Residual deformation and stiffness changes of frozen soils subjected to high- and low-amplitude cyclic loading

The present paper reports the results of a laboratory experiment that aimed to investigate the residual deformation and stiffness changes of frozen silty clays under cyclic triaxial loading. Two sets of cyclic stress magnitude — namely, low and high level — were applied to the reconstituted artificial frozen soil specimens with identical properties, and the effect of six levels of confining pressure was examined. The results indicate that two distinct development categories of residual axial strain with number of loading cycles are induced by the low- and high-level cyclic stress. The dynamic Young’s modulus derived from each test experiences a significant increase with the number of loading cycles, which is partly attributed to the cyclic densification. A special observation from the tests under high-level cyclic stress along with a confining pressure of 0.3 MPa also indicates that the dynamic Young’s modulus keeps as a relatively constant value when the change of residual volumetric deformation transfers from compression to dilation. The empirical relationships were proposed to properly reflect the development of the residual axial strain and dynamic Young’s modulus with the number of loading cycles.