Abstract:Jinping First Stage Hydropower Station is an important cascade hydropower station located on Yalong River in Sichuan Province. The primary mission of this project is to generate power and meanwhile to intercept sand,control flood,store energy. The project adopts a 305 m concrete hyperbolic arch dam which is the highest arch dam in the world. The geological structures in dam site are very complex and the height of the slope is about 1 000 m. There are many different weak structural planes in rock mass of the dam foundation such as fault,lamprophyre dike,innerlayer compressed zone,deep-seated fracture,which are disadvantageous to the stability of the dam foundation and abutment. The global geomechanical model experiment is conducted to study the stabilities of the dam foundation and the abutment of Jinping First Stage Hydropower Station. The model considers the various factors influencing the stabilities of dam foundation and abutment during test,which includes overloading as well as strength-decreasing of weak structural planes in the rock mass of the dam foundation. A kind of model test material called as temperature analogous material whose strength varies with temperature in the process of experiment is adopted to simulate the decreasing of the weak structural planes. The temperature analogous material and model test technique are developed for the first time. Then,the comprehensive method that considers both overloading and strength-decreasing is successfully applied to the model. Deformation characters,failure conditions and mechanisms of the dam foundation and abutment are achieved. The safety evaluation on the model experiment indicates that the global safety factor for the dam foundation and abutment is 4.7-5.0. In addition,the reinforcing measures for the weak areas are advised.