Elasto-plastic model of structured marine clay under general loading conditions

In this paper, we propose an isotropic hardening elastoplastic model for structured marine clay that can describe its strength and deformation behavior under general loading conditions. A series of drained true triaxial tests were performed on structured and remolded marine clay to investigate the effect of intermediate principal stress. The test results show that the intermediate principal stress has a considerable effect, not only on the strength, but also on the deformation behavior of marine clay. A modified stress-dilatancy equation is defined in transformed stress space to capture this feature. Then, the model is extended to consider the influence of structure by incorporating the superloading surface concept. Compared with the modified Cam-Clay model, the proposed model requires only two additional parameters, which can be determined conveniently from triaxial and oedometer tests. The proposed model was validated by performing undrained triaxial tests and drained true triaxial tests at various confining stresses and Lode angles, respectively, on remolded and structured clay.