Abstract:The diversion tunnel for Jinping Hydropower Station is located in the region with high mountainan and great gorge. The surrounding rockmasses of the tunnel are of deep embedded depth,long length and high ground stress. The problems of high stress and high external water pressure are prominent. Based on the design principle that the surrounding rockmass can be regarded as the main supporting structure for underground projects,this paper analyzes the deformation,stress distribution and plastic zone of the surrounding rockmass during the processes of excavation and supporting of the power tunnel for Jinping Hydropower Station project by using elastoplastic FEM. The influence of different seepage control schemes on the working behaviors of the liner and surrounding rock is studied comparatively. According to the numerical results,suggestions for supporting design of diversion tunnel with high groundwater level and deep embedded depth are proposed.