Influence of the Principal Stress Rotation on the Stiffness and Damping Ratio of Frozen Clay under Cyclic Loading

Studying the dynamic characteristics of frozen clay can offer a useful reference for the design of engineering projects and stability analysis in cold regions. This study conducted several cyclic hollow torsional shear and cyclic triaxial experiments to study the effect of cyclic stress ratios and confining pressures on the stiffness and damping ratio characteristics of frozen clay under the condition of principal stress rotation and fixation. The frozen clay samples tended to undergo progressive failure under principal stress rotation and brittle failure under the fixed direction of the principal stress axis. In addition, the stiffness and damping ratio were significantly more sensitive to dynamic stress amplitude and confining pressure under principal stress rotation. Affected by principal stress rotation, the maximum stiffness attenuation was approximately 10%–20%, whereas the minimum damping ratio measured was approximately 30%–70%. Therefore, the results obtained in this study facilitate a rational understanding of the mechanical behavior of frozen soil under principal stress rotation.