Dynamic Shear Modulus and Damping Ratio of Compacted Silty Clay Subjected to Freeze–Thaw Cycles

Subgrade and foundation soils undergo freeze and thaw cycles in seasonally frozen regions that leads to changes in its mechanical properties, causing the degradation of its service performance. This study aims to investigate the effects of freeze–thaw cycles on the dynamic mechanical properties of compacted silty clay. Specifically, the effects of number of freeze–thaw cycle, confining pressure, initial compaction degree, and initial water content on the dynamic shear modulus and damping ratio were studied by using resonant column tests. The test results showed that both maximum dynamic shear modulus and maximum damping ratio of the compacted silty clay sample had a decreasing trend with the increasing number of freeze–thaw cycles. In addition, the maximum dynamic shear modulus was significantly increased with the initial compaction degree and it was decreased with the initial water content, while the maximum damping ratio was decreased with the initial compaction degree and it was increased with the initial water content. Finally, the empirical models of maximum dynamic shear modulus and maximum damping ratio were proposed to consider the varied parameters.