Abstract:Because of complex geological structure,the deformation failure mechanism and instability mode of high rock slope are usually very complicated. The deformation and failure mode are analyzed by the base friction experiment during the excavation of left bank slope at Jinping I Hydropower Station. The experimental results show that:(1) the failure mode is sliding and fracturing;and (2) rock masses are cut into instable blocks by lamprophyre veins X and fault f42–9,and then fail. Based on above-mentioned results,a numerical model of the high rock slope in left bank is built with FLAC3D;and the joints and faults are modeled with low-strength material. The results of numerical simulation in the excavation process show that the controlling factors for rock cracking and slope failure can be observed for the faults f5,f8,f42–9,SL44–1 and lamprophyre veins X. Then,factors of safety are calculated through the strength reduction method with numerical model of the high rock slope. Under natural state,the factor of safety of rock slope is 1.277;after excavation,the factor of safety equals 1.152;and the factor of safety will be 1.385 after anchorage cables being applied. The study shows that the potential instable zones of the slope by physical and numerical simulation methods are consistent;and the results are acceptable.