A hybrid time-domain half-plane FE/BE approach for SH-wave scattering of alluvial sites

In this paper, a hybrid time-domain half-plane finite element-boundary element method (FEM/BEM) is developed to analyze the arbitrarily shaped alluvial sites subjected to propagating vertically incident plane SH-wave. First, the model is decomposed into two parts, a closed alluvial domain and an open valley-shaped feature as the surrounding medium. The former part is modeled by a conventional FE approach and, a recently proposed half plane BEM is successfully applied to prepare the model of the latter part. After satisfying the continuity conditions at the interface, the coupled equations are solved step-by-step in FE framework to obtain the unknown values. In the use of the method, the interface of the basin needs to be discretized by BE meshes. Finally, the prepared computer algorithm is validated by solving some practical examples. The results show that the models are very simple and, the formulation has the appropriate accuracy. Furthermore, due to the significant reduction of the boundary elements in the half-plane BEM compared to the full plane BEM, the duration of the analysis and error waves in this formulation decreased. Therefore, the proposed hybrid method can be easily used in the nonlinear analysis of site response and the seismic interaction of soil-structure.