PARAMETER CORRECTION METHOD OF BURGERS MODEL FOR COARSE-GRAINED SOIL CONSIDERING CONFINING PRESSURE

Based on the hypothesis that only deviatoric stress causes creep deformation, conventional Burgers model is not proper for the creep properties considering the influence of confining pressure. It is mainly used to characterize the creep behavior law of rock. Obviously different from rock, coarse-grained soil is a granular material, whose creep properties are closely related to confining pressure. To describe the creep behavior of coarse-grained soil considering the influence of confining pressure, a three-dimensional creep theoretical solution is derived firstly. Based on this solution, a practical parameter inversion method is presented to obtain the Burgers model parameters of coarse-grained soil under the same confining pressure but different deviatoric stress. Secondly, lab triaxial creep tests are summarized, and the power function is found felicitous to characterize the variation law between confining pressure and Burgers model parameters. Based on this, a parameter correction method of Burgers model is proposed to describe creep properties of coarse-grained soil considering the influence of confining pressure. Finally, three creep tests of coarse-grained soil are presented to demonstrate the validity of the proposed method.