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Ground reaction curves for circular excavations in non-homogeneous,axisymmetric strain-softening rock masses 被引量:7
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作者 J.González-Cao F.Varas +1 位作者 F.G.Bastante L.R.Alejano 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2013年第6期431-442,共12页
Fast methods to solve the unloading problem of a cylindrical cavity or tunnel excavated in elasto-perfectly plastic, elasto-brittle or strain-softening materials under a hydrostatic stress feld can be derived based on... Fast methods to solve the unloading problem of a cylindrical cavity or tunnel excavated in elasto-perfectly plastic, elasto-brittle or strain-softening materials under a hydrostatic stress feld can be derived based on the self-similarity of the solution. As a consequence, they only apply when the rock mass is homogeneous and so exclude many cases of practical interest. We describe a robust and fast numerical technique that solves the tunnel unloading problem and estimates the ground reaction curve for a cylindrical cavity excavated in a rock mass with properties depending on the radial coordinate, where the solution is no longer self-similar. The solution is based on a continuation-like approach(associated with the unloading and with the incremental formulation of the elasto-plastic behavior), fnite element spatial discretization and a combination of explicit sub-stepping schemes and implicit techniques to integrate the constitutive law, so as to tackle the diffculties associated with both strong strain-softening and elasto-brittle behaviors. The developed algorithm is used for two practical ground reaction curve computation applications. The frst application refers to a tunnel surrounded by an aureole of material damaged by blasting and the second to a tunnel surrounded by a ring-like zone of reinforced(rock-bolted) material. 展开更多
关键词 Tunnel convergence ground reaction curves Strain-softening rock masses Tunnel with an aureole of a different material
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Ground stress and its impact on the stability of the surrounding rock in the Lüliang mining area 被引量:5
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作者 Wang Lianguo Lu Yinlong 《Mining Science and Technology》 EI CAS 2011年第5期625-630,共6页
Ground stress is the fundamental cause of deformation and failure during underground structural engineering. Field stress measurements in the main coal bed in the Lueliang mining area were made by the bore hole, stres... Ground stress is the fundamental cause of deformation and failure during underground structural engineering. Field stress measurements in the main coal bed in the Lueliang mining area were made by the bore hole, stress relief method. From these data the ground stress distribution of the mining area was obtained. The relationship between the horizontal principal stress and the deformation and failure of a roadway is discussed with an engineering example. The results indicate that horizontal stress dominates in the shallow crust in the Ltiliang mining area. Roadways at different angles to the maximum principal stress have different levels of stress concentration. This leads to a significant difference in stability of the corresponding roadways. These research results provide an important criterion for determining roadway position and direction, stope layout, and roadway support design. 展开更多
关键词 ground stress measurementBoring stress-relief methodDistribution ruleStability of surrounding rock
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Tunnelling through weak and fragile rocks of Himalayas 被引量:1
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作者 Goel R.K. 《International Journal of Mining Science and Technology》 SCIE EI 2014年第6期783-790,共8页
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... 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 monitoring shall be followed seriously to reduce the geological surprises. 展开更多
关键词 Varying geology Mixed geology Weak and fragile rocks Himalayan tunnelling ground condition Squeezing
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Rock characterization while drilling and application of roof bolter drilling data for evaluation of ground conditions 被引量:5
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作者 Jamal Rostami Sair Kahraman +1 位作者 Ali Naeimipour Craig Collins 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2015年第3期273-281,共9页
Despite recent advances in mine health and safety, roof collapse and instabilities are still the leading causes of injury and fatality in underground mining operations. Improving safety and optimum design of ground su... Despite recent advances in mine health and safety, roof collapse and instabilities are still the leading causes of injury and fatality in underground mining operations. Improving safety and optimum design of ground support requires good and reliable ground characterization. While many geophysical methods have been developed for ground characterizations, their accuracy is insufficient for customized ground support design of underground workings. The actual measurements on the samples of the roof and wall strata from the exploration boring are reliable but the related holes are far apart, thus unsuitable for design purposes. The best source of information could be the geological back mapping of the roof and walls, but this is disruptive to mining operations, and provided information is only from rock surface.Interpretation of the data obtained from roof bolt drilling can offer a good and reliable source of information that can be used for ground characterization and ground support design and evaluations. This paper offers a brief review of the mine roof characterization methods, followed by introduction and discussion of the roof characterization methods by instrumented roof bolters. A brief overview of the results of the preliminary study and initial testing on an instrumented drill and summary of the suggested improvements are also discussed. 展开更多
关键词 Roof bolter Rock characterization Three-dimensional(3D) visualization of ground ground support optimization
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Discussion on bearing capacity of soft rock ground based on in-situ load test
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作者 Gao Wenhua Zhu Jianqun Huang Ziyong Liu Dong 《Engineering Sciences》 EI 2010年第4期37-41,共5页
The suitability of five methods was discussed here,taking the typical results from in-situ load test of Renshou Mansion and Caifu Plaza in Yueyang City for example.It shows that bearing capacity can be obtained by the... The suitability of five methods was discussed here,taking the typical results from in-situ load test of Renshou Mansion and Caifu Plaza in Yueyang City for example.It shows that bearing capacity can be obtained by the proportion load and limit load from p-s curve with the first and the second point of contraflexure easily.It is recommended that the accurate value of bearing capacity can be obtained by hyperbola fitting method and minimum curvature radius method theoretically.The rebound method is clear in principle,in which the elastoplasticity characteristic is thought about.Out of consideration for the unsteadiness and unobviousness of bearing capacity from relative settlement method,it can be only adopted as reference.So bearing capacity of soft rock ground should be determined by weathering condition of soft rock and curve type. 展开更多
关键词 rock mechanics soft rock bearing capacity of ground in-situ load test of rock ground characteristic curve
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Site specific probabilistic seismic hazard analysis at Dubai Creek on the west coast of UAE 被引量:1
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作者 Ayman A. Shama 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2011年第1期143-152,共10页
A probabilistic seismic hazard analysis (PSHA) was conducted to establish the hazard spectra for a site located at Dubai Creek on the west coast of the United Arab Emirates (UAE). The PSHA considered all the seism... A probabilistic seismic hazard analysis (PSHA) was conducted to establish the hazard spectra for a site located at Dubai Creek on the west coast of the United Arab Emirates (UAE). The PSHA considered all the seismogenic sources that affect the site, including plate boundaries such as the Makran subduction zone, the Zagros fold-thrust region and the transition fault system between them; and local crustal faults in UAE. PSHA indicated that local faults dominate the hazard. The peak ground acceleration (PGA) for the 475-year return period spectrum is 0.17 g and 0.33 g for the 2,475-year return period spectrum. The hazard spectra are then employed to establish rock ground motions using the spectral matching technique. 展开更多
关键词 seismic hazard PSHA subduction zone rock ground motion spectral matching logic tree fault
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