Static & Dynamic Stability Study And Failure Mechanism Investigation Of Typical Blocks Of Baise RCC Gravity Dam

The working stress state and the stability of typical blocks of Baise RCC Gravity Dam are computed and studied based on the 3D non-linear finite element method (FEM) and rigid body-spring element method (RBSM). The analysis of failure process, failure mode, failure mechanism of the dam are studied with overload method and combined method in which rock strength parameters are decreased while water load is overloaded to a certain degree. In this paper, the following works are done.Firstly, the displacement, stress, strain fields and the working state of dam body and foundation are evaluated by FEM. By overloading the upstream water level and reducing rock strength parameters, the failure process of dam foundation is simulated and the failure mode and paths are determined. The results show that when overload method is used, damaged area develops from up-stream to down stream with failure front stays near the interface between dam body and bedrock. When combined method is applied, damaged area develops from down stream to up-stream, besides, controlling effect of discontinuous joints is shown. At normal storage water level, the combined safety factors are 4.05 and 3.75 for 9B and 4B respectively.Secondly, based on the analysis of FEM, the likely sliding blocks and sliding paths can be determined quantitatively using static and dynamic analysis of RBSM. Ami-sliding safety factors are attained when total sliding force and total anti-sliding force are calculated through normal stress and shear stress acting on the element interfaces. The study shows that the most likely sliding path is located shallowly under the rock bed and the sliding path runs close to a line from tensile area at damheel to dam toe. Staircase sliding paths buried less than 14 meters bellow dam heel are also dangerous, but they are not the most dominant. The safety factors of the most likely sliding paths are 4.15 and 3.05 for 9B and 4B respectively at normal water storage level.Finally, respect to the beam effect induced by special high ratio of modulus of elasticity of Baise gravity dam, the sensitivity analysis are carried out to study the relation among displacement, stress state of dam and rock bed parameters.