2011年《岩石力学与岩土工程学报》英文版第1期电子版 [复制链接]

Qihu Qian^1*, Xiaoping Zhou²
Received 21 December 2010; received in revised form 25 January 2011; accepted 5 February 2011

Recent catastrophic landslides and mitigation in China

Yueping Yin
China Geological Survey, Beijing, 100035, China
Received 13 January 2011; received in revised form 5 February 2011; accepted 10 February 2011


Abstract: Increasing population density and development of mountainous terrain have brought human settlements within reach of landslide hazards. In recent years, due to the shortening of return period for severe natural events such as heavy rainfall, snowline retreating, great earthquake together with human activities, catastrophic landslides happened more frequently than before, resulting in large-scale casualties due to the increasing occurrences of rapid long-runout rock avalanches, especially in China. This paper presents some typical case histories related to the catastrophic landslides, including the Guanling rock avalanche, the Yigong rockslide-debris avalanche, the Wenchuan earthquake-induced landslides and the Danba landslide. They occurred in the last decade. Moreover, taking the Jiweishan catastrophic rockslide-fragment flow and the Yuhuangge landslide located in the new Wushan Town for examples, early-warning system and risk management on landslides are discussed in detail.
Key words: catastrophic landslides; rainfall; snowline retreating; earthquake; human activities; mitigation

Simulations of explosion-induced damage to underground rock
chambers

G.W. Ma1, H. Hao1, F. Wang2
1 School of Civil and Resource Engineering, The University of Western Australia, Crawley, WA 6009, Australia
2 Defense Science and Technology Agency, Singapore, 109679, Singapore
Received in 19 January 2011; received in revised form 20 February 2011; accepted 25 February 2011


Abstract: A numerical approach is presented to study the explosion-induced pressure load on an underground rock chamber wall and its resultant damage to the rock chamber. Numerical simulations are carried out by using a modified version of the commercial software AUTODYN. Three different criteria, i.e. a peak particle velocity (PPV) criterion, an effective strain (ES) criterion, and a damage criterion, are employed to examine the explosion-induced damaged zones of the underground rock chamber. The results show that the charge chamber geometry, coupling condition and charge configuration affect significantly the dynamic pressure exerted on the rock chamber wall. Thus the chamber is damaged. An inaccurate approximation of pressure boundary ignoring the influences of these factors would result in an erroneous prediction of damaged area and damage intensity of the charge chamber. The PPV criterion yields the largest damaged zone while the ES criterion gives the smallest one. The presented numerical simulation method is superior in consideration of the chamber geometry, loading density, coupling condition and rock quality. The predicted damage intensity of rock mass can be categorized quantitatively by an isotropic damage scalar. Safe separation distance of adjacent chambers for a specific charge weight is also estimated.
Key words: underground explosion; rock damage; numerical simulation; safe separation distance

Laboratory tests and numerical simulations of brittle marble and squeezing schist at Jinping II hydropower station, China

Chunsheng Zhang*, Weijiang Chu, Ning Liu, Yongsheng Zhu, Jing Hou
East China Investigation and Design Institute, China Hydropower Engineering Consulting Group Co., Hangzhou, 310014, China
Received 1 January 2011; received in revised form 5 February 2011; accepted 16 February 2011


Abstract: Four 16.7 km-long tunnels with diameters ranging from 12.4 to 14.6 m are now under construction at Jinping II hydropower station along the Yalong River. The tunnels pass through Triassic rocks below Jinping Mountain. The tunnels are characterized with high overburden, long alignment and complex geological conditions. Brittle failure in marble and squeezing in schist are the primary problems in tunnelling. This paper introduces the studies of laboratory tests on Jinping II marble as well as numerical prediction of excavation damaged zone (EDZ) of tunnel section in brittle marble and determination of reinforced concrete lining thickness for restraining time-dependent deformation in the schist tunnel section. Laboratory tests indicate that Jinping II marble presents a complex brittle-ductile-plastic transition behavior of post-peak response with increasing confining pressure. Such behavior can be described numerically with the Hoek-Brown model. The EDZ was calibrated and predicted using both fast Lagrangian analysis of continua (FLAC) and particle flow code (PFC). The predicted result of EDZ in sections with different qualities of rock mass under various overburden pressures is quite helpful in understanding EDZ characterization and support design. A power-law creep model was used to support the lining design, especially in determining the lining thickness. Field convergence measurement data over 19 months were used to calibrate the creep model properties, followed by a sensibility analysis of reinforced concrete lining thickness that was launched to present the maximum lining compressive stress.
Key words: deep tunnel; time-dependent behavior; excavation damaged zone (EDZ); squeezing; marble

Risk assessment of CO2 injection processes and storage in carboniferous formations: a review

