Constitutive modeling of plastic effects of cyclic principal stress rotation of natural soft clay

A constitutive model which can reflect the plastic effects of the principal stress rotation of natural soft clay is proposed based on the anisotropic bounding surface model. For the unloading conditions of the cyclic principal stress rotation, the mapping rules of relocatable projection center is incorporated to deal with the plastic deformation under these unloading conditions. The plastic accumulation behavior with a cyclic fluctuation pattern is described reasonably by incorporating the inherent anisotropic elasticity. Meanwhile, the non-coaxiality variation during cyclic rotation is simulated by considering the influences of stress ratio and coupling the non-coaxial flow with coaxial flow. The proposed model is validated through the undrained behaviors tests under the pure principal stress rotation of Wenzhou natural soft clay. The results show that the proposed bounding surface model can reasonably capture the deformation effects of the cyclic principal stress rotation of natural soft clay.