Hydro-thermal characteristics and deformation behaviors of silty clay subjected to freeze–thaw cycles

In cold regions, hydro-thermal characteristics and deformation behaviors of soils are important factors to evaluate the stabilities of engineering. In this study, the volumetric unfrozen water contents and deformations of silty clay exposed to freeze–thaw cycles were experimentally investigated, as well as dry density and porosity. The results showed that, in the first fifteen freeze–thaw cycles, the volumetric unfrozen water content, deformation, dry density, and porosity greatly changed. Besides, the influence of water seepage on volumetric unfrozen water content of soils is larger than that of the water migration during freeze–thaw cycles, the residual volumetric unfrozen water contents of soils are mainly determined by the lowest ambient temperature. Furthermore, the freeze–thaw actions make opposite effects on the soils with different dry densities, namely, the dense soils with high densities are expanded, while the soils with low densities are compressed after freeze–thaw cycles. There is a critical dry density and residual porosity where the soil samples does not change its volumes, dry densities, and porosities. For the silty clay, the critical dry density is around 1.60 g/cm3, and the residual porosity ranges from 0.40 to 0.41.