The Three-Dimensional Finite Element Analysis Of Abutment Stability Of Concrete Arch Dam

Abutment stability and security is very important in the design and analysis of the arch dam. The stability of arch dam is sustained by abutment rock mass. At the stage of survey, neglecting the partial geologic defect of batholiths (such as joints, fracture or soft interlayer, etc.) will probably induce instability destruction of arch dam. Therefore, it's vital for arch dam construction that how to solve the abutment stability to make the comprehensive and reliable evaluation of abutment stability. The main tasks of this paper are as follow:Firstly, the principle and application scope of various methods for sliding analysis of arch dam abutment all over the word are introduced, and the advantages and disadvantages of each method are compared. The basic theories of elastic-plastic and contact non-linear applied in the amylases based on finite element method (FEM) of hydraulic structure engineering are discussed.Then, the paper studies the applications and implementation technology of elastic-plastic model and contact nonlinear in large-scale common finite software ANSYS and explains the principles of methods calculating abutment safety factor against sliding including overload method, safety reduction method and method of safety factor in point. Later, the implementation steps of each method are proposed. Adopting the parametric language APDL in the software ANSYS, the paper compiles program successfully for iterative calculation of safety reduction method according to it's theory to realize the second development of the calculation of stability.Meanwhile, as a practical example, paper researches analog simulation on three-dimensional geologic structure of arch dam,realizes the automatic creation of finite element model including fault, load exerting and problem solving using program prepared already. During the analysis,three-dimensional constitutive relationship of dam foundation is considered, ideal elastic-plastic model is adopted,meanwhile, this paper studies the influence that stress and stability of dam body effects on rock mass weak structure on the complex foundation,analyses stress and strain of arch dam, and develops three-dimensional nonlinear finite element program of concrete arch dam.Finally, this paper makes an all-directional assessment of stability of arch dam abutment by overload method, safety reduction method and method of safety factor in point. Moreover, the program, developed in this paper, will use in iteration method of calculating for the safety factor of dam abutment slip plane of fault. In this way, the accuracy and feasibility of the program can be verified. And also, this paper can provide a valuable reference for the analysis of dam abutment stability in the actual project and the shape optimization of arch dam, whose aim is the stability safety coefficients.