An elasto-plastic constitutive model for partially saturated soils with various suction

An isotropic hardening elasto-plastic constitutive model for partially saturated soils was developed on the basis of some experimental evidences and theoretical considerations. The model was derived using an assosiated flow rule. Two yield functions, two hardening modulus and a failure criterion have been contained in the model. The model presented consists of ten experimental parameters, which are easily determined from triaxial compression test results for saturated and partially saturated samples with different kinds of suctions. The predicted behaviour for isotropic compression and triaxial compression tests of a clayer soil with different kinds of suctions have been compared with available experimental data. It is shown that the model reasonably represents the changes with increasing suction in stress-strain behaviour for a clayer soil.