Parameters for an Elasto-Plasto-Damage Model for the Stress–Strain Behavior of Cohesive Soils

This article presents a constitutive model for cohesive soils that exhibits the post-peak strain-softening behavior. The model combines the elements of plasticity with damage mechanics to simulate the stress–strain behavior. The total strain increment is composed of an elasto-damage strain increment and a plastic strain increment. The post-peak stress drop is captured by the elasto-damage formulation, while the plasticity is superimposed beyond the elastic range. The elasto-damage strain increment is found using the elasto-damage formulation, while the plastic strain increment is found using either the Drucker–Prager classical plasticity model or as a function of the damage strain. To calibrate this model, an experimental program was conducted on a cohesive soil at different densities and water contents. The various physical and mechanical properties of this soil were determined. Triaxial compression tests, unconfined compression test, and hydrostatic tests were performed, in order to obtain the model parameters at different conditions. These parameters were used to calibrate the model, which was coded in FORTRAN computer programs to simulate the stress–strain behavior of cohesive soils. The model was verified and found to be a good predictor of the response of cohesive soil for the selected stress path.