A cyclic bounding surface plasticity model for saturated clay with initial anisotropy

The initial anisotropy of natural soft clay tends to have a significant influence on its subsequent cyclic behaviors. The current elastoplastic constitutive models for cyclic behaviors of saturated clay always adopt an elliptic yield surface similar to the one in the modified Cam-clay model. However, studies have demonstrated that these kinds of models which adopt an elliptic yield surface are not suitable for predicting the characteristics of K0-consolidated soils under the extension state, due to its over-predicted elastic region. In this paper, within the framework of the generalized isotropic hardening rule, by introducing the initial anisotropic tensor to the formation of the bounding surface and combining with the transformed stress tensors which are based on the spatially mobilized plane (SMP) yield criterion, a new bounding surface plasticity model for saturated clay with initial anisotropy is proposed. The predicted results by the model for the monotonic and cyclic triaxial tests both on isotropically and anisotropically consolidated clays demonstrate that the bounding surface model can reasonably describe the initial anisotropy and the subsequent cyclic behaviors of saturated clay.