NUMERICAL INVESTIGATION ON NEAR FIELD RESPONSE TO EXCAVATION OF MINE-BY NICHE AT MONT TERRI SITE
LI Lianchong1，LIU Huihai2，BIRKHOLZER Jens2，VIETOR Tim3
(1. School of Civil and Hydraulic Engineering，Dalian University of Technology，Dalian，liaoning 116024，China；
2. Earth Sciences Division，Lawrence Berkeley National Laboratory，Berkeley 94720，USA；
3. National Cooperative for the Disposal of Radioactive Waste(NAGRA)，Wettingen 5521，Switzerland)
Abstract：In 2008，the Mine-by(MB) Niches were constructed in Mont Terri underground rock laboratory. One of niches，MB Niche2，was selected to investigate the deformation and the coupled hydro-mechanical behavior of the Opalinus clay near excavation. Based on the engineering geological conditions of MB Niche2，a geomechanical simulator incorporating the two-part Hooke?s model(TPHM) was employed to simulate the excavation process of MB Niche2. Numerical results show that near the roof of Niche recorded a maximum of 10 mm of inward movement. Near sidewalls，the damage zone developed up to an average distance of 1.4 m into the rock matrix. Pore pressure increase became visible at about 11 m ahead of the mine-by excavation face. With niche advancing，the zones with local higher pore pressure are mainly found near the edge of the damage zones. The maximum pore water pressure reaches about 3.3 MPa near the advancing face of excavation. Compared with those based on the conventional Hooke?s law(SPHM)，the results based on TPHM are more consistent with the field data sets，which indicates to some extent that TPHM can better capture the physical nature of natural strain(true strain) in porous and fractured rocks and highlights the importance of having appropriate conceptual and numerical models available that accurately capture the complex coupled behavior in response to excavation.
李连崇1，Liu Huihai2，Birkholzer Jens2，Vietor Tim3. Mont Terri试验场Mine-by巷道开挖近场响应模拟分析[J]. 岩石力学与工程学报, 2014, 33(8): 1626-1634.
LI Lianchong1，LIU Huihai2，BIRKHOLZER Jens2，VIETOR Tim3. NUMERICAL INVESTIGATION ON NEAR FIELD RESPONSE TO EXCAVATION OF MINE-BY NICHE AT MONT TERRI SITE. , 2014, 33(8): 1626-1634.
[1] BOSSART P，THURY M. Mont Terri rock laboratory—project，programme 1996 to 2007 and results[R]. Wabern，Switzerland：Swiss Geological Survey，2008.
[2] VIETOR T. Mine-by test in Mont Terri rock laboratory-MB experiment[R]. Wettingen，Switzerland：NAGRA，2011.
[3] LIONCO A，ASSIS A. Behavior of deep shafts in rock considering nonlinear elastic models[J]. Tunneling and Underground Space Technology，2000，15(4)：445–451.
[4] CORKUM A G，MARTIN C D. Modeling a mine-by test at the Mont Terri rock laboratory，Switzerland[J]. International Journal of Rock Mechanics and Mining Sciences，2007，44(6)：846–859.
[5] WENG M C，JENG F S，HSIEH Y M，et al. A simple model for stress-induced anisotropic softening of weak sandstones[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(2)：155–166.
[6] 包雪阳，施行觉. 岩石非线性弹性的实验研究及其P-M模型的理论解释[J]. 岩石力学与工程学报，2004，23(20)：3 397–3 404.(BAO Xueyang，SHI Xingjue. Experiment research and interpretation on nonlinear elasticity of rock using P-M model[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(20)：3 397–3 404.(in Chinese))
[7] JAEGER J C，COOK N G W，ZIEMMERMAN R W. Fundamentals of rock mechanics[M]. 4th ed. Oxford：Blackwell，2007：75–89.
[8] LIU H H，RUTQVIST J，BERRYMAN J C. On the relationship between stress and elastic strain for porous and fractured rock[J]. International Journal of Rock Mechanics and Mining Sciences，2009，46(2)：289–296.
[9] 李连崇，LIU Huihai，赵 瑜. 基于双应变胡克模型的岩石非线性弹性行为分析[J]. 岩石力学与工程学报，2012，31(10)：2 119–2 126. (LI Lianchong，LIU Huihai，ZHAO Yu. Investigation on nonlinear elastic behaviour of rocks based on a two-part Hooke?s model[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(10)：2 119–2 126.(in Chinese))
[10] ZHANG C L，ROTHFUCHS T，DITTRICH J，et al. Investigations on self-sealing of indurated clay[R]. Braunschweig，Germany：GRS，2008.
[11] JOBMANN M，WILSNACK T H，VOIGT H D. Investigation of damage-induced permeability of Opalinus clay[J]. International Journal of Rock Mechanics and Mining Sciences，2010，47(5)：279–285.
[12] JAEGGI D，NUSSBAUM C，VIETOR T. MB experiment：visualization of EDZ-fractures around the MB Niche by using the in-situ resin impregnation technique[R]. Wettingen，Switzerland：NAGRA，2012.
[13] Mont Terri Consortium. Characterisation of the dry shotcrete sprayed in MB Niche for modelling works[R]. Bern：Geotechnisches Institute AG，2009.
[14] KELSALL P C，CASE J B，CHABAMES C R. Evaluation of excavation-induced changes in rock permeability[J]. International Journal of Rock Mechanics and Mining Sciences，1984，21(3)：123–135.
[15] BOSSART P，MEIER P M，MOERI A，et al. Structural and hydrogeological characterisation of the excavation-disturbed zone in the Opalinus clay(Mont Terri Project，Switzerland)[J]. Applied Clay Science，2004，26(5)：429–448.
[16] LIU H H，HOUSEWORTH J，RUTQVIST J，et al. Report on modeling coupled processes in the near field of a of a clay repository[R]. Berkeley，USA：Lawrence Berkeley National Laboratory，2012.
[17] BOCK H. RA experiment：updated review of the rock mechanics properties of the Opalinus clay of the Mont Terri URL based on laboratory and field testing[R]. Bad Bentheim，Germany：QS Consult，2009.
[18] GRASLE W，PLISCHKE I. Laboratory testing(LT) experiment：mechanical behavior of Opalinus clay[R]. Hannover，Germany：BGR，2010.
2014, Vol. 33 
