最危险的部位是在受围岩压力最大的左侧拱肩处;随着二衬厚度的变化,二衬总应力在不同的部位均发生相应变化,但变化幅度均不大。相关研究结论为后续类似大跨浅埋偏压隧道的合理设计与施工提供参考依据。%The asymmetrical stress condition of the Large-span bias-pressured shallow tunnels can cause many problems easily ,such as structural deformation and cracking .These problems have attracted more and more attentions from engi-neering and technology research field in recent years .The Houpianliang large-span bias-pressured shallow tunnel in Xing-tai section of Xingtai - Fenyang highway was taken as an example to numerically analyze the mechanical characteristics of the structure by adopting ANSYS ,according to the data of site measurement of surrounding rock pressure and the princi -ple of load structure method .The results indicate that :the actual measured surrounding rock pressure is consistent with the bias terrain ,which means the surrounding rock pressure is influenced by topography significantly ;the total stress of the second lining is mainly controlled by the stress from bending moment and is less influenced by the stress from axial force ,the weakest part within the scope of the arch ring is the left spandrel which is subject to maximum pressure ;with the change of the

  9. Study of thermo-mechano-damage coupling behavior of surrounding rock of deep tunnel%热-应力-损伤耦合作用下深埋隧洞围岩稳定性分析

    Institute of Scientific and Technical Information of China (English)

    贾善坡; 吴渤; 陈卫忠; 伍国军; 高敏; 龚俊

    2014-01-01

    以热力学和弹塑性力学理论为基础,分析岩石热-力完全耦合作用及其对力学参数和热特性参数的影响,建立了岩石热-力-损伤耦合模型及其参数演化方程,以ABAQUS软件为平台对其进行二次开发,并通过典型算例验证了岩石热-力完全耦合的重要性。然后以某深埋软岩隧洞为例,研究温度和开挖卸载共同作用下的隧洞围岩力学行为和损伤过程。计算结果表明:温度对岩石的力学性质和损伤演化过程影响显著,开挖损伤和热应力诱发的损伤对围岩热力学参数的影响不可忽略;所提出的力学模型可以有效反映围岩损伤演化、调热圈演化以及热力学参数演化,具有一定的借鉴作用。%Based on the theories of thermo-mechanics and elastoplastic mechanics, the thermo-mechanical coupling effects of rock and their effects on mechanical and thermal parameters are analyzed. By defining the evolution equations of thermo-mechanical coupling parameters under the damage of temperature effects and mechanics, a new coupled thermo-mechanical damage model with improved Mohr-Coulomb criterion is established, and the numerical implementation in ABAQUS is given. Using finite element method, a typical example was given to verify the importance of the thermo-mechanical fully coupling of rock. Taking a deep tunnel of clay stone as background, the evolution and distribution of damage, temperature and coupling parameters of the surrounding rock are simulated in detail. The results show that the temperature has a great influence on rock properties and damage evolution. Also, the damage by excavation and thermal stress has a great influence on conducting and diffusing of heat. The proposed model can depict the excavation damage, control heat circle and coupling parameters evolution, and may provide a new tool for associated applications.

  10. 基于长期强度的节理岩体洞室蠕变特性研究%Study of creep characteristics of tunnel opening in joint rock mass based on long-term strength

    Institute of Scientific and Technical Information of China (English)

    于超云; 唐春安

    2014-01-01

    In order to reveal the creep properties of tunnel opening in joint rock mass, the Rock Failure Process Analysis System is used by the introduction of long-term strength of rock and the elastic-brittle consid-ered constitutive for meso-unit, which is different from the traditional methods of elastic-plastic or viscoelastic plastic constitutive to analyze the rheological properties of jointed rock on the view of macroscopic. The numer-ical simulations of jointed rock cavern under different conditions are investigated, and the effects of joint inter-val and joint angle on the creep and failure characteristics are analyzed. The calculation results show that the uniaxial creep deformation for rock mass decreases with the increase of joint interval and it increases with the increase of dip angle of joint plane if the angle is smaller than 45 ° , while the result will be quite on the contra-ry if the angle is larger than 45 ° . If the angle is 45 ° , a large number of failures in surrounding rock emerge and the characteristic accelerating creep stages are exhibited.%为了进一步探究节理岩体蠕变特性,摆脱传统意义上从宏观弹塑或粘弹塑本构的角度分析岩体流变特性的方法,将细观单元视为弹脆性的本构关系,采用考虑岩石长期强度的岩石破裂过程分析系统,通过对不同工况下的节理岩体洞室数值模拟,得到了节理间距和节理夹角对围岩蠕变特性及其破坏特征的影响规律。结果表明:节理岩体洞室围岩的蠕变量随着节理面间距的增大而减小;当节理面的水平夹角小于45°时,节理岩体洞室围岩蠕变量随着节理面夹角的增大而增大,但当节理面倾角大于45°时,蠕变量反而随着节理面倾角的增大而减小,当节理面倾角等于45°时,围岩出现大量破坏,并表现出加速蠕变的特征。

  11. General model for boring tool optimization

    Science.gov (United States)

    Moraru, G. M.; rbes, M. V. Ze; Popescu, L. G.

    2016-08-01

    Optimizing a tool (and therefore those for boring) consist in improving its performance through maximizing the objective functions chosen by the designer and/or by user. In order to define and to implement the proposed objective functions, contribute numerous features and performance required by tool users. Incorporation of new features makes the cutting tool to be competitive in the market and to meet user requirements.

  12. The biomechanics of burrowing and boring.

    Science.gov (United States)

    Dorgan, Kelly M

    2015-01-15

    Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically from sand; in mud, sediment grains are suspended in an organic matrix that fails by fracture. Macrofauna extend burrows through this elastic mud by fracture. Sand is granular and non-cohesive, enabling grains to more easily move relative to each other, and macrofaunal burrowers use fluidization or plastic rearrangement of grains. In both sand and mud, peristaltic movements apply normal forces and reduce shear. Excavation and localized grain compaction are mechanisms that plastically deform sediments and are effective in both mud and sand, with bulk excavation being used by larger organisms and localized compaction by smaller organisms. Mechanical boring of hard substrata is an extreme form of excavation in which no compaction of burrow walls occurs and grains are abraded with rigid, hard structures. Chemical boring involves secretion to dissolve or soften generally carbonate substrata. Despite substantial differences in the mechanics of the media, similar burrowing behaviors are effective in mud and sand.

  13. Undular bore theory for the Gardner equation.

    Science.gov (United States)

    Kamchatnov, A M; Kuo, Y-H; Lin, T-C; Horng, T-L; Gou, S-C; Clift, R; El, G A; Grimshaw, R H J

    2012-09-01

    We develop modulation theory for undular bores (dispersive shock waves) in the framework of the Gardner, or extended Korteweg-de Vries (KdV), equation, which is a generic mathematical model for weakly nonlinear and weakly dispersive wave propagation, when effects of higher order nonlinearity become important. Using a reduced version of the finite-gap integration method we derive the Gardner-Whitham modulation system in a Riemann invariant form and show that it can be mapped onto the well-known modulation system for the Korteweg-de Vries equation. The transformation between the two counterpart modulation systems is, however, not invertible. As a result, the study of the resolution of an initial discontinuity for the Gardner equation reveals a rich phenomenology of solutions which, along with the KdV-type simple undular bores, include nonlinear trigonometric bores, solibores, rarefaction waves, and composite solutions representing various combinations of the above structures. We construct full parametric maps of such solutions for both signs of the cubic nonlinear term in the Gardner equation. Our classification is supported by numerical simulations.

  14. Analysis of Metamorphic Rock Tunnel Deformation Influencing Factors and Mechanism by Monitoring Measurement%基于监控测量的石英片岩区变质岩隧道变形影响因素及机理分析

    Institute of Scientific and Technical Information of China (English)

    于卫云; 李伟

    2016-01-01

    为研究石英片岩区隧道变形破坏机理及影响因素,本文以油坊坪隧道作为研究对象,在对隧道围岩物理力学特性及工程地质条件进行调查分析的基础上,结合隧道变形监测方案,总结归纳了石英片岩隧道的变形破坏过程。研究发现:该变质岩隧道变形破坏多发生在节理裂隙发育,含有地下水,且含有蒙脱石、伊利石、高岭土等膨胀性矿物的围岩之中,且隧道变形破坏具有滞后性、多样性、变形速率快、变形时间长等特点;隧道围岩变形量均超过其对应围岩级别的预留变形量,油坊坪隧道进出口段及拱顶部位沉降变形速率范围为10~35 mm /d。在监测过程中,底板最终沉降最大值为130.5 mm,最小值为15.3 mm,拱顶沉降最大值为131.1 mm,最小值为27.8 mm;隧道变形破坏主要由重力驱动型、应力驱动型和应力-结构驱动型3种。%For the study of metamorphic rock tunnel deformation failure mechanism and influence factors,this paper takes oil mill ping metamorphic rock tunnel as the research object,on the surrounding rock physical and mechanical properties and engineering geological conditions on the basis of investigation and analysis,combined with the tunnel deformation monitoring,sums up the deformation and failure process of the metamorphic rock tunnel.Study found:metamorphic rock tunnel surrounding rock is mainly affected by ground stress,rock mass characteristics and groundwater three factors;Tunnel surrounding rock deformation than its corresponding reserve level of surrounding rock deformation,Oil Mill Flat tunnel section and arch parts import and export settlement rate range for 10 ~35 mm /d.In the process of monito-ring,the maximum floor final settlement is 130.5 mm,minimum value is 15.3 mm,a maximum of 131.1 mm,vault subsidence minimum value is 27.8 mm.;Tunnel deformation damage mainly driven by the gravity driven,stress and stress and

  15. Catalog of worldwide tidal bore occurrences and characteristics

    Science.gov (United States)

    Bartsch-Winkler, S.; Lynch, David K.

    1988-01-01

    Documentation of tidal bore phenomena occurring throughout the world aids in defining the typical geographical setting of tidal bores and enables prediction of their occurrence in remote areas. Tidal bores are naturally occurring, tidally generated, solitary, moving water waves up to 6 meters in height that form upstream in estuaries with semidiurnal or nearly semidiurnal tide ranges exceeding 4 meters. Estuarine settings that have tidal bores typically include meandering fluvial systems with shallow gradients. Bores are well defined, having amplitudes greater than wind- or turbulence-caused waves, and may be undular or breaking. Formation of a bore is dependent on depth and velocity of the incoming tide and river outflow. Bores may occur in series (in several channels) or in succession (marking each tidal pulse). Tidal bores propagate up tidal estuaries a greater distance than the width of the estuary and most occur within 100 kilometers upstream of the estuary mouth. Because they are dynamic, bores cause difficulties in some shipping ports and are targets for eradication. Tidal bores are known to occur, or to have occurred in the recent past, in at least 67 localities in 16 countries at all latitudes, including every continent except Antarctica. Parts of Argentina, Canada, Central America, China, Mozambique, Madagascar, Northern Europe, North and South Korea, the United Kingdom, and the U.S.S.R. probably have additional undiscovered or unreported tidal bores. In Turnagain Arm estuary in Alaska, bores cause an abrupt increase in salinity, suspended sediment, surface character, and bottom pressure, a decrease in illumination of the water column, and a change in water temperature. Tidal bores occurring in Turnagain Arm, Alaska, have the

  16. Discrete/Finite Element Modelling of Rock Cutting with a TBM Disc Cutter

    Science.gov (United States)

    Labra, Carlos; Rojek, Jerzy; Oñate, Eugenio

    2017-03-01

    This paper presents advanced computer simulation of rock cutting process typical for excavation works in civil engineering. Theoretical formulation of the hybrid discrete/finite element model has been presented. The discrete and finite element methods have been used in different subdomains of a rock sample according to expected material behaviour, the part which is fractured and damaged during cutting is discretized with the discrete elements while the other part is treated as a continuous body and it is modelled using the finite element method. In this way, an optimum model is created, enabling a proper representation of the physical phenomena during cutting and efficient numerical computation. The model has been applied to simulation of the laboratory test of rock cutting with a single TBM (tunnel boring machine) disc cutter. The micromechanical parameters have been determined using the dimensionless relationships between micro- and macroscopic parameters. A number of numerical simulations of the LCM test in the unrelieved and relieved cutting modes have been performed. Numerical results have been compared with available data from in-situ measurements in a real TBM as well as with the theoretical predictions showing quite a good agreement. The numerical model has provided a new insight into the cutting mechanism enabling us to investigate the stress and pressure distribution at the tool-rock interaction. Sensitivity analysis of rock cutting performed for different parameters including disc geometry, cutting velocity, disc penetration and spacing has shown that the presented numerical model is a suitable tool for the design and optimization of rock cutting process.

  17. FEASIBILITY TESTING AND INVESTIGATION ON A NEW TECHNOLOGY FOR HARD ROCK TUNNELING WITH A COLLIMATED ABRASIVE WATER JET%采用准直管磨料射流掘进硬岩巷(隧) 道的可行性试验与探讨

    Institute of Scientific and Technical Information of China (English)

    李晓红; 王建生; 杨林; 卢义玉; 孙家骏

    2001-01-01

    为了提高坚硬岩石巷道的掘进速度和质量,研究了准直管磨料射流用于岩石巷道掘进的方案,分析了准直管磨料射流装备的结构特点和工作原理。试验研究了准直管结构参数、磨料参数、进给速度对射流切割效果的影响。初步研究表明这一设想基本可行,是一种值得探讨的新型掘进方法。%A new-type tunneling system, Collimated Abrasive Water Jet(CAWJ)cutter, is develped to increase the tunneling speed and improve the cutting quality in hard rock. And its characteristics of configuration and operating principle are discussed. The effects of cutting hard rock with various operating parameters on the cutting efficiency of CAWJ are analyzed. Research results show that it is primarily feasible for tunneling hard rock with CAWJ.

  18. Large Bore Powder Gun Qualification (U)

    Energy Technology Data Exchange (ETDEWEB)

    Rabern, Donald A. [Los Alamos National Laboratory; Valdiviez, Robert [Los Alamos National Laboratory

    2012-04-02

    A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has been established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.

  19. 极高地应力软岩隧道双层支护技术%Technologies for Double-shell Support of Tunnels in Soft Rock with Extra-high Ground Stress

    Institute of Scientific and Technical Information of China (English)

    司剑钧

    2014-01-01

    Liangshui tunnel on Lanzhou-Chongqing railway is located in soft rock of carbon phyllite.The rock has extra-high ground stress,with the maximum horizontal principal stress ranging from 6.5 MPa to 11.3 MPa.In the early stage of the tunnel construction,serious deformation occurred to the primary support structure,which resulted in distorted and fractured steel arches,instability of the support structure and interference of the primary support structure into the lining clearance.Therefore,the distorted primary support structure had to be dismantled and even cracks occurred to the secondary lining at local positions.In the paper,double-shell primary support experiment and double-shell secondary lining experiment are made,so as to solve the above-mentioned problems.In the experiments,the primary support deformation,the surrounding rock pressure,the contact pressure,the steel arch stress,the steel bar stress and the concrete stress are studied.Conclusions drawn are as follows:1 )The deformation of the double-shell primary support is relatively small,the stress of the shotcrete,steel arches,secondary lining concrete and secondary lining steel bars have not exceeded the allowable stresses of these materials,and the double-shell primary support works well;2 )Due to the adoption of the double-shell primary support,the steel bar binding process can be reduced,no additional lining formwork jumbos are needed,the construction organization is more convenient,and construction efficiency is relatively high.%兰渝铁路两水隧道洞身主要通过炭质千枚岩软岩地层,隧道为极高地应力状态,最大水平主应力值为6.5~11.3 MPa。施工前期,隧道初期支护结构变形较大,部分钢拱架扭曲、断裂,支护结构失稳,初期支护结构侵入衬砌净空,拆换拱情况频繁发生,局部地段二次衬砌开裂。针对前期施工中出现的问题,分别开展双层初期支护和双层衬砌试验,对试验段初期支护

  20. Strata control in tunnels and an evaluation of support units and systems currently used with a view to improving the effectiveness of support, stability and safety of tunnels.

    CSIR Research Space (South Africa)

    Haile, AT

    1998-12-01

    Full Text Available This report details a methodology for rational design of tunnel support systems based on a mechanistic evaluation of the interaction between the components of a tunnel support system and a highly discontinuous rock mass structure. This analysis...

  1. Key technologies of drilling process with raise boring method

    OpenAIRE

    Zhiqiang Liu(Institute of High Energy Physics); Yiping Meng

    2015-01-01

    This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are describe...

  2. Analysis of TBM Tunneling Speed in Hard Rock and Influence of Tunneling Speed on Project Economics%TBM(隧道掘进机)的硬岩掘进速度分析及其对项目经济的影响

    Institute of Scientific and Technical Information of China (English)

    李准; 吴刘忠球

    2014-01-01

    The cost assessment of TBM equipment for hard rock should be combined with the whole process of the project construction.The whole project management should include project duration,daily expenses,labor,materials and ma-chinery costs.The duration of the project depends largely on the TBM advance rates,however the accurate speed value is difficult to estimate.The study shows that in the certain geological conditions,driving speed can be judged according to penetration rate and utilization rate of TBM.Based on practice,a driving speed probabilistic assessment method is put forward in this paper,moreover,an evaluation is made on influence of TBM tunneling speed on project economics and the rock strength grade and lithology are reflected by cash flow theory,which provides a new evaluation model for inno-vation of reasonable economic use of TBM and can be widely used in the analysis of tunneling rate range and quantifica-tion of economical efficiency data of TBM.%硬岩TBM施工成本的评估应当与项目建设全过程相结合,而项目全过程管理包括项目工期及日常开销、人工、材料和机械成本等。而项目工期与成本主要取决于TBM的掘进速度。研究发现,在既定地质条件下,掘进速度可以依据TBM穿透速度和利用率来判断。文章通过实例,提出掘进速度的概率评估法,同时利用现金流理论,评价TBM掘进速度对项目经济的影响,建立评价模型,反映了岩体强度等级和围岩岩性。这为革新TBM合理经济利用提供了新的评价模式,可广泛应用于分析掘进率范围并量化设备经济效率数据。

  3. A novel surface-repairing technique for gun bore

    Institute of Scientific and Technical Information of China (English)

    SU Bing; YU Xu-dong; WU Bin; WANG Cheng-tao

    2005-01-01

    A novel surface-repairing technique for gun bore was investigated, which was combined with the merits such as anti-erosion wear, damage-repairing, and etc. It was accomplished by adhering a special rare earth nanocom posite evenly to the micro-surface of gun bore. The effectiveness of this technique was approved by the target-firing using a domestic automatic rifle with chromium-coated bore. Its characteristics were discussed based on the surface analyses of the rifle bore by secondary ion mass spectrometry(SIMS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.

  4. Intraoperative wide bore nasogastric tube knotting: A rare incidence.

    Science.gov (United States)

    Lamba, Sangeeta; Sethi, Surendra K; Khare, Arvind; Saini, Sudheendra

    2016-01-01

    Nasogastric tubes are commonly used in anesthetic practice for gastric decompression in surgical patients intraoperatively. The indications for its use are associated with a number of potential complications. Knotting of small-bore nasogastric tubes is usually common both during insertion and removal as compared to wide bore nasogastric tubes. Knotting of wide bore nasogastric tube is a rare complication and if occurs usually seen in long standing cases. We hereby report a case of incidental knotting of wide bore nasogastric tube that occurred intraoperatively.

  5. Investigation of a mesospheric bore event over northern China

    Directory of Open Access Journals (Sweden)

    Q. Li

    2013-03-01

    Full Text Available A mesospheric bore event was observed using an OH all-sky airglow imager (ASAI at Xinglong (40.2° N, 117.4° E, in northern China, on the night of 8–9 January 2011. Simultaneous observations by a Doppler meteor radar, a broadband sodium lidar, and TIMED/SABER OH intensity and temperature measurements are used to investigate the characteristics and environment of the bore propagation and the possible relations with the Na density perturbations. The bore propagated from northeast to southwest and divided the sky into bright and dark halves. The calculations show that the bore has an average phase velocity of 68 m s−1. The crests following the bore have a horizontal wavelength of ~ 22 km. These parameters are consistent with the hydraulic jump theory proposed by Dewan and Picard, as well as the previous bore reports. Simultaneous wind measurements from the Doppler meteor radar at Shisanling (40.3° N, 116.2° E and temperature data from SABER on board the TIMED satellite are used to characterize the propagating environment of the bore. The result shows that a thermal-Doppler duct exists near the OH layer that supports the horizontal propagation of the bore. Simultaneous Na lidar observations at Yanqing (40.4° N, 116.0° E suggest that there is a downward displacement of Na density during the passage of the mesospheric bore event.

  6. Size segregation in a granular bore

    Science.gov (United States)

    Edwards, A. N.; Vriend, N. M.

    2016-10-01

    We investigate the effect of particle-size segregation in an upslope propagating granular bore. A bidisperse mixture of particles, initially normally graded, flows down an inclined chute and impacts with a closed end. This impact causes the formation of a shock in flow thickness, known as a granular bore, to travel upslope, leaving behind a thick deposit. This deposit imprints the local segregated state featuring both pure and mixed regions of particles as a function of downstream position. The particle-size distribution through the depth is characterized by a thin purely small-particle layer at the base, a significant linear transition region, and a thick constant mixed-particle layer below the surface, in contrast to previously observed S-shaped steady-state concentration profiles. The experimental observations agree with recent progress that upward and downward segregation of large and small particles respectively is asymmetric. We incorporate the three-layer, experimentally observed, size-distribution profile into a depth-averaged segregation model to modify it accordingly. Numerical solutions of this model are able to match our experimental results and therefore motivate the use of a more general particle-size distribution profile.

  7. Soft rocks in Argentina

    Institute of Scientific and Technical Information of China (English)

    Giambastiani; Mauricio

    2014-01-01

    Soft rocks are a still fairly unexplored chapter in rock mechanics. Within this category are the clastic sedimentary rocks and pyroclastic volcanic rocks, of low to moderate lithification (consolidation, cemen-tation, new formed minerals), chemical sedimentary rocks and metamorphic rocks formed by minerals with Mohs hardness less than 3.5, such as limestone, gypsum, halite, sylvite, between the first and phyllites, graphitic schist, chloritic shale, talc, etc., among the latter. They also include any type of rock that suffered alteration processes (hydrothermal or weathering). In Argentina the study of low-strength rocks has not received much attention despite having extensive outcrops in the Andes and great impact in the design criteria. Correlation between geomechanical properties (UCS, deformability) to physical index (porosity, density, etc.) has shown promising results to be better studied. There are many studies and engineering projects in Argentina in soft rock geological environments, some cited in the text (Chihuído dam, N. Kirchner dam, J. Cepernic Dam, etc.) and others such as International Tunnel in the Province of Mendoza (Corredor Bioceánico), which will require the valuable contribution from rock mechanics. The lack of consistency between some of the physical and mechanical parameters explored from studies in the country may be due to an insufficient amount of information and/or non-standardization of criteria for testing materials. It is understood that more and better academic and professional efforts in improv-ing techniques will result in benefits to the better understanding of the geomechanics of weak rocks.

  8. Large Deformation Control Technologies for Soft Rock of Xingyuan Tunnel on Mudanjiang-Suifenhe Railway%牡绥铁路兴源隧道软岩大变形控制技术

    Institute of Scientific and Technical Information of China (English)

    徐松

    2016-01-01

    为解决东北地区高地应力软岩隧道产生的大变形问题,针对薄层状炭质泥岩夹砂岩,从台阶长度高度、主要的技术措施以及施工组织措施等方面进行研究。主要研究结论如下:1)在开挖和支护技术上,上台阶高度为3.5 m,采用单层 I25b 工字钢、89洞身管棚,锁脚采用89大直径长锁脚,增加纵向型钢连接及全环径向注浆加固等支护措施;2)施工组织措施上,采取快挖快支快封闭、仰拱二次衬砌适时跟进的施工原则。采用以上软岩隧道施工方法,有效地控制了围岩变形,确保了施工安全,加快了施工进度。%Study is made on large deformation of soft rock tunnel with high ground stress located in thin bedded carbonaceous mudstone interbedded sandstone in Northeast China in terms of bench height and length,construction technologies and construction organization.Some conclusions are drawn as follows:1)The height of top heading is 3.5 m;and single-layer H-steel I25b,89 mm pipe roof,longitudinal shaped steel and radial grouting are adopted.2)The construction principle of rapid excavation,rapid support,rapid close and invert lining timely is adopted.Finally,the deformation of surrounding rocks has been brought under effective control;the construction safety has been guaranteed and the construction schedule has been shortened.

  9. Intelligent Displacement Back Analysis of Surrounding Rock Parameters of the Mined Subway Tunnel in Changchun%长春地铁暗挖隧道围岩参数智能位移反分析

    Institute of Scientific and Technical Information of China (English)

    王志斌; 麻凤海; 张碧雪

    2015-01-01

    为了更加真实的反映岩土体整体特性主要力学参数的取值,以长春地铁某暗挖区间现场监测位移值为依据,通过敏感性分析,确定了该地区对地表变形影响最大的力学参数为弹性模量 E和内摩擦角φ,运用Madis GTS三维正算模型、BP神经网络模型组成的智能位移反分析系统对其进行了反分析。运用反分析得到的参数值进行数值模拟,将得到的监测断面位移值与实测值进行了对比,并根据断面的位移云图对隧道围岩的稳定性进行了评价,验证了反分析结果的合理性和准确性。%In order to determine the value of the main mechanical parameters that could truely reflect the global property of rock and soil ,the mining section of Changchun subway was taken as the engineering background ,and it was confirmed that the mechanical parameters with the greatest impact on the surface deformation were the elasticity modulus E and in-ternal friction angle φ,based on the sensitivity analysis of the field monitoring displacement data .And then the intelli-gent displacement back analysis system formed by the Midas GTS 3D forward solution model and BP neural network was applied for the back analysis of these parameters .The new parameters obtained from the back analysis were used in the simulation analysis ,and the displacement value was calculated and then compared with the monitoring data .According to the displacement cloud picture of the section ,the stability of the tunnel surrounding rock was evaluated ,and the rational-ity and accuracy of the back analysis result was verified .

  10. E-plastic limit equilibrium analysis on water-bearing rock in deep tunnel based on strain-softening%基于应变软化深埋巷道含水围岩的弹塑性极限平衡分析

    Institute of Scientific and Technical Information of China (English)

    刘树新; 刘长武; 张飞; 曹磊

    2011-01-01

    After excavating tunnel in rock mass, secondary stress presents in the wall rock with water-bearing,because the in-situ rock stress distribution and the infiltrative hydraulic pressure action is disturbed. The unbalanced stress is the major reason of rock mass deformation, displacement and even destroy. Based on Mohr-Coulomb and elastic-plasticity theory and rock damage caused by rock strain-softening, taking circular section of underground deep tunnel as example, the paper calculates and analyses the relationship between plastic range and supporting force in the case of limit equilibrium. The study establishes theoretical foundation for actual underground project construction and support engineering.%在岩体内开挖巷道后,由于干扰了原岩应力分布和渗透水压力的作用,巷道含水围岩中呈现次生应力,这种新出现的不平衡应力是引起岩体产生变形、位移,甚至破坏的主要根源.以圆形截面巷道为例,结合莫尔-库仑理论从围岩弹塑性变形的角度出发,在考虑了围岩应变软化所引起围岩损伤的基础上,计算和分析了地下巷道含水围岩达到极限平衡时围岩塑性区范围与相应支护抗力之间的关系,为实际地下工程施工和支护提供了理论基础.

