Shear strength equation of soils in a wide suction range under various initial void ratios

Abstract

Shear strength equation is a basic theory for solving many geotechnical engineering problems. Although the shear strength equation has received widespread attention, shear strength of clay under wide suction range and different initial void ratio conditions cannot be well predicted. This study aims to establish a new strength equation applicable to soils within a wide suction range. Considering the capillary and adsorptive parts of soil–water interactions, a cohesion expression related to the degree of adsorbed water saturation Sra and the effective stress related to the degree of capillary water saturation Src are proposed. After that, based on the Mohr–Coulomb theory, a shear strength equation of unsaturated soils in a wide range of suction under various is proposed. Five parameters are included in the equation. It is easy to calibrate them through shear tests on saturated and the fully dried soils. It is verified that not only the sandy clay till and clayed silt but also the expansive soil's shear strength in wide ranges of suction under various can be well predicted.