Manchao He1, Sousa Luis1, 2, Sousa Rita3, Gomes Ana2, Vargas Jr. Eurípedes4, Na Zhang1
1 State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing, 100083, China
2 University of Porto, Porto, 4200-465, Portugal
3 Massachusetts Institute of Technology, Cambridge, MA 02139, USA
4 Catholic University of Rio de Janeiro, Rio de Janeiro, CEP 22451-900, Brazil
Received 15 January 2011; received in revised form 7 February 2011; accepted 10 February 2011


Abstract: Over the last decades, people from almost all over the world have realized that it is necessary to quickly develop strategies for the control and reduction of greenhouse gases (GHG) emissions. Among various GHGs, carbon dioxide (CO2) is the most abundant GHG. Its underground storage involves less risk and lower levels of dangerousness. The paper briefly describes the most effective technologies available in the market for background processes to storage (capture and transport) CO2, as well as the more secure solutions for its storage, in particular for the geological storage in carboniferous formations. This paper also outlines the methodologies for the risk assessment involved in storage of CO2, with a particular focus on cases where the injection is made into unminable coal seams and in abandoned coal mines. Methodologies used for risk analysis are described in detail with particular emphasis on Bayesian network (BN). Some applications regarding the risk assessment of CO2 injection processes and CO2 storage in carboniferous formations and contamination of aquifers are presented and analyzed. Finally, based on the applications of BN, several conclusions are drawn.
Key words: risk assessment; underground storage of CO2; coal mines; monitoring

Practical studies on rockfall simulation by DDA

Guichen Ma1*, Hiroyuki Matsuyama2, Satoshi Nishiyama3, Yuzo Ohnishi4
1 School of Civil Engineering, Gifu University, Gifu, 501-1193, Japan
2 West Nippon Expressway Co., Ltd., Osaka, 530-003, Japan
3 School of Civil Engineering, Kyoto University, Kyoto, 615-8540, Japan
4 Kyoto University, Kyoto, 615-8540, Japan
Received 4 January 2011; received in revised form 25 January 2011; accepted 5 February 2011


Abstract: In this paper, simulations of real rockfall by discontinuous deformation analysis (DDA) are conducted. In the simulations, the energy losses of rockfall are categorized into three types, i.e. the loss by friction, the loss by collision, and the loss by vegetation. Modeling of the energy loss using absolute parameters is conducted by the DDA method. Moreover, in order to verify the applicability and validity of the proposed DDA, field tests on rockfall and corresponding simulations of rockfall tests by DDA are performed. The simulated results of rockfall velocity and rockfall jumping height agree well with those obtained from the field tests. Therefore, the new technique properly considers the energy-absorption ability of slope based on vegetation condition and shape of the rockfall, and provides a new method for the assessment and preventive design of rockfall.
Key words: discontinuous deformation analysis (DDA); rockfall; numerical simulations; field experiment; cut slope; highway

Key rock mechanical problems of underground powerhouse in Shuibuya hydropower station

Aiqing Wu1*, Qigui Yang2, Xiuli Ding1, Huoming Zhou1, Bo Lu1

1 Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan 430010, China
2 Changjiang Institute of Survey, Planning, Design and Research, Wuhan, 430010, China
Received 8 January 2011; received in revised form 14 February 2011; accepted 18 February 2011


Abstract: The complicated rock structures and the stability of surrounding rocks of the underground powerhouse were the key rock mechanical problems in Shuibuya hydropower station. In order to overcome the related rock mechanical problems encountered during its construction, a comprehensive research was carried out for the underground powerhouse in Shuibuya hydropower station based on a detailed geological survey. It covers the investigations on the initial in-situ stress distribution features, rock mechanical properties, engineering rock mass classifications by different methods, numerical modeling for stability and support analysis, proper measures for rock excavation and support. The results show that the rock excavations of the underground powerhouse under the given geological conditions can be controlled effectively. Some measures, suggested by the designers, are proved to be rational and effective. These measures mainly consist of: (1) the soft rock replacements by concrete in local area below the crane beam, (2) the shotcrete and reinforcement by rock bolts and anchor cables in surrounding rocks, and (3) 2 m concrete placement on the rock bench between adjacent tailrace tubes. The engineering practice shows that the treated surrounding rocks have a good overall stability. The deformation behaviors observed by safety equipments are within the designing limits. The research conclusions on the related rock mechanical problems, prior to the underground powerhouse excavations, are reliable.
Key words: Shuibuya hydropower station; underground powerhouse; stability of surrounding rocks; rock excavation and support; soft rock replacement

An extended displacement discontinuity method for analysis of stress wave propagation in viscoelastic rock mass

