An Application of Finite Element-Infinite Element Coupled Boundary in Three-Dimensional Nonlinear Dynamic Response Analysis of Earth Dams With Deep Overburdened Layer

There are many risks of earthquake disaster acknowledged in the construction of embankment dam with deep overburdened layer in highly seismic region, and its dynamic response analysis under strong earthquake is the basis to predict and analyze the earthquake disaster. It is very important to carry out a three-dimensional nonlinear dynamic response analysis on the dam, of which the processing of the model boundary in numerical simulation determines the accuracy and calculation efficiency of the solution thereof. In this paper, two deep overburdened layer finite element boundary models and finite element-infinite element coupled boundary models were established to explore the applicability of infinite element in dynamic calculation with deep overburdened layer embankment dam based on a deep overburdened layer sand-gravel dam, and their dynamic responses under the anti-seismic effect were calculated. According to the analysis results, a significant impact was imposed by different boundaries on the extremum of dam acceleration, and the distribution characteristics of the maximum acceleration in the dam indicated a tendency of consistency. Furthermore, the interaction between the dam body and dam foundation shall be not ignored. The seismic waves gradually attenuated during deep overburdened layer propagation after the incidence of bed rock, and the dynamic response of dam body weakened with the increase of dam foundation area. Compared with the finite boundary model, the acceleration, dynamic displacement and dynamic shear strain calculated by the finite element -infinite element coupled boundary model indicated a significantly lower value against larger calculation results of the finite boundary model in dam foundation area, which is closer to the results of the finite element-infinite element coupled boundary model. Therefore, the finite element -infinite element coupled boundary can simulate the infinite domain of dam foundation effectively to realize the propagation and dissipation of seismic waves in deep overburdened layer and eliminate the adverse effects of seismic waves reflection on dam structure. The research results of this paper allow for decision-making basis for the design and construction of similar dams, as well as the prevention and control of earthquake disaster.