Dynamic Response Analysis of Periodic Alluvial Valleys under Incident Plane SH-Waves

Abstract

Combined with the region-matching technique, a periodic indirect boundary element method (PIBEM) is developed to investigate the scattering and diffraction of plane SH-waves by periodic alluvial valleys embedded in a layered half-space. By introducing Green’s functions for equivalent uniformly distributed loads acting on an inclined line to simulate the scattered fields outside the periodic valleys, the discretization effort is reduced to a single valley. And by using only a single irregularity as the computation cell to solve wave scattering problem of periodic irregularities (an infinite number of irregularities), the presented new method has the merits of high accuracy, low computational cost in CPU time, and low memory requirement. The implementation of the method is described in detail, and the accuracy of the method is verified by comparing its degenerated results with the analytical results of a single semi-elliptic valley, the semi-analytical results of two valleys and the IBEM results of multiple valleys. Numerical simulations are first performed in the frequency domain and then in the time domain using the inverse FFT. In addition, the time domain results reinforce the validity and reliability of the new method. The presented PIBEM can be used to study the various wave scattering problems of plane SH-waves by periodic topographies in a layered half-space.