  11. Research on the Application of Energy Conservative Principal in Lining Design of Tunnel with V-class Surrounding Rock%能量守恒原理在吁级围岩隧道衬砌设计中的应用研究

    Institute of Scientific and Technical Information of China (English)

    胡磊; 王志杰; 许瑞宁; 马安震; 何晟亚

    2014-01-01

    There exists energy delivery and transformation in the closed surrounding rock - tunnel lining system during the process of tunnel construction. When thermal energy transformation is left out of consideration and the surrounding rock is treated as an elastic body, the release of static energy of surrounding rock equals the increase in the elastic strain energy of tunnel lining. According to this energy conservative principle, Liu Hongyan and other researchers[1 2] calculated the thickness of lining of single track tunnel subject to Ⅲ-class surrounding rock. Based on these research findings, this paper further studies the application of energy conservative principle in V-class tunnel lining design. V-class surrounding rock of the three-dimensional FLAC3D model is established, dynamically simulating the process of tunnel excavation. With MATLAB language to the program of elastic strain energy density function, elastic strain energy of each unit of solid model is obtained, thus, static energy curves of surrounding rock associated with excavation depth within the specific scope of monitoring surrounding rock are finally obtained. According to the above curves, we are able to obtain the release value of static energy of surrounding rock. Additionally, toughness tests of steel fiber reinforced concrete ( SFRC) members are conducted, which leads to the finding of the relationship between energy expenditure of SFRC trisection beam under critical conditions and that of SFRC tunnel lining. Thus, theoretical tunnel lining thickness can be defined by solving the energy equation deduced from the energy expenditure relationship, and proved to satisfy the safety requirements. The research results show that, the tunnel lining design method with energy conservative principles is no longer limited by the conditions of II,Ⅲ-class surrounding rock in small section tunnels, and it is also applicable to the lining design of large section tunnels with Ⅴ-class surrounding rock.%在

  12. Formulating entompathogens for control of boring beetles in avocado orchards

    Science.gov (United States)

    A foam formulation of Beauveria bassiana was adapted to control boring beetles in avocado orchards. The two geographically independent avocado growing areas in the United States are threatened by emerging diseases vectored by boring beetles. In the California growing region, Fusarium dieback is vect...

  13. Nozzle assembly for an earth boring drill bit

    Energy Technology Data Exchange (ETDEWEB)

    Madigan, J. A.

    1985-09-24

    A nozzle assembly for an earth boring drill bit of the type adapted to receive drilling fluid under pressure and having a nozzle bore in the bottom thereof positioned closely adjacent the well bore bottom when the bit is in engagement therewith with the bore having inner and outer portions. The nozzle assembly comprises a generally cylindrical nozzle member of abrasion and erosion resistant material, selected from a plurality of such members, each being of the same outer diameter but having passaging therein of different cross-sectional area. The nozzle member is adapted to be fitted in the inner portion of the nozzle bore in sealing relationship therewith for forming a first seal for the nozzle assembly. The nozzle assembly further comprises a locknut, separate from the nozzle member, for detachbably securing the nozzle member in the nozzle bore, formed at least in part of an abrasion and erosion resistant material. The locknut has a threaded side wall engageable with the outer portion of the nozzle bore, and an aperture therethrough for enabling a stream of drilling fluid from the nozzle member to flow therethrough and being so configured in section as to receive a tool for turning the lockout to install it in and remove it from the nozzle bore.

  14. Earthquake resistant design of rock oil tanks

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, M.; Iwano, M.; Izumi, H.; Shiba, Y.; Sugihara, Y.

    1983-01-01

    In order to establish a rational procedure of the earthquake resistant design of large rock caverns, such as oil storage tanks on nuclear power plants, experimental and numerical studies were conducted. Dynamic strains during earthquakes were observed on the lining of a railway tunnel constructed in a hard rock mountain, while the seismic motion in the surrounding rock was examined precisely. The observation clarified that the lining strain of the tunnel was linearly and statically related to the rock strain and the ratio of the lining strain to the rock strain was dominated by the relative stiffness of the lining and rock. Based on the results of the earthquake observation, numerical models were proposed for the estimation of the dynamic strains of rock caverns. A good agreement between the calculated strains and the observed ones assured the adequacy of the numerical models.

  15. Application of water jet assisted drag bit and pick cutter for the cutting of coal measure rocks. Final technical report. [Tests of combination in different rocks

    Energy Technology Data Exchange (ETDEWEB)

    Ropchan, D.; Wang, F.D.; Wolgamott, J.

    1980-04-01

    A laboratory investigation was made of the effects of high pressure water jets on the cutting forces of drag bit cutters in sedimentary rocks. A hard and soft sandstone, shale and limestone were tested with commercially obtainable conical and plow type drag bits on the EMI linear cutting machine. About 1200 cuts were made at different bit penetration, jet orientation, and water pressure to determine the reduction of cutting forces on the bit from the use of the water jet. Both independent and interactive cutting was used. The greatest reduction in cutting forces were with both of the sandstones; the drag forces were reduced about 30 percent and the normal forces about 60 percent at 5000 psi water pressure with the nozzle behind the bit. The method was less effective in the shale, except at 10,000 psi water pressure the reduction in drag force was about 55 percent. Of the rocks tested, the limestone was least affected by the water jet. The cutting forces for the plow bit showed continuous change with wear so a machined conical bit was used for most of the testing. Tests with the plow bit did show a large reduction in cutting forces by using the water jet with worn bits. An economic analysis of equipping a drag bit tunnel boring machine indicated that the water jet system could reduce costs per foot in sandstone by up to 40 percent.

  16. Tunnel design considering stress release effect

    Institute of Scientific and Technical Information of China (English)

    Van-hung DAO

    2009-01-01

    In tunnel design,the determination of installation time and the stiffness of supporting structures is very important to the tunnel stability.This study used the convergence-confinement method to determine the stress and displacement of the tunnel while considering the counter-pressure curve of the ground base,the stress release effect,and the interaction between the tunnel lining and the rock surrounding the tunnel chamber.The results allowed for the determination of the installation time,distribution and strength of supporting structures.This method was applied to the intake tunnel in the Ban Ve Hydroelectric Power Plant,in Nghe An Province,Vietnam.The results show that when a suitable displacement u0 ranging from 0.0865 m to 0.0919 m occurrs,we can install supporting structures that satisfy the stability and economical requirements.

  17. Study on the Distribution Regularity of the Temperature of Sur-rounding Rock and Inner Gas at Tunnel in Paramo Area%高寒地区隧道围岩及洞内气体温度分布规律研究

    Institute of Scientific and Technical Information of China (English)

    邹一川; 夏才初; 张国柱

    2012-01-01

    文章依托内蒙古自治区绥满国道主干线博牙高速林场隧道工程,通过设置温度监测断面,对隧道洞内气温及不同部位、不同深度的围岩温度进行了监测分析。结果表明:(1)隧道洞内气温随时间呈三角函数变化;(2)离隧道洞口越远,洞内气温年平均值越高,年温度振幅越小;(3)隧道拱脚处的温度低于边墙、拱腰和拱顶的温度,在隧道未贯通时,拱脚与拱顶最大温差可达3℃。%Based on the Boya highway tunnel project in Suiman National road in Inner Mongolia,the article performs monitoring and analysis on temperature of the tunnel and surrounding rock under different areas and different depths by setting the temperature monitoring sec-tion.The result shows that:1.the temperature inside the tunnel changes with time by a trigo-nometric function;2.the farther away from the tunnel entrance,the higher of the average temperature inside the tunnel,and the smaller the temperature amplitude;3.The temperature at root pile is lower than that at side wall,haunch and vault.The largest temperature differ-ence between root pile and vault can reach 3℃ before tunnel opening.

  18. 隧道爆破开挖围岩动力损伤效应数值模拟%Numerical simulation of dynamic damage effect of surrounding rocks for tunnels by blasting excavation

    Institute of Scientific and Technical Information of China (English)

    左双英; 肖明; 续建科; 史文兵

    2011-01-01

    采用数值模拟技术预估岩体开裂深度及爆破损伤影响范围对工程设计可以起到事先指导作用,对施工安全具有重大意义,其中科学的、合理的损伤模型及迭代计算方法是关键.基于FLAC3D程序的用户自定义本构模块,将考虑累积应变和荷载作用时间的Yang-Liu率相关动力损伤模型与Mohr-Coulomb弹塑性本构进行耦合,将围岩破坏过程中的损伤特性反映在荷载增量迭代计算中,形成了弹塑性动力损伤本构模型,详细推导了损伤应力修正迭代计算方法.对一圆形隧道爆破开挖进行模拟,探讨了爆破诱发的质点振动衰减特征及围岩损伤分布规律.分析结果表明,爆破产生的质点振动速度峰值与其所造成的损伤具有很好的相关性.该爆破损伤模型及模拟方法可以为类似工程提供一定参考.%It can not only play a guiding role in engineering design in advance predicting the cracking depth and damaged range of surrounding rocks by blasting excavation in use of numerical simulation method, but also is of great significance to construction safety; in which, a scientific and reasonable damage model and iterative calculation method are most important key technique. Based on the user-defined constitutive modules of the fast Lagrangian analysis of continua in three dimensions (FLAC3D) procedure, Yang-Liu dynamic damage model dependent on strain rate considering cumulative strain and load time is embedded in Mohr-Coulomb elastoplastic model. The rock damage characteristic is reflected in the iteration calculation process of a incremental load; thus an elastoplastic dynamic damage constitutive model is formed. Subsequently, iterative format of damaged and modified stresses is derived in detail. In simulating a circular tunnel by blasting excavation, a discussion and analysis for characteristics of vibration attenuation and distribution rules of damage in surrounding rock mass induced by blasting are carried

  19. 随机介质理论下隧道围岩渐进破坏过程数值实验研究%Numerical Experiment Research on the Progressive Failure Process of the Surrounding Rock of the Tunnel under the Stochastic Medium Theory

    Institute of Scientific and Technical Information of China (English)

    商拥辉; 李航; 张波; 方前程

    2015-01-01

    The strength subtraction is introduced to safety evaluation of tunnel surrounding rock,combining with “the shallow tunnel rapid construction double small spacing tunnels,wear interchange structure under the shield tunnel and the surface of the structure containing joint,irregular fissure of mountain highway tunnel”engi-neering examples,using real damage of material analysis software RFPA -2D ,the finite element model of each strength reduction factor is set up.Viscoelastic artificial boundary is adopted to eliminate the influence of boundary conditions on the calculation precision in model,and the model achieves the mesoscopic structure unit of surround-ing rock of the mean and the defects of random distribution by means of random medium theory,it also reveals the dynamic gradual damage process of surrounding rock,the primitive phase change damage evolution mechanism and characteristics of rock mass structural plane under different working conditions,the mesoscopic damage of surround-ing rock is thought to be caused by non average of rock nonlinear material macroscopic unit,the calculation results judged in failure of tunnel surrounding rock with different step reduction in crack development trends and the num-ber of cell damage,and calculates safety factor in the sense of the safety reserve.At the same time,combining ABAQUS with RFPA -2D two different finite element models,comparatively analyzing the random medium theory and continuum theory combining strength subtraction in differences of the evaluation of surrounding rock stability.%将强度折减法引入到隧道围岩安全评价中,结合“浅埋暗挖快速施工双线小间距隧道、盾构下穿立交结构隧道和结构面含有节理、不规则裂隙的山体公路隧道”等工程实例,借助材料真实破坏分析软件 RFPA-2D,建立每个强度折减系数下的有限元模型。模型采用了黏弹性人工边界来消除边界条件对计算精度的影响,并借助随机介

  20. Strength and deformation properties of volcanic rocks in Iceland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Andreassen, Katrine Alling

    2016-01-01

    rock from Iceland has been the topic for rock mechanical studies carried out by Ice-landic guest students at the Department of Civil Engineering at the Technical University of Den-mark over a number of years in cooperation with University of Iceland, Vegagerðin (The Icelandic Road Directorate......) and Landsvirkjun (The National Power Company of Iceland). These projects involve engineering geological properties of volcanic rock in Iceland, rock mechanical testing and parameter evaluation. Upscaling to rock mass properties and modelling using Q- or GSI-methods have been studied by the students......Tunnelling work and preinvestigations for road traces require knowledge of the strength and de-formation properties of the rock material involved. This paper presents results related to tunnel-ling for Icelandic water power plants and road tunnels from a number of regions in Iceland. The volcanic...

  1. High- Speed railway lines in Germany: Experience in Tunnelling in Karstic Geology and Discussion oF Tunnel Driving Methods

    Institute of Scientific and Technical Information of China (English)

    Rudolf Pottler

    2004-01-01

    In the course of Deutsche Bahn's new high - speed railway line between Nuremberg and Ingolstadt, a number of tunnels are being constructed, with a total length of about 15 km. One of the longest tunnel is the 7,250 m long Irlahüll tunnel.The tunnel was driven in karst geology. It was not expected that karst phenomena would be so widespread. This forced client, designer and contractor to take a new approach to the project. Different tools were developed to handle the problems on site. Additional site investigations had to be performed to identify karst phenomena in the vicinity of the tunnel. For validating the stability and serviceability of the tunnel, a new way of defining the probability of failure of the construction had to be found. Based on the experience of the tunnel driving at the high - speed railway line in Germany between Nuremberg and Ingolstadt, two different methods of tunnelling are discussed: Drill and blast ( New Austrian Tunnelling Method: NATM) and the use of tunnel boring machines (TBM).

  2. Chemical characterization and ecotoxicity of three soil foaming agents used in mechanized tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Baderna, Diego, E-mail: diego.baderna@marionegri.it [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Lomazzi, Eleonora [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Passoni, Alice [Unit of Analytical Instrumentation, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Pogliaghi, Alberto; Petoumenou, Maria Ifigeneia [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Bagnati, Renzo [Unit of Analytical Instrumentation, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Lodi, Marco [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Viarengo, Aldo; Sforzini, Susanna [Department of Sciences and Technological Innovation (DiSIT), University of Piemonte Orientale “A. Avogadro”, 15121 Alessandria (Italy); Benfenati, Emilio [Laboratory of Environmental Chemistry and Toxicology, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy); Fanelli, Roberto [Department of Environmental Health Sciences, IRCCS – Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milan (Italy)

    2015-10-15

    Highlights: • An integrated approach was applied to study three foaming agents. • Several compounds not reported on the safety data sheets were identified by HRMS. • Environmental impacts were investigated with a battery of biological assays. • An ecotoxicological ranking of the products was obtained. - Abstract: The construction of tunnels and rocks with mechanized drills produces several tons of rocky debris that are today recycled as construction material or as soil replacement for covering rocky areas. The lack of accurate information about the environmental impact of these excavated rocks and foaming agents added during the excavation process has aroused increasing concern for ecosystems and human health. The present study proposes an integrated approach to the assessment of the potential environmental impact of three foaming agents containing different anionic surfactants and other polymers currently on the market and used in tunnel boring machines. The strategy includes chemical characterization with high resolution mass spectrometry techniques to identify the components of each product, the use of in silico tools to perform a similarity comparison among these compounds and some pollutants already listed in regulatory frameworks to identify possible threshold concentrations of contamination, and the application of a battery of ecotoxicological assays to investigate the impact of each foaming mixture on model organisms of soil (higher plants and Eisenia andrei) and water communities (Daphnia magna). The study identified eleven compounds not listed on the material safety data sheets for which we have identified possible concentrations of contamination based on existing regulatory references. The bioassays allowed us to determine the no effect concentrations (NOAECs) of the three mixtures, which were subsequently used as threshold concentration for the product in its entirety. The technical mixtures used in this study have a different degree of toxicity

  3. Chemical characterization and ecotoxicity of three soil foaming agents used in mechanized tunneling.

    Science.gov (United States)

    Baderna, Diego; Lomazzi, Eleonora; Passoni, Alice; Pogliaghi, Alberto; Petoumenou, Maria Ifigeneia; Bagnati, Renzo; Lodi, Marco; Viarengo, Aldo; Sforzini, Susanna; Benfenati, Emilio; Fanelli, Roberto

    2015-10-15

    The construction of tunnels and rocks with mechanized drills produces several tons of rocky debris that are today recycled as construction material or as soil replacement for covering rocky areas. The lack of accurate information about the environmental impact of these excavated rocks and foaming agents added during the excavation process has aroused increasing concern for ecosystems and human health. The present study proposes an integrated approach to the assessment of the potential environmental impact of three foaming agents containing different anionic surfactants and other polymers currently on the market and used in tunnel boring machines. The strategy includes chemical characterization with high resolution mass spectrometry techniques to identify the components of each product, the use of in silico tools to perform a similarity comparison among these compounds and some pollutants already listed in regulatory frameworks to identify possible threshold concentrations of contamination, and the application of a battery of ecotoxicological assays to investigate the impact of each foaming mixture on model organisms of soil (higher plants and Eisenia andrei) and water communities (Daphnia magna). The study identified eleven compounds not listed on the material safety data sheets for which we have identified possible concentrations of contamination based on existing regulatory references. The bioassays allowed us to determine the no effect concentrations (NOAECs) of the three mixtures, which were subsequently used as threshold concentration for the product in its entirety. The technical mixtures used in this study have a different degree of toxicity and the predicted environmental concentrations based on the conditions of use are lower than the NOAEC for soils but higher than the NOAEC for water, posing a potential risk to the waters due to the levels of foaming agents in the muck.

  4. Snow and ice blocking of tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Lia, Leif

    1998-12-31

    Hydroelectric power development in cold regions causes much concern about operational reliability and dam safety. This thesis studies the temperature distribution in tunnels by means of air temperature measurements in six tunnel spillways and five diversion tunnels. The measurements lasted for two consecutive winters. The air through flow tunnel is used as it causes cooling of both rock and water. In open spillway tunnels, frost reaches the entire tunnel. In spillway tunnels with walls, the frost zones reach about 100 m from the downstream end. In mildly-inclined diversion tunnels, a frost free zone is located in the middle of the tunnel and snow and ice problems were only observed in the inlet and outlet. Severe aufeis is accumulation is observed in the frost zones. The heat transfer from rock to air, water and ice is calculated and used in a prediction model for the calculation of aufeis build-up together with local field observation data. The water penetration of snow plugs is also calculated, based on the heat balance. It takes 20 to 50 days for water to enter the blocked tunnel. The empirical values are 30 to 60 days, but only 1 day if the temperature of the snow pack is 0{sup o}C. Sensitivity analyses are carried out for temperature variations in rock, snow, water and ice. Systematic field observation shows that it is important for hydropower companies to know about the effects of snow and ice blocking in an area. A risk analysis of dam safety is presented for a real case. Finally, the thesis proposes solutions which can reduce the snow and ice problems. 79 refs., 63 figs., 11 tabs.

  5. Effect of centrifugal forces on dimensional error of bored shapes

    Science.gov (United States)

    Arsuaga, M.; de Lacalle, L. N. López; Lobato, R.; Urbikain, G.; Campa, F.

    2012-04-01

    Boring operations of deep holes with a slender boring bar are often hindered by the precision because of their low static stiffness and high deformations. Because of that, it is not possible to remove much larger depths of cuts than the nose radius of the tool, unlike the case of turning and face milling operations, and consequently, the relationship between the cutting force distribution, tool geometry, feed rate and depth of cut becomes non-linear and complex. This problem gets worse when working with a rotating boring head where apart from the cutting forces and the variation of the inclination angle because of shape boring, the bar and head are affected by de centrifugal forces. The centrifugal forces, and therefore the centrifugal deflection, will vary as a function of the rotating speed, boring bar mass distribution and variable radial position of the bar in shape boring. Taking in to account all this effects, a load and deformation model was created. This model has been experimentally validated to use as a corrector factor of the radial position of the U axis in the boring head.

  6. Rock fill in a KBS-3 repository. Rock material for filling of shafts and ramps in a KBS-3V repository in the closure phase

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland (Geodevelopment International AB/SWECO AB, Lund (Sweden))

    2008-09-15

    The content of large blocks in blasted rock makes it impossible to fill and compact the material effectively unless those larger than about 500 mm are removed. Tunnel Boring Machine (TBM) muck gives flat chips, that are usually not longer than a couple of decimeters, and serves better as backfill. The granulometrical composition of both types can be more suitable for effective compaction by crushing, which is hence a preferable process. Use of unsorted, unprocessed blasted rock can only be accepted if the density and physical properties, like self-compaction, are not important. Crushing of blasted rock and TBM muck for backfilling can be made in one or two steps depending on the required gradation. Placement of rock fill is best made by use of tractors with blades that push the material forwards over already placed and compacted material. The dry density of well graded rock fill effectively compacted by very heavy vibratory rollers can be as high as 2,400 kg/m3. For road compaction by ordinary vibratory rollers common dry density values are in the interval 2,050 to 2,200 kg m3. Blasted rock dumped and moved on site by tractors can get an average dry density of 1,600-1,800 kg/m3 without compaction. Crushed, blasted rock and TBM muck placed by tractors in horizontal layers and compacted by 5-10 t vibrating rollers in the lower part of the rooms, and moved by tractors to form inclined layers compacted by vibrating plates in the upper part, would get a dry density of 1,900-2,000 kg/m3. Flushing water over the rock fill in conjunction with the compaction work gives more effective densification than dry compaction. Based on recorded settlement of Norwegian rock fill dams constructed with water flushing it is estimated that the self-compaction of a 5 m high backfill of crushed rock or TBM muck causes a settlement of the top of the backfill of about 8 mm while a 200 m high shaft fill would undergo compression by more than half a meter. Repeated, strong earthquakes may

  7. Osedax borings in fossil marine bird bones

    Science.gov (United States)

    Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L.

    2011-01-01

    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth's history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

  8. Comparative analyses of model tests and in-situ monitoring of zonal disintegration of rock mass in deep tunnels%深部巷道围岩分区破裂现象的试验与现场监测对比分析研究

    Institute of Scientific and Technical Information of China (English)

    陈旭光; 张强勇; 杨文东; 李术才; 刘德军; 王汉鹏

    2011-01-01

    With the development of national economy and the drying up of shallow resources, the embedded depth of rock mass engineering becomes more and more deep. The phenomenon of zonal disintegration appears and is monitored in surrounding rock mass of deep tunnels. The special geological engineering phenomenon has attracted scholars' great attention in the field rock mechanics. However, the knowledge on the fracture shape and forming mechanism of the zonal disintegration is not quite enough. There is doubt about whether or not the connection on the in-situ TV observation can represent the whole tunnel impersonally. There is argument that the fractured zones are the concentric circle of the cavity or the spirals and slip lines- The issue determines the essence of the zonal disintegration and whether or not it is an unexplained new phenomenon by using the theory in existence. In order to know about the phenomenon in substance, geo-mechanical model tests are carried out on the deep mine tunnel of Dingji Coal Mine in Huainan Mine area. Comparing the results of in-situ monitoring with those of model tests, the main characteristics and changing laws of the zonal disintegration are summarized. The zonal disintegration is the circular pull fracture which is concentric to the cavity. The research results are important for understanding the failure modes and revealing the deformation and failure mechanism of surrounding rock mass in deep tunnels.%为了从本质上认识一些深部巷道中出现的围岩破裂区和完整区间隔排列的分区破裂现象.以淮南矿区丁集煤矿深部巷道工程为研究对象进行了模型试验研究.并通过对现场监测结果和模型试验结果的对比研究与相互验证,归纳分析出了分区破裂现象的主要特征和变化规律,指出分区破裂是与洞室呈同心圆的环状拉破坏断裂.研究结果对于认识深部洞室围岩的破坏方式,揭示深部洞室围岩的变形破坏机理具有重要意义.

  9. Numerical analysis of surface subsidence in asymmetric parallel highway tunnels

    Directory of Open Access Journals (Sweden)

    Ratan Das

    2017-02-01

    Full Text Available Tunnelling related hazards are very common in the Himalayan terrain and a number of such instances have been reported. Several twin tunnels are being planned for transportation purposes which will require good understanding for prediction of tunnel deformation and surface settlement during the engineering life of the structure. The deformational behaviour, design of sequential excavation and support of any jointed rock mass are challenging during underground construction. We have raised several commonly assumed issues while performing stability analysis of underground opening at shallow depth. For this purpose, Kainchi-mod Nerchowck twin tunnels (Himachal Pradesh, India are taken for in-depth analysis of the stability of two asymmetric tunnels to address the influence of topography, twin tunnel dimension and geometry. The host rock encountered during excavation is composed mainly of moderately to highly jointed grey sandstone, maroon sandstone and siltstones. In contrast to equidimensional tunnels where the maximum subsidence is observed vertically above the centreline of the tunnel, the result from the present study shows shifting of the maximum subsidence away from the tunnel centreline. The maximum subsidence of 0.99 mm is observed at 4.54 m left to the escape tunnel centreline whereas the maximum subsidence of 3.14 mm is observed at 8.89 m right to the main tunnel centreline. This shifting clearly indicates the influence of undulating topography and in-equidimensional noncircular tunnel.

  10. Collecting Rocks

    Institute of Scientific and Technical Information of China (English)

    孙铮

    2007-01-01

    My hobby is collecting rocks.It is very special,isn’t it?I began to collect rocks about four years ago.I usually go hiking in the mountains,or near the river to look for rocks.When I find a rock,I pick it up and clean it with the brush and water.Then I put it into my bag.Most of the rocks I have collected are quartzite~*.They are really

  11. 液压钻车与履带式挖掘机配套技术在大断面岩巷掘进中的应用%Application of Hydraulic Drilling and Supporting Technologies Crawler Excavators in Heavy Section Rock Lane Boring

    Institute of Scientific and Technical Information of China (English)

    常春锋

    2013-01-01

      五阳煤矿的现有资源濒临枯竭,扩区工程迫在眉睫,如何实现大断面岩巷的快速掘进,直接决定了扩区的开发进度。五阳煤矿以中央胶带大巷为试点,通过引入全液压钻车与履带式挖掘机等设备,经过优化爆破参数、改良施工工序和合理安排劳动组织等方法,在大断面岩巷炮掘方面实现了大的提升。%The current resources of Wuyang Coal Mine have become critically depleted ,and expanding area engineering was imminent , it directly determines the progress of the development of expansion by how to realize the rapid excavation of large cross section rock roadway.It makes central belt roadway of Wuyang Coal Mine a experimental unit ,and it optimized blasting parameters and improved construction process and made reasonable arrangement of labor organization and other methods ,and it achieved a big promotion of heavy section rock lane blasting.

  12. Experiments at the Aespoe Hard Rock Laboratory[Information for the general public

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-12-01

    A dress rehearsal is being held in preparation for the construction of a deep repository for spent nuclear fuel at SKB's underground Hard Rock Laboratory (HRL) on Aespoe, outside Oskarshamn. Here we can test different technical solutions on a full scale and in a realistic environment. The Aespoe HRL is also used for field research. We are conducting a number of experiments here in collaboration with Swedish and international experts. In the Zedex experiment we have compared how the rock is affected around a drill-and-blast tunnel versus a bored tunnel. In a new experiment we will investigate how much the rock can take. A narrow pillar between two boreholes will be loaded to the point that the rock's ultimate strength is exceeded (Aespoe Pillar Stability Experiment). In the Demo Test we are demonstrating emplacement of the copper canisters and the surrounding bentonite in the deposition holes. In the Prototype Repository we study what long-term changes occur in the barriers under the conditions prevailing in a deep repository. Horizontal deposition: Is it possible to deposit the canisters horizontally without compromising safety? Backfill and Plug Test: The tunnels in the future deep repository for spent nuclear fuel will be filled with clay and crushed rock and then plugged. Canister Retrieval Test: If the deep repository should not perform satisfactorily for some reason, we want to be able to retrieve the spent fuel. The Lot test is intended to show how the bentonite behaves in an environment similar to that in the future deep repository. The purpose of the TBT test is to determine how the bentonite clay in the buffer is affected by high temperatures. Two-phase flow means that liberated gas in the groundwater flows separately in the fractures in the rock. This reduces the capacity of the rock to conduct water. Lasgit: By pressurizing a canister with helium, we can measure how the gas moves through the surrounding buffer. Colloid Project: Can very small

  13. Experiments at the Aespoe Hard Rock Laboratory[Information for the general public

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-12-01

    A dress rehearsal is being held in preparation for the construction of a deep repository for spent nuclear fuel at SKB's underground Hard Rock Laboratory (HRL) on Aespoe, outside Oskarshamn. Here we can test different technical solutions on a full scale and in a realistic environment. The Aespoe HRL is also used for field research. We are conducting a number of experiments here in collaboration with Swedish and international experts. In the Zedex experiment we have compared how the rock is affected around a drill-and-blast tunnel versus a bored tunnel. In a new experiment we will investigate how much the rock can take. A narrow pillar between two boreholes will be loaded to the point that the rock's ultimate strength is exceeded (Aespoe Pillar Stability Experiment). In the Demo Test we are demonstrating emplacement of the copper canisters and the surrounding bentonite in the deposition holes. In the Prototype Repository we study what long-term changes occur in the barriers under the conditions prevailing in a deep repository. Horizontal deposition: Is it possible to deposit the canisters horizontally without compromising safety? Backfill and Plug Test: The tunnels in the future deep repository for spent nuclear fuel will be filled with clay and crushed rock and then plugged. Canister Retrieval Test: If the deep repository should not perform satisfactorily for some reason, we want to be able to retrieve the spent fuel. The Lot test is intended to show how the bentonite behaves in an environment similar to that in the future deep repository. The purpose of the TBT test is to determine how the bentonite clay in the buffer is affected by high temperatures. Two-phase flow means that liberated gas in the groundwater flows separately in the fractures in the rock. This reduces the capacity of the rock to conduct water. Lasgit: By pressurizing a canister with helium, we can measure how the gas moves through the surrounding buffer. Colloid Project: Can very small

  14. Influence of pressure conditions and back-filling materials on the durability of bore-hole ground loops; Lebensdauer von Erdwaermesonden in Bezug auf Druckverhaeltnisse und Hinterfuellung

    Energy Technology Data Exchange (ETDEWEB)

    Rohner, R. [E. Rohner, Arnegg (Switzerland); Rybach, L.; Salton, M. [Swiss Federal Institute of Technology (ETHZ), Institut fuer Geophysik, Zuerich (Switzerland)

    2001-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses the influence of the relatively high pressures found in ground loops at depths of more than 200 metres and the effects caused by overloading the ground loops. The latter can cause the back-filling between the ground loop and the surrounding rock to freeze. The report describes tests carried out on 70-metre and 265-metre deep test bore-hole installations. The results of investigations into the influence of such pressure conditions on the materials of the ground loop and their service life are presented. The results are also compared with simulations using the FRACTure and EED calculation programmes. Details are given on the bore-holes with respect to their geology and construction. The report concludes that bore-hole ground loops can be considered as being very robust components with a long service life, provided they are designed and installed according to accepted professional standards.

