ANALYSIS AND DISCUSSION OF FAILURE MECHANISM AND FRACTURE SURFACE OF SLOPE UNDER EARTHQUAKE
ZHENG Yingren1，2，YE Hailin1，3，HUANG Runqiu3
(1. Department of Civil Engineering，Logistical Engineering University，Chongqing 400041，China；2. Chongqing Engineering and Technology Research Center of Geological Hazard Prevention and Treatment，Chongqing 400041，China；3. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu，Sichuan 610059，China)
Abstract：The failure mechanism of slope under earthquake is the premise of slope¢s dynamic stability analysis. Presently，pseudo-static method and dynamic time-history analysis method are commonly used，which regard the failure mechanism of slope under earthquake as shear failure，and take the shear sliding surface obtained by limit equilibrium method as failure surface under dynamic effect of earthquake without considering the tension failure under seismic load. It may lead to inaccuracy in the stability analysis of slope under earthquake. Investigation of the slopes during Wenchuan earthquake shows that tension failures mostly appear in the upper part of the landslides，and even some rock and soil masses are thrown out，which is an obvious enlightenment. So the FLAC dynamic strength reduction and program of FLAC3D with the function of tensile and shear failure analysis are adopted to study failure mechanism of slope under earthquake numerically. The study shows that the failure of slope under earthquake is made up of the tension failure in the upper part of the fracture zone and the shear failure in the lower part instead of shear sliding failure. A method of locating the fracture surface of slope under earthquake through several ways is provided，which is an accurate foundation for dynamic stability analysis of slopes.
