PENG Jun1, 2, RONG Guan1, 2, ZHOU Chuang-bing1, 2, CAI Ming3, PENG Kun4
1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; 2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering (Wuhan University), Ministry of Education, Wuhan 430072, China; 3. Bharti School of Engineering, Laurentian University, Sudbury, Ontario P3E2C6, Canada; 4. China Shipbuilding NDRI Engineering Co., Ltd., Shanghai 200063, China
Abstract：The Mohr-Coulomb and Hoek-Brown failure criteria are the two most widely used ones at present. To simulate brittle failure of rocks in deep tunnels, the models based on these two failure criteria have been proposed, including the CWFS (cohesion weakening and friction strengthening) model, the DISL (damage initiation and spalling limit) model, and the BDP (brittle ductile plastic) model. These models have been used to simulate brittle failure of hard rocks. However, because of the issues of strain hardening under high confinement and large ambiguity in model parameter determination, it is very challenging to apply these models in practical engineering application. Based on the variation of the GSI (geological strength index) value during compression of rocks and by defining the GSI value as a function of plastic strain and confinement, a strain-dependent GSI-softening model, which is based on the Hoek-Brown failure criterion, is proposed in this study. This model is implemented in FLAC3D to simulate the triaxial compression tests on T2b marble in Jinping-II Hydropower Station and the Tennessee marble. It is found that the proposed model is able to simulate the mechanical behaviors of the brittle-ductile transition observed in the triaxial compression tests on Jinping and Tennessee marbles. Finally, this model is used to evaluate the relaxation depth of a headrace tunnel in Jinping-II Hydropower Station, and the calculated depths are in good agreement with the field observations.
彭俊, 荣冠, 周创兵, 蔡明, 彭坤. 一种基于GSI弱化的应变软化模型[J]. 岩土工程学报, 2014, 36(3): 499-507.
PENG Jun, RONG Guan, ZHOU Chuang-bing, CAI Ming, PENG Kun. A strain-softening model based on GSI softening. Chinese J. Geot. Eng., 2014, 36(3): 499-507.
[1] 张春生, 陈祥荣, 侯 靖, 等. 锦屏二级水电站深埋大理岩力学特性研究[J]. 岩石力学与工程学报, 2010, 29(10): 1999-2009. (ZHANG Chun-sheng, CHEN Xiang-rong, HOU Jing, et al. Study of mechanical behavior of deep-buried marble at Jinping II hydropower station[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(10): 1999-2009. (in Chinese)) [2] MARTIN C D. The strength of massive Lac du Bonnet granite around underground openings[D]. Winnipeg: Department of Civil and Geological Engineering, University of Manitoba, 1993. [3] MARTIN C D. Seventeenth Canadian geotechnical colloquium: The effect of cohesion loss and stress path on brittle rock strength[J]. Canadian Geotechnical Journal, 1997, 34(5): 698-725. [4] HAJIABDOLMAJID V, KAISER P K, MARTIN C D. Modelling brittle failure of rock[J]. International Journal of Rock Mechanics & Mining Sciences, 2002, 39(6): 731-741. [5] HAJIABDOLMAJID V. Mobilization of strength in brittle failure of rock[D]. Kingston, Ontario: Department of Mining Engineering, Queen's University, 2001. [6] GOLCHINFAR N, CAI M. Modeling depth of failure using brittle Mohr-Coulomb failure model[C]// Proc 21st Canadian Rock Mech. Symp, Edmonton, 2012: 127-135. [7] CUNDALL P, CARRANZA-TORRES C, HART R. A new constitutive model based on the Hoek-Brown criterion[C]// Proceedings of the 3rd International FLAC Symposium. Sudbury: A.A. Balkema Press, 2003: 17-25. [8] DIEDERICHS M S. The 2003 Canadian geotechnical colloquium: Mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunneling[J]. Canadian Geotechnical Journal, 2007, 44(9): 1082-1116. [9] HOEK E, BROWN E T. Underground excavations in rock[M]. London: Institution of Mining and Metallurgy, 1980. [10] HOEK E, BROWN E T. Empirical strength criterion for rock masses[J]. Journal of the Geotechnical Engineering Division, ASCE, 1980, 106(GT9): 1013-1035. [11] HOEK E, WOOD D, SHAH S. A modified Hoek-Brown criterion for jointed rock masses[C]// Proceedings of the ISRM-Eurock Symposium on Rock Characterization. Chester, 1992: 209-213. [12] HOEK E. Strength of rock and rock masses[J]. ISRM News Journal, 1994, 2(2): 4-16. [13] HOEK E, CARRANZA-TORRES C, CORKUM B. Hoek- Brown criterion-2002 edition[C]// Proc NARMS-TAC Conference. Toronto, 2002: 267-273. [14] HOEK E, KAISER P K, BAWDEN W F. Support of Underground Excavations in Hard Rock[M]. Rotterdam, Netherlands: A.A. Balkema Press, 1997. [15] MARTIN C D, CHANDLER N A. The progressive fracture of Lac du Bonnet granite[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1994,31(6)：643-659. [16] EBERHARDT E, STEAD D, STIMPSON B. Quantifying progressive prepeak brittle fracture damage in rock during uniaxial compression[J]. International Journal of Rock Mechanics & Mining Sciences, 1999, 36(3): 361-380. [17] DIEDERICHS M S, KAISER P K, EBERHARDT E. Damage initiation and propagation in hard rock tunnelling and the influence of near-face stress rotation[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41: 785-812. [18] CAI M, KAISER P K, TASAKA Y, et al. Generalized crack initiation and crack damage stress thresholds of brittle rock masses near underground excavations[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(5): 833-847. [19] CAI M, KAISER P K, UNO H, et al. Estimation of rock mass strength and deformation modulus of jointed hard rock masses using the GSI system[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(1): 3-19. [20] CAI M, KAISER P K, TASAKA Y, et al. Determination of residual strength parameters of jointed rock masses using the GSI system[J]. International Journal of Rock Mechanics and Mining Sciences, 2007, 44(2): 247-265. [21] WAWERSIK W R, FAIRHURST C. A study of brittle rock fracture in laboratory compression experiments[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, 1970, 7(5): 561-575. [22] 严 鹏, 卢文波, 陈 明, 等. 深部岩体开挖方式对损伤区影响的试验研究[J]. 岩石力学与工程学报, 2011, 30(6): 1097-1106. (YAN Peng, LU Wen-bo, CHEN Ming, et al. In-situ test research on influence of excavation method on induced damage zone in deep tunnel[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(6): 1097-1106. (in Chinese))
