A bounding surface model for creeping soft clays under cyclic loading

In order to simulate the mechanical behavior of creeping soft clay under cyclic loading,a time-dependent constitutive model was developed within the theoretical framework of bounding surface plasticity to incorporate the effects of cyclic path and rheological behavior.The model was based on the concept of delayed plastic strain.It was assumed that the total strain could be decomposed into an immediate elastic part,an immediate plastic part,and a delayed part,where the delayed strain could further be divided into volumetric creep strain and deviatoric creep strain.The model had a few extra parameters more than those of the traditional Cam-clay model,which could be easily determined by conventional laboratory tests.The predictive capacities of model were examined by comparing with cyclic test data of creeping saturated soft clay of Shanghai.It was shown that the agreement between the model predictions and experimental results was satisfactory in general,and the proposed model could simulate realistically the main mechanical behavior of creeping soft clay of Shanghai under cyclic loading.