Surface Wave Dispersion in a Layered Medium for Varying Subsurface Scenarios

Abstract

Surface wave techniques are widely used to characterize a site based on shear wave velocity (Vs) or stiffness variation with depth. It utilizes the dispersion property of Rayleigh wave in a heterogeneous media. Dispersion curve is obtained from analyzing collected field test data and the final Vs profile is extracted from the inversion of the generated dispersion curve. The varying subsoil structures influence whether one or more Rayleigh modes will participate in the resulting wave propagation phenomenon. So, neglecting the higher mode participation may sometimes results in a completely different velocity profile than the actual existing one. In this paper, a detailed and comprehensive numerical study has been performed using finite element method for different types of soil profiles with different half-space impedances to assess how it affects the surface wave dispersion phenomenon. In addition to that, the effect of different data acquisition parameters on surface wave dispersion has also been studied.