L. F. Fan1, F. Ren1, G. W. Ma2*
1 School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, 639798, Singapore
2 School of Civil and Resource Engineering, The University of Western Australia, Crawley, WA 6009, Australia
Received 19 January 2011; received in revised form 18 February 2011; accepted 25 February 2011


Abstract: An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM). The discontinuities in a rock mass are divided into two groups. The primary group with an average geometrical size larger than or in the same order of magnitude of wavelength of a concerned stress wave is defined as “macro-joints”, while the secondary group with a high density and relatively small geometrical size compared to the wavelength is known as “micro-defects”. The rock mass with micro-defects is modeled as an equivalent viscoelastic medium while the macro-joints in the rock mass are modeled explicitly as physical discontinuities. Viscoelastic properties of a micro-defected sedimentary rock are obtained by longitudinally impacting a cored long sedimentary rod with a pendulum. Wave propagation coefficient and dynamic viscoelastic modulus are measured. The EDDM is then successfully employed to analyze the wave propagation across macro-joint in VRM. The effect of the rock viscosity on the stress wave propagation is evaluated by comparing the results of VRM from the presented EDDM with those of an elastic rock mass (ERM) from the conventional displacement discontinuity method (CDDM). The CDDM is a special case of the EDDM under the condition that the rock viscosity is ignored. Comparison of the reflected and transmitted waves shows that the essential rock viscosity has a significant effect on stress wave attenuation. When a short propagation distance of a stress wave is considered, the results obtained from the CDDM approximate to the EDDM solutions, however, when the propagation distance is sufficiently long relative to the wavelength, the effect of rock viscosity on the stress wave propagation cannot be ignored.
Key words: stress wave propagation; extended displacement discontinuity method (EDDM); viscoelastic rock mass (VRM); micro-defect; macro-joint

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

Mowen Xie, Zengfu Wang, Xiangyu Liu, Bo Xu
School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
Received 28 September 2010; received in revised form 11 January 2011; accepted 8 February 2011


Abstract: Even Unzen volcano has been declared to be in a state of relative dormancy, the latest formed lava lobe No.11 now represents a potential slope failure mass based on the latest research. This paper concentrates on the stability of the lava lobe No.11 and its possible critical sliding mass. It proposes geographic information systems (GIS) based three-dimensional (3D) slope stability analysis models. It uses a 3D locating approach to identify the 3D critical slip surface and to analyze the 3D stability of the lava lobe No.11. At the same time, the new 3D approach shows the effectiveness in selecting the range of the Monte Carlo random variables and locating the critical slip surface in different parts of the lava lobe No.11. The results are very valuable for judging the stability of the lava lobe and assigning the monitoring equipments.
Key words: three-dimensional (3D) slope stability; limit equilibrium equation; Unzen volcano; lava lobe; geographic information systems (GIS)

Influence of differential settlement on pavement structure of widened roads based on large-scale model test

Xiaolin Weng1, 2, Wei Wang3
1 Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, Xi’an, 710064, China
2 CCCC First Highway Consultants Co., Ltd., Xi’an, 710068, China
3 Henan Vocational and Technical College of Communications, Zhengzhou, 450005, China
Received 29 December 2010; Received in revised form 5 February 2011; accepted 15 February 2011


Abstract: This study introduced at first the background of numerous highway widening projects that have been developed in recent years in China. Using a large ground settlement simulator and a fiber Bragg grating (FBG) strain sensor network system, a large-scale model test, with a similarity ratio of 1:2, was performed to analyze the influence of differential settlement between new and old subgrades on pavement structure under loading condition. The result shows that excessive differential settlement can cause considerable tensile strain in the pavement structure of a widened road, for which a maximum value (S) of 6 cm is recommended. Under the repetitive load, the top layers of pavement structure are subjected to the alternate action of tensile and compressive strains, which would eventually lead to a fatigue failure of the pavement. However, application of geogrid to the splice between the new and the old roads can reduce differential settlement to a limited extent. The new subgrade of a widened road is vulnerable to the influence of dynamic load transferred from the above pavement structures. While for the old subgrade, due to its comparatively high stiffness, it can well spread the load on the pavement statically or dynamically. The test also shows that application of geogrid can effectively prevent or defer the failure of pavement structure. With geogrid, the modulus of resilience of the subgrade is increased and inhomogeneous deformation can be reduced; therefore, the stress/strain distribution in pavement structure under loading condition becomes uniform. The results obtained in this context are expected to provide a helpful reference for structural design and maintenance strategy for future highway widening projects.
Key words: widened subgrade; differential settlement; fiber Bragg grating (FBG) strain sensor; model test

2011年《岩石力学与岩土工程学报》英文版第1期
共有10篇论文。

强，太强悍啦！
谢谢！！！！