State paramenter based model for unsaturated soils

DIEGO MANZANAL; M. PASTOR; J.A. FERNANDEZ MERODO

Toronto

Conferencia; 14th Pan-American Conference Soil Mechanics and Geotechnical Engineering; 2011

Canadian Geotechnical Society & ISSMGE

This paper presents a state parameter based model for partially saturated soils based on Generalized Plasticity. The proposed model is based on two pairs of work conjugated 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 monotonic and cyclic behaviour with a single set of constitutive parameters. The developed constitutive model has a hydro-mechanical formulation including modified water retention curve, relating the saturation degree and the normalized suction. The model includes two important features of the hydraulic behaviours of soils: void ratio dependency and hydraulic hysteresis. Comparison between model simulations and series of experimental data available, both cohesive and granular, are given to illustrate the accuracy of the enhanced generalized Plasticity equation.