A Simple Model for Unsaturated Soils Based on Critical State

Different phenomena influence the strength and volumetric behavior of unsaturated soils. Among the most important are suction hardening, hydraulic hysteresis and the influence of volumetric strain on the soil-water retention curves. Fully coupled hydro-mechanical models require including all three phenomena in their constitutive relationships. Among these phenomena, suction hardening is the most influencing as it determines the apparent preconsolidation stress, the position of the loading-collapse yield surface and the shift of both the isotropic consolidation and the critical state lines. In this paper, a simple fully coupled hydro-mechanical model is presented. Numerical simulations show comparable results to more complex models.