Insight into shear strength functions of unsaturated granulates by DEM analyses

Based on numerical experiments using the distinct element method, revised with the capillary water contact model proposed, this paper presents an insight into the shear strength functions of unsaturated granulates. The studies indicate that there appears to be a unique peak/residual shear strength envelope if it is described by the generalized effective stress (GES) proposed. The curve of GES due to suction is observed to be analogous to the water-retention curve, and is correlated with the particle gradation. The two shear strength functions proposed appear to be able to reflect both the nonlinear feature and the effect of particle gradation for unsaturated soils.