Modeling the dependency of Suction Stress Characteristic Curve on void ratio in unsaturated soils

Abstract

Geotechnical problems associated with unsaturated soils are common in semi-arid climates, where the upper soil layers are naturally unsaturated. Once a soil becomes unsaturated, its mechanical properties become different from its saturated counterpart. The main part of effective stress in unsaturated soils resulting from the soil moisture can be defined by the Suction Stress Characteristic Curve (SSCC). Although, the suction stress characteristic curve is determined from shear strength tests, but recent works show that the SSCC can be connected to the Soil Water Characteristic Curve (SWCC). This paper presents a simple and novel approach to model the effect of void ratio changes on SSCC in unsaturated soils. The proposed approach can be easily utilized with existing Soil Water Characteristic Curve (SWCC) equations to model any changes in suction stress for unsaturated soils. The main advantage of the suggested method is in fact its dependency to just one parameter, simply calibrated by the conventional water retention tests. This characteristic is so applicable in hydro mechanical constitutive models of unsaturated soils. Finally, the efficiently predicting of the experimental results implicitly demonstrates the applicability of effective stress principle using the concept of Suction Stress Characteristic Curve (SSCC) for unsaturated soils.