Kinematic hardening model for overconsolidated clays

Abstract

Abstract The proposed model puts a particular emphasis on accurate simulation of stress-strain behaviour of overconsolidated clays both within the small strain region of high stiffness and during the large-scale yielding. To achieve this, the model utilizes existing formulations which proved to be successful in description of clay behaviour in these regions, and makes an attempt to bridge between them. The model utilizes the principles of the multiple surface kinematic hardening plasticity and is constituted by three elliptical yield surfaces in triaxial stress space. Two of the surfaces are rotated ellipses of the same shape, representing the boundaries of the linear elastic and small strain regions, while the third one is the rotating elliptical MIT-E3 large-scale yield surface with a non-associated flow rule. All three surfaces are subject to both kinematic and isotropic hardening with corresponding hardening rules. The model requires 17 parameters, out of them eight are small strain and nine are large strain parameters. Performance of the model in prediction of the stress path dependency of clay behaviour was evaluated against experimental data obtained on undisturbed Laval samples of Bothkennar clay.