CRACKING MECHANISM OF SURROUNDING ROCK INDUCED BY RELEASE OF EXCAVATION LOAD IN DEEP TUNNEL
YANG Jianhua1,2,ZHANG Wenju1,2,LU Wenbo 1,2,CHEN Ming1,2,YAN Peng1,2
(1. State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,
Hubei 430072,China;2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering,Ministry
of Education,Wuhan University,Wuhan,Hubei 430072,China)
Abstract:For a case of circular deep tunnel,the effect of abrupt in-situ stress release in terms of cracking in surrounding rocks is investigated by adopting an initiation model of cracks under biaxial compressions. In addition,a formula of the stress intensity factor is employed. The results show that,compared to a quasi-static process of stress release,the transient release of in-situ stress on excavation face generates an additional dynamic stress in surrounding rocks. In this circumstance,the radial unloading and the circumferential loading are enlarged by this additional stress,thus cracking in surrounding rocks is aggravated during this transient process. The shorter the release duration of stress is,the greater the amplitude of the additional stress and the cracking extent become.
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YANG Jianhua1,2,ZHANG Wenju1,2,LU Wenbo 1,2,CHEN Ming1,2,YAN Peng1,2. CRACKING MECHANISM OF SURROUNDING ROCK INDUCED BY RELEASE OF EXCAVATION LOAD IN DEEP TUNNEL. , 2013, 32(6): 1222-1228.
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