Impact of Hydraulic Hysteresis on the Small-Strain Shear Modulus of Low Plasticity Soils

Abstract

AbstractExperimental studies have observed that the small-strain shear modulus (Gmax) of unsaturated soils measured during hydraulic hysteresis has a greater magnitude during imbibition than during drainage when plotted as a function of matric suction. To capture this behavior, a semiempirical model was developed to interpret the impacts of the stress state and hydraulic hysteresis on Gmax of low plasticity soils. Different from previous empirical relationships for Gmax, this model incorporates elastoplastic constitutive relationships, which integrate the effects of mean effective stress and hardening because of either plastic changes in volume or changes in the degree of saturation. The effective stress is defined as the sum of the net normal stress and the product of the effective saturation and matric suction, facilitating integration of the soil-water retention curve parameters into the model. An experimental testing program involving measurement of Gmax of compacted silt during hydraulic hysteresis w...