A Structured Cam-Clay Model with a Damage Variable

A plastic constitutive model, namely a structured Cam-clay model with a damage variable, is here established based on the modified Cam-clay model. The resultant compression curve of undisturbed soil is simplified to a polyline based on the theoretical framework of the critical state model, and a yield surface that considers structural parameters is adopted to express the progressive damage of the soil structure by incorporating the damage variable D. The proposed model can reflect the stress–strain relationships of structural clays exhibiting different amounts of damage, and can also reflect changes in the structural features of clays induced by different mean effective stresses and stress paths. The model was verified by comparing the cumulative plastic strains (with different mean effective stresses and stress ratios) from triaxial test results with those predicted by the model; these showed good agreement.