  15. Tunnels: different construction methods and its use for pipelines installation

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Tales; Soares, Ana Cecilia; Assis, Slow de; Bolsonaro, Ralfo; Sanandres, Simon [Petroleo do Brasil S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    In a continental dimensions country like Brazil, the pipeline modal faces the challenge of opening ROW's in the most different kind of soils with the most different geomorphology. To safely fulfill the pipeline construction demand, the ROW opening uses all techniques in earthworks and route definition and, where is necessary, no digging techniques like horizontal directional drilling, micro tunneling and also full size tunnels design for pipelines installation in high topography terrains to avoid geotechnical risks. PETROBRAS has already used the tunnel technique to cross higher terrains with great construction difficult, and mainly to make it pipeline maintenance and operation easier. For the GASBOL Project, in Aparados da Serra region and in GASYRG, in Bolivia, two tunnels were opened with approximately 700 meters and 2,000 meters each one. The GASBOL Project had the particularity of being a gallery with only one excavation face, finishing under the hill and from this point was drilled a vertical shaft was drilled until the top to install the pipeline section, while in GASYRG Project the tunnel had two excavation faces. Currently, two projects are under development with tunnels, one of then is the Caraguatatuba-Taubate gas pipeline (GASTAU), with a 5 km tunnel, with the same concepts of the GASBOL tunnel, with a gallery to be opened with the use of a TBM (Tunneling Boring Machine), and a shaft to the surface, and the gas pipeline Cabiunas-Reduc III (GASDUC III) project is under construction with a 3.7 km tunnel, like the GASYRG tunnel with two faces. This paper presents the main excavation tunneling methods, conventional and mechanized, presenting the most relevant characteristics from both and, in particular, the use of tunnels for pipelines installation. (author)

  16. Numerical investigation of fracture behavior of tunnel by excavation loading

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; TANG Chun-an; MA Tian-hui; DUAN Dong

    2007-01-01

    A rock failure process analysis model, RFPA2D code, a two-dimensional numerical code, were proposed. The code not only satisfied the global equilibrium, strain consistent and nonlinear constitutive relationship of rock and soil materials but also took into account the heterogeneous characteristics of rock materials at macroscopic and microscopically level. The failure behavior of tunnel could be simulated by this numerical model. The model could realistically simulate the fracture behavior of tunnel by excavation loading, strength limits, and post peak response for both tension and compression. As the proposed method was used to conduct the stability analysis of tunnel, the safety factor of tunnel was defined as the ratio of actual shear strength parameter to critical failure shear strength parameter. Not only the safety factor of tunnel with specific physics meaning can be obtained, but also the overall failure process and the location of failure surface may also be determined at the same time.

  17. REINFORCING MECHANISM AND SIMULATING METHOD FOR REINFORCING EFFECTS OF SYSTEMICALLY GROUTED BOLTS IN DEEP-BURIED HARD ROCK TUNNELS%深埋硬岩隧洞系统砂浆锚杆的加固机制与加固效果模拟方法

    Institute of Scientific and Technical Information of China (English)

    吴文平; 冯夏庭; 张传庆; 邱士利; 李占海

    2012-01-01

    Systematically grouted bolts, as the main support structure of deep-buried hard rock tunnels, compose the bolt-rock composite structure with surrounding rocks. which reinforces the mechanical property of surrounding rocks. Based on the Mohr-Coulomb(M-C) criterion, the stress condition and the strength of the composite structure meeting the M-C criterion were derived under high-stress conditions. Combining with the rock mass deterioration model(RDM) of brittle rock, an approach to determine the mechanical parameters of the composite structure was presented. The difference of mechanical parameters between two different composite structures of bolt-elastic surrounding rock and bolt-yielding surrounding rock was taken into account. In this approach, the mechanical parameters of the bolt-yielding surrounding rock composite structure were associated with present equivalent plastic strain of surrounding rocks. A numerical method, which could model the reinforcing effect of normally grouted bolts laid out systematically during excavating and supporting stages, was proposed. It is identified that this method has an advantage over other methods in modeling the effect of supporting time on surrounding rock stability. Finally, the method was applied to evaluate the stability of surrounding rocks, and related references were provided for design and construction of the diversion tunnel #2 of Jinping Ⅱ hydropower station.%系统布置的砂浆锚杆是深埋硬岩隧洞主要支护结构,锚杆与围岩组成锚杆-围岩复合结构体,使围岩的力学特性得到改善.基于岩体的莫尔-库仑(M-C)屈服准则,推导锚杆-围岩复合结构体满足M-C准则的应力条件.结合岩体劣化本构模型,提出确定锚杆-围岩复合结构体力学参数的方法.锚杆与弹性围岩和屈服围岩组成的锚杆-围岩复合结构体的力学参数确定方法不同,锚杆与屈服围岩组成的锚杆-围岩复合结构体的力学参数与围岩当前状态的等

  18. Concept development for HLW disposal research tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Queon, S. K.; Kim, K. S.; Park, J. H.; Jeo, W. J.; Han, P. S. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    In order to dispose high-level radioactive waste in a geological formation, it is necessary to assess the safety of a disposal concept by excavating a research tunnel in the same geological formation as the host rock mass. The design concept of a research tunnel depends on the actual disposal concept, repository geometry, experiments to be carried at the tunnel, and geological conditions. In this study, analysis of the characteristics of the disposal research tunnel, which is planned to be constructed at KAERI site, calculation of the influence of basting impact on neighbor facilities, and computer simuation for mechanical stability analysis using a three-dimensional code, FLAC3D, had been carried out to develop the design concept of the research tunnel.

  19. Rock Stars

    Institute of Scientific and Technical Information of China (English)

    张国平

    2000-01-01

    Around the world young people are spending unbelievable sums of money to listen to rock music. Forbes Magazine reports that at least fifty rock stars have incomes between two million and six million dollars per year.

  20. KREEP Rocks

    Institute of Scientific and Technical Information of China (English)

    邹永廖; 徐琳; 欧阳自远

    2004-01-01

    KREEP rocks with high contents of K, REE and P were first recognized in Apollo-12 samples, and it was confirmed later that there were KREEP rock fragments in all of the Apollo samples, particularly in Apollo-12 and-14 samples. The KREEP rocks distributed on the lunar surface are the very important objects of study on the evolution of the moon, as well as to evaluate the utilization prospect of REE in KREEP rocks. Based on previous studies and lunar exploration data, the authors analyzed the chemical and mineral characteristics of KREEP rocks, the abundance of Th on the lunar surface materials, the correlation between Th and REE of KREEP rocks in abundance, studied the distribution regions of KREEP rocks on the lunar surface, and further evaluated the utilization prospect of REE in KREEP rocks.

  1. Monitoring the moisture condition in a tunnel lining with help of MREs

    NARCIS (Netherlands)

    Visser, J.H.M.; Polder, R.B.; Peelen, W.H.A.

    2009-01-01

    A dummy segment from a bored tunnel with cast-in MREs was used to investigate if the moisture content of the concrete lining could be determined. The results were compared with two other in-situ resistivity measurements and correlated to the moisture content measured on cores drilled from the dummy

  2. A maintenance concept for concrete tunnel linings in soft soil conditions

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Leegwater, G.; Polder, R.B.

    2008-01-01

    In the European project TUNCONSTRUCT a life cycle cost method for management and maintenance of underground structures is developed. Within the project TNO is concerned with the durability of the concrete lining. In this paper the concept is explained by means of a case of a bored road tunnel (in so

  3. A maintenance concept for concrete tunnel linings in soft soil conditions

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Leegwater, G.; Polder, R.B.

    2008-01-01

    In the European project TUNCONSTRUCT a life cycle cost method for management and maintenance of underground structures is developed. Within the project TNO is concerned with the durability of the concrete lining. In this paper the concept is explained by means of a case of a bored road tunnel (in

  4. Rockburst Generation in Discontinuous Rock Masses

    Science.gov (United States)

    He, Ben-Guo; Zelig, Ravit; Hatzor, Yossef H.; Feng, Xia-Ting

    2016-10-01

    We study rockburst generation in discontinuous rock masses using theoretical and numerical approaches. We begin by developing an analytical solution for the energy change due to tunneling in a continuous rock mass using linear elasticity. We show that the affected zone where most of the increase in elastic strain energy takes place is restricted to an annulus that extends to a distance of three diameters from the tunnel center, regardless of initial tunnel diameter, magnitude of in situ stress, and in situ stress ratio. By considering local elastic strain concentrations, we further delineate the Rockbursting Prone Zone found to be concentrated in an annulus that extends to one diameter from the tunnel center, regardless of original stress ratio, magnitude, and the stiffness of the rock mass. We proceed by arguing that in initially discontinuous rock masses shear stress amplification due to tunneling will inevitably trigger block displacements along preexisting discontinuities much before shear failure of intact rock elements will ensue, because of the lower shear strength of discontinuities with respect to intact rock elements, provided of course that the blocks are removable. We employ the numerical discrete element DDA method to obtain, quantitatively, the kinetic energy, the elastic strain energy, and the dissipated energy in the affected zone in a discontinuous rock due to tunneling. We show that the kinetic energy of ejected blocks due to strain relaxation increases with increasing initial stress and with decreasing frictional resistance of preexisting discontinuities. Finally, we demonstrate how controlled strain energy release by means of top heading and bench excavation methodology can assist in mitigating rockburst hazards due to stain relaxation.

  5. Rock Art

    Science.gov (United States)

    Henn, Cynthia A.

    2004-01-01

    There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

  6. Rock Art

    Science.gov (United States)

    Henn, Cynthia A.

    2004-01-01

    There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

  7. Rock Finding

    Science.gov (United States)

    Rommel-Esham, Katie; Constable, Susan D.

    2006-01-01

    In this article, the authors discuss a literature-based activity that helps students discover the importance of making detailed observations. In an inspiring children's classic book, "Everybody Needs a Rock" by Byrd Baylor (1974), the author invites readers to go "rock finding," laying out 10 rules for finding a "perfect" rock. In this way, the…

  8. Crude oil underground stockpiling projects being completed. ; First underground rock-bed tank in Japan. Kansei majikana chika sekiyu bichiku project. ; Nippon de saisho no chika ganban tank

    Energy Technology Data Exchange (ETDEWEB)

    Tokimasa, H. (Japan Natinal Oil Corp., Tokyo (Japan)); Makita, T. (Japan Underground Oil Storage Co. Ltd., Tokyo (Japan))

    1993-07-15

    Three crude oil underground stockpiling projects in Japan were outlined. The cavity was dug in base rock below underground water level to store crude oil in it as dug. The water sealing system by natural or artificial underground water pressure was adopted to prevent from water leakage, and the most stable egg figure was also adopted for the cavity cross section. In the Kuji area, Iwate-Pref., the water sealing tunnel and boring were constructed over the cavity before main digging to keep an underground water level and decrease a rock permeability because of more permeable base rock including a large amount of cracks. In the Kikuma area, Ehime-Pref., since there are an oil refinery and many residents near the Cavity, various environmental measures were necessary in digging. In the Kusikino area, Kagoshima-Pref., since a new fault was found during digging, the cross section figure was modified, and grouting was also adopted because of a large amount of spring water. 6 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lindeboom, H.

    1982-06-15

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

  10. Reliability analysis of idealized tunnel support system using probability-based methods with case studies

    NARCIS (Netherlands)

    Gharouni-Nik, M.; Naeimi, M.; Ahadi, S.; Alimoradi, Z.

    2014-01-01

    In order to determine the overall safety of a tunnel support lining, a reliability-based approach is presented in this paper. Support elements in jointed rock tunnels are provided to control the ground movement caused by stress redistribution during the tunnel drive. Main support elements contribute

  11. 谈六盘山隧道软岩大变形段施工处理技术%On large deformation section construction treatment technique of Liupanshan Tunnel soft rock

    Institute of Scientific and Technical Information of China (English)

    刘胜锁

    2015-01-01

    Combining with Liupanshan Tunnel large deformation engineering example,the paper analyzes reasons for tunnel deformation,and makes out factual treatment measures and methods according to the tunnel large deformation features,so as to provide some reference for similar large deformation section construction treatment.%结合六盘山隧道大变形工程实例,对隧道大变形产生的原因进行了分析,并依据隧道大变形特征,制定了具体的处理措施与方法,对同类隧道大变形段施工处理有一定的参考价值。

  12. 溜管抛石精度控制技术及在港珠澳大桥隧道基础施工中的应用%Accuracy control techniques of fall pipe rock dumping and its application in tunnel foundation construction of the Hongkong- Zhuhai- Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    梁天戈; 伍绍博; 苏怀平

    2015-01-01

    Fall pipe rock dumping is used in the deepwater construction, it can ensure the safety and stability of subsea facilities effectively. We discussed the development in accuracy control techniques of fall pipe rock dumping, include the development of dumping vessel with its technologies, the application of seabed survey integrating system, fall pipe rock dumping system with its related instruments. We focused on the accuracy control management system of fall pipe rock dumping in the island and tunnel project of the Hongkong-Zhuhai-Macao Bridge, analyzed the accuracy of all pipe rock dumping using the data from a typical construction. The improvement and development of the accuracy control techniques in this project were reflected.%溜管抛石施工工艺用于深水作业,是保障水下设施安全性、稳定性的有效施工手段。文章叙述了溜管抛石精度控制技术的发展现状,主要包括抛石船及相关技术发展、海床测量集成系统和溜管抛石系统及仪器应用,重点阐述在港珠澳大桥岛隧工程中溜管抛石系统化精度控制管理,采用典型施工期实测数据分析溜管抛石精度,说明溜管抛石精度控制技术的提高与发展。

  13. Mechanism of zonal disintegration in surrounding rock mass around deep rock engineering and its application

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The mechanical behaviors of deep rock mass are different from those of shallow rock mass.Through cases of Jinping II Hydropower Station,the special phenomenon of zonal disintegration in the surrounding rock mass around the diversion tunnels,is analyzed.On the basis of fracture mechanics,a new strength criterion for deep rock mass is derived.The new nonlinear strength criterion that is relative to the rock mass rating classification can be applied to the study of the tensile failure of deep rock mass.Subsequently,zonal disintegration model is established,and the radius of fractured zone and none-fractured zone of deep surrounding rock mass around cylindrical tunnel are obtained,their exact positions and the evolution law of zonal disintegration of surrounding rock mass is determined.To validate the present model,comparison between calculation results and the experiment observation on facture and failure around underground openings is carried out.It is found that the numerical simulation result is in good agreement with the experimental one on failure modes around the hole.Through sensitivity analysis,the effects of stress condition,cohesion and the angle of internal friction on the phenomenon of zonal disintegration are determined.Finally,the present model is adopted in the analysis of the zonal disintegration in the surrounding rock mass around the diversion tunnels in Jinping II Hydropower Station.Meanwhile,the magnitude and distributions of fractured zones are determined by numerical simulation.

  14. Small-bore hypervelocity Electromagnetic Launcher research facility

    Science.gov (United States)

    Hurn, T. W.; Chapelle, S.; Lupan, S. P.; Holland, L.; Homeyer, W. G.; Rawls, J. M.

    1993-01-01

    A small-bore hypervelocity Electromagnetic Launcher laboratory research facility has been developed which has launched a 2-g projectile to a velocity in excess of 3.5 km/sec. This turn-key laboratory includes a 1 cm, square-bore railgun with a helium gas preaccelerator; a modular 328 kJ capacitor bank; a fiber-optically linked programmable logic control system with a graphical operator interface; a data acquisition system with current, magnetic, and projectile position diagnostics; and a flight range which provides in-flight velocity measurements and safely stops and contains the projectile. The control system fires the preaccelerator and, on receipt of an optical signal, fires the capacitor bank modules simultaneously or in a staggered mode. Armature separation and stalling limit the overall performance of the system. Changes in pulse shape and bore materials significantly improved performance. Attention is given to methods used to minimize armature separation and improve performance.

  15. Design of a 20 T, 200 mm bore resistive magnet

    Energy Technology Data Exchange (ETDEWEB)

    Gao, B.J.; Bird, M.D.; Bole, S.; Eyssa, Y.M.; Schneider-Muntau, H.J. [National High Magnetic Field Lab., Tallahassee, FL (United States)

    1996-07-01

    A 20 tesla, three coil, 200 mm bore, 20 MW resistive magnet is being designed at the National High Magnetic Field Laboratory in Tallahassee, FL., USA, in cooperation with the High Magnetic Field Laboratory of Grenoble, France. The outer two coils are axially-cooled and are connected electrically in series producing a central field of 11.27 T in a 365 mm warm bore while consuming 13.5 MW of power. The 6.5 MW inner coil (insert) is a poly-Bitter design with two sub-coils connected electrically in parallel and they together are connected in series to the two outer coils. The field of the inner coil is 8.78 T resulting in a 20 T total field in a 200 mm warm bore. All four coils are made of hard copper.

  16. Pressure versus current scaling in a blocked bore rail gun

    Science.gov (United States)

    Barrett, B. D.; Eubank, Eric; Nunnally, W. C.

    1993-07-01

    The paper presents experimental results from a blocked bore plasma armature rail gun. A piezoelectric transducer mounted in the bore blocking structure recorded time-resolved pressures over a range of input currents from 50 to 150 kA. The bore block is located at four positions where peak current occurs for the four respective charging voltages to power the system. Problems associated with obtaining these measurements and the solutions employed are discussed. Average distances from the block face to the armature current centroid are estimated assuming a pressure balance between the magnetic and neutral pressures. The averages of the measured pressures were found to be proportional to the input current raised to the power of 1.655.

  17. Dimension effects in plasma immersion ion implantation of cylindrical bore

    CERN Document Server

    Tian Xiu Bo; Tong Hong Hui; Chu, P K

    2002-01-01

    Plasma immersion ion implantation is a new technique pertaining to ion implantation. Different from the case of exterior surface treatment, plasma immersion ion implantation of interior surface possesses dimension effects. Consequently it is a challenge to implant the inner wall of a cylindrical bore due to this finite dimension.The ion energy cannot be linearly changed with applied voltage and there exists a saturation value due to overlap effect of plasma sheath. The plasma in the bore may rapidly be depleted, which is attributed to finite plasma volume and plasma-sheath con-flowing effect. For instance the plasma depletion time is about 0.55 mu s when a bore with a diameter of 20 cm is treated under conditions of applied voltage of 30 kV and plasma density of 2 x 10 sup 1 sup 5 ions/cm sup 3. Interior plasma-source hardware may be an effective solution

  18. 'Escher' Rock

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

  19. 'Escher' Rock

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

  20. Carpal Tunnel Syndrome

    Science.gov (United States)

    ... arm. Just a passing cramp? It could be carpal tunnel syndrome. The carpal tunnel is a narrow passageway of ligament and ... difficult. Often, the cause is having a smaller carpal tunnel than other people do. Other causes include ...

  1. Physical Simulation for Large-Bore Copper Vapor Laser

    Institute of Scientific and Technical Information of China (English)

    YU De-Li; WANG Run-Wen; TAO Yong-Xiang

    2000-01-01

    On the basis of the electric circuit differential equations and the nonlinear partial differential equations of kinetics,a kinetic model for a series of large-bore copper-vapor lasers is carried out. Through the consistent computational results the radial kinetic parameters such as the stimulating electric field and the plasma electron temperature are presented. The factors, which evidently influence the output power and the beam quality of the large-bore copper-vapor laser, are the buffer gas pressure and the charging voltage.

  2. Does Polishing a Rifle Bore Reduce Bullet Drag?

    Science.gov (United States)

    2012-01-17

    thus lower drag. A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore Boat...drag on the bullets. 15. SUBJECT TERMS Ballistic coefficient, aerodynamic drag, rifle bore, bore polishing, Remington 700 5R 16. SECURITY...A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore Boat Tail and a 125

  3. Melioidosis from contaminated bore water and successful UV sterilization.

    Science.gov (United States)

    McRobb, Evan; Kaestli, Mirjam; Mayo, Mark; Price, Erin P; Sarovich, Derek S; Godoy, Daniel; Spratt, Brian G; Currie, Bart J

    2013-08-01

    Two cases of melioidosis at a residence in rural northern Australia were linked to the unchlorinated domestic bore (automated well) water supply, which was found to have a high concentration of Burkholderia pseudomallei. Using multilocus sequence typing, clinical B. pseudomallei isolates from both cases were identical to an isolate from the bore water supply. A simple UV sterilizer reduced B. pseudomallei from the domestic water supply to undetectable levels. We have shown that UV treatment is highly effective for remediation of water contaminated with B. pseudomallei and recommend its consideration in households where individuals may be at heightened risk of contracting melioidosis.

  4. Analysis of the phenomenon of material expansiveness in tunnels built in anhydrite. Outcomes and experiences

    Directory of Open Access Journals (Sweden)

    del Campo, J. M.

    2012-12-01

    Full Text Available The serious geotechnical problems arising in many tunnels bored in material giving rise to stability problems as a result of being expansive, makes the water channelizers. These are materials which are easily washed with sulphates dissolving with water causing the massif to become decompressed and to remould, aggravating and transferring the problem beyond the tunnel’s immediate environment. In the particular case of layers of anhydrite between argillite, it also happens that the primary support and subsequent lining must have exceptional strength to resist the pressures the terrain may transmit in the medium to long term. This article describes the most relevant aspects of the hydromechanical behaviour of sulphated soil and rock and presents some experiments, concluding with various aspects associated to the phenomenon of swelling in tunnels and its possible treatment.

    Los graves problemas geotécnicos sucedidos en numerosos túneles europeos excavados en materiales que generan problemas de estabilidad, como consecuencia de su expansividad, los convierten en canalizadores de aguas. Estos materiales son fácilmente lavables al disolverse los sulfatos con el agua, provocando una decompresión y remoldeo del macizo, agravando y trasladando el problema más allá del inmediato entorno del túnel. En el caso particular de presencia de capas de anhidrita entre argilitas, además de la adopción de medidas de sostenimiento y revestimiento especiales, el sostenimiento primario y el revestimiento posterior deben ser excepcionalmente resistentes a las presiones que pueden llegar a transmitir el terreno a medio y largo plazo. En este artículo se describen los aspectos más relevantes de comportamiento hidromecánico de los suelos y las rocas sulfatadas y se presentan algunas experiencias, concluyendo sobre aspectos asociados al fenómeno de hinchamiento en túneles y su posible tratamiento.

  5. 'Earhart' Rock

    Science.gov (United States)

    2004-01-01

    This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock informally named 'Earhart' on the lower slopes of 'Endurance Crater.' The rock was named after the pilot Amelia Earhart. Like 'Escher' and other rocks dotting the bottom of Endurance, scientists believe fractures in Earhart could have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Rover team members do not have plans to investigate Earhart in detail because it is located across potentially hazardous sandy terrain. This image was taken on sol 219 (Sept. 4) by the rover's panoramic camera, using its 750-, 530- and 430-nanometer filters.

  6. Bore hole image well logging technique

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Young Kwon; Kim, Geon Young; Bae, Dae Seok; Kim, Kyung Su; Ryu, Ji Hoon; Park, Kyung Woo; Ji, Sung Hoon

    2009-08-15

    As one of the investigation method which the underground geological features is direct drill investigation geological features condition of underground directness it will can confirm visually there is a strong point but the drill nose in compliance with war potential or a shock from the digging through process which it knows the orientation scattering, or, the capital where the destruction action which is mechanical will accompany it will be, also to the case where the ground condition is defective the nose Oh there is a possibility of being difficult also oneself getting to the evaluation which ground is accurate with being difficult, it operated and it was come. As the method which solves like this problem drill worker image photographing which is the possibility of getting the burn was introduced in about the drill worker wall. Drill worker image photographing it will be able to classify with 3 kind of electricity, the sound wave and optical science etc. on a large scale and these people are controlled and respectively amplitude and staring reaction of electric resistivity reaction and the sound wave, in order for the pixel price which digitizes optical science photograph etc. to confront clearly in spatial location it will be able to provide information concretely about rock floor etc., discontinuity surface situation and of the public wall travelling and inclination and the clearance

  7. Rock Art

    OpenAIRE

    Huyge, Dirk

    2009-01-01

    Rock art, basically being non-utilitarian, non-textual anthropic markings on natural rock surfaces, was an extremely widespread graphical practice in ancient Egypt. While the apogee of the tradition was definitely the Predynastic Period (mainly fourth millennium BCE), examples date from the late Palaeolithic (c. 15,000 BCE) until the Islamic era. Geographically speaking, “Egyptian” rock art is known from many hundreds of sites along the margins of the Upper Egyptian and Nubian Nile Valley and...

  8. Rock blocks

    OpenAIRE

    Turner, W.

    2007-01-01

    Consider representation theory associated to symmetric groups, or to Hecke algebras in type A, or to q-Schur algebras, or to finite general linear groups in non-describing characteristic. Rock blocks are certain combinatorially defined blocks appearing in such a representation theory, first observed by R. Rouquier. Rock blocks are much more symmetric than general blocks, and every block is derived equivalent to a Rock block. Motivated by a theorem of J. Chuang and R. Kessar in the case of sym...

  9. Excavation of the SPS tunnel (view of a section prior to lining by a concrete shell)

    CERN Multimedia

    1974-01-01

    The SPS ring (6911 m in circumference) is housed at a depth of 40 m (average) under the surface. The tunnel with an overall cross-sectional diameter of 4.8 m was drilled by big tunnelling machines (see 7406022X, 7406027X) into the molasse rock present in the Geneva basin. After the passage of the tunnelling machine the tunnel walls were lined with a concrete layer of about 30cm thickness.

  10. Construction of tunnel Bôrik

    Directory of Open Access Journals (Sweden)

    Jozef Čížik

    2009-09-01

    Full Text Available When tunneling engineers talk on NATM, they often mean different things because some of them define it as a special technique,but others as a sort of philosophy. Recently the scene has been complicated by new terms and even alternative names, when discussingcertain aspects of NATM.The NATM integrates the principles of the behaviour of rock masses under load and monitoring the performance of undergroundconstruction during construction. The NATM is not a set of specific excavation and support techniques. Based on the computationof the optimal cross section, just a thin shotcrete protection is necessary. Additionally, geotechnical instruments are installed to measurethe later deformation of excavation. Therefore a monitoring of the stress distribution within the rock is possible. This monitoring makesthe method very flexible, even at surprising changes of the geomechanical rock consistency during the tunneling work.

