Seismic Amplification of Soil Ground with Spatially Varying Shear Wave Velocity Using 2D Spectral Element Method

Abstract

ABSTRACT Spatial variability of soils can have a profound effect on seismic site amplification, which cannot be reasonably captured using conventional one-dimensional analyses. In this study, the shear-wave velocity of soils is modelled as a 2D spatially correlated random field. Extensive simulations are conducted to quantify the influence of spatial variability of soils on site amplification using 2D Spectral Element Method. Key influential factors include variation and spatial correlation of shear wave velocity in both horizontal and vertical directions. Numerical simulations show that site amplification at resonance frequencies is subdued, and its variation depends on these influential factors. Spatial correlations of site amplification are also investigated, showing that the correlation range of site amplification is frequency dependent. The correlation range is much longer at low frequencies than that at high frequencies. The analyses imply that length scales of both soil heterogeneity and wavelength should be considered simultaneously when quantifying the spatial variability of ground motion amplification.