Dynamic Stability Of Concrete Gravity Dam Under Complicated Geological Conditions

With the rapid development of economy in our country, the existing shortage of traditional energy has aroused people’s attention gradually. How to vigorously develop clean energy and seek alternative sources of energy have been treated as the primary way to solve the energy problem in the new century. Hydroelectric energy is a kind of clean renewable energy. Besides, it is an indispensable important factor for our country’s industrial development and people’s daily life. The development of hydropower generation science and technology has aroused the world’s attention from all walks of life. Concrete gravity dam building is one of the important dam types in hydro-technical constructions and has been constructed widely in the southwest and northwest regions of our country. While great challenge has been pressed on our hydropower development enterprise because of the complex geological conditions in southwest mountain areas.According to the long-term development project of China, the integral part of large and medium-sized hydropower development will be focused on the high altitude and low temperature areas in the future. However complex geological structures, frequent earthquakes and geological disasters will challenge the accuracy and safety of high dams seismic design. Considering the complexity of gravity dam foundation and the distribution characteristics of the fractured rock mass, this paper aim at analyzing and groping for the development of plastic sliding region in the dam foundation, estimating the potential sliding channel, and studying the stability under dynamic effect.The uncertainty of the strength parameters of complex rock has significant impact on the gravity dam security, this paper adopts strength subtraction of double coefficient to discuss the effect of cohesive force and internal friction angle on the gravity dam’s stability based on Mohr-Coulomb criterion. In addition, the scope of the rock strength parameters will be researched under different discriminant indexes, two dimensional values area of the material strength parameters will be drawn under different conditions.Because the anisotropic characteristics and uncertainty of joint rock mass has influence on rock’s strength parameters, this paper analyses the strength characteristics of anisotropic joint rock in theory and points out the shortage and the existing problems of this analytic procedure. By establishing numerical model of joint rock, the numerical simulation with finite difference program (FLAC3D) is putted forward to study the anisotropic strength characteristics of the joint rock mass.In view of the influence of complex rock foundation on the stability against sliding of concrete gravity dam in constitutive level and the distribution of the fractured rock mass, the ubiquitous model and strength subtraction method are combined to analysis the destruction form of joint rock foundation, the maximal displacement of dam crest and the influence of different joint angles on the safety factor.