Estimation of elastic wave velocity through unsaturated soil slope as function of water content and shear deformation

Abstract

The objective of this study was to estimate the elastic wave velocity of an unsaturated soil slope, and to verify its applicability. The elastic wave velocity in a silty sand was measured. The individual influence of the volumetric water content and the tilt angle on the normalized wave velocity through unsaturated soil were investigated through a series of varied slope model tests. The relationship function of the normalized wave velocity-volumetric water content-tilt angle was established. To verify the proposed estimation function, a series of fixed slope model tests was carried out. The relationship functions were used to estimate the behaviors of the wave velocity in rainfall-induced slope failure model tests. The applicability of the proposed relationship functions for the wave velocity behaviors was also presented. It was found that the estimation function is highly consistent with the measurements for the wave velocity behaviors through unsaturated soil slope in the presented test conditions. In addition, the effects of the rainfall duration/initial water content, density, slope angle and surface layer thickness on the decrease rate of the normalized wave velocity with the volumetric water content and the tilt angle within the test conditions in this study were seen to be small.