Numerical Simulation And Reliability Research On High Concrete Arch Dam

Arch dam is both economic and reliability, and famous for its beautiful and reasonable size. In the arch dam stress analysis, traditional calculation method is arch-cantilever method. But with the development of the computer science, the finite element method (FEM) can not only consider the various complicated factors to arch dams, but also it's more actual for engineering and the calculation speed is much faster than traditional method. ANSYS is a large software for finite element method with powerful programming function, strong entity modeling, strong grid partition tools, powerful solver, convenient processor. This paper used ANSYS in a dam for analysis. Without any doubt, seismic load is quite important to the high arch dam. Engineering anti-seismic capability is the key to ensure safety. Therefore, this paper calculated the stress and displacement of a high concrete arch dam with finite element method based on ANSYS.We usually use safety coefficient method to measure arch dam's safety. Dams'safety coefficient based on contained analysis or corresponding computer program. But this kind of analysis ignored the random of relevant load and arch dams'bearing capacity, and the concept of safety coefficient is not clear enough. Reliability analysis which is based on probability and statistics can overcome this shortcoming. The structure reliability means the probability of completing reserved function within the prescribed period time and condition. Reliability design Reliability design is done with admitting the prerequisite of failure possibility. The intensity reliability is the main problem in the structure reliability, which comes from the probability that structure material strength is greater than the stress caused by load, but not from a general safety coefficient. Arch dam itself and working conditions are very complex, involving more random variable and highly nonlinear implicit limit state function. Therefore, it's hard to calculate its reliable index. This paper showed us a method for calculating reliability of arch dam based on neural network and particle swarm optimization.Taking Dagangshan arch dam for example, this paper focused on following job on the basis of previous studies by finite element method:1. I had put 3D arch dam's dynamic water pressure model into practice under the linear elastic condition with ANSYS's APDL, and analyzed the dam's stress and displacement under the basic static load, temperature load, and earthquake load. Results showed that dam heel area had a greater tensile stress. So dam heel position creates cracks is inevitable. For the jointing arch dam, this paper preliminary realized the analysis under basic static load.2. For the need of major arch dams'reliability analysis, according to the reliability theory, solving reliability index boils down to minimum solution of the objective function under restriction. By the penalty function method, constraint optimization can be transformed to unconstrained one. Using particle swarm optimization algorithm can solve this unconstrained optimization problem. Firstly, use the large general structure analysis software ANSYS to get many functions corresponding random variables. Secondly, the neural network was trained by the random variables and the corresponding functions as the training sample to get highly nonlinear model. Lastly, use the above reliability method to realize the arch dam's reliability calculation with MATLAB.