Experimental investigation on shear characteristics of ice–frozen clay interface

In cold regions, the shear characteristics of ice–frozen soil interface have significant effect on the slope stability and the mechanical behaviors of frozen soil. To investigate shear characteristics of ice–frozen clay interface, a series of cryogenic direct shear tests under different initial water contents (i.e., 14, 16, and 18%) and initial void ratios (i.e., 1, 0.8 and 0.6) were conducted at various temperatures (i.e., −1, −2 and − 3 °C), respectively. Experimental results indicated that the temperature and initial water content determine the shear stress properties and dilatancy types of ice–frozen clay interface. The shear stress exhibits softening behavior at the temperature of −3 °C and the softening behavior decreases with increasing of temperature. Under low normal stresses and temperatures, the interface tends to dilate during the shearing process, and presents contraction before dilatancy with increasing of temperature and normal stress. Finally, the influences of temperature and initial water content on shear stiffness, shear strength, friction angle and adhesion of interface were analyzed and discussed.