  11. Tunnel support design by comparison of empirical and finite element analysis of the Nahakki tunnel in mohmand agency, pakistan

    Directory of Open Access Journals (Sweden)

    Riaz Asif

    2016-03-01

    Full Text Available The paper analyses the geological conditions of study area, rock mass strength parameters with suitable support structure propositions for the under construction Nahakki tunnel in Mohmand Agency. Geology of study area varies from mica schist to graphitic marble/phyllite to schist. The tunnel ground is classified and divided by the empisical classification systems like Rock mass rating (RMR, Q system (Q, and Geological strength index (GSI. Tunnel support measures are selected based on RMR and Q classification systems. Computer based finite element analysis (FEM has given yet another dimension to design approach. FEM software Phase2 version 7.017 is used to calculate and compare deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems.

  12. Design of concrete structures for durability. Example: Chloride penetration in the lining of a bored tunnel

    NARCIS (Netherlands)

    Siemes, A.J.M.

    1998-01-01

    The present design method for durability of concrete is based on a set of rules that give no objective in-sight in the service life to expect from the concrete structure. An objective comparison between different durability measures is therefor not possible. Especially if the lack of durability can

  13. Tunnel Boring Machine Technology for a Deeply Based Missile System. Volume I, Application Feasibility. Part 1.

    Science.gov (United States)

    1980-08-01

    chart 5% Calcareous cement 5% Classification: Argillized , cherty, micaceous, calcareous felds- pathic sandstone Origin: Alluvium deposits Physical...Texture: Fine medium qrained sand with clay clasts, well sorted, argillized calcareous cementing, medium porosity and permeability Mineralogical...Composition: Quartz sand 75% Feldspathic sand 15% Clay clasts 5% Calcareous cement 5. Classification: Argillized , feldspathic w/clay clasts, calcareous

  14. Thermal modeling of bore fields with arbitrarily oriented boreholes

    Science.gov (United States)

    Lazzarotto, Alberto

    2016-04-01

    The accurate prediction of the thermal behavior of bore fields for shallow geothermal applications is necessary to carry out a proper design of such systems. A classical methodology to perform this analysis is the so-called g-function method. Most commercial tools implementing this methodology are designed to handle only bore fields configurations with vertical boreholes. This is a limitation since this condition might not apply in a real installation. In a recent development by the author, a semi-analytical method to determine g-function for bore fields with arbitrarily oriented boreholes was introduced. The strategy utilized is based on the idea introduced by Cimmino of representing boreholes as stacked finite line sources. The temperature along these finite lines is calculated by applying the superposition of the effects of each linear heat source in the field. This modeling technique allows to approximate uneven heat distribution along the boreholes which is a key feature for the calculation of g-functions according to Eskilson's boundary conditions. The method has been tested for a few simple configurations and showed results that are similar compare to previous results computed numerically by Eskilson. The method has been then successfully applied to the g-function calculation of an existing large scale highly asymmetrical bore field.

  15. Quality Designed Twin Wire Arc Spraying of Aluminum Bores

    Science.gov (United States)

    König, Johannes; Lahres, Michael; Methner, Oliver

    2015-01-01

    After 125 years of development in combustion engines, the attractiveness of these powerplants still gains a great deal of attention. The efficiency of engines has been increased continuously through numerous innovations during the last years. Especially in the field of motor engineering, consequent friction optimization leads to cost-effective fuel consumption advantages and a CO2 reduction. This is the motivation and adjusting lever of NANOSLIDE® from Mercedes-Benz. The twin wire arc-spraying process of the aluminum bore creates a thin, iron-carbon-alloyed coating which is surface-finished through honing. Due to the continuous development in engines, the coating strategies must be adapted in parallel to achieve a quality-conformed coating result. The most important factors to this end are the controlled indemnification of a minimal coating thickness and a homogeneous coating deposition of the complete bore. A specific system enables the measuring and adjusting of the part and the central plunging of the coating torch into the bore to achieve a homogeneous coating thickness. Before and after measurement of the bore diameter enables conclusions about the coating thickness. A software tool specifically developed for coating deposition can transfer this information to a model that predicts the coating deposition as a function of the coating strategy.

  16. High performance projectile seal development for non perfect railgun bores

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, T.R.; Vine, F.E. Le; Riedy, P.E.; Panlasigui, A. [Maxwell Labs., Inc., San Diego, CA (United States); Hawke, R.S.; Susoeff, A.R. [Lawrence Livermore National Lab., CA (United States)

    1997-01-01

    The sealing of high pressure gas behind an accelerating projectile has been developed over centuries of use in conventional guns and cannons. The principal concern was propulsion efficiency and trajectory accuracy and repeatability. The development of guns for use as high pressure equation-of-state (EOS) research tools, increased the importance of better seals to prevent gas leakage from interfering with the experimental targets. The development of plasma driven railguns has further increased the need for higher quality seals to prevent gas and plasma blow-by. This paper summarizes more than a decade of effort to meet these increased requirements. In small bore railguns, the first improvement was prompted by the need to contain the propulsive plasma behind the projectile to avoid the initiation of current conducting paths in front of the projectile. The second major requirements arose from the development of a railgun to serve as an EOS tool where it was necessary to maintain an evacuated region in front of the projectile throughout the acceleration process. More recently, the techniques developed for the small bore guns have been applied to large bore railguns and electro-thermal chemical guns in order to maximize their propulsion efficiency. Furthermore, large bore railguns are often less rigid and less straight than conventional homogeneous material guns. Hence, techniques to maintain seals in non perfect, non homogeneous material launchers have been developed and are included in this paper.

  17. Boring and Drilling Tools. Pre-Apprenticeship Phase 1 Training.

    Science.gov (United States)

    Lane Community Coll., Eugene, OR.

    This self-paced student training module on boring and drilling tools is one of a number of modules developed for Pre-apprenticeship Phase 1 Training. Purpose of the module is to enable students to identify, select, and understand the proper use of many common awls, bits, and drilling tools. The module may contain some or all of the following: a…

  18. Research on Valve Body Design of Large Bore Sodium Valve

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Large bore sodium valve is one kind of key equipments of China Demonstration Fast Reactor (CDFR). It is installed in the pipeline before and behind SG units as a locking mechanism. Valve body which is used to bear pressure is the core of sodium valve design.

  19. INTERNAL TIDES, SOLITARY WAVES AND BORES IN SHALLOW SEAS

    Institute of Scientific and Technical Information of China (English)

    王涛; 高天赋

    2001-01-01

    Remote sensing and in situ observations of internal tides, solitary waves and bores in shallow water are briefly reviewed in this paper. The emphasis is laid on interpreting SAR images based on oceanographic measurements, and analyzing characteristics of internal waves in the China Seas. Direc-tions for future research are discussed.

  20. Rational Distribution of Heat Loss in Well Bore

    Institute of Scientific and Technical Information of China (English)

    Li Jingqin; Chen Yanhua; Xiang Xinyao

    1996-01-01

    @@ Introduction It is not easy to produce viscous crude because of its heavy viscosity. At present, viscous crude is mainly recovered by thermal recovery, i.e. by steam injection. In the course of steam injection, heat loss, especially that in well bore has a direct influence on thermal productive effectiveness.

  1. Determination of Muzzle Velocity Loss by Bore Wear Pattern

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-xin; WANG Gui-yu

    2007-01-01

    A method to determine muzzle velocity loss according to the actual measured bore wear pattern is proposed.Therefore, it is unnecessary to conduct live firing and other experiments for determination of muzzle velocity loss. It has been applied to a national military standard since July 1, 2004.

  2. CNLC Provides Well-Bore Technical Services Worldwide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ BRIEF INTRODUCTION of CNLC China National Logging Corporation (CNLC), a subsidiary of CNPC Services & Engineering Ltd.,which provides well bore technical services at international market solely on behalf of CNPC, is a specialized service company mainly engaged in: 1. Wire-line logging, mud logging, well testing,well completion, perforating and other relevant engineering services.

  3. INTERNAL TIDES, SOLITARY WAVES AND BORES IN SHALLOW SEAS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Remote sensing and in situ observations of internal tides, solitary waves and bores in shallow water are briefly reviewed in this paper. The emphasis is laid on interpreting SAR images based on oceanographic measurements, and analyzing characteristics of internal waves in the China Seas. Directions for future research are discussed.

  4. 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.

  5. MECHANISM AND CATASTROPHE THEORY ANALYSIS OF CIRCULAR TUNNEL ROCKBURST

    Institute of Scientific and Technical Information of China (English)

    PAN Yue; ZHANG Yong; YU Guang-ming

    2006-01-01

    Mechanism of circular tunnel rockburst is that, when the carrying capacity of the centralized zone of plastic deformation in limiting state reduces, the comparatively intact part in rock mass unloads by way of elasticity; rockburst occurs immediately when the elastic energy released by the comparatively intact part exceeds the energy dissipated by plastic deformation. The equivalent strain was taken as a state variable to establish a catastrophe model of tunnel rockburst, and the computation expression of the earthquake energy released by tunnel rockburst was given. The analysis shows that, the conditions of rockburst occurrence are relative to rock's ratio of elastic modulus to descendent modulus and crack growth degree of rocks; to rock mass with specific rockburst tendency, there exists a corresponding critical depth of softened zone, and rockburst occurs when the depth of softened zone reaches.

  6. Number of Well Bores Started (Spud) During the Fiscal Year on Federal Lands

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — This table contains the total number of well bores started (spudded), by state, during each fiscal year. "Spudding in," or to "spud" a well bore, means to begin...

  7. Comparative study of static and dynamic parameters of rock for the Xishan Rock Cliff Statue

    Institute of Scientific and Technical Information of China (English)

    Jin JIANG; Jin-zhong SUN

    2011-01-01

    Ultrasonic wave testing was applied to investigate the quality and weathering status of rock specimens obtained in two borings situated in the Xishan Buddha rock slope in Taiyuan,China.This paper pays special attention to the distribution of bulk density,dynamic parameters and static parameters of rock specimens as well as the relationship between static and dynamic parameters.The results illustrate that the distribution of both parameters is identical along the depth of two drilled holes in the rock slope.When the hole depth increases,the density of rock mass,saturated compression strength and static elastic modulus,dynamic elastic modulus and wave velocity also show increase tendency.The weathering degree in the rock mass ranging from the surface of cliffto the depth of 2.5 m is the highest while the rock mass is unsalted and more rigid when the depth is larger than 3.0 m.The relationship between dynamic elastic modulus,sonic wave velocity and horizontal depth indicates that dynamic elastic modulus is more sensitive than sonic wave velocity.Conversely,by comparing quantity relationship between static elastic modulus and sonic wave velocity,it is found that the composition of rock has a great influence on the relationship between static and dynamic parameters,that is,inequality of rock composition will lead to dispersion and abnormality of the distribution of static and dynamic parameters.

  8. 高地应力软岩隧道大变形控制及支护对策研究%Study of the control of large deformation and countermeasures of supporting of the high geo-stress soft rock tunnel

    Institute of Scientific and Technical Information of China (English)

    张天宇

    2015-01-01

    兰渝铁路黑山隧道出口DK98+890~DK100+242段属高地应力软岩,在施工过程中初期支护出现严重破坏及大变形,对施工造成了不利影响。本文基于高地应力条件下二叠系板岩、碳质板岩地层的试验与理论研究,得到了该地层的变形规律及支护受力特征;同时现场试验证明,采用H175全环钢架结合深孔锚杆、喷射C30早高强混凝土可以有效地解决软岩隧道高地应力大变形问题,实际应用效果良好。%The DK98+890 to DK100+242 section of Lanzhou-Chongqing Railway's Heishan Tunnel's exit is high geo-stress soft rock. In the early stages of its construction,severe damages and large deformation happened on the sup-porting, exerting bad influences on the construction. Based on the experiment and theoretical study of the formation of permian slate and carbonaceous slate under the condition of high geo-stress, the deformation rule of the formation and mechanics characteristics of the supporting were found. And according to the field test, the problem of large deformation of the high geo-stress of the soft rock tunnel can be solved effectively by using the H175 full-circular steel frame, deep hole bolting and C30 early and high strength concrete.

  9. 浅埋隧道洞口段Ⅳ级围岩开挖方案比选数值分析%Numerical Analysis of the Scheme for the Portal Excavation of a Shallow Tunnel in a Grade Ⅳ Rock Mass

    Institute of Scientific and Technical Information of China (English)

    杨灵; 韩立军; 蔚立元

    2013-01-01

    In light of the geological conditions of the Beigushan tunnel, the differences of force applied on the surrounding rock and the supporting structure, as well as the relative deformation law concerning the exit section, by different construction methods were compared. An analysis was performed and a construction method was selected based on the construction procedures and characteristics. It was concluded that the Beigushan tunnel should be constructed by the method of arched heading with reserved core soil, since this scheme not only complies with tunnel design specifications and meets the requirements of stability, but is also simple and cost effective.%结合隧址地质特征,运用有限元数值分析方法,对比分析了北固山隧道出口段在采用不同开挖工法条件下围岩和支护结构受力与变形规律的差异,同时结合施工工序和工程特点对不同开挖方法的选取进行了分析比选,最后得出了北固山隧道出口段采用弧形导洞预留核心土法开挖是符合隧道设计规范、又满足围岩及支护稳定性要求的施工方案,且施工工艺简易,经济.研究成果将对同类地质条件下隧道的设计和施工具有指导意义.

  10. The distribution of worm borings in brachiopod shells from the Caradoc Oil Shale of Estonia.

    OpenAIRE

    Vinn, Olev

    2005-01-01

    International audience; Abundant worm borings were found in some brachiopod shells (Clitambonites, Estlandia, Nicolella) from the Ordovician (Caradoc) oil shale in North Estonia. 9 of 21 brachiopod genera (43 %) have been bored. Excluding the size and thickness of valves, no common morphological feature discriminates the brachiopods with borings from those without them. The Trypanites are host-specific, and the frequency of bored valves varies from 6.5 % in Bekkerina to 51 % in Estlandia. The...

  11. Electron tunnel sensor technology

    Science.gov (United States)

    Waltman, S. B.; Kaiser, W. J.

    1989-01-01

    The recent development of Scanning Tunneling Microscopy technology allows the application of electron tunneling to position detectors for the first time. The vacuum tunnel junction is one of the most sensitive position detection mechanisms available. It is also compact, simple, and requires little power. A prototype accelerometer based on electron tunneling, and other sensor applications of this promising new technology are described.

  12. DDA模拟TBM破岩机理%TBM Failure Rock Mechalism with DDA Simulation

    Institute of Scientific and Technical Information of China (English)

    施文俊; 袁宝远

    2012-01-01

    TBM is the main tool of the modern tunneling, tunneling excavation in the many tunnels have been successfully applied. In many domestic construction process, due to the extremely complex geological conditions, hard rock and lithologic changes, TBM rims appear to be turned, chipping, fracture, abrasion degree of knife ring shift too large and empty sharpening etc, and it has seriously affected the mining progress and mining efficiency. In order to solve these issues, the general mechanism of TBM rock is described, based on this, the DDA simple simulation of rock in a variety of combinations of structural plane loads of damage, more directly reflect the process of breaking rock.

  13. 30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boring-type machines equipped for auxiliary... AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for auxiliary face ventilation. Each boring-type continuous-mining machine that is submitted for approval...

  14. 46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ferrous metal borings, shavings, turnings, or cuttings... Requirements for Certain Material § 148.04-13 Ferrous metal borings, shavings, turnings, or cuttings (excluding... described as ferrous metal borings, shavings, turnings, or cuttings on board vessels (excluding stainless...

  15. Modelling of blast-induced damage in tunnels using a hybrid finite-discrete numerical approach

    Directory of Open Access Journals (Sweden)

    Amichai Mitelman

    2014-12-01

    Full Text Available This paper presents the application of a hybrid finite-discrete element method to study blast-induced damage in circular tunnels. An extensive database of field tests of underground explosions above tunnels is used for calibrating and validating the proposed numerical method; the numerical results are shown to be in good agreement with published data for large-scale physical experiments. The method is then used to investigate the influence of rock strength properties on tunnel durability to withstand blast loads. The presented analysis considers blast damage in tunnels excavated through relatively weak (sandstone and strong (granite rock materials. It was found that higher rock strength will increase the tunnel resistance to the load on one hand, but decrease attenuation on the other hand. Thus, under certain conditions, results for weak and strong rock masses are similar.

  16. Art Rocks with Rock Art!

    Science.gov (United States)

    Bickett, Marianne

    2011-01-01

    This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

  17. Art Rocks with Rock Art!

    Science.gov (United States)

    Bickett, Marianne

    2011-01-01

    This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

  18. THE STRESS IMPACT ON MECHANICAL PROPERTIES OF ROCKS IN HYDRO FRACTURING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    B. GURUPRASAD

    2012-02-01

    Full Text Available Ground water is considered to be the best safe protected drinking water source and bore wells are drilled in hard crystalline rock terrains for drinking water, irrigation and industrial purposes. Even after scientific location, some bore wells yield inadequate quantity of water or fail to yield. The success of bore wells depend largely onnumber, length, dilation and interconnectivity of fractures encountered on drilling. Considering the cost factor involved in drilling a new bore well, rejuvenation of failed bore well through some technique is thought off. The innovative technology of ‘hydro fracturing’ is a new interdisciplinary approach of Hydro mechanical tostimulate the bore well to improve the yield by applying water pressure into bore well by using a heavy duty mechanical compressor. The hydro fracturing technique was first used in oil well to increase oil and gas production. In this research paper, the hydraulic pressure applied increases with depth reflecting the rigidness,toughness of rock. The fracture development, propagation of fracture and stress behavior depends on the physical and mechanical properties of rocks. The hydro fracturing process has been conducted in three depth zones ranging from 8 m to 45 m below ground level in Annavasal union of Pudukottai district, Tamil Nadu, India. The Pressure application varies depending on the geological formations. This study pertains to a part of research work. The minimum and maximum pressures applied are 1 and 10 N/mm2 respectively. The maximumpressure of 10 N/mm2 has been recorded in the third zone, where the country rock is charnockite which is generally massive, compact and dense rock. Generally for the igneous rock in the third zone in the depth range of 40 to 50 m, more than 7 N/mm2 of pressure has been applied indicating extremely strong nature with uniaxial compressive strength 100 – 300 N/mm2, tensile strength 7- 25 N/mm2. Out of 37 bore wells 32.4% of bore wells have shown

  19. Thermally induced rock stress increment and rock reinforcement response

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, M. [KMS Hakala Oy, Nokia (Finland); Stroem, J.; Nujiten, G.; Uotinen, L. [Rockplan, Helsinki (Finland); Siren, T.; Suikkanen, J.

    2014-07-15

    This report describes a detailed study of the effect of thermal heating by the spent nuclear fuel containers on the in situ rock stress, any potential rock failure, and associated rock reinforcement strategies for the Olkiluoto underground repository. The modelling approach and input data are presented together repository layout diagrams. The numerical codes used to establish the effects of heating on the in situ stress field are outlined, together with the rock mass parameters, in situ stress values, radiogenic temperatures and reinforcement structures. This is followed by a study of the temperature and stress evolution during the repository's operational period and the effect of the heating on the reinforcement structures. It is found that, during excavation, the maximum principal stress is concentrated at the transition areas where the profile changes and that, due to the heating from the deposition of spent nuclear fuel, the maximum principal stress rises significantly in the tunnel arch area of NW/SW oriented central tunnels. However, it is predicted that the rock's crack damage (CD, short term strength) value of 99 MPa will not be exceeded anywhere within the model. Loads onto the reinforcement structures will come from damaged and loosened rock which is assumed in the modelling as a free rock wedge - but this is very much a worst case scenario because there is no guarantee that rock cracking would form a free rock block. The structural capacity of the reinforcement structures is described and it is predicted that the current quantity of the rock reinforcement is strong enough to provide a stable tunnel opening during the peak of the long term stress state, with damage predicted on the sprayed concrete liner. However, the long term stability and safety can be improved through the implementation of the principles of the Observational Method. The effect of ventilation is also considered and an additional study of the radiogenic heating effect on the

  20. Analysis of two variants of sequential excavation of a cross section of the Bôrik Tunnel

    Directory of Open Access Journals (Sweden)

    Vavrek Pavol

    2001-09-01

    Full Text Available The Bôrik tunnel has been designed as a double tube tunnel intended for one – way traffic. Both tunnel tubes with the lengths of 999 and 993 meters are mutually interconnected by two escape entries. The Bôrik tunnel is part of the D1 Mengusovce – Jánovce motorway structure. The tunnel goes through sound und semi – rock forquarternary basic (dolomite und quarternary sediments (in the tunnel portals – glacial und deluvial sediments.The tunneling project operations were carried out by Geoexperts Firm (fig. 1 - variant No 1. The alternative tunneling project operations were carried out by Profesor Ing. J. Hatala, CSc. (fig. 2 – variant No 2. During excavation of the tunnel a rock pillar of varying thickness is considered. The arbitration oh both variants was realised using mathematical modelling. The mathematic model involves:• The effect of rock bolts on the stability of the rock massif,• The influence of shotcrete on the stabilization of the tunnel tubes,• The effect of the protective umbrella in the portal section,• relaxation of stresses in the rock massif after partial excavation,• Time sequence execution of each excavation.The Mohr – Coulomb constituded model was used in the analysis. On the basis of the analysis using mathematical modelling, it is possible to state that the texcavation of the Bôrik tunnel is better in terms of stress state with variant number one.

  1. Attachable rock bolters for roadheaders

    Energy Technology Data Exchange (ETDEWEB)

    Weibezahn, K. [Wirth Maschinen- und Bohrgeraete-Fabrik GmbH, Erkelenz (Germany); West, M. [Deilmann-Haniel Mining Systems GmbH (Germany)

    2004-07-01

    Roadheaders are used in mining and tunnelling in medium hard rock formations. The excavated space is made safe either by NATM-technology or a steel support system. The application of a rock bolting system up to now was restricted to formations that can cope with at least some support lag. A new system was developed in close cooperation between WIRTH Maschinen- und Bohrgeraetefabrik GmbH and deilmann-haniel mining systems gmbh that allows to carry out rock bolting with two drill rigs whicht are attached to the cutting boom of the roadheader even in front of the cutter head directly after cutting. Alternatively a robot may be attached to above named system that enables remotely controlled shot-creting close to the face.

  2. ROCK ON

    National Research Council Canada - National Science Library

    Thomas Grose

    2014-01-01

    ..., however, was music - especially the high-pitched sounds of pop and rock, which boosted energy output by up to 40 percent. By contrast, classical music's lower pitches barely raised effectiveness. O...

  3. Comparison of input parameters regarding rock mass in analytical solution and numerical modelling

    Science.gov (United States)

    Yasitli, N. E.

    2016-12-01

    Characteristics of stress redistribution around a tunnel excavated in rock are of prime importance for an efficient tunnelling operation and maintaining stability. As it is a well known fact that rock mass properties are the most important factors affecting stability together with in-situ stress field and tunnel geometry. Induced stresses and resultant deformation around a tunnel can be approximated by means of analytical solutions and application of numerical modelling. However, success of these methods depends on assumptions and input parameters which must be representative for the rock mass. However, mechanical properties of intact rock can be found by laboratory testing. The aim of this paper is to demonstrate the importance of proper representation of rock mass properties as input data for analytical solution and numerical modelling. For this purpose, intact rock data were converted into rock mass data by using the Hoek-Brown failure criterion and empirical relations. Stress-deformation analyses together with yield zone thickness determination have been carried out by using analytical solutions and numerical analyses by using FLAC3D programme. Analyses results have indicated that incomplete and incorrect design causes stability and economic problems in the tunnel. For this reason during the tunnel design analytical data and rock mass data should be used together. In addition, this study was carried out to prove theoretically that numerical modelling results should be applied to the tunnel design for the stability and for the economy of the support.

  4. Rock engineering: La Grande Complex, Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, D.K.; Levay, J.

    1982-08-01

    The paper presents an overview of rock engineering considerations in the Complex as related particularly to excavation and support problems. Examples are chosen to show the range of geological conditions encountered together with the engineering philosophy that has governed their treatment. Experience gained with unlined tunnels and channels for hydraulic purposes is discussed.

  5. 高应力大断面破碎围岩巷道二次强力支护支架设计%Design of Secondary High-Capacity Support to Large-Section Tunnel with Fractured Surrounding Rock Excavated on High-Stress Condition

    Institute of Scientific and Technical Information of China (English)

    陈新明; 郜进海

    2012-01-01

    To design high capacity support to deep large-section tunnel excavated in high-stress condition with fractured surrounding rock, for different section patterns of supports, the stresses and displacements of tunnel surrounding rock were analyzed with the change of lateral pressure coefficients. Particularly, the effect of height of double-layered I-section beam on the bearing capacity was investigated. As a result, an arched support with bottom arch superimposed and fully-closed I-section beam was developed with horse-shoe shaped structure. The bearing capacity of developed structure is 2.5 times higher than that of support using I-section beam. Underground field test shows that the deformation of the surrounding rock could be effectively controlled when the proposed secondary arched support is adopted.%为解决深部高应力大断面破碎围岩巷道支护难的问题,分析了不同支架断面形式随侧压系数的变化巷道围岩应力和位移的变化特征,以及双层工字钢梁的高度对承载受力大小影响特征.开发了适用于高应力大断面破碎围岩巷道拱形叠加底拱全封闭工字钢支架,该支架采用矿用工钢上下重叠并连接成整体的全封闭马蹄形结构,支架的整体承载能力比工字钢对棚提高了2.5倍以上.井下试验结果表明,拱形叠加底拱全封闭工字钢支架二次强力支护可以有效控制巷道围岩变形.

  6. Predator-prey interactions between shell-boring beetle larvae and rock-dwelling land snails

    NARCIS (Netherlands)

    Baalbergen, Els; Helwerda, Renate; Schelfhorst, Rense; Castillo Cajas, Ruth F.; van Moorsel, Coline H. M.; Kundrata, Robin; Welter-Schultes, Francisco W.; Giokas, Sinos; Schilthuizen, Menno

    2014-01-01

    Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be

  7. 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.

  8. Speed Regulator for Permanent Magnet DC Boring Machine

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper a variable-speed system for a loaded permanent magnet direct current boring machine (PMDCBM) is described in details. The voltage adjustment of PMDCBM is accomplished by means of solid state switch with a high gain Darlington transistor. The device designed possesses good variable speed characteristic and Iow loss at low speed. The speed can be regulated automatically to hold at an ideal value according to the load.

  9. Bore-hole survey at Camp Century, 1989

    DEFF Research Database (Denmark)

    Dahl-Jensen, Dorthe; Gundestrup, NS.; Hansen, BL.

    1993-01-01

    A combination of the directional surveys of the Camp Century borehole from 1966, 1967, 1969 and 1989 has revealed a deformation pattern similar to that measured at Dye-3, South Greenland and Byrd Station, Antarctica showing high deformation rate for Wisconsin ice. Compared to the Dye-3 profile, t......, the deformation shows the same pattern even in details. The surface velocity obtained by integrating the bore hole deformation is in agreement with that obtained from satellite measurements Udgivelsesdato: jan...

  10. The propagation of internal undular bores over variable topography

    Science.gov (United States)

    Grimshaw, R.; Yuan, C.

    2016-10-01

    In the coastal ocean, large amplitude, horizontally propagating internal wave trains are commonly observed. These are long nonlinear waves and can be modelled by equations of the Korteweg-de Vries type. Typically they occur in regions of variable bottom topography when the variable-coefficient Korteweg-de Vries equation is an appropriate model. Of special interest is the situation when the coefficient of the quadratic nonlinear term changes sign at a certain critical point. This case has been widely studied for a solitary wave, which is extinguished at the critical point and replaced by a train of solitary waves of the opposite polarity to the incident wave, riding on a pedestal of the original polarity. Here we examine the same situation for an undular bore, represented by a modulated periodic wave train. Numerical simulations and some asymptotic analysis based on Whitham modulation equations show that the leading solitary waves in the undular bore are destroyed and replaced by a developing rarefaction wave supporting emerging solitary waves of the opposite polarity. In contrast the rear of the undular bore emerges with the same shape, but with reduced wave amplitudes, a shorter overall length scale and moves more slowly.

