A Review of the Existing Data on Soil-Freezing Experiments and Assessment of Soil-Freezing Curves Derived from Soil-Water Retention Curves

This study focuses on the investigation of the predictive capability of the Clausius-Clapeyron (C-C) equation in conjunction with soil-water retention characteristics to estimate soil-freezing curves (SFC). The Clausius-Clapeyron equation together with soil-water retention (SWR) models can provide a quick estimation of SFCs. However, the validity of the equilibrium assumption may not be applicable in all scenarios of freezing and thawing. The overall goal of this