A large number of world-class high arch dams are currently under construction or will soon be built in West China. These dam projects are usually located in high mountains and deep valleys with complicated geological conditions. The global stability and safety of dam and foundation is a major concern. Geo-mechanical model test is one of the main methods to study this problem. Three test methods of geo-mechanical model are presented in this paper. The overloading method is used to test the overload capability. The strength reduction method is used to study the strength reserve capability. The comprehensive method combines overloading and strength reduction methods. According to the model similarity theory, the safety coefficients by three kinds of model test are established, and the testing technique based on temperature-dependent similar material for simulating strength reduction is also proposed. These basic studies offered the theory and technical supports for dam model test. Finally, the 3D geomechanical model test has been applied to Xiaowan arch dam (294.5m high) to study the global stability, failure process and mechanisms. These research results have been applied in practical project and provide an important scientific basis for the evaluation of stability, safety and reinforcement effect.
With the development of hydropower projects to implement the strategy of electricity transmission from western region to eastern region in China, a number of high dams and large reservoirs are under construction or to be built. These large projects are mainly located on the great rivers in West China, characterized by complicated topographical and geological conditions. The hydropower projects include Xiaowan arch dam (294.5 m high) on the Lancang River, Xiluodu arch dam (278 m high) and Jinping I arch dam (305 m high) on the Yalong River, Baihetan arch dam (284 m high) and Longpan arch dam (278 m high) on the Jinsha River, Dagangshan arch dam (210 m high) on the Dadu River, and so on. Analyzing and evaluating the stability and safety of these large projects is currently need in engineering fields and academic studies [1-3]. Geo-mechanical model test is one of the main methods to address this issue .