Using large-scale shearing device,isotropic consolidated-drained triaxial tests under different confining pressures were carried out for three relative density overburden materials of Shuangjiangkou earth dam.Based on the analysis of test and the relationship between shear dilatancy ratio and stress state,a new stress-dilatancy equation,which is available for coarse-grained soils, was set forward, and the mothed to determine the parameters of dilatancy equation was given through analyzing the relationship of the parameters of dilatancy equation and confining pressure.The new dilatancy equation reflected the relationship between the shear dilatancy ratio and current stress ratio and the relationship between failure stress ratio and confining pressure.Using the present dilatancy equation and Rowe’s dilatancy law,the triaxial compression test results of several kinds of coarse-grained soils were predicted. The results showed that the effect of simulating the dilatancy characteristics of coarse-grained soil by the present dilatancy equation is better than Rowe’s dilatancy law.
