Dynamic behavior of thawed saturated saline silt subjected to freeze-thaw cycles

Owing to the coupled influences of traffic loading, freeze-thaw cycles, and salt expansion, saline silt subgrades easily suffer from the frost boiling disaster, which compromises the stability of subgrades. In this study, to analyze the coupled influences on the dynamic behavior of saline silt, cyclic triaxial tests were conducted on thawed saturated saline silt from the Yellow River Delta in China. The evolution of dynamic behavior was analyzed considering the existence of salt and freeze-thaw cycles. The results suggested that the cyclic shear stress decreased with increasing salt content and freeze-thaw cycles at the same cyclic shear strain. The dynamic shear modulus decreased and the damping ratio increased with increasing salt content and freeze-thaw cycles. Empirical formulas were established and verified to predict the dynamic shear modulus and damping ratio of the thawed saturated saline silt. This study provides a useful guideline for evaluating and designing saline silt subgrades in seasonal frozen regions.