Implications of a Generalized Effective Stress on the Constitutive Modelling of Unsaturated Soils

Summary

The major consequences of the application of the effective stress concept to unsaturated soils are investigated. Several experimental data sets are re-examined in the light of a generalized effective stress, intended to describing the mechanical behaviour of porous media. The critical state lines at different saturation states tend to converge remarkably toward a unique saturated line in the deviatoric stress versus mean effective stress plane. The effective stress interpretation is also applied to isotropic paths and compared with traditional net stress conception. The accent is finally laid on the key feature for constitutive frameworks based on a unified stress, namely the sufficiency of a unique mechanical yield surface.