  11. Ethylene glycol as bore fluid for hollow fiber membrane preparation

    KAUST Repository

    Le, Ngoc Lieu

    2017-03-31

    We proposed the use of ethylene glycol and its mixture with water as bore fluid for the preparation of poly(ether imide) (PEI) hollow fiber membranes and compared their performance and morphology with membranes obtained with conventional coagulants (water and its mixture with the solvent N-methylpyrrolidone (NMP)). Thermodynamics and kinetics of the systems were investigated. Water and 1:1 water:EG mixtures lead to fast precipitation rates. Slow precipitation is observed for both pure EG and 9:1 NMP:water mixture, but the reasons for that are different. While low osmotic driving force leads to slow NMP and water transport when NMP:water is used, the high EG viscosity is the reason for the slow phase separation when EG is the bore fluid. The NMP:water mixture produces fibers with mixed sponge-like and finger-like structure with large pores in the inner and outer layers; and hence leading to a high water permeance and a high MWCO suitable for separation of large-sized proteins. As compared to NMP:water, using EG as bore fluid provides fibers with a finger-like bilayered structure and sponge-like layers near the surfaces, and hence contributing to the higher water permeance. It also induces small pores for better protein rejection.

  12. Colloquium on mine shaft, roadway and tunnel. Proceedings; Kolloquium Schacht, Strecke und Tunnel 2005. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The conference intended to outline the economic mechanisms of the coal sector and to show the importance of mining and tunneling and the competence in problem solving acquired in this area. Efficient and sustainable use of domestic reserves may help to ensure long-term supply and keep prices stable. Most of the required infrastructure will be located underground in this highly populated country. Technologies of tunneling and horizontal drilling are described and illustrated by the example of a new Cologne underground railway project. Mining and tunnelling have much in common, e.g. drilling and shotfiring, overburden removal, rock strength, supports, protection against liquid and gas leakage, ventilation and air conditioning. Projects like the new Austrian high-speed railway track or the 'Loetschbergbasistunnel' project in Switzerland are examples of tunneling project which are clearly comparable with the construction of a new coal mine.

  13. A study of rock bolting failure modes

    Institute of Scientific and Technical Information of China (English)

    Cao Chen; Jan Nemcik; Ren Ting; Naj Aziz

    2013-01-01

    Rock bolting has advanced rapidly during the past 4 decades due to a better understanding of load transfer mechanisms and advances made in the bolt system technology.Bolts are used as permanent and temporary support systems in tunnelling and mining operations.A review of has indicated that three systems of reinforcement devices have evolved as part of rock bolt and ground anchor while the rock is not generally thought of as being a component of the reinforcement system.A classification of rock bolting reinforcement systems is presented,followed by the fundamental theory of the load transfer mechanism.The failure mode of two phases of rock bolting system is formularised.The failure modes of cable bolting are discussed using a bond strength model as well as an iterative method.Finally,the interfacial shear stress model for ribbed bar is introduced and a closed form solution is obtained using a tri-line stress strain relationship.

  14. RESEARCH ON SELECTION OF STEEL AND STEEL GRID FOR TUNNEL SUPPORT IN SOFT ROCK WITH HIGH GEOSTRESS%高地应力软岩隧道中型钢与格栅支护适应性现场对比试验研究

    Institute of Scientific and Technical Information of China (English)

    张德华; 刘士海; 任少强

    2014-01-01

    meters in length each. Numerical simulations were carried out. The settlement of the tunnel crown and the arch foot,the horizontal convergence,the surrounding rock pressure and the stress of initial supporting steel framework were compared through experiments and numerical simulation. The section with the steel frame had the settlement and the horizontal convergence controlled more effectively than the one with the steel grid. But the contact pressure of surrounding rock and steel reached 336 kPa,much higher than the cases of the section with steel grid support. In the section of steel grid,the settlement of tunnel crown reached 350 mm after a week,with the rapid displacement increasing. To control the deformation of the surrounding rock,multiple support including the steel grid and the steel frame were set up. The settlement of tunnel crown reached a stable value of 446 mm and the surrounding rock pressure reached 190 kPa. The deformation of surrounding rocks and the stress of initial supporting steel frameworks were finally effectively controlled,so as to indicate that the multiple support is an effective measure of controlling the large deformation of surrounding rocks.

  15. 'Wopmay' Rock

    Science.gov (United States)

    2004-01-01

    This approximate true-color image taken by NASA's Mars Exploration Rover Opportunity shows an unusual, lumpy rock informally named 'Wopmay' on the lower slopes of 'Endurance Crater.' The rock was named after the Canadian bush pilot Wilfrid Reid 'Wop' May. Like 'Escher' and other rocks dotting the bottom of Endurance, scientists believe the lumps in Wopmay may be related to cracking and alteration processes, possibly caused by exposure to water. The area between intersecting sets of cracks eroded in a way that created the lumpy appearance. Rover team members plan to drive Opportunity over to Wopmay for a closer look in coming sols. This image was taken by the rover's panoramic camera on sol 248 (Oct. 4, 2004), using its 750-, 530- and 480-nanometer filters.

  16. Smooth Blasting Technique of Irregular Section Tunnel's Excavation in Broken Rock Mass%破碎岩体内异形断面巷道掘进的光面爆破技术

    Institute of Scientific and Technical Information of China (English)

    钟福生; 陈建宏; 范文录

    2012-01-01

    The reasonable smooth blasting parameters and blasting holes layout for irregular section tunnel within the vein was studied and analyzed by adopting the design principle of smooth blasting parameters and taking into con-sidr ration of the actual conditions (the ore body is broken) in Yong-sha-ba mining district of Kailin Phosphorite Mi1-x. The EPE-tubes was used to locate cartridges precisely to meet the design requirements of radial and axial decouple charge. The blasting result is satisfactory,and the irregular section tunnel has formed a good shape,and there is almost no roof-fall accident directly, which creates favorable conditions for subsequent bolt and mesh support construction.%根据破碎岩体光面爆破参数的设计原理,结合开阳磷矿用沙坝矿区破碎矿体的实际条件,研究分析了脉内异形断面巷道的合理光面爆破参数和炮孔布置形式.通过采用EPE管对药卷间距进行精确定位,使之满足轴向和径向不耦合装药的设计要求,试验获得了良好的光爆效果.异形断面巷道成型良好,顶板基本无直接冒项现象,为后续的锚网支护创造了良好条件.

  17. Numerical modeling of tunneling-induced seismicity

    Science.gov (United States)

    Rinaldi, Antonio Pio; Urpi, Luca

    2017-04-01

    Removal of rock mass in mining environment has been associated since long-time with seismic event of magnitude 3 and above, with the potential to cause damage to the infrastructures or even loss of human life. Although with similarities with mining, relatively unknown up to now are seismic events induced by tunneling. However with modern mechanized tunneling techniques, making possible to digging deeper and longer underground infrastructure, the risk is not negligible. As an example, the excavation of the 57km long Gotthard Base Tunnel has been associated more than hundred seismic events, with the largest one having magnitude of ML 2.4, damaging the tunnel infrastructures. For future scenario of deep geological storage of nuclear waste, tunneling will constitute the primary activity during site construction. Hence, it will be crucial to understand the risk associated with the underground construction operation that can reactivate seismogenic features nearby the future location of emplacement tunnels. Here we present numerical simulation aimed at understanding the potential for inducing seismicity during tunnel construction. The stress changes and their evolution during the excavation are evaluated with a finite element solver (FLAC3d). A strain-softening friction model is then used to simulate the occurrence of a sudden slip on a fault zone (if critical conditions for reactivation are reached). We also present a sensitivity analysis of the potential for inducing different seismic events by different tunnel sizes at varying distance from a nearby failure plane, with the final purpose of evaluating safety of a potential nuclear repository site on the short- and long-term.

  18. Hypersonic Tunnel Facility (HTF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Hypersonic Tunnel Facility (HTF) is a blow-down, non-vitiated (clean air) free-jet wind tunnel capable of testing large-scale, propulsion systems at Mach 5, 6,...

  19. Transonic Dynamics Tunnel (TDT)

    Data.gov (United States)

    Federal Laboratory Consortium — The Transonic Dynamics Tunnel (TDT) is a continuous flow wind-tunnel facility capable of speeds up to Mach 1.2 at stagnation pressures up to one atmosphere. The TDT...

  20. Road and Railroad Tunnels

    Data.gov (United States)

    Department of Homeland Security — Tunnels in the United States According to the HSIP Tiger Team Report, a tunnel is defined as a linear underground passageway open at both ends. This dataset is based...

  1. Quantum theory of tunneling

    CERN Document Server

    Razavy, Mohsen

    2014-01-01

    In this revised and expanded edition, in addition to a comprehensible introduction to the theoretical foundations of quantum tunneling based on different methods of formulating and solving tunneling problems, different semiclassical approximations for multidimensional systems are presented. Particular attention is given to the tunneling of composite systems, with examples taken from molecular tunneling and also from nuclear reactions. The interesting and puzzling features of tunneling times are given extensive coverage, and the possibility of measurement of these times with quantum clocks are critically examined. In addition by considering the analogy between evanescent waves in waveguides and in quantum tunneling, the times related to electromagnetic wave propagation have been used to explain certain aspects of quantum tunneling times. These topics are treated in both non-relativistic as well as relativistic regimes. Finally, a large number of examples of tunneling in atomic, molecular, condensed matter and ...

  2. Hypersonic Tunnel Facility (HTF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Hypersonic Tunnel Facility (HTF) is a blow-down, non-vitiated (clean air) free-jet wind tunnel capable of testing large-scale, propulsion systems at Mach 5, 6,...

  3. Source rock

    OpenAIRE

    Abubakr F. Makky; Mohamed I. El Sayed; Ahmed S. Abu El-Ata; Ibrahim M. Abd El-Gaied; Mohamed I. Abdel-Fattah; Zakaria M. Abd-Allah

    2014-01-01

    West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro), and well log data of some Cretaceous sequences including Abu Roash (E, F and G members), Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history ...

  4. A new method for controlling of floor heave of deep tunnels in soft rocks by mini-tube grouting piles of crushed stones%微型碎石管注桩治理深部软岩巷道底鼓新方法

    Institute of Scientific and Technical Information of China (English)

    谢芳; 王金安

    2013-01-01

    针对造成巷道底鼓的物理和力学两种重要机制,研究并提出微型碎石管注桩治理深部软岩巷道底鼓的新方法.在物理机制方面,微型碎石桩具有渗透性极好的特点,在巷道施工和使用期间可汲取岩体中的渗水并透过碎石桩中的插管排出,从而降低软岩层因遇水膨胀导致的变形;在力学机制方面,微型碎石桩一方面通过钻孔置换出少部分底板软岩,从体量上减少变形岩体,另一方面能利用碎石桩体的侧向可压缩性耗散岩体水平变形,底板岩层中的水平地应力得以释放,极大减缓了促使底鼓变形的力学作用;通过微型碎石桩中的插管注浆加固底板岩体,提高了底板复合地基整体承载力.通过数值分析,阐明该方法在治理软岩巷道底鼓机制上的有效性.%Focusing on two important mechanisms of physics and mechanics that give rise to the floor heave of tunnels , a new method of controlling the floor heave of deep tunnels in soft rocks was proposed by means of mini-tube grouting piles of crushed stones. In physical aspect, the method utilizes the characteristics of good permeability of crushed stone pile to absorb the water in rockmass and drainage out through the tubes in the pile during the construction and application of the tunnels, resulting in the decrease in expansion deformation of soft rock due to water saturation. In mechanical aspect, partial volume in floor stratum has been replaced, on one hand, by the installed mini piles which reduce the volume of the deforming rock body, and on the other hand, amount of horizontal deformation are dissipated through the lateral compressive deformation of the crushed stone pile, and the horizontal stress is released. As a result, the mechanical affect that induces the heave deformation in floor stratum is considerably reduced. By means of grouting the crushed stones through the tube inserted in the pile, the floor stratum is reinforced and the

  5. The Tunnels of Samos

    Science.gov (United States)

    Apostol, Tom M. (Editor)

    1995-01-01

    This 'Project Mathematics' series video from CalTech presents the tunnel of Samos, a famous underground aquaduct tunnel located near the capital of Pithagorion (named after the famed Greek mathematician, Pythagoras, who lived there), on one of the Greek islands. This tunnel was constructed around 600 BC by King Samos and was built under a nearby mountain. Through film footage and computer animation, the mathematical principles and concepts of why and how this aquaduct tunnel was built are explained.

  6. Magnetic tunnel junctions (MTJs)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We review the giant tunnel magnetoresistance (TMR) in ferromagnetic-insulator-ferromagnetic junctions discovered in recent years, which is the magnetoresistance (MR) associated with the spin-dependent tunneling between two ferromagnetic metal films separated by an insulating thin tunnel barrier. The theoretical and experimental results including junction conductance, magnetoresistance and their temperature and bias dependences are described.

  7. An Optimization Model of Tunnel Support Parameters

    Directory of Open Access Journals (Sweden)

    Su Lijuan

    2015-05-01

    Full Text Available An optimization model was developed to obtain the ideal values of the primary support parameters of tunnels, which are wide-ranging in high-speed railway design codes when the surrounding rocks are at the III, IV, and V levels. First, several sets of experiments were designed and simulated using the FLAC3D software under an orthogonal experimental design. Six factors, namely, level of surrounding rock, buried depth of tunnel, lateral pressure coefficient, anchor spacing, anchor length, and shotcrete thickness, were considered. Second, a regression equation was generated by conducting a multiple linear regression analysis following the analysis of the simulation results. Finally, the optimization model of support parameters was obtained by solving the regression equation using the least squares method. In practical projects, the optimized values of support parameters could be obtained by integrating known parameters into the proposed model. In this work, the proposed model was verified on the basis of the Liuyang River Tunnel Project. Results show that the optimization model significantly reduces related costs. The proposed model can also be used as a reliable reference for other high-speed railway tunnels.

  8. ENGINEERING GEOLOGY PROPERTIES OF 'KONJSKO' TUNNEL

    Directory of Open Access Journals (Sweden)

    Ivan Grabovac

    2004-12-01

    Full Text Available Investigation works for the design of the Konjsko Tunnel with two pipes, part of the Split-Zagreb Motorway, provided relevant data on rock mass and soil properties for construction of the prognose engineering-geological longitudinal sections. West tunnel portals are situated in tectonically deformed and partly dynamically metamorphosed Eocene flysch marls, while east ones are located in Senonian limestones. There is an overthrust contact between flysch marls and limestones. With the beginning of the excavations, rock mass characteristics were regularly registered after each blasting and actual longitudinal engineering-geological cross-sections were constructed as well as cross-sections of the excavation face. There were some differences between prognosticated and registered sections since it was infeasible to accurately determine the dip of the overthrust plane that was at shallow depth below the tunnel grade line and also due to the occurrence of transversal faults that intersected the overthrust. Data collected before and during the tunnel construction complemented the knowledge on geological structure of the surroundings and physical-mechanical characteristics of strata (the paper is published in Croatian.

  9. Analytical and numerical modeling for the effects of thermal insulation in underground tunnels

    Institute of Scientific and Technical Information of China (English)

    Liu W.V.; Apel D.B.; Bindiganavile V.S.; Szymanski J.K

    2016-01-01

    The heat flow generated from the infinite rock mass surrounding the underground tunnels is a major cause for the increasing cooling demands in deep mine tunnels. Insulation layers with lower thermal con-ductivities on tunnel walls and roof ceilings are believed to supply a thermo-barrier for heat abatement. However, it is found that no systematic theoretical investigations were made to predict and confirm the effectiveness of underground thermal insulation. Specifically, investigations on the underground insula-tion problems involving heat flows through the semi-infinite hot rock mass and insulation layer were not sufficient. Thus, in this paper, the thermal characteristics, accompanied with heat flow through the semi-infinite rock mass and the insulation layer, were modeled by both analytical and numerical meth-ods with focus on underground mine tunnels. The close agreements between models have indicated that the thermal insulation applied on tunnel surfaces is able to provide promising heat abatement effects.

  10. Stress Monitoring for Anchor Rods System in Subway Tunnel Using FBG Technology

    Directory of Open Access Journals (Sweden)

    Xiaolin Weng

    2015-01-01

    Full Text Available This paper presents a model test, used on the tunnels on Xi’an Metro Line 2, as the prototype for evaluating the reinforcing effect of the anchor rod in tunnel construction in loess areas. An independently designed fiber Bragg grating (FBG sensor was used to monitor the seven strain conditions of the rock bolts during the construction. The result shows that the axial stress of the rock bolt changes after the excavation and increases steadily with the growing pressure in the wall rock. Results additionally show that the anchor rods at the tunnel vault are subjected to a compressive stress that remains relatively constant after the primary and the secondary lining, while those at the spandrel and the corner of the tunnel are subjected to increased tensile stress. This paper demonstrates the feasibility and the superiority of FBG technology for tunnel model tests.

  11. Rock Paintings.

    Science.gov (United States)

    Jones, Julienne Edwards

    1998-01-01

    Discusses the integration of art and academics in a fifth-grade instructional unit on Native American culture. Describes how students studied Native American pictographs, designed their own pictographs, made their own tools, and created rock paintings of their pictographs using these tools. Provides a list of references on Native American…

  12. Ayers Rock

    Institute of Scientific and Technical Information of China (English)

    王慧茹

    2002-01-01

    Ayers Rock is right in the centre of Australia.It's nearly two thousand kilometres______Sydney.So we flew most of the way.h was rather cloudy______But after we left the mountains behind us, there was hardly a cloud in thesky.

  13. Intellektuaalne rock

    Index Scriptorium Estoniae

    2007-01-01

    Briti laulja-helilooja ja näitleja Toyah Willcox ning Bill Rieflin ansamblist R.E.M. ja Pat Mastelotto King Krimsonist esinevad koos ansamblitega The Humans ja Tuner 25. okt. Tallinnas Rock Cafés ja 27. okt Tartu Jaani kirikus

  14. Intellektuaalne rock

    Index Scriptorium Estoniae

    2007-01-01

    Briti laulja-helilooja ja näitleja Toyah Willcox ning Bill Rieflin ansamblist R.E.M. ja Pat Mastelotto King Krimsonist esinevad koos ansamblitega The Humans ja Tuner 25. okt. Tallinnas Rock Cafés ja 27. okt Tartu Jaani kirikus

  15. Proton tunneling in solids

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, J.

    1998-10-01

    The tunneling rate of the proton and its isotopes between interstitial sites in solids is studied theoretically. The phonons and/or the electrons in the solid have two effects on the tunneling phenomenon. First, they suppress the transfer integral between two neighbouring states. Second, they give rise to a finite lifetime of the proton state. Usually the second effect is large and the tunneling probability per unit time (tunneling rate) can be defined. In some cases, however, a coherent tunneling is expected and actually observed. (author)

  16. A Study of the Occurrence of Mesospheric Bore at the Equatorial Region in Brazil

    Science.gov (United States)

    Medeiros, A. F.; Fechine, J.; Buriti, R. A.; Takahashi, H.; Gobbi, D.

    An all-sky CCD imager capable of measuring wave structure in the OH, O2 and OI (557.7 nm) airglow emissions was operated in the equatorial region at São João do Cariri (Cariri), Brazil, (7 S, 36 W), in collaboration with Instituto Nacional de Pesquisas Espaciais (INPE). A study of the occurrence of mesospherics bores was done. This work used data from September 2000 to September 2002, also were used photometer data. It was detected 64 events like mesospheric bore during this observation period. The analyses did not show a seasonal behavior. It was analyzed as well the following aspects: multiples bore case in the same night, parameters observed of wave train of the bore. The high activity of gravity waves was observed before bore events in most of the case corroborating the generation mechanism proposed by Dewan and Picard (1998, 2001). Some nights presented more than two bore events.

  17. Turbulent mixing and wave radiation in non-Boussinesq internal bores

    DEFF Research Database (Denmark)

    Borden, Zac; Koblitz, Tilman; Meiburg, Eckart

    2012-01-01

    Bores, or hydraulic jumps, appear in many natural settings and are useful in many industrial applications. If the densities of the two fluids between which a bore propagates are very different (i.e., water and air), the less dense fluid can be neglected when modeling a bore analytically-a single......-layer hydraulic model will accurately predict a bore's speed of propagation. A two-layer model is required, however, if the densities are more similar. Mass is conserved separately in each layer and momentum is conserved globally, but the model requires for closure an assumption about the loss of energy across...... a bore. In the Boussinesq limit, it is known that there is a decrease of the total energy flux across a bore, but in the expanding layer, turbulent mixing at the interface entrains high speed fluid from the contracting layer, resulting in an increase in the flux of kinetic energy across the expanding...

  18. Geological Hazards analysis in Urban Tunneling by EPB Machine (Case study: Tehran subway line 7 tunnel

    Directory of Open Access Journals (Sweden)

    Hassan Bakhshandeh Amnieh

    2016-06-01

    Full Text Available Technological progress in tunneling has led to modern and efficient tunneling methods in vast underground spaces even under inappropriate geological conditions. Identification and access to appropriate and sufficient geological hazard data are key elements to successful construction of underground structures. Choice of the method, excavation machine, and prediction of suitable solutions to overcome undesirable conditions depend on geological studies and hazard analysis. Identifying and investigating the ground hazards in excavating urban tunnels by an EPB machine could augment the strategy for improving soil conditions during excavation operations. In this paper, challenges such as geological hazards, abrasion of the machine cutting tools, clogging around these tools and inside the chamber, diverse work front, severe water level fluctuations, existence of water, and fine-grained particles in the route were recognized in a study of Tehran subway line 7, for which solutions such as low speed boring, regular cutter head checks, application of soil improving agents, and appropriate grouting were presented and discussed. Due to the presence of fine particles in the route, foam employment was suggested as the optimum strategy where no filler is needed.

  19. Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials

    Science.gov (United States)

    2015-05-01

    Technical Report ARWSB-TR-15003 Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials Mark E. Todaro...SUBTITLE Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...thermomechanical effects that occur at the bore of large and medium caliber guns during firing. Hence, PLH has been used not only to gain insight into the erosion

  20. Successive impact of tidal bores on sedimentary processes: Arcins channel, Garonne River

    Science.gov (United States)

    Reungoat, David; Leng, Xinqian; Chanson, Hubert

    2017-03-01

    A tidal bore is a hydrodynamic shock, propagating upstream as the tidal flow turns to rising, with macro-tidal conditions in a funnel shaped system with shallow waters. The tidal bore of the Garonne River was extensively investigated in the Arcins channel between 2010 and 2013, typically over one to two days. In 2015, new field measurements were repeated systematically at the same site on 29 August-1 September 2015 and on 27 October 2015. The nature of the observations was comprehensive, encompassing hydrodynamics and turbulence, as well as sediment properties and transport. The tidal bore occurrence had a marked effect on the velocity and suspended sediment field, including a rapid flow deceleration and flow reversal during the bore passage, with very large suspended sediment concentrations (SSCs) during the passage of the tidal bore front and early flood tide, as well as very large suspended sediment flux during the very early flood tide. The suspended sediment concentration (SSC) data indicated a gradual increase in initial mean SSC estimate prior to the bore from 29 August to 1 September 2015. A comparison between suspended sediment flux data showed very significant suspended sediment flux on the first day of tidal bore occurrence, with a decreasing magnitude over the next three days. The data suggested a two-stage bed scour process: at each tidal bore event, surface erosion occurred initially, in the form of stripping; the first stage was followed by delayed mass erosion, occurring about 5-15 min after the tidal bore.

  1. Dynamic Response of Underground Circular Lining Tunnels Subjected to Incident P Waves

    Directory of Open Access Journals (Sweden)

    Hua Xu

    2014-01-01

    Full Text Available Dynamic stress concentration in tunnels and underground structures during earthquakes often leads to serious structural damage. A series solution of wave equation for dynamic response of underground circular lining tunnels subjected to incident plane P waves is presented by Fourier-Bessel series expansion method in this paper. The deformation and stress fields of the whole medium of surrounding rock and tunnel were obtained by solving the equations of seismic wave propagation in an elastic half space. Based on the assumption of a large circular arc, a series of solutions for dynamic stress were deduced by using a wave function expansion approach for a circular lining tunnel in an elastic half space rock medium subjected to incident plane P waves. Then, the dynamic response of the circular lining tunnel was obtained by solving a series of algebraic equations after imposing its boundary conditions for displacement and stress of the circular lining tunnel. The effects of different factors on circular lining rock tunnels, including incident frequency, incident angle, buried depth, rock conditions, and lining stiffness, were derived and several application examples are presented. The results may provide a good reference for studies on the dynamic response and aseismic design of tunnels and underground structures.

  2. Gravity Flow in Proposed Enteral Tube Small-Bore Connectors.

    Science.gov (United States)

    Hurt, Ryan T; Epp, Lisa M; Pattinson, Adele K; Duellman, Wanda M; Corner, Stephen M; Mundi, Manpreet S

    2017-04-01

    Enteral nutrition (EN) misconnections have been identified as a serious and potential deadly problem. An international effort led by EN industry leaders has developed a small-bore enteral connector (ENFit) that in theory will reduce the frequency of misconnections. Despite the potential benefit of preventing misconnections, the full impact of adoption of the ENFit connector is unknown. To assess the impact of transitioning to ENFit on our home EN (HEN) patients, the current study evaluated gravity feeding comparing 2 proposed small-bore connectors to the legacy (current connector) using various commercial formulas. Six commonly used enteral formulas in our facility with varying density and viscosity were tested in triplicate. Forty milliliters of formula was poured into a syringe connected to an ENFit or legacy (current) feeding connector attached to varying French size tubes. The time it took formula to flow through the connectors was recorded, and the test was repeated in triplicate. All formulas took significantly longer to flow through the first ENFit connector compared with the legacy connector ( P gravity flow, as ENFit tubes are being developed and adopted.

  3. A new method for boring of non-circular holes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; HU De-jin

    2006-01-01

    A revolving electromagnetic actuation mechanism composed of an electromagnetic stator and an electromagnetic rotor has been developed for boring non-circular holes.The main component of the rotor is a flexure-hinged based flexible body.There are four pole-pair coils in the stator supplying actuation currents.The micro-displacement between the stator and rotor can be controlled by changing the currents applied in the pole-pair coils.Through linearization of the actuation force near the static action point,a linear relationship between the control current and the actuation force was established,and the synchronizing control method of the electromagnetic actuation mechanism is presented here.With two-factor analysis of the linearization error of the actuation force,the influences of control current and micro-displacement to the linearization error of the actuation force were studied.Then,the principle for designing the basic parameters of the magnetic actuation mechanism is put forward.The calibration of the mechanism indicates that the relationship between the micro-displacement of the rotor and the control current has linear characteristics in the required micro-displacement range.Simulation tests show that the turning radius of the rotor changes with the control current.The proposed mechanism can feasibly supply a controllable micro displacement to the boring bar.

  4. Gun bore flaw image matching based on improved SIFT descriptor

    Science.gov (United States)

    Zeng, Luan; Xiong, Wei; Zhai, You

    2013-01-01

    In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

  5. Development of large bore superconducting magnet for wastewater treatment application

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui Ming; Xu, Dong; Shen, Fuzhi; Zhang, Hengcheng; Li, Lafeng [State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China)

    2017-03-15

    Water issue, especially water pollution, is a serious issue of 21st century. Being an significant technique for securing water resources, superconducting magnetic separation wastewater system was indispensable. A large bore conduction-cooled magnet was custom-tailored for wastewater treatment. The superconducting magnet has been designed, fabricated and tested. The superconducting magnet was composed of NbTi solenoid coils with an effective horizontal warm bore of 400 mm and a maximum central field of 2.56T. The superconducting magnet system was cooled by a two-stage 1.5W 4K GM cryocooler. The NbTi solenoid coils were wound around an aluminum former that is thermally connected to the second stage cold head of the cryocooler through a conductive copper link. The temperature distribution along the conductive link was measured during the cool-down process as well as at steady state. The magnet was cooled down to 4.8K in approximately 65 hours. The test of the magnetic field and quench analysis has been performed to verify the safe operation for the magnet system. Experimental results show that the superconducting magnet reached the designed magnetic performance.

