Unified Model for Small-Strain Shear Modulus of Variably Saturated Soil

The small-strain shear modulus G0 is a property fundamental to the deformation response of soils to dynamic loading. It depends on soil mineralogy, particle characteristics, void ratio, effective stress, and the degree of saturation. Some theories have been established to predict G0 of soils under variably saturated conditions. Accordingly, a new unified model was developed for G0 of different soils under variably saturated conditions. The model is based on two conceptual mechanisms: material hardening/softening, which is considered using the degree of saturation as a variable, and interparticle contact forces carried by the soil skeleton, which is considered using the effective stress as a variable. By utilizing suction stress theory, it is demonstrated that G0 can be correlated to the parameters of the soil-water retention curve. Results from the literature for 22 soils along with new results for 7 soils were used to validate the model under variably saturated conditions and a range of total stresses.