Effects of water saturation and distribution on small-strain stiffness

Abstract

The purpose of this study is to investigate the role of the degree of saturation and water distribution patterns on small strain soil properties. First, we measure P- and S-wave velocities of fine sands mixed with varying degrees of water saturation Sw = 0, 5, 30, 60, and 100% during the vertical loading under zero-lateral strain conditions. Next, we use a simple geometry analysis combined together with soil index properties to provide the first-order approximation of capillary pressure. Then, we consider the effect of capillarity on soil skeleton stiffness to analyze the data in the context of Gassmann's framework. Finally, we investigate the effect of water distribution patterns on small strain soil properties. Results show that water distribution pattern is a critical factor to control the low perturbation soil properties. Furthermore, a specific surface appears to be a good indicator to predict the effective stress- and pore size-dependent capillary pressure in the determination of small strain geophysical properties.