A half-plane time-domain BEM for SH-wave scattering by a subsurface inclusion

Abstract

A direct time-domain numerical approach named the half-plane boundary element method is proposed based on the half-space Green's functions for seismic analysis of a homogeneous linear elastic half-plane in presence of arbitrarily shaped subsurface inclusions, subjected to propagating obliquely incident SH-waves. It is assumed that inclusion is completely connected to the surrounding domain. In the use of the method, only the interfaces need to be discretized to create the model. First, the problem is decomposed into two parts including a pitted half-plane and a closed filled solid. Then, the influence coefficients of the matrices are obtained by applying the method to each part. By satisfying the boundary/continuity conditions on the interfaces, a coupled equation is finally formed to determine unknown boundary values in each time-step. After implementing the method in an advanced developed algorithm, its efficiency is investigated by solving some practical examples and compared with those of the published works. The results show that the proposed method has an appropriate accuracy for analyzing seismic inclusion problems. To complete the results, the synthetic seismograms of the surface are presented for circular/elliptical subsurface inclusions. Then, three-dimensional amplification patterns are illustrated for some specific cases. The method can be recommended to geotechnical/mechanical engineers for transient analysis of different topographic features, seismic isolation and composite materials.