Microscale Numerical Modeling of the Tensile Strength of Wet Granular Soils

A micromechanical model is presented to evaluate the tensile strength of wet granular soils at low saturation (below 30%). The solid particles are modeled as rigid spheres using the Discrete Element Method (DEM). The capillary water is assumed to be in a pendular state and is idealized as liquid bridges at the particle-to-particle contacts. A microscale hydraulic hysteresis mechanism is introduced to model the soil during wetting and drying phases. Direct tension test computational simulations were conducted at different water contents. Results of conducted simulations highlight the difference between the isostatic tensile strength and the uniaxial tensile strength that is typically measured in direct tension experiments. The results also suggest that the tensile strength of an assembly of granular material during a drying stage is larger than that during a wetting stage.