Generalized plasticity state parameter-based model for saturated and unsaturated soils. Part II: Unsaturated soil modeling

The aim of this paper is to extend the generalized plasticity state parameter-based model presented in part 1 to reproduce the hydro-mechanical behavior of unsaturated soils. The proposed model is based on two pairs of stress-strain variables and a suitable hardening law taking into account the bonding-debonding effect of suction and degree of saturation. A generalized state parameter for unsaturated state is proposed to reproduce soil behavior using a single set of material parameters. Generalized plasticity gives a suitable framework to reproduce not only monotonic stress path but also cyclic behavior. The hydraulic hysteresis during a drying-wetting cycle and the void ratio effect on the hydraulic behavior is introduced. Comparison between model simulations and a series of experimental data available, both cohesive and granular, are given to illustrate the accuracy of the enhanced generalized plasticity equation. Copyright (C) 2010 John Wiley & Sons, Ltd.