Modified Duncan-Chang Model Considering Physical Properties of Saturated Clays

Abstract

A series of undrained triaxial compression tests of saturated clays under different conditions were performed to study whether it is possible to determine parameters specifying Duncan-Chang model simply by using the physical parameters. The test results show that both the initial tangent modulus and peak deviatoric stress decrease with increasing initial void ratio and plasticity index of the soil under the same confining pressure. Whereas, they increase with increasing confining pressure of the soil with the same initial void ratio and plasticity index. A new synthesized physical parameter λ is defined based on the test results in this work. The functional relationships among the parameters K, peak deviatoric stress in Duncan-Chang model and the parameter λ are established to develop a modified Duncan-Chang model by considering physical properties of soil. In this model, only two input parameters, i.e., λ and the damage ratio Rf, are needed to predict the stress-strain relationships of the soil. In order to check the accuracy of the proposed model, laboratory tests were conducted to evaluate against the predicted results. The results show that the stress-strain relationships of saturated clays can be well described by the proposed model.