Deformation Research of Silty Clay under Freeze-Thaw Cycles

To explore the dynamic properties of silty clay in seasonally frozen ground under repeated freeze-thaw cycles, an unconsolidated undrained dynamic triaxial test was conducted on such properties under various confining pressures, number of freeze-thaw cycles, and dynamic stress amplitudes. The test results showed that due to the impact of freeze-thaw cycles, the inherent structure of the soil underwent some major changes, in which the resilient strain increased and the resilient modulus decreased. However, as the number of freeze-thaw cycles increased, the effect was reduced and eventually tended to be stable. As the number of freeze-thaw cycles increased, the cumulative plastic strain of the soil rose rapidly, and the soil samples became more prone to fracture at low stress amplitudes and small number of vibrations. The more the number of freeze-thaw cycles, the higher the cumulative plastic strain rate generated under a single dynamic stress amplitude. Moreover, with the increase in the confining pressure, the failure form of the thawed silty clay gradually evolved from a plastic fracture to a brittle one. The research results of this paper were helpful to further understand the influence of freeze-thaw cycle on the dynamic properties of silty clay, and provide data support for the subsequent research on the mechanism of roadbed diseases under the load in seasonally frozen ground.