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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.
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Received: 08 November 2013
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2014, Vol. 33 
