FAILURE MECHANISM AND CRITERION OF COUNTER-TILT ROCK SLOPES AT WUXIA GORGE SECTION IN THREE GORGES
RESERVOIR AREA
YIN Kunlong1，ZHOU Chunmei2，CHAI Bo3
(1. Faculty of Engineering，China University of Geosciences，Wuhan，Hubei 430074，China；2. School of Resource and Civil Engineering，Wuhan Institute of Technology，Wuhan，Hubei 430073，China；3. School of Environmental Studies，
China University of Geosciences，Wuhan，Hubei 430074，China)
Abstract：Gongjiafang slope #2 is a counter-tilt slope consisted of thick/thin and soft/hard rocks layers at Wuxia Gorge section in the Three Gorges Reservoir area. It had undergone a complicated failure process of bending to slipping. In order to study its failure mechanism and criterion，the rock structures of the counter-tilt slope were investigated and its deformation process and failure mechanism influenced by rising water level of the reservoir were analyzed. A set of analysis models，i.e. superposed cantilever model，independent cantilever beam model were proposed to decide the failure criterions of the counter-tilt slope by comparing the slope stresses with the rock strength. The finite element method was employed to analyze the parameter reduction of rock and the laws of deformation and failure. The strata structure of the upper hard rock strata and the lower soft rock strata and the deep and steep river are the key reasons to induct bending deformation onto the counter-tilt slope in the Wuxia Gorge area. The counter-tilt slope with different layer thicknesses has multiple failure stages and different criteria with the superposition cantilever model appropriate for thin soft rocks and the independent cantilever beam model fit for thick rocks. The shear strength of thin marlstone may be reduced to 85% of its normal strength after the rock softening and the slope failure developes from the lower part to the upper part.
GOODMAN R E，BRAY J W. Toppling of rock slopes[C]// Proceedings of Specialty Conference on Rock Engineering for Foundations and Slopes. New York：[s.n.]，1977：201-234．
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2014, Vol. 33 
