| Dam-reservoir dynamic interaction is one of the most important influence factors of the dynamic response of concrete dams subjected to the strong earthquakes.Reasonable determination of the hydrodynamic pressures duringearthquakes and their effects on the dam are the basis of the safety evaluation of the dams. The method of Westergaard added mass which is widely applied in many projects and some numberial methods such as finite element method can not meet the demond of accurate value and efficiency of engineering implication very well.In this dissertation, the hydrodynamic pressures are computed based on SBFEM and are applied on the numerical model. Then, the responses of the concrete dam during earthquakes are computed by means of combining SBFEM (scaled Boundary Element Method)and FEM(Finite Element Method). Different results computed under different engineering conditions are analyzed and compared. The major content of this dissertation is organized as follows:(1) Different hydrodynamic pressures derived by Westergaard and Chopra are computed by the programs compiled by Fortran to compare with the pressures which is derived on the basic of SBFEM to prove the correctness of SBFEM.(2) Finite element software,Abaqus, is applied to obtain the responses of elastic model and plastic model based on Westergaard added mass theory and SBFEM.Because SBFEM can reduce the dimension of problem region and take the compressibility of water and the absorption of the sludge into account, the method of FEM-SBFEM combining calculation can improve the computing efficiency and the accuracy of results largely.(3) The method of FEM-SBFEM combining calculation is used to analyze the responses of dam during earthquakes under different conditions such as being subjected by earthquakes with different peak value,different water level,different stiffness of dam and different absorption ratio of silt. The reseach fidings are valuable for the high dam construction and the seismic safety evaluation. |
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