  6. Stress dilatancy analysis of shallow tunnels subjected to unsymmetrical pressure

    Institute of Scientific and Technical Information of China (English)

    杨小礼; 王金明

    2008-01-01

    Numerical simulation using finite differential code was conducted for the single line railway and four-lane road shallow tunnels subjected to unsymmetrical pressure. The mechanical behavior of weak rock mass was studied considering the influences of stress dilatancy on the failure mechanisms, and the results of numerical simulation were compared with the analytical solutions in specifications. The results show that the dilatancy angle has great influences on the surrounding rock displacement and the shape of failure face for the shallow tunnels. When the dilatancy angle equals zero, the failure face of the surrounding rock forms and extends to the ground surface. With the dilatancy angle increasing, the loose region decreases gradually, and failure surface discontinues. When the dilatancy angle equals the friction angle, the loose region is only distributed in a small range around the crown and sidewalls. On the side of smaller buried depth, the difference of break angle between numerical simulation and the code is less than 10% for single line railway tunnels with the dilatancy angle of zero. However, for the four-lane road tunnels, the difference reaches 20.8%. On the side of larger buried depth, the break angles are smaller than those by the code, the difference reaches 16.8% for single line railway tunnels, and 13.8% for four-lane road tunnels. With the dilatancy angle increasing, especially the dilatancy angle approximating to internal friction angle, it is on safe side to calculate the break angle using the analytical solution method of specifications. Therefore, the influence of stress dilatancy should be considered while determining the failure mechanisms of shallow tunnels subjected to unsymmetrical pressure in weak rocks.

  7. Study on Surrounding Rock Classification of Railway Tunnel with HiPParion Laterite Stratum in West Piedmont of Lvliang Mountain%吕梁山西麓三趾马红土铁路隧道围岩分级研究

    Institute of Scientific and Technical Information of China (English)

    郭乐; 蔡云廷; 王家鼎

    2014-01-01

    The Hipparion laterite stratum in west piedmont of Lvliang Mountain is characterized by thick deposition, good continuity and lots of type sections, and has always been the research hotspot of Hipparion laterite. But, the study on its engineering geology features and geo-mechanics properties still remains very weak. So, surrounding rock classification in Hipparion laterite stratum is a new geological question faced by tunnel construction of Lvliang section of Middle and Southern Shanxi Railway project. Based on on-site monitoring, laboratory test and practical experience, this study researched the physical and mechanical indexes and strength property of Hipparion laterite, and analyzed relevant effects on Hipparion-laterite surrounding rock stability, including the underground water effect, fissuring effect, sandy soil interlayer effect, and the coupling effect of various factors. Finally, this study quantitatively discussed how to class the Hipparion-laterite surrounding rocks respectively under the conditions of homogeneity and multiple factors.%吕梁山西麓地区三趾马红土地层沉积厚度大、连续性好、典型剖面多,历来为三趾马红土研究的热点地区,但有关其工程地质特征及岩土力学性质方面的研究非常薄弱。三趾马红土围岩分级是山西中南部铁路通道工程吕梁段隧道建设面临的一项工程地质新问题。通过现场监测、室内试验研究及工程实践经验,研究三趾马红土的物理力学指标及强度特性,对影响三趾马红土围岩稳定性的地下水作用、裂隙作用、砂土夹层作用及各因素耦合作用进行分析,最后对三趾马红土在均质和多因素条件下围岩分级进行定量化探讨。

  8. Rock mass characterization for Copenhagen Metro using face logs

    DEFF Research Database (Denmark)

    Hansen, Sanne Louise; Galsgaard, Jens; Foged, Niels Nielsen

    2015-01-01

    of relevant rock mass properties for tunnelling in Danian limestone has previously been difficult, as core logging shows a high degree of induced fracturing and core loss due to drilling disturbance, with an underestimation of the RQD values, and other rock mass properties, compared to face logging. However......, describing rock mass characteristics using detailed face logging with geological description and recording of induration and fracturing, giving a field RQD value during excavation, combined with televiewer logs, when available, has shown to be a valuable tool for rock mass characterization compared...

  9. The Nolans Bore rare-earth element-phosphorus-uranium mineral system: geology, origin and post-depositional modifications

    Science.gov (United States)

    Huston, David L.; Maas, Roland; Cross, Andrew; Hussey, Kelvin J.; Mernagh, Terrence P.; Fraser, Geoff; Champion, David C.

    2016-08-01

    Nolans Bore is a rare-earth element (REE)-U-P fluorapatite vein deposit hosted mostly by the ~1805 Ma Boothby Orthogneiss in the Aileron Province, Northern Territory, Australia. The fluorapatite veins are complex, with two stages: (1) massive to granular fluorapatite with inclusions of REE silicates, phosphates and (fluoro)carbonates, and (2) calcite-allanite with accessory REE-bearing phosphate and (fluoro)carbonate minerals that vein and brecciate the earlier stage. The veins are locally accompanied by narrow skarn-like (garnet-diopside-amphibole) wall rock alteration zones. SHRIMP Th-Pb analyses of allanite yielded an age of 1525 ± 18 Ma, interpreted as the minimum age of mineralisation. The maximum age is provided by a ~1550 Ma SHRIMP U-Pb age for a pegmatite that predates the fluorapatite veins. Other isotopic systems yielded ages from ~1443 to ~345 Ma, implying significant post-depositional isotopic disturbance. Calculation of initial ɛNd and 87Sr/86Sr at 1525 Ma and stable isotope data are consistent with an enriched mantle or lower crust source, although post-depositional disturbance is likely. Processes leading to formation of Nolans Bore began with north-dipping subduction along the south margin of the Aileron Province at 1820-1750 Ma, producing a metasomatised, volatile-rich, lithospheric mantle wedge. About 200 million years later, near the end of the Chewings Orogeny, this reservoir and/or the lower crust sourced alkaline low-degree partial melts which passed into the mid- and upper-crust. Fluids derived from these melts, which may have included phosphatic melts, eventually deposited the Nolans Bore fluorapatite veins due to fluid-rock interaction, cooling, depressurisation and/or fluid mixing. Owing to its size and high concentration of Th (2500 ppm), in situ radiogenic heating caused significant recrystallisation and isotopic resetting. The system finally cooled below 300 °C at ~370 Ma, possibly in response to unroofing during the Alice Springs

  10. Geotechnical basis for underground energy storage in hard rock

    Science.gov (United States)

    Farquhar, O. C.

    1982-03-01

    Underground pumped hydroelectric storage requires the excavation of caverns in hard rock. Hard rock caverns, also, are one option for compressed air stoage. Preliminary design studies for both technologies at a specific site were completed. The geotechnical aspects of these storage systems are discussed from a generic viewpoint. Information about effective use of hard rock openings, including tunnels and shafts, comes mainly from other types of underground projects. These are power houses for hydroelectric and conventional pumped storage schemes, as well as transportation facilities and mines. Rock strength, support, instrumentation, costs, management, and experimental work are among the items considered. Mapping of geologic structures, rock fragmentation, and rock mass properties is also discussed. The general conclusions are that rock types favorable for underground energy storage are present at suitable depths in many areas and that they can be identified by adequate geotechnical exploration prior to detailed design.

  11. Resonance Enhanced Tunneling

    CERN Document Server

    Matsumoto, S; Matsumoto, Sh.

    2000-01-01

    Time evolution of tunneling in thermal medium is examined using the real-time semiclassical formalism previously developed. Effect of anharmonic terms in the potential well is shown to give a new mechanism of resonance enhanced tunneling. If the friction from environment is small enough, this mechanism may give a very large enhancement for the tunneling rate. The case of the asymmetric wine bottle potential is worked out in detail.

  12. Tunnelling in Dante's Inferno

    Science.gov (United States)

    Furuuchi, Kazuyuki; Sperling, Marcus

    2017-05-01

    We study quantum tunnelling in Dante's Inferno model of large field inflation. Such a tunnelling process, which will terminate inflation, becomes problematic if the tunnelling rate is rapid compared to the Hubble time scale at the time of inflation. Consequently, we constrain the parameter space of Dante's Inferno model by demanding a suppressed tunnelling rate during inflation. The constraints are derived and explicit numerical bounds are provided for representative examples. Our considerations are at the level of an effective field theory; hence, the presented constraints have to hold regardless of any UV completion.

  13. Microsystem Aeromechanics Wind Tunnel

    Data.gov (United States)

    Federal Laboratory Consortium — The Microsystem Aeromechanics Wind Tunnel advances the study of fundamental flow physics relevant to micro air vehicle (MAV) flight and assesses vehicle performance...

  14. Ulnar tunnel syndrome.

    Science.gov (United States)

    Bachoura, Abdo; Jacoby, Sidney M

    2012-10-01

    Ulnar tunnel syndrome could be broadly defined as a compressive neuropathy of the ulnar nerve at the level of the wrist. The ulnar tunnel, or Guyon's canal, has a complex and variable anatomy. Various factors may precipitate the onset of ulnar tunnel syndrome. Patient presentation depends on the anatomic zone of ulnar nerve compression: zone I compression, motor and sensory signs and symptoms; zone II compression, isolated motor deficits; and zone III compression; purely sensory deficits. Conservative treatment such as activity modification may be helpful, but often, surgical exploration of the ulnar tunnel with subsequent ulnar nerve decompression is indicated.

  15. A foam formulation of an entomopathogenic fungus for control of boring beetles in avocado orchards

    Science.gov (United States)

    A foam formulation of Beauveria bassiana was adapted to control boring beetles in avocado orchards. The two geographically independent avocado growing areas in the United States are threatened by emerging diseases vectored by boring beetles. In the California growing region, Fusarium dieback is vect...

  16. Method and apparatus for completing a non-vertical portion of a subterranean well bore

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, J.F.; Spatz, E.C.; Salerni, J.V.; Peterson, E.R.; Weirich, J.B.

    1989-09-19

    This patent describes an apparatus for completing a well bore having a deviated configuration including an essentially vertical entry portion communicating with a curved portion extending away from the top surface of the well and communicating with a generally linear bore portion traversable with a production formation. It comprises: a plurality of tubular screen elements; a plurality of tubular stabilizer housings threadably interconnecting the tubular screen elements, thereby forming a tool string; means for securing the stabilizer elements in a radially retracted position during run-in of the screen elements into the generally linear portion of the well bore; and fluid pressure means for radially expanding the stabilizer elements into engagement with the wall of the generally linear portion of the well bore, thereby centering the tubular screen elements relative to the generally linear portion of the well bore. The method of completing a deviated subterranean well bore having a generally vertical entry portion and a nonvertical bore portion traversing a production formation. It comprises the steps of: inserting in the non-vertical well portion a plurality of tubular screen elements interconnected by tubular stabilizing housings; each stabilizer housing mounting a plurality of peripherally spaced, radially shiftable stabilizer elements; and placing the stabilizer elements in a radially retracted position during run in. The stabilizer elements being movable from retracted position and movable radially outwardly to engage the well bore when the tubular screen elements are positioned in the production formation.

  17. Geological Investigation and Tunnel Excavation Aspects of the Weakness Zones of Xiang'an Subsea Tunnels in China

    Science.gov (United States)

    Shi, Peixin; Zhang, Dingli; Pan, Jianli; Liu, Wei

    2016-12-01

    Tunneling through weakness zones under deep seawater involves significant risks and may have disastrous consequences. This paper presents a case study of geological investigation and excavation aspects of subsea tunnels in major weakness zones. The subject is the Xiang'an subsea tunnels, the first subsea tunnel project in mainland China. The Xiang'an subsea tunnels passed through four major weakness zones, mainly consisting of highly to completely weathered rock mass. The weakness zones were characterized by a combination of long-distance and short-distance, destructive and nondestructive methods, which supplement and verify information with each other. The weakness zones were treated by full-face curtain grouting, using both cementitious and chemical grouts. The interrelationship between the settlement at tunnel crown and ground surface, as well as the interrelationship between ground settlement and ground cracking, were explored based on instrumentation data recorded during tunneling on land. The pre-warning, warning, and limiting values of tunnel crown settlement during excavation of each heading of subsea sections were established to protect the seabed against cracking. Engineering means and methods were developed to control the ground deformation during excavation.

  18. Aespoe Hard Rock Laboratory. Annual Report 2011

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-03-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2011 is given below.

  19. Aespoe hard rock laboratory. Annual report 2010

    Energy Technology Data Exchange (ETDEWEB)

    2011-02-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2010 is given below

  20. Persistence motives in irrational decisions to complete a boring task.

    Science.gov (United States)

    Halkjelsvik, Torleif; Rise, Jostein

    2015-01-01

    We explored a novel task paradigm where participants from the online work marketplace Amazon Mechanical Turk were given the choice to quit or continue an unfinished boring task for identical economic rewards. In Studies 1a and 1b, about half the participants chose to continue (corresponding to an average of 55 and 35 cents in foregone earnings). Participants' self-reported reasons for continuing involved various types of persistence motives, reflecting a desire to persist or complete per se. Studies 2, 3a, 3b, and 3c ruled out the possibility that people continued because they enjoyed the task or believed there were additional rewards for continuing. Study 4 showed that the choice to quit/continue was associated with the manner in which the choice was presented (persistence test vs. decision-making test) and individual differences in dispositional persistence motives. The present data indicate that motivational forces independent of the focal reward may affect intertemporal decisions.

  1. TRANSMISSION BEHAVIOR OF MUD-PRESSURE PULSE ALONG WELL BORE

    Institute of Scientific and Technical Information of China (English)

    LIU Xiu-shan; LI Bo; YUE Yu-quan

    2007-01-01

    In oil and gas industry, mud-pulse telemetry has been widely used to obtain directional data, drilling parameters, formation evaluation data and safety data, etc. Generally, the drilling mud in most current models was considered to be a single-phase fluid through which the mud pulses travel, despite the fact that the drilling mud is composed of two or more phases. In this article, a multiphase flow formula was proposed to calculate the mud-pulse velocity as mud solids and free-gas content change, and a mathematical model was put forward to simulate the dynamic-transmission behavior of the mud-pressure pulse or waves. Compared to conventional methods, the present model provides more accurate mud-pulse attenuation, and the dynamic-transmission behavior of drilling-mud pulses along well bores can also be easily examined. The model is valuable in improving the existing mud-pulse systems and developing new drilling-mud pulse systems.

  2. Deep bore hole instrumentation along San Francisco Bay Bridges

    Energy Technology Data Exchange (ETDEWEB)

    Bakun, W.; Bowman, J.; Clymer, R.; Foxall, W.; Hipley, P.; Hollfelder, J.; Hutchings, L.; Jarpe, S.; Kasameyer, P.; McEvilly, T.; Mualchin, L.; Palmer, M.

    1998-10-01

    The Bay Bridges down hole network consists of sensors in bore holes that are drilled 100 ft. into bedrock around and in the San Francisco Bay. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty- one sensor packages at fifteen sites. Extensive financial support is being contributed by Caltrans, UCB, LBL, LLNL-LDRD, U.C. Campus/Laboratory Collaboration (CLC) program, and USGS. The down hole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 73 1 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes.

  3. Method for completing a non-vertical portion of a subterranean well bore

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, J.F.; Spatz, E.C.; Salerni, J.V.; Peterson, E.R.; Weirich, J.B.

    1990-04-10

    This patent describes a method of completing a well bore having a deviated configuration including an entry portion communicating with a curved portion extending downwardly in the well from the entry portion and a generally linear end portion traversable with a production formation. It comprises: forming a conduit including well isolation means, at least one screen element and at least one stabilizer means having at least one movable stabilizer portion movable from a first retracted position to a second expanded position; running the conduit into the well bore and manipulating the conduit to facilitate passage of the conduit through the curved portion of the well bore; setting the well isolation means to position the tubular screen means approximate the linear portion of the well bore; and actuating the stabilizer members to the second expanded position to engage the adjacent wall of the well bore and position the screen means away from the adjacent wall.

  4. Boring crustaceans damage polystyrene floats under docks polluting marine waters with microplastic.

    Science.gov (United States)

    Davidson, Timothy M

    2012-09-01

    Boring isopods damage expanded polystyrene floats under docks and, in the process, expel copious numbers of microplastic particles. This paper describes the impacts of boring isopods in aquaculture facilities and docks, quantifies and discusses the implications of these microplastics, and tests if an alternate foam type prevents boring. Floats from aquaculture facilities and docks were heavily damaged by thousands of isopods and their burrows. Multiple sites in Asia, Australia, Panama, and the USA exhibited evidence of isopod damage. One isopod creates thousands of microplastic particles when excavating a burrow; colonies can expel millions of particles. Microplastics similar in size to these particles may facilitate the spread of non-native species or be ingested by organisms causing physical or toxicological harm. Extruded polystyrene inhibited boring, suggesting this foam may prevent damage in the field. These results reveal boring isopods cause widespread damage to docks and are a novel source of microplastic pollution.

  5. Virtual photons in macroscopic tunneling

    CERN Document Server

    Aichmann, Horst; Bruney, Paul

    2015-01-01

    Tunnelling processes are thought to proceed via virtual waves due to observed superluminal (faster than light) signal speeds. Some assume such speeds must violate causality. These assumptions contradict, for instance, superluminally tunnelled music and optical tunnelling couplers applied in fiber communication. Recently tunnelling barriers were conjectured to be cavities, wherein the tunnelled output signal is not causally related with the input. The tests described here resolve that tunnelling waves are virtual, propagations are superluminal, and causality is preserved.

  6. TBM滚刀破岩过程影响因素数值模拟研究%Numerical simulaiton of influence factors for rock fragmentation by TBM cutters

    Institute of Scientific and Technical Information of China (English)

    孙金山; 陈明; 陈保国; 卢文波; 周传波

    2011-01-01

    全断面岩石掘进机(TBM)的破岩效率主要受刀盘设计和岩体特征的影响.采用颗粒流方法建立了岩石试件与滚刀的数值模型,对TBM滚刀破岩过程的影响因素进行了分析.研究表明,单刃滚刀交替作用下强度较低的岩石中易形成规则的张拉裂纹而生成较大岩碴;强度较高的岩石中滚刀的侧向挤压促使形成块度较小的片状岩碴;双刃滚刀作用下岩石表面受到强烈挤压后出现较大的拉应力,使岩石更易破碎,且仅在强度较高的岩石中才易形成透镜状岩碴.滚刀破岩过程中存在能耗最小的最佳间距,该最佳间距随着岩石强度的增大而减小.滚刀破岩过程中,结构面对裂纹扩展具有显著的控制性作用,并阻隔损伤向结构面下的岩石中渗透;随着结构面与滚刀侵入方向夹角的减小,结构面将引导裂纹向岩石深部扩展,而当夹角较大时,结构面则会引导裂纹横向扩展,易导致大块岩碴的形成.%The cutterhead and rock mass characteristics affect the excavation efficiency of full face rock tunnel boring machine (TBM) strongly.The numerical models are made by the particle flow code method (PFC2D) to simulate the rock fragmentation under TBM disc cutters.Numerical simulation tests show that some factors influence the rock fragmentation process strongly.In the relative weak rocks, the regular tension cracks and the big mucks form more easily, when the disc cutters penetrate rocks altemately; in hard rocks,the formation of small disc shape mucks depends on the lateral extrusion of cutter rings.Under the double disc cutters, the rocks crush more easily because of the tension stress which comes form strong compression of cuaers, and the disc shape mucks only form in very hard rocks.There is optimal cutter spacing for different strength rocks, which increase with rock strength decreases.In the process of rock fragmentation, discontinuities control the propagation process of cracks

  7. New developments of technology in rock engineering in China

    Institute of Scientific and Technical Information of China (English)

    Qian Qihu

    2012-01-01

    In terms of rock engineering and technology in hydropower construction, the slope stability and monitoring techniques for high slopes of Three Gorges Project, the stability and support technology for high slopes of hydropower projects in deep river valley, the stabilization techniques for underground cavern group with large span and high side walls are introduced in this paper. As for rock engineering and technology in highway and railway construction, the Qinghai-Tibet Railway -- new construction techniques in permafrost, the support techniques for large squeezing deform- ation in Wuqiaoling Tunnel, the construction techniques for tunnels in alpine and high-altitude region, the geological prediction techniques for tunnels in karst region, the microseismic monitoring and early warning techniques for rock- bursts in deep and long tunnels are presented. For rock engineering and technology in mining engineering, the innova- tive techniques for roadway support in mines, the simultaneous extraction technique of pillarless coal and gas in coal seams with low permeability, the safe and efficient deep open mining technology, advances in monitoring, early warning and treatment of mine dynamic disasters are discussed. In addition, the new anchorage techniques and precision blasting technique in rock engineering are introduced.

  8. Model Test Study of the Anchor Bolt Arrangement in a Loess Subway Tunnel%黄土地铁隧道锚杆布置方式的模型试验研究

    Institute of Scientific and Technical Information of China (English)

    郑甲佳; 撒蕾; 郭永建

    2014-01-01

    文章利用平面应变三向加载装置进行室内模型试验,对无锚杆、全环锚杆和边墙锚杆三种锚杆布置方式进行了对比试验,并参考工程现场测试结果,对系统锚杆在黄土地铁隧道中的作用进行了研究;通过模型试验获得了适合黄土地铁隧道的锚杆相似材料,实现了“先加载,后挖洞”以及锚杆和衬砌联为一体的试验方法。通过对比发现:系统锚杆能较好地控制掌子面周围的塑性区发展;边墙锚杆在隧道洞室开挖支护后能加快围岩应力调整,且能有效改善衬砌的受力情况;综合考虑经济因素,认为边墙锚杆支护系统在浅埋暗挖黄土地铁围岩中加固效果较好,实际施工中应予以保留。%In this paper, a three-axial loading device of plane strain is used for a laboratory model test. Contrast tests are carried out for three kinds of anchor bolt arrangements, i.e., an arrangement with no anchor bolts, a whole-section arrangement of anchor bolts, and an arrangement of anchor bolts on the sidewall. The role of the anchor bolt system in a loess subway tunnel is studied in reference to field test results. Data regarding anchor bolts applied to a loess subway tunnel are obtained by model testing, and "loading-before-excavation" and anchor-lining integration are realized. By contrast, the development of a plastic zone around the working face is well controlled by the anchor bolt system; after excavation and support of the tunnel cavern, the sidewall anchor bolt can comply quickly with surrounding rock stress and effectively improve the stress distribution of the lining. Considering the economic factors, the sidewall anchor support system is a good method for reinforcing surrounding rock in shallow-bored loess subway tunnels and should be adopted in actual construction.

  9. A Review of Rock Bolt Monitoring Using Smart Sensors.

    Science.gov (United States)

    Song, Gangbing; Li, Weijie; Wang, Bo; Ho, Siu Chun Michael

    2017-04-05

    Rock bolts have been widely used as rock reinforcing members in underground coal mine roadways and tunnels. Failures of rock bolts occur as a result of overloading, corrosion, seismic burst and bad grouting, leading to catastrophic economic and personnel losses. Monitoring the health condition of the rock bolts plays an important role in ensuring the safe operation of underground mines. This work presents a brief introduction on the types of rock bolts followed by a comprehensive review of rock bolt monitoring using smart sensors. Smart sensors that are used to assess rock bolt integrity are reviewed to provide a firm perception of the application of smart sensors for enhanced performance and reliability of rock bolts. The most widely used smart sensors for rock bolt monitoring are the piezoelectric sensors and the fiber optic sensors. The methodologies and principles of these smart sensors are reviewed from the point of view of rock bolt integrity monitoring. The applications of smart sensors in monitoring the critical status of rock bolts, such as the axial force, corrosion occurrence, grout quality and resin delamination, are highlighted. In addition, several prototypes or commercially available smart rock bolt devices are also introduced.

  10. Tunnel fire dynamics

    CERN Document Server

    Ingason, Haukur; Lönnermark, Anders

    2015-01-01

    This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

  11. Ultrafast scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  12. CERN Rocks

    CERN Document Server

    2004-01-01

    The 15th CERN Hardronic Festival took place on 17 July on the terrace of Rest 3 (Prévessin). Over 1000 people, from CERN and other International Organizations, came to enjoy the warm summer night, and to watch the best of the World's High Energy music. Jazz, rock, pop, country, metal, blues, funk and punk blasted out from 9 bands from the CERN Musiclub and Jazz club, alternating on two stages in a non-stop show.  The night reached its hottest point when The Canettes Blues Band got everybody dancing to sixties R&B tunes (pictured). Meanwhile, the bars and food vans were working at full capacity, under the expert management of the CERN Softball club, who were at the same time running a Softball tournament in the adjacent "Higgs Field". The Hardronic Festival is the main yearly CERN music event, and it is organized with the support of the Staff Association and the CERN Administration.

  13. 40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA

    Science.gov (United States)

    Fleck, Robert J.; Hagstrum, Jonathan T.; Calvert, Andrew T.; Evarts, Russell C.; Conrey, Richard M.

    2014-01-01

    The 40Ar/39Ar investigations of a large suite of fine-grained basaltic rocks of the Boring volcanic field (BVF), Oregon and Washington (USA), yielded two primary results. (1) Using age control from paleomagnetic polarity, stratigraphy, and available plateau ages, 40Ar/39Ar recoil model ages are defined that provide reliable age results in the absence of an age plateau, even in cases of significant Ar redistribution. (2) Grouping of eruptive ages either by period of activity or by composition defines a broadly northward progression of BVF volcanism during latest Pliocene and Pleistocene time that reflects rates consistent with regional plate movements. Based on the frequency distribution of measured ages, periods of greatest volcanic activity within the BVF occurred 2.7–2.2 Ma, 1.7–0.5 Ma, and 350–50 ka. Grouped by eruptive episode, geographic distributions of samples define a series of northeast-southwest–trending strips whose centers migrate from south-southeast to north-northwest at an average rate of 9.3 ± 1.6 mm/yr. Volcanic activity in the western part of the BVF migrated more rapidly than that to the east, causing trends of eruptive episodes to progress in an irregular, clockwise sense. The K2O and CaO values of dated samples exhibit well-defined temporal trends, decreasing and increasing, respectively, with age of eruption. Divided into two groups by K2O, the centers of these two distributions define a northward migration rate similar to that determined from eruptive age groups. This age and compositional migration rate of Boring volcanism is similar to the clockwise rotation rate of the Oregon Coast Range with respect to North America, and might reflect localized extension on the trailing edge of that rotating crustal block.

  14. A draining concept for tunnels with the aim of optimizing their geothermal utilization; Concept de drainage des tunnels en vue d'une optimisation de l'utilisation geothermique (valorisation du potentiel geothermique des tunnels - Recherche d'optimisation)

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, J.

    2006-07-01

    Since almost 30 years, the geothermal potential of mountain water has been exploited in Swiss tunnels. The first known application was at the southern mouth of the St. Gotthard road tunnel, where the draining water was collected for heating a waiting-room in Airolo. The present report prepared for the Swiss Federal Office of Energy (SFOE) examines the possibilities for enhancing the efficiency and thus the potential of this geothermal application. They include: a) Reducing thermal losses by thermally insulating the water pipes along the tunnel. b) Increasing the usable quantity of water by providing additional drillings along the tunnel. c) Providing more than one water pipe, thus allowing to collect water of different temperatures in separate pipes. d) New technologies: add heat exchangers to tunnel construction elements in direct contact with the rocks, e.g. rock anchors, liners, concrete elements in the floor. The last chapter examines possible improvements for two large tunnels currently in project.

  15. Tidal bores, turbulence and mixing above deep-ocean slopes

    Science.gov (United States)

    Winters, Kraig

    2016-11-01

    A tidally driven, stably-stratified turbulent boundary layer over supercritically sloping topography is simulated numerically using a spectral LES approach (Winters, 2015, 2016). The near boundary flow is characterized by quasi-periodic, bore-like motions, whose temporal signature is compared to the high-resolution ocean mooring data of van Haren (2006). The relatively thick bottom boundary layer remains stably stratified owing to the regular cycling of unmixed ambient fluid into the turbulent boundary layer and episodic expulsion events where fluid is ejected into the stratified interior. The effective diffusivity of the flow near the boundary is estimated by means of a synthetic dye tracer experiment. The average dissipation rate within the dye cloud is computed and combined with the diffusivity estimate to yield an overall mixing efficiency of 0.15. Both the estimated diffusivity and dissipation rates are in reasonable agreement with the microstructure observations of Kunze et al. (2012) when scaled to the environmental conditions at the Monterey and Soquel Canyons and to the values estimated by van Haren and Gostiaux (2012) above the sloping bottom of the Great Meteor Seamount in the Canary Basin.

  16. Continuous circulation apparatus for air drilling well bore operations

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, J.L.

