GENERAL FORMULATION OF A THREE DIMENSIONAL CONSTITUTIVE MODEL FOR PARTIALLY AND FULLY SATURATED SOILS BASED ON GIVEN FABRIC YIELD MODEL

摘要

A new general three-dimensional constitutive model is proposed for partially and fully saturated soils based on the Given Fabric Yield (GFY) model in Leroueil and Barbosa (2000) and Ghorbel (2006).Mohr-Coulomb failure criterion equations are adopted for the hexagon cone yield surfaces, and three constant-principal-stress planes are selected for the cap yield surfaces. Apparent cohesions are modified from constants to variables relating to activation of cap yield surfaces, so that consistent transition from shear yield to shear failure for cone model and continuous linking between the cap and cone yield surfaces can be fulfilled. The complex nonlinearity of the normally consolidation curve of the partially saturated soil can be considered in the strain hardening law. The anisotropic kinematic hardening effect due to suction is also illustrated. Generally, the parameters involved in the proposed model can be simply determined from laboratory experiments.