LAUSR

Soil properties vary in space even within a soil layer. Nevertheless, site response analyses are typically conducted using a best-characterized shear wave velocity (Vs) profile without considering its fluctuation. In this study, the random field theory is adopted to model heterogeneous Vs profiles for a range of coefficient of variations (COVs) and correlation lengths (CLs). Linear 1D site responses are analyzed with the randomized profiles to quantify the influence of spatial Vs variation on the propagated ground motions. Results reveal that a higher COV of randomized Vs profiles leads to a lower mean ground response compared with a homogeneous Vs profile. The variation of CL does not significantly affect the surface response and peak ground acceleration profile, but is shown to influence the degree of fluctuation of the maximum shear strain profiles. For idealized profiles, the effect of heterogeneous Vs on ground response can be approximately predicted by using reduced Vs and enlarged small strain damping that are dependent on COV.