Strength criterion for frozen saline sand considering effects of loading rates

The external conditions such as confining pressures and loading rates have significant influences on the strength of frozen saline soil. A series of conventional triaxial compression tests under different loading rates are carried out for Delingha frozen saline sand at a temperature of -15℃ with the confining pressures varying from 0.5 to 8 MPa. A strength criterion for the frozen saline sand, including the influences of loading rates, is established by use of the generalized nonlinear strength theory. Based on the conventional triaxial compression test results, the strength function in p-q plane is well fitted by the parabolic equation, and the relationship between loading rates and friction angles is analyzed. The strength function in π plane derived from the modified Lade-Duncan model considering the influences of loading rates and hydrostatic pressures is used. The proposed strength criterion can reflect the nonlinear strength characteristics of frozen saline sand, including the influences of change in the loading rates, pressure melting and ice crushing.