Bounding surface SANICLAY plasticity model for cyclic clay behavior

Natural clays are anisotropic in their in situ state and have an undisturbed shear strength in excess of the remolded strength. In addition, most of the structures founded on clay deposits must be designed to withstand cyclic loads such as earthquakes or ocean waves. When subjected to cyclic loadings, clay exhibits complex response. A realistic modeling of clay response under irregular loading requires an appropriate description of the stress-strain relationship. This paper extends the formulation of a Simple ANIsotropic CLAY plasticity (SANICLAY) model by incorporation of a bounding surface formulation for simulation of clay response under cyclic loading. The most important elements of the proposed formulation are incorporation of bounding surface plasticity concept with proper repositioning of the projection center and adoption of a new damage parameter. These have led to significantly improved simulation of clay response in cyclic loading. The model is developed with the aim of maintaining the simplicity and yet including an adequate level of sophistication for successful modeling of the key features of clay response. The formulation is presented in detail followed by validation of the model demonstrating its capabilities in capturing a number of important characteristic features of clay response in cyclic loading. Copyright (c) 2013 John Wiley & Sons, Ltd.