Abstract
In this paper, after reviewing the approach to generalize the elastoplastic model for soils with the initially stress-induced anisotropy by the SMP criterion, the inviscid Sekiguchi-Ohta model is revised by using a transformed stress tensor σij, which is deduced from what makes the SMP criterion become a cone with an axis at the space diagonal line in the transformed principal stress space. The revised model is then extended to be a unified elastoplastic model for clay and sand by introducing a new hardening parameter H, which can describe the negative and positive dilatancy characteristics of soils. Model complexity is controlled through only adding one material parameter to those of the Sekiguchi-Ohta model. Extensive comparisons with experimental data from drained shear tests in different stress paths show that the proposed model gives excellent predictions, and especially for K0 normally consolidated clay, the model is more realistic than the Sekiguchi-Ohta model in predicting the deformation and strength of soils. Finally, the elastoplastic constitutive tensor is derived for the application of model to finite element computation.