    1982-02-16

    An apparatus is disclosed for maintaining a continuous supply of air pressure downhole during a well bore drilling operation, even during the addition of a pipe section to the drill string. It consists of a housing installed at the surface of the well at the position of the drilling equipment wherein the upper end of the drill string is separated from the drive mechanism in order that a new piece of drill pipe may be added to the drill string, a flapper or closure member pivotally secured within the housing normally held in an open position by the outer periphery of the drill string and spring urged in a direction toward the open end of the sleeve through which the drive mechanism passes when the drive mechanism has been backed off or removed for the addition of a section of pipe to the drill string, and a by-pass line in communication with the interior of the housing for directing air pressure from the air supply to the housing when the flapper member is in the closed position whereby the air pressure may be circulated downwardly through the drill string for maintaining the air circulation downhole during the entire drilling operation.

  17. Static design of steel-concrete lining for traffic tunnels

    Science.gov (United States)

    Vojtasik, Karel; Mohyla, Marek; Hrubesova, Eva

    2017-09-01

    Article summarizes the results of research focused on the structural design of traffic tunnel linings that have been achieved in the framework of a research project TE01020168 that supports The Technology Agency of Czech Republic. This research aim is to find and develop a process for design structure parameters of tunnel linings. These are now mostly build up by a shotcrete technology. The shotcrete is commonly endorsed either with steel girders or steel fibres. Since the installation a lining structure is loaded while strength and deformational parameters of shotcrete start to rise till the setting time elapses. That’s reason why conventional approaches of reinforced concrete are not suitable. As well as there are other circumstances to step in shown in this article. Problem is solved by 3D analysis using numerical model that takes into account all the significant features of a tunnel lining construction process inclusive the interaction between lining structure with rock massive. Analysis output is a view into development of stress-strain state in respective construction parts of tunnel lining the whole structure around, including impact on stability of rock massive. The proposed method comprises all features involved in tunnel fabrication including geotechnics and construction technologies.

  18. Research on the closure and creep mechanism of circular tunnels

    Institute of Scientific and Technical Information of China (English)

    LI Lian-chong; TANG Chun-an; MA Tian-hui; ZHAO Xing-dong

    2008-01-01

    A numerical code called Rock Failure Process Analysis (RFPA2D) was employed to investigate the closure, damage and failure behavior of the horizontal tunnels. In his code the time-dependent deformation was described in terms of evolution of mesoscopic structure, leading to progressive degradation of elastic modulus and failure strength of material. In terms of material degradation, a series of numerical simulations were performed to study the convergence and subsequent failure in circular tunnels. The numerical esults provide a complete illumination for the closure, damage and failure behavior with different loading conditions. It is shown that the depth and the ratio of far field stresses play an important role in the creep behavior of tunnels. Creep failure is expected to occur in the direction of the smallest far field stress component, which means that rheological failure of tunnels is influenced not only by the rock characteristic around the tunnels but also by the orientation and distribution of far field stress on a global scale.

  19. Virtual photons in macroscopic tunneling

    OpenAIRE

    Aichmann, Horst; Nimtz, Guenter; Bruney, Paul

    2015-01-01

    Tunnelling processes are thought to proceed via virtual waves due to observed superluminal (faster than light) signal speeds. Some assume such speeds must violate causality. These assumptions contradict, for instance, superluminally tunnelled music and optical tunnelling couplers applied in fiber communication. Recently tunnelling barriers were conjectured to be cavities, wherein the tunnelled output signal is not causally related with the input. The tests described here resolve that tunnelli...

  20. Back-analysis for Determining the Rheological Parameter of Rock

    Institute of Scientific and Technical Information of China (English)

    Xu Wenhuan; Zhu Dayong

    1994-01-01

    In this paper,a new method of back analysis for determmning the parameters of rheological surrounding rock is proposed. This method is based on the elasticviscoelastic correspondence principle, and the theological parameters are back analyzed from the measured displacemenrs during construction of the tunnel.A numerical exampie proves that the proposed method is applicanle to engineering practice.

  1. Quantitative Determination of Noa (Naturally Occurring Asbestos) in Rocks : Comparison Between Pcom and SEM Analysis

    Science.gov (United States)

    Baietto, Oliviero; Amodeo, Francesco; Giorgis, Ilaria; Vitaliti, Martina

    2017-04-01

    The quantification of NOA (Naturally Occurring Asbestos) in a rock or soil matrix is complex and subject to numerous errors. The purpose of this study is to compare two fundamental methodologies used for the analysis: the first one uses Phase Contrast Optical Microscope (PCOM) while the second one uses Scanning Electron Microscope (SEM). The two methods, although they provide the same result, which is the asbestos mass to total mass ratio, have completely different characteristics and both present pros and cons. The current legislation in Italy involves the use of SEM, DRX, FTIR, PCOM (DM 6/9/94) for the quantification of asbestos in bulk materials and soils and the threshold beyond which the material is considered as hazardous waste is a concentration of asbestos fiber of 1000 mg/kg.(DM 161/2012). The most used technology is the SEM which is the one among these with the better analytical sensitivity.(120mg/Kg DM 6 /9/94) The fundamental differences among the analyses are mainly: - Amount of analyzed sample portion - Representativeness of the sample - Resolution - Analytical precision - Uncertainty of the methodology - Operator errors Due to the problem of quantification of DRX and FTIR (1% DM 6/9/94) our Asbestos Laboratory (DIATI POLITO) since more than twenty years apply the PCOM methodology and in the last years the SEM methodology for quantification of asbestos content. The aim of our research is to compare the results obtained from a PCOM analysis with the results provided by SEM analysis on the base of more than 100 natural samples both from cores (tunnel-boring or explorative-drilling) and from tunnelling excavation . The results obtained show, in most cases, a good correlation between the two techniques. Of particular relevance is the fact that both techniques are reliable for very low quantities of asbestos, even lower than the analytical sensitivity. This work highlights the comparison between the two techniques emphasizing strengths and weaknesses of

  2. Wind Tunnel Testing Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — NASA Ames Research Center is pleased to offer the services of our premier wind tunnel facilities that have a broad range of proven testing capabilities to customers...

  3. INCAS TRISONIC WIND TUNNEL

    Directory of Open Access Journals (Sweden)

    Florin MUNTEANU

    2009-09-01

    Full Text Available The 1.2 m x 1.2 m Trisonic Blowdown Wind Tunnel is the largest of the experimental facilities at the National Institute for Aerospace Research - I.N.C.A.S. "Elie Carafoli", Bucharest, Romania. The tunnel has been designed by the Canadian company DSMA (now AIOLOS and since its commissioning in 1978 has performed high speed aerodynamic tests for more than 120 projects of aircraft, missiles and other objects among which the twin jet fighter IAR-93, the jet trainer IAR-99, the MIG-21 Lancer, the Polish jet fighter YRYDA and others. In the last years the wind tunnel has been used mostly for experimental research in European projects such as UFAST. The high flow quality parameters and the wide range of testing capabilities ensure the competitivity of the tunnel at an international level.

  4. Quantum tunneling with friction

    Science.gov (United States)

    Tokieda, M.; Hagino, K.

    2017-05-01

    Using the phenomenological quantum friction models introduced by P. Caldirola [Nuovo Cimento 18, 393 (1941), 10.1007/BF02960144] and E. Kanai [Prog. Theor. Phys. 3, 440 (1948), 10.1143/ptp/3.4.440], M. D. Kostin [J. Chem. Phys. 57, 3589 (1972), 10.1063/1.1678812], and K. Albrecht [Phys. Lett. B 56, 127 (1975), 10.1016/0370-2693(75)90283-X], we study quantum tunneling of a one-dimensional potential in the presence of energy dissipation. To this end, we calculate the tunneling probability using a time-dependent wave-packet method. The friction reduces the tunneling probability. We show that the three models provide similar penetrabilities to each other, among which the Caldirola-Kanai model requires the least numerical effort. We also discuss the effect of energy dissipation on quantum tunneling in terms of barrier distributions.

  5. Water Tunnel Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s High-Pressure Water Tunnel Facility in Pittsburgh, PA, re-creates the conditions found 3,000 meters beneath the ocean’s surface, allowing scientists to study...

  6. Wind Tunnel Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This ARDEC facility consists of subsonic, transonic, and supersonic wind tunnels to acquire aerodynamic data. Full-scale and sub-scale models of munitions are fitted...

  7. 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。

  8. The influence of vibrations on surface roughness formed during precision boring

    Science.gov (United States)

    Korzeniewski, Dariusz; Znojkiewicz, Natalia

    2017-01-01

    In this paper, the analysis of vibrations on surface roughness generated during boring with the application of the conventional boring tool and one with the damper is presented. The experiments included the measurement of vibration accelerations carried out with the piezoelectric sensor, as well as the evaluation of surface roughness parameters after each machining pass. The obtained results reveal that in the investigated range, no stability loss was found. Furthermore, the growth of the rotational speed induces the increase of vibration level, as well as the growth of the differences between the vibration values generated during boring with the conventional tool and one equipped with damper. Vibrations have also the direct influence on the machined surface roughness. In case of the tool equipped with the damper, the tool's overhang L had more intense influence than rotational speed n. However, for the conventional boring tool this dependency was unequivocal.

  9. Estimation of the equilibrium formation temperature in the presence of bore fluid invasion

    DEFF Research Database (Denmark)

    Poulsen, Søren Erbs; Nielsen, S.B.; Balling, N.

    2012-01-01

    Bottom hole temperatures (BHTs) measured during drilling operations are thermally disturbed by the drilling process. This paper presents a method, CSMI (Cylindrical Source Model with Invasion of bore mud filtrate), for estimating equilibrium formation temperatures with probability distributions...... from BHT measurements in the presence of bore fluid invasion. The scheme is based on finite element analysis in conjunction with Markov chain Monte Carlo inversion. The axisymmetric forward model assumes a cylindrical source of finite radius and contrasting thermal parameters, which includes...... the possibility of invasion (advection) of mud filtrate into the formation. In a synthetic example, it is demonstrated that given bore fluid invasion and a low and high temperature of the bore mud and formation, respectively, the equilibrium formation temperature and the uncertainty hereon is underestimated...

  10. Observation of Optical Undular Bores in Multiple Four-Wave Mixing

    National Research Council Canada - National Science Library

    Fatome, J; Finot, C; Millot, G; Armaroli, A; Trillo, S

    2014-01-01

    ... (strong multiple four-wave mixing). In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores...

  11. Respiratory Complications Associated with Insertion of Small-Bore Feeding Tube in Critically Ill Patients

    Directory of Open Access Journals (Sweden)

    Jeong Am Ryu

    2014-05-01

    Full Text Available Small-bore flexible feeding tubes decrease the risk of ulceration of the nose, pharynx, and stomach compared with large-bore and more rigid tubes. However, small-bore feeding tubes have more respiratory system complications, such as pneumothorax, hydropneumothorax, bronchopleural fistula, and pneumonia, which are associated with significant morbidity and mortality. Thus, it is important to confirm the correct position of feeding tubes. Chest X-ray is the gold standard to detect tracheal malpositioning of the feeding tube. We present three cases in which intubated patients exhibited an altered mental state. An assistant guide wire was used at the insertion of small-bore feeding tubes. These conditions are thought to be potential risk factors for tracheobronchial malpositioning of feeding tubes.

  12. Boring sponges, an increasing threat for coral reefs affected by bleaching events

    National Research Council Canada - National Science Library

    Carballo, José L; Bautista, Eric; Nava, Héctor; Cruz-Barraza, José A; Chávez, Jesus A

    2013-01-01

    .... We tested the hypothesis that coral reefs affected by bleaching events are currently heavily infested by boring sponges, which are playing a significant role in the destruction of their physical structure...

  13. Study on orientation fracture blasting with shaped charge in rock

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of the theories of mechanics of explosive and rock fracture mechanics, the mechanism of crack initiation and its expansion of directional fracture controlled blasting with shaped charges in rock were studied, then the blasting parameters were designed and tested by a model test in laboratory and field experiment. The experimental and test results showed that the energy from blasting is directionally concentrated for the cumulative action. The directional expansion of cracks is satisfactory, the results of the model test and field test suggested that the orientation fracture blasting with shaped charge is a good means of excavating tunnels or cutting rock.

  14. In situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The seven long tunnels of Jinping II hydropower station are deeply buried.The width and evolution characteristics of excavation damaged zone(EDZ) are the key problem to the design of tunnels excavation and supports.In order to study this problem,several specific experimental tunnels with different overburden and geometric sizes were excavated at this site.Digital borehole camera,sliding micrometer,cross-hole acoustic wave equipment and acoustic emission apparatus were adopted.This paper introduced the comprehensive in situ experimental methods through pre-installed facilities and pre-drilled boreholes.Typical properties of the surrounding rock mass,including cracks,deformation,elastic wave and micro fractures,were measured during the whole process of the tunnel excavation.The width and characteristics of formation and evolution of tunnels EDZ were analyzed under different construction methods involving of TBM and drilling and blasting,the test tunnels were excavated by full-face or two benches.The relationships between EDZ and tunnel geometry sizes,overburden and excavation method were described as well.The results will not only contribute a great deal to the analysis of rock mass behavior in deeply buried rock mass,but also provide direct data for support design and rockburst prediction.

  15. Gravity Tunnel Drag

    CERN Document Server

    Concannon, Thomas

    2016-01-01

    The time it takes to fall down a tunnel through the center of the Earth to the other side takes approximately 42 minutes, but only when given several simplifying assumptions: a uniform density Earth; a gravitational field that varies linearly with radial position; a non-rotating Earth; a tunnel evacuated of air; and zero friction along the sides of the tunnel. Though several papers have singularly relaxed the first three assumptions, in this paper we relax the final two assumptions and analyze the motion of a body experiencing these types of drag forces in the tunnel. Under such drag forces, we calculate the motion of a transport vehicle through a tunnel of the Earth under uniform density, under constant gravitational acceleration, and finally under the more realistic Preliminary Reference Earth Model (PREM) density data. We find the density profile corresponding to a constant gravitational acceleration better models the motion through the tunnel compared to the PREM density profile, and the uniform density m...

  16. Effect of fluid viscosity on wave propagation in a cylindrical bore in micropolar elastic medium

    Indian Academy of Sciences (India)

    Sunita Deswal; Sushil K Tomar; Rajneesh Kumar

    2000-10-01

    Wave propagation in a cylindrical bore filled with viscous liquid and situated in a micropolar elastic medium of infinite extent is studied. Frequency equation for surface wave propagation near the surface of the cylindrical bore is obtained and the effect of viscosity and micropolarity on dispersion curves is observed. The earlier problems of Biot and of Banerji and Sengupta have been reduced as a special case of our problem.

  17. Solid-to-hybrid transitioning armature railgun with non-conforming-to-prejudice bore profile

    Science.gov (United States)

    Solberg, Jerome Michael

    2012-12-04

    An improved railgun, railgun barrel, railgun projectile, and railgun system for accelerating a solid-to-hybrid transitioning armature projectile using a barrel having a bore that does not conform to a cross-sectional profile of the projectile, to contact and guide the projectile only by the rails in a low pressure bore volume so as to minimize damage, failure, and/or underperformance caused by plasma armatures, insulator ablation, and/or restrikes.

  18. Case Histories of Four Extremely Intense Rockbursts in Deep Tunnels

    Science.gov (United States)

    Zhang, Chuanqing; Feng, Xia-Ting; Zhou, Hui; Qiu, Shili; Wu, Wenping

    2012-05-01

    In the process of excavating seven parallel tunnels at the Jinping II Hydropower Station, several extremely intense rockbursts occurred, killing and injuring construction workers and damaging several sets of equipment. Based on the characteristics and mechanisms of these rockbursts, four typical events were selected and their temporal and spatial characteristics were here described in detail. The geological conditions revealed after the rockbursts were surveyed carefully. The responses of support elements were also analyzed. The details documented in each case provide not only an important reference for understanding the development mechanisms of rockbursts but also a basis for the selection and development of rockburst prevention measures in deep hard rock tunnels.

  19. Rollerjaw Rock Crusher

    Science.gov (United States)

    Peters, Gregory; Brown, Kyle; Fuerstenau, Stephen

    2009-01-01

    The rollerjaw rock crusher melds the concepts of jaw crushing and roll crushing long employed in the mining and rock-crushing industries. Rollerjaw rock crushers have been proposed for inclusion in geological exploration missions on Mars, where they would be used to pulverize rock samples into powders in the tens of micrometer particle size range required for analysis by scientific instruments.

  20. COMPARISON OF TUNNELLING METHODS NATM AND ADECO-RS

    Directory of Open Access Journals (Sweden)

    Linda Černá Vydrová

    2015-04-01

    Full Text Available The New Austrian Tunnelling Method (NATM has been often used in the Czech Republic in last two decades. One of the methods, without application in the Czech Republic, is an Italian method called ADECO-RS, which has reached significant use in Italy and some other countries. It is the method of controlled deformation, which uses mainly the horizontal anchoring of the tunnel face to reinforce the area in front of the face (advance core. This technology is especially important in weak and soft rocks where is necessary to excavate quickly and smoothly with minimum disruption of initial stress state of the rock mass in the vicinity of the excavation. The use of NATM can be in some cases uneconomical and technically inadequately challenging and in such cases would be appropriate to choose another technology. Given the facts above, in the Czech environment there is no data available for comparison of these methods not only in terms of numerical modelling, but also in terms of feasibility and usability. The paper summarizes history of the tunnelling methods and it is closer devoted to NATM and ADECO-RS tunnelling approaches. The basic principles of both methods are set and further the comparison of these methods is made on a theoretical level. The paper hereinafter includes the analysis of fibreglass face anchors application during the construction of three-aisled Veleslavín Station and the impact assessment of tunnel face anchoring during the excavation of ventilation tunnel on the newly built part of the Prague Metro „V.A“. The paper also deals with practical knowledge gained during the technical visit of Italian Val di Sambro Tunnel which is built according to ADECO-RS approach. These findings are essential for the correct interpretation of Lunardi method.

  1. A Multi-Instrument Measurement of a Mesospheric Bore at the Equator

    Science.gov (United States)

    Shiokawa, K.; Suzuki, S.; Otsuka, Y.; Ogawa, T.; Nakamura, T.; Mlynczak, M. G.; Russell, J. M., III

    2005-01-01

    We have made a comprehensive measurement of mesospheric bore phenomenon at the equator at Kototabang, Indonesia (0.2 deg S, 100.3 deg E), using an airglow imager, an airglow temperature photometer, a meteor radar, and the SABER instrument on board the TIMED satellite. The bore was detected in airglow images of both OH-band (peak emission altitude: 87 km) and 557.7-nm (96 km) emissions, as east-west front-like structure propagating northward with a velocity of 52-58 m/s. Wave trains with a horizontal wavelength of 30-70 km are observed behind the bore front. The airglow intensity decreases for all the mesospheric emissions of OI (557.7 nm), OH-band, O2-band (altitude: 94 km), and Na (589.3 nm) (90 km) after the bore passage. The rotational temperatures of both OH-band and O2-band also decrease approximately 10 K after the bore passage. An intense shear in northward wind velocity of 80m/s was observed at altitudes of 84-90 km by the meteor radar. Kinetic temperature profile at altitudes of 20-120 km was observed near Kototabang by TIMED/SABER. On the basis of these observations, we discuss generation and ducting of the observed mesospheric bore.

  2. Improvement of machining accuracy in precision micro-boring system by forecasting compensatory control technique

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the design of a micro-boring servo system. A piezoelectric actuator is employed to compensate the deflection errors of the cutter in the radial direction to reduce the force-induced errors in the workpiece. In order to bore small and deep holes, the boring bar is designed with a new structure consisting of two concentric bars, one being used for error measuring and the other for error compensation. As a result, the size of the micro-boring bar is not af fected even after the piezoelectric actuator and strain gauges have been incorporated. The outer diameter of the boring bar used is 16 mm and the length to diameter ratio is greater than 9. A Forecasting Compensatory Control (FCC) technique is adopted in this system for error prediction and error compensation. The off-line forecasting compensatory control simulation and on-line cutting results have verified that the roundness form errors in the workpiece can be re duced up to 60 percent with the developed micro-boring servo system.

  3. An undular bore solution for the higher-order Korteweg-de Vries equation

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, T R [School of Mathematics and Applied Statistics, University of Wollongong, Wollongong, 2522, NSW (Australia); Smyth, N F [School of Mathematics, University of Edinburgh, The King' s Buildings, Mayfield Road, Edinburgh, EH9 3JZ (United Kingdom)

    2006-09-15

    Undular bores describe the evolution and smoothing out of an initial step in mean height and are frequently observed in both oceanographic and meteorological applications. The undular bore solution for the higher-order Korteweg-de Vries (KdV) equation is derived, using an asymptotic transformation which relates the KdV equation and its higher-order counterpart. The higher-order KdV equation considered includes all possible third-order correction terms (where the KdV equation retains second-order terms). The asymptotic transformation is then applied to the KdV undular bore solution to obtain the higher-order undular bore. Examples of higher-order undular bores, describing both surface and internal waves, are presented. Key properties, such as the amplitude and speed of the lead soliton and the width of the bore, are found. An excellent comparison is obtained between the analytical and numerical solutions. Also, it is illustrated how an asymptotic transformation and numerical solutions can be combined to generate hybrid asymptotic-numerical solutions, thus avoiding the severe instabilities associated with numerical schemes for the higher-order KdV equation. (letter to the editor)

  4. A 233 km Tunnel for Lepton and Hadron Colliders

    CERN Document Server

    Summers, D J; Datta, A; Duraisamy, M; Luo, T; Lyons, G T

    2012-01-01

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of $e^+e^-$, $p \\bar{p}$, and $\\mu^+ \\mu^-$ collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV $e^+e^-$ colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV $e^+ e^-$ collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV $p \\bar{p}$ collider uses the high intensity Fermilab $\\bar{p}$ source, exploits high cross sections for $p \\bar{p}$ production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconduct...

  5. A 233 km tunnel for lepton and hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T. [Dept. of Physics and Astronomy, University of Mississippi-Oxford, University, MS 38677 (United States)

    2012-12-21

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  6. Analysis and management of risks experienced in tunnel construction

    Directory of Open Access Journals (Sweden)

    Cagatay Pamukcu

    2015-12-01

    Full Text Available In this study, first of all, the definitions of "risk", "risk analysis", "risk assessment" and "risk management" were made to avoid any confusions about these terms and significance of risk analysis and management in engineering projects was emphasized. Then, both qualitative and quantitative risk analysis techniques were mentioned and within the scope of the study, Event Tree Analysis method was selected in order to analyze the risks regarding TBM (Tunnel Boring Machine operations in tunnel construction. After all hazards that would be encountered during tunnel construction by TBM method had been investigated, those hazards were undergoing a Preliminary Hazard Analysis to sort out and prioritize the risks with high scores. When the risk scores were taken into consideration, it was seen that the hazards with high risk scores could be classified into 4 groups which are excavation + support induced accidents, accidents stemming from geologic conditions, auxiliary works, and project contract. According to these four classified groups of initiating events, Event Tree Analysis was conducted by taking into care 4 countermeasures apart from each other. Finally, the quantitative and qualitative consequences of Event Tree Analyses, which were undertaken for all initiating events, were investigated and interpreted together by making comparisons and referring to previous studies.

  7. Sedimentary environments of organic matter from Middle Permian source rocks in northern Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    MIAO Jianyu; KOU Hansheng; ZHOU Lifa; HAN Zhongyuan

    2006-01-01

    A systematic analysis of the inorganic and organic geochemistry of Middle Permian source rocks comprising carbonate rocks and mudstones was carried out, with samples collected from the outcrop and bore of the Junggar, Turpan and Ili basins in northern Xinjiang. This study confirmed that sedimentary parameters for an ancient water body, such as inorganic geochemistry and paleosalinity, have a close relation to the organic matter of source rocks. It is also disclosed that phytane predominance in the source rocks is mainly due to a reducing environment. Biomarkers, such as gammacerane and β-carotene, in the samples reflect a specific salinity in the sedimentary environments. Sedimentary zones with a strong reducing environment are more likely to produce deposits of primary organic matter, which will be buried and preserved contemporarily. Consequently, the source rocks are generally high in organic content and better in organic type than ordinary ones, and vice versa.

  8. Electromagnetic receiver with capacitive electrodes and triaxial induction coil for tunnel exploration

    Science.gov (United States)

    Kai, Chen; Sheng, Jin; Wang, Shun

    2017-09-01

    A new type of electromagnetic (EM) receiver has been developed by integrating four capacitive electrodes and a triaxial induction coil with an advanced data logger for tunnel exploration. The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of surface-tunnel-borehole EM detection for deep ore deposit mapping. The use of capacitive electrodes enables us to record the electrical field (E-field) signals from hard rock surfaces, which are high-resistance terrains. A compact triaxial induction coil integrates three independent induction coils for narrow-tunnel exploration applications. A low-time-drift-error clock source is developed for tunnel applications where GPS signals are unavailable. The three main components of our tunnel EM receiver are: (1) four capacitive electrodes for measuring the E-field signal without digging in hard rock regions; (2) a triaxial induction coil sensor for audio-frequency magnetotelluric and controlled-source audio-frequency magnetotelluric signal measurements; and (3) a data logger that allows us to record five-component MT signals with low noise levels, low time-drift-error for the clock source, and high dynamic range. The proposed tunnel EM receiver was successfully deployed in a mine that exhibited with typical noise characteristics. [Figure not available: see fulltext. Caption: The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of the surface-tunnel-borehole EM (STBEM) detection for deep ore deposit mapping. The use of a capacitive electrode enables us to record the electrical field (E-field) signals from hard rock surfaces. A compact triaxial induction coil integrated three induction coils, for narrow-tunnel applications.

  9. USING GROUND PENETRATING RADAR TO DETERMINE THE TUNNEL LOCATION BURIED UNDER THE GLACIER

    Directory of Open Access Journals (Sweden)

    Deryuga Andrey Mikhaylovich

    2013-09-01

    Full Text Available The works were carried out with the help of ground penetrating radar “Grot-10”. Doublet broadband antennas with the central frequency of 100 MHz were used. Georadar measures the speed of EM waves v in ice-saturated soil and then the value ε′ is calculated. The radargrams received as a result of georadar survey, which represents stacked data (the two-way time is indicated on vertical scale, were transformed into depth sections, which reflect the space structure located below ground. The distance between the bottom landing and buried mountain road near the north tunnel portal is 78,5 m (profile # 1, and the distance from the upper landing is 84,5 m (profile no. 2. Later, in the April 2003 during the hole boring with the diameter 1,2 m the vertical distance between the upper landing, where ground penetrating works were carried out, and the carpet road of the tunnel was calculated. This distance appeared to be 83 m, that means, the discrepancy between boring and georadar data (84,5 m was only 1,5 m. Thus, the results of ground penetrating investigations helped the workers of glacier to make the correct conclusion on time about the location and burial depth of the tunnel.

  10. Advanced Rock Drilling Technologies Using High Laser Power

    Science.gov (United States)

    Buckstegge, Frederik; Michel, Theresa; Zimmermann, Maik; Roth, Stephan; Schmidt, Michael

    Drilling through hard rock formations causes high mechanical wear and most often environmental disturbance. For the realization of an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) power plant a new and efficient method for tunneling utilising laser technology to support mechanical ablation of rock formations will be developed. Laser irradiation of inhomogeneous rock surfaces causes irregular thermal expansion leading to the formation of cracks and splintering as well as melting and slag-formation. This study focuses on the interaction of laser irradiation with calcite, porphyrite and siderite rock formations. A high power disc laser system at 1030nm wavelength is used to investigate the specific energy necessary to remove a unit volume depending on interaction times and applied power. Specific energies have been measured and an increase of fragility and brittleness of the rock surface has been observed.

  11. Sulphate reduction in the Aespoe HRL tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson, G. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Geology; Laaksoharju, M. [ed.; Skaarman, C. [GeoPoint AB, Sollentuna (Sweden); Pedersen, K. [Goeteborg Univ. (Sweden). Dept. of Genetics, Microbiology and Molecular Biology; Rhen, I. [VBB Viak (Sweden); Tullborg, E.L. [Terralogica AB (Sweden); Wallin, B. [Geokema AB (Sweden); Wikberg, P. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    1995-12-01

    Evidence and indications of sulphate reduction based on geological, hydrogeological, groundwater, isotope and microbial data gathered in and around the Aespoe Hard Rock Laboratory tunnel have been evaluated. This integrated investigation showed that sulphate reduction had taken place in the past but is most likely also an ongoing process. Anaerobic sulphate-reducing bacteria can live in marine sediments, in the tunnel sections under the sea and in deep groundwaters, since there is no access to oxygen. The sulphate-reducing bacteria seem to thrive when the Cl{sup -} concentration of the groundwater is 4000-6000 mg/l. Sulphate reduction is an in situ process but the resulting hydrogen-sulphide rich water can be transported to other locations. A more vigorous sulphate reduction takes place when the organic content in the groundwater is high (>10 mg/l DOC) which is the case in the sediments and in the groundwaters under the sea. Some bacteria use hydrogen as an electron donor instead of organic carbon and can therefore live in deep environments where access to organic material is limited. The sulphate-reducing bacteria seem to adapt to changing flow situations caused by the tunnel construction relatively fast. Sulphate reduction seems to have occurred and will probably occur where conditions are favourable for the sulphate-reducing bacteria such as anaerobic brackish groundwater with dissolved sulphate and organic carbon or hydrogen. 59 refs, 37 figs, 6 tabs.

  12. Sulphate reduction in the Aespoe HRL tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson, G. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Geology; Laaksoharju, M. [ed.; Skaarman, C. [GeoPoint AB, Sollentuna (Sweden); Pedersen, K. [Goeteborg Univ. (Sweden). Dept. of Genetics, Microbiology and Molecular Biology; Rhen, I. [VBB Viak (Sweden); Tullborg, E.L. [Terralogica AB (Sweden); Wallin, B. [Geokema AB (Sweden); Wikberg, P. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    1995-12-01

    Evidence and indications of sulphate reduction based on geological, hydrogeological, groundwater, isotope and microbial data gathered in and around the Aespoe Hard Rock Laboratory tunnel have been evaluated. This integrated investigation showed that sulphate reduction had taken place in the past but is most likely also an ongoing process. Anaerobic sulphate-reducing bacteria can live in marine sediments, in the tunnel sections under the sea and in deep groundwaters, since there is no access to oxygen. The sulphate-reducing bacteria seem to thrive when the Cl{sup -} concentration of the groundwater is 4000-6000 mg/l. Sulphate reduction is an in situ process but the resulting hydrogen-sulphide rich water can be transported to other locations. A more vigorous sulphate reduction takes place when the organic content in the groundwater is high (>10 mg/l DOC) which is the case in the sediments and in the groundwaters under the sea. Some bacteria use hydrogen as an electron donor instead of organic carbon and can therefore live in deep environments where access to organic material is limited. The sulphate-reducing bacteria seem to adapt to changing flow situations caused by the tunnel construction relatively fast. Sulphate reduction seems to have occurred and will probably occur where conditions are favourable for the sulphate-reducing bacteria such as anaerobic brackish groundwater with dissolved sulphate and organic carbon or hydrogen. 59 refs, 37 figs, 6 tabs.

  13. Suppression of tunneling rate fluctuations in tunnel field-effect transistors by enhancing tunneling probability

    Science.gov (United States)

    Mori, Takahiro; Migita, Shinji; Fukuda, Koichi; Asai, Hidehiro; Morita, Yukinori; Mizubayashi, Wataru; Liu, Yongxun; O’uchi, Shin-ichi; Fuketa, Hiroshi; Otsuka, Shintaro; Yasuda, Tetsuji; Masahara, Meishoku; Ota, Hiroyuki; Matsukawa, Takashi

    2017-04-01

    This paper discusses the impact of the tunneling probability on the variability of tunnel field-effect transistors (TFETs). Isoelectronic trap (IET) technology, which enhances the tunneling current in TFETs, is used to suppress the variability of the ON current and threshold voltage. The simulation results show that suppressing the tunneling rate fluctuations results in suppression of the variability. In addition, a formula describing the relationship between the tunneling rate fluctuations and the electric field strength is derived based on Kane’s band-to-band tunneling model. This formula indicates that the magnitude of the tunneling rate fluctuations is proportional to the magnitude of the fluctuations in the electric field strength and a higher tunneling probability results in a lower variability. The derived relationship is universally valid for any technologies that exploit enhancement of the tunneling probability, including IET technology, channel material engineering, heterojunctions, strain engineering, etc.

  14. Test with different stress measurement methods in two orthogonal bore holes in Aespoe HRL

    Energy Technology Data Exchange (ETDEWEB)

    Janson, Thomas; Stigsson, Martin [Golder Associates AB, Stockholm (Sweden)

    2002-12-01

    conclusions have been drawn, based on the stress measurements and deeper investigations: The following stress state is obtained at the target volume at about -455 m. The minimum horizontal stress is between 10 and 13 MPa, which is lower than the theoretical vertical stress. The maximum horizontal stress is 24 {+-}5 MPa, most likely within the upper range. The vertical stress is between 15 and 20 MPa, most probably is this value only local due to the presence of a nearby fracture. The local disturbance of the stress field in the rock mass, due to discontinuities has been demonstrated. This also indicates one of the problems with stress measurements in boreholes. In the area with significant anisotropic stress conditions all the tested methods were able to determine the orientation of the principal major horizontal stress within {+-} 10 deg. The microscopy investigations confirm two sets of microcracks in the overcored core. One set was parallel and near the bore hole bottom and one set was perpendicular to the bottom and located a bit away from the hole bottom. The results from the overcoring may be influenced by microcracks, causing additional non-elastic strains. Only the results from the DDGS seem to have been influenced, indicating that the hollow cylinder of a 3D stress cell may be less sensitive for stress induced sample disturbance than core samples from the 2D Door stopper cell. The determination of Young's modulus in a medium grained crystalline rock with heterogeneity may not be trivial using core samples. The results from the determination influence the calculated stresses. Hydraulic fracturing most likely measures the most correct value of the minimum horizontal stress, provided that the induced fracture is aligned with the borehole. If the rock behaves reasonable elastic the overcoring methods provide stress magnitudes with an uncertainty of 15-20%. It seems likely that the overcoring methods may overestimate the stress magnitudes at large depth, due to the

  15. Fragility Analysis of a Concrete Gravity Dam Embedded in Rock and Its System Response Curve Computed by the Analytical Program GDLAD_Foundation

    Science.gov (United States)

    2012-06-01

    Mining Science, and Geomechanics Abstracts 22(3):121–140. Bieniawski, Z. T. 1979. Tunnel design by rock mass classifications. Technical Report GL...quantitative description of discontinuities in rock masses. International Journal of Rock Mechanics, Mining Science and Geomechanical Abstracts 15:319–368

  16. Aespoe Hard Rock Laboratory. Annual Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. The work performed at Aespoe HRL during 2006 is in this report described in six chapters: Geo-science - experiments, analysis and modelling to increase the knowledge of the surrounding rock; Natural barriers - experiments, analysis and modelling to increase the knowledge of the repository barriers under natural conditions; Engineered barriers - demonstration of technology for and function of important engineered parts of the repository barrier system; Aespoe facility - operation, maintenance, data management, monitoring, public relations etc; Environmental research; and finally, International co-operation.

  17. Tidal Bore detection in the Garonne River using high frequency GNSS data

    Science.gov (United States)

    Frappart, Frédéric; Roussel, Nicolas; Darrozes, José; Bonneton, Philippe; Bonneton, Natalie; Detandt, Guillaume; Perosanz, Felix; Loyer, Sylvain

    2016-04-01

    A tidal bore is a positive surge propagating upstream that may form when a rising tide with significant amplitude enters shallow, gently sloping and narrowing rivers. Tidal bores have a significant impact on the river ecosystem behavior, especially in terms of sediment transport. Most of the existing field studies were limited to visual observations. Only a few field experiments have been devoted to a quantitative study of the tidal bore dynamics. We carried out a field study in August, 2015, using a GNSS buoy to measure the tidal bore in the Garonne River (France) at Podensac located 140 km upstream of the estuary mouth. Precise Point Positioning and Differential GNSS techniques were used to determine the river surface height variations with a 20 Hz sampling rate. This site was selected owing to the presence of well-developed undular tidal bores and also because of the absence of any significant curvature of the river at this location, which limits the complexity of the tidal bore structure. The Gironde estuary is located in the Bay of Biscay, on the southwest coast of France, and is formed from the meeting of the rivers Dordogne and Garonne. In the Gironde mouth, the mean neap tidal range and mean spring tidal range is 2.5 m and 5 m, respectively. As the tide propagates upstream a marked ebbflood asymmetry occurs in the upper reaches of the estuary and the wave is amplified. This large amplitude tidal wave propagates in the Garonne and Dordogne rivers up to 160 km from the estuary mouth. Both GNSS buoy and reference station use a Leica AR10 antenna and GR25 receiver. Both stations (reference and buoy) acquired data with a 20 Hz sampling rate. GNSS data were processed using RTKLib. Results allowed to detect the the wave train of the tidal bore that caused an elevation of the surface of around 1.5 m. Comparisons were performed using acoustic data showing a good agreement between both sources of data.

  18. Usage of Empirical-Statical-Dynamical (ESD method for data extrapolation in Tunnel Construction

    Directory of Open Access Journals (Sweden)

    Zafirovski Zlatko

    2016-01-01

    Full Text Available This article describes a methodology that shows how it is possible to integrate all these approaches in a problem for extrapolation of the parameters for hydrotechical tunnels. During the design process for tunnels in hydrotechics, one of the main problems is how to extrapolate the deformability and shear strentgh rock mass parameters from the zone of testing to the whole area (volume of interes for interaction analyses between structure abd natural environments. Computers development in recent decades has contributed to the development of numerical calculation method in rock mechanics which enabled new and wider possibilities of stress and deformation calculation. This had significantly stimulated the development of rock mechanics and tunneling as scientific and technical discipline as well as the wider application of research results into practice.

  19. Early times in tunneling

    CERN Document Server

    García-Calderón, G; Garcia-Calderon, Gaston; Villavicencio, Jorge

    2000-01-01

    Exact analytical solutions of the time-dependent Schr\\"odinger equation with the initial condition of an incident cutoff wave are used to investigate the traversal time for tunneling. The probability density starts from a vanishing value along the tunneling and transmitted regions of the potential. At the barrier width it exhibits, at early times, a distribution of traversal times that typically has a peak $\\tau_p$ and a width $\\Delta \\tau$. Numerical results for other tunneling times, as the phase-delay time, fall within $\\Delta \\tau$. The B\\"uttiker traversal time is the closest to $\\tau_p$. Our results resemble calculations based on Feynman paths if its noisy behaviour is ignored.

  20. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  1. Femtosecond scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.J.; Donati, G.P.; Rodriguez, G.; Gosnell, T.R.; Trugman, S.A.; Some, D.I.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). By combining scanning tunneling microscopy with ultrafast optical techniques we have developed a novel tool to probe phenomena on atomic time and length scales. We have built and characterized an ultrafast scanning tunneling microscope in terms of temporal resolution, sensitivity and dynamic range. Using a novel photoconductive low-temperature-grown GaAs tip, we have achieved a temporal resolution of 1.5 picoseconds and a spatial resolution of 10 nanometers. This scanning tunneling microscope has both cryogenic and ultra-high vacuum capabilities, enabling the study of a wide range of important scientific problems.

  2. Stress-strain relations for swelling anhydritic clay rocks – A review

    Science.gov (United States)

    Breuer, Simon; Blum, Philipp; Butscher, Christoph

    2015-04-01

    The swelling of clay-sulfate rocks is a major threat in tunnel engineering, causing serious damage to tunnels and producing high additional costs during tunnel construction and operation. The swelling leads to geomechanical processes that may result in heave of the tunnel invert, destruction of the lining or uplift of the entire tunnel section. Heave-pressure-time relations are needed when predictions should be made about the mechanical behavior of swelling rock. For pure clay rocks, there is a linear relation between the swelling heave (strain) and the logarithm of pressure (Grob 1972). A generally accepted relation for clay-sulfate rocks, however, is still lacking to date. Therefore, finding appropriate and sustainable counter measures for an actual tunneling project affected by swelling remains extremely difficult. Grob (1972) proposed the linear relation between heave and the logarithm of pressure ("semi-logarithmic swelling law") not only for clay rocks, but also for clay-sulfate rocks. Pimentel (2007), however, presented laboratory experiments indicating that the semi-logarithmic swelling law may be inadequate for describing the swelling of clay-sulfate rocks. The laboratory tests revealed three different stages in the swelling process, including minimal deformation and prevented gypsum crystallization at high pressures (> 6 MPa); large deformation and gypsum crystallization at medium pressures; and only small deformation, possibly along with gypsum dissolution, at low pressures (water inflow into the rock, which cannot be reflected by general strain-stress relations. The present study critically reviews stress-strain relations for swelling anhydritic clay rocks proposed by various authors. Subsequently, published laboratory data from oedometric swelling tests are presented that may confirm the proposed stress-strain relationships. Finally, these data are re-examined by comparing each of the proposed relations with the same data set. Based on these results, a

  3. Tunneling in Axion Monodromy

    CERN Document Server

    Brown, Jon; Shiu, Gary; Soler, Pablo

    2016-01-01

    The Coleman formula for vacuum decay and bubble nucleation has been used to estimate the tunneling rate in models of axion monodromy in recent literature. However, several of Coleman's original assumptions do not hold for such models. Here we derive a new estimate with this in mind using a similar Euclidean procedure. We find that there are significant regions of parameter space for which the tunneling rate in axion monodromy is not well approximated by the Coleman formula. However, there is also a regime relevant to large field inflation in which both estimates parametrically agree. We also briefly comment on the applications of our results to the relaxion scenario.

  4. Tunneling in axion monodromy

    Science.gov (United States)

    Brown, Jon; Cottrell, William; Shiu, Gary; Soler, Pablo

    2016-10-01

    The Coleman formula for vacuum decay and bubble nucleation has been used to estimate the tunneling rate in models of axion monodromy in recent literature. However, several of Coleman's original assumptions do not hold for such models. Here we derive a new estimate with this in mind using a similar Euclidean procedure. We find that there are significant regions of parameter space for which the tunneling rate in axion monodromy is not well approximated by the Coleman formula. However, there is also a regime relevant to large field inflation in which both estimates parametrically agree. We also briefly comment on the applications of our results to the relaxion scenario.

  5. Long distance tunneling

    CERN Document Server

    Ivlev, B I

    2005-01-01

    Quantum tunneling between two potential wells in a magnetic field can be strongly increased when the potential barrier varies in the direction perpendicular to the line connecting the two wells and remains constant along this line. A periodic structure of the wave function is formed in the direction joining the wells. The resulting motion can be coherent like motion in a conventional narrow band periodic structure. A particle penetrates the barrier over a long distance which strongly contrasts to WKB-like tunneling. The whole problem is stationary. The coherent process can be influenced by dissipation.

  6. Geotechnical Descriptions of Rock and Rock Masses.

    Science.gov (United States)

    1985-04-01

    weathering is presented by Dornbusch (1982). 39. Mechanical, or physical, weathering of rock occurs primarily by (a) freeze expansion (or frost wedging...34Engineering Classifica- tion of In-Situ Rock," Technical Report No. AFWL-TR-67-144, Air Force Weapons Laboratory, Kirtland Air Force Base, N. Mex. Dornbusch , W

  7. Electro-Pulse-Boring (EPB):Novel Super-Deep Drilling Technology for Low Cost Electricity

    Institute of Scientific and Technical Information of China (English)

    Hans O.Schiegg; Arild Rdland; Guizhi Zhu; David A Yuen

    2015-01-01

    The inexhaustible heat deposit in great depths (5–10 km) is a scientific fact. Such deposit occurs around the globe. Thereby, everybody is enabled to generate autonomously clean and renew-able energy, ample electricity and heat. The economical exploration and exploitation of this super-deep geothermal heat deposit requires a novel drilling technique, because the currently only deep drilling method (Rotary) is limited to about 5 km, due to the rising costs, depending exponentially on depth. Electro-pulse-boring (EPB) is a valuable option to Rotary drilling. EPB, originally investigated in Russia, is ready to be developed for industrialization. The feasibility of EPB is proven by many boreholes drilled up to 200 m in granite (crystalline). Estimates show outstanding low costs for drilling by EPB: 100€/m for a borehole with a large diameter (Ø) such as 20"(50 cm), independent on depth and applicable likewise for sediments and crystalline rocks, such as granite. The current rate of pene-tration (ROP) of 3 m per hour is planned to be augmented up to 35 m per hour, and again, irrespec-tive whether in sedimentary or crystalline formations. Consequently, a 10 km deep borehole with Ø 50 cm will ultimately be drilled within 12 days. EPB will create new markets, such as: (i) EPB shallow drilling for geotechnics, energy piles, measures in order to mitigate natural hazards, etc., (ii) EPB deep drilling (3–5 km) for hydro-geothermics, exploration campaigns etc. and (iii) EPB super-deep drilling (5–10 km) for petro-geothermics, enabling the economic generation of electricity. The autonomous and unlimited supply with cost efficient electricity, besides ample heat, ensures reliably clean and renew-able energy, thus, high supply security. Such development will provide a substantial relief to cope with the global challenge to limit the climate change below 2 ºC. The diminution of fossil fuels, due to the energy transition in order to mitigate the climate change, implies

  8. 隔河岩电站引水隧洞群洞开挖研究%Excavation of Inlet Tunnels at Geheyan Power S tation

    Institute of Scientific and Technical Information of China (English)

    LIU; Li-xin

    2001-01-01

    The Geheyan Power Station on the Qingjiang river has four inlet tunnels, on the right bank, with its excavation diameter of 11.3 m to 12.5 m, after-lining diam eter of 9.5 m, axis-to-axis spacing of 24 m. The thickness of the pillar betwe en tunnels should usually be more than two times of tunnel diameter to ensure th e stability of surrounding rock during excavation. In this paper, the excavation methods of tunnels with the pillar thickness as small as the tunnel diameter, s uch as smooth surface blasting, shotcrete support protection, are emphatically d iscussed.

  9. 极强岩爆条件下开敞式TBM施工措施探讨与应用%An Exploration into and the Application of Construction Measures to the Open-Type TBM Under the Conditions of Extremely Serious Rock Burst

    Institute of Scientific and Technical Information of China (English)

    朱玉江

    2012-01-01

    每一台隧道掘进机(TBM)都是针对一定的地质条件设计制造的,其针对性强、通用性较差,在不良地质条件下,既需要TBM设备配置具有适应性,又必须采取适当的施工措施。结合锦屏二级电站引水隧洞TBM施工实践中遇到的大埋深、高地应力、极强岩爆的地质条件,研究了加强初期支护、岩面喷水、应力释放孔、应力释放导洞等解决措施,并付诸实施,取得了较好的应用效果,可为类似工程提供参考。%Each tunnel-boring machine(TBM) is designed and made especially for certain geological conditions,in which case it is strong in dealing with certain geological conditions but poor in universality.Under poor geological conditions,it is necessary not only for the allocation of the TBM equipment to have good adaptability but also for proper construction measures to be taken.With the TBM construction practice of the water-leading tunnel of the second-stage power station at Jinping as a practical example,which is conducted under the geological conditions of being deeply buried,high in geological stress and extremely serious in rock burst,discussed in the paper are such solutions as strengthening the initial support,spraying water over the rock surface,boring stress-releasing holes,digging stress-releasing guide shafts,etc.All those above-mentioned construction measures are put into practice and achieves fairly good application results.The paper may serve as a useful reference for other projects of similar types.

  10. Energy analysis for damage and catastrophic failure of rocks

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of energy.The main scope and the achievable objectives of the energy-based research system were expatiated.It was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy dissipation.It was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak load.For both hard and soft rocks,the energy dissipated after peak load accounts for a greater proportion.More energy would be required for rock failure under equal biaxial compression than under unequal biaxial compression.The total absorbed energy is different for rock failure under high-rate loading and low-rate loading.More fragmented failure pattern usually corresponds to higher energy absorption.The mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt rock.The energy accumulation,transfer,dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics theory.Furthermore,the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated numerically.It was demonstrated that energy is likely to be released from the weakest surface under compression,which triggers the global failure of rocks.

  11. A preliminary study of the turbulence features of the tidal bore in the Qiantang River, China

    Institute of Scientific and Technical Information of China (English)

    谢东风; 潘存鸿

    2013-01-01

    In this paper, the turbulence characteristics of the tidal flow in the Qiantang River, China, the world-famous Qiantang bore, are studied. A detailed field observation at the Yanguan section of the Qiantang River was carried out during the spring tide in October 2010 with a continuous collection of high frequency turbulence data. The data analysis shows that the hydrodynamic processes are characterized by a strong tidal bore. Statistics of the turbulence such as the probability distributions of the turbulent components, the variance terms and the covariance terms are found consistent with those of previous studies of estuaries without the tidal bore. However, along the vertical profile, the distributions of all variables become more scattered downwards. The horizontal turbulence fluctuations are of a similar magnitude while the vertical turbulence has a fluctuation magnitude about 1/3 of that of the horizontal turbulences. The fluctuation strengths and the Reynolds stresses are much larger than those of other estuaries when the bore arrives. The bottom shear stress varies periodically with the tides, less than 0.44 N/m2 during the ebb but is increased drastically at the bore arrival, with the maximum being 0.92 N/m2. A good linear relationship is found between the bottom shear stress and the bottom suspended sediment concentration.

  12. Sediment resuspension and the generation of intermediate nepheloid layers by shoaling internal bores

    Science.gov (United States)

    Masunaga, Eiji; Arthur, Robert S.; Fringer, Oliver B.; Yamazaki, Hidekatsu

    2017-06-01

    Numerical simulations of sediment resuspension due to shoaling internal bores are performed with a nonhydrostatic model, SUNTANS. Results show strong sediment resuspension induced by internal bores and a turbidity layer intruding offshore in the interior of the water column, known as an intermediate nepheloid layer (INL). Sediment resuspension processes and INLs reproduced in the model are in good agreement with observational data from Otuschi Bay, Japan. The formation of INLs by shoaling internal waves is explained as follows: (1) strong receding currents due to a previous run-up bore cause sediment resuspension along the slope, (2) the interaction of the receding currents and a subsequent run-up bore induce horizontal flow convergence and strong upward currents, (3) the upward currents lift the suspended sediments into the interior of the water column, (4) the run-up bore intrudes below the suspended sediments and forms an INL within the pycnocline. Sediment resuspension processes are also investigated for various internal Iribarren number conditions. The internal Iribarren number represents the ratio of the topographic slope to the internal wave steepness. In low internal Iribarren number conditions, strong currents near the bottom result in sediment resuspension and INL formation. In high internal Iribarren number conditions, sediment resuspension is weak, and INLs do not form.

  13. Characterizing fractures and shear zones in crystalline rock using anisotropic seismic inversion and GPR imaging

    Science.gov (United States)

    Doetsch, Joseph; Krietsch, Hannes; Lajaunie, Myriam; Jordi, Claudio; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansrudi

    2017-04-01

    Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. In the framework of an in-situ stimulation experiment at the Grimsel Test Site, a detailed rock mass characterization was carried out, combining geological and geophysical methods. While geological observations from tunnel mapping, core- and geophysical borehole-logging are reliable, the obtained data could just be interpolated between tunnels and boreholes. The geophysical surveys, including ground-penetration radar (GPR) imaging and tunnel-tunnel seismic tomography were able to image shear and fracture zones throughout the experimental volume. Clear GPR reflections up to a distance of 30 m from the tunnels allow to define the geometry of tunnel-mapped shear zones in the center of the experimental volume. Anisotropic traveltime inversion of tunnel-tunnel seismic data reveals fracture zones as low velocity zones and ductile shear zones as areas of increased seismic anisotropy. It is thus possible to characterize both type and geometry of shear and fracture zones, which is important for the planned rock stimulation. Combining the GPR and seismic results with the geological information, the geological model could be significantly improved, demonstrating the potential to characterize even subtle geological features in 3D.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

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

  15. Prediction of Soil Deformation in Tunnelling Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Jinxing Lai

    2016-01-01

    Full Text Available In the past few decades, as a new tool for analysis of the tough geotechnical problems, artificial neural networks (ANNs have been successfully applied to address a number of engineering problems, including deformation due to tunnelling in various types of rock mass. Unlike the classical regression methods in which a certain form for the approximation function must be presumed, ANNs do not require the complex constitutive models. Additionally, it is traced that the ANN prediction system is one of the most effective ways to predict the rock mass deformation. Furthermore, it could be envisaged that ANNs would be more feasible for the dynamic prediction of displacements in tunnelling in the future, especially if ANN models are combined with other research methods. In this paper, we summarized the state-of-the-art and future research challenges of ANNs on the tunnel deformation prediction. And the application cases as well as the improvement of ANN models were also presented. The presented ANN models can serve as a benchmark for effective prediction of the tunnel deformation with characters of nonlinearity, high parallelism, fault tolerance, learning, and generalization capability.

  16. Improved RMR Rock Mass Classification Using Artificial Intelligence Algorithms

    Science.gov (United States)

    Gholami, Raoof; Rasouli, Vamegh; Alimoradi, Andisheh

    2013-09-01

    Rock mass classification systems such as rock mass rating (RMR) are very reliable means to provide information about the quality of rocks surrounding a structure as well as to propose suitable support systems for unstable regions. Many correlations have been proposed to relate measured quantities such as wave velocity to rock mass classification systems to limit the associated time and cost of conducting the sampling and mechanical tests conventionally used to calculate RMR values. However, these empirical correlations have been found to be unreliable, as they usually overestimate or underestimate the RMR value. The aim of this paper is to compare the results of RMR classification obtained from the use of empirical correlations versus machine-learning methodologies based on artificial intelligence algorithms. The proposed methods were verified based on two case studies located in northern Iran. Relevance vector regression (RVR) and support vector regression (SVR), as two robust machine-learning methodologies, were used to predict the RMR for tunnel host rocks. RMR values already obtained by sampling and site investigation at one tunnel were taken into account as the output of the artificial networks during training and testing phases. The results reveal that use of empirical correlations overestimates the predicted RMR values. RVR and SVR, however, showed more reliable results, and are therefore suggested for use in RMR classification for design purposes of rock structures.

  17. The Rock Cycle

    Science.gov (United States)

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  18. Injury patterns in recreational rock climbers.

    Science.gov (United States)

    Rooks, M D; Johnston, R B; Ensor, C D; McIntosh, B; James, S

    1995-01-01

    We studied 39 recreational rock climbers to determine the incidence and pattern of injuries sustained in the sport at their level. Eleven climbers (26%), who climbed beyond the sport level, had sustained a major injury from a fall. Thirty-five climbers (89%) sustained at least one significant injury. Fifty percent of the injuries involved the hand or wrist. Only seven climbers (19%) had evidence of a digital pulley injury (climber's finger). Four climbers (11%) had evidence of a carpal tunnel syndrome. Twenty climbers (50%) had tendinitis in an upper extremity on physical examination.

  19. Tunnelling with wormhole creation

    Energy Technology Data Exchange (ETDEWEB)

    Ansoldi, S. [National Institute of Nuclear Physics (INFN) (Italy); Tanaka, T., E-mail: tanaka@yukawa.kyoto-u.ac.jp [Kyoto University, Department of Physics (Japan)

    2015-03-15

    The description of quantum tunnelling in the presence of gravity shows subtleties in some cases. We discuss wormhole production in the context of the spherically symmetric thin-shell approximation. By presenting a fully consistent treatment based on canonical quantization, we solve a controversy present in the literature.

  20. INCAS SUBSONIC WIND TUNNEL

    Directory of Open Access Journals (Sweden)

    Corneliu STOICA

    2009-09-01

    Full Text Available The INCAS Subsonic Wind Tunnel is a closed circuit, continuous, atmospheric pressure facility with a maximum speed of 110 m/s. The test section is octagonal ,of 2.5 m wide, 2.0 m high and 4 m long. The tunnel is powered by a 1200 kW, air cooled variable speed DC motor which drives a 12 blade, 3.5 m diameter fan and is equipped with a six component pyramidal type external mechanical balance with a 700 Kgf maximum lift capacity.The angle of attack range is between -45º and +45º while the yaw angle range is between -140º and +216º .The data acquisition system has been modified recently to allow the recording of all test data on a PC - type computer using LABVIEW and a PXI – type chassis containing specialized data acquisition modules.The tunnel is equipped with a variable frequency electrical supply system for powered models and a 10 bar compressed air supply for pneumatic flow control applications.In the recent years the subsonic wind tunnel has been intensively used for tests within several European projects (AVERT, CESAR and others.