Experimental research on dilatancy characteristics of coarse-grained soils by triaxial compression test

Dilatancy is a basic behavior of soils which is closely related to strength and deformation behaviors of soils and makes soils significantly different from normal elastic materials. A large-scale triaxial compression testing machine was used to study the dilatancy characteristics of coarse-grained soils of earth rock dam. The results show that the confining pressure has a significant effect on the dilatancy of coarse-grained soils, the soil first shrinks and then expands under low confining pressure, and the soil mainly produces shear shrinkage deformation under high confining pressure. When the soil changes from shear shrinkage to dilatancy, the strain ratio of soil changes abruptly. Rowe dilatancy model can reflect the dilatancy deformation characteristics of coarse-grained soils. The parameter K_f of the model tends to be constant with the increase of axial strain, and the parameter K_f of coarse-grained soils is smaller when the confining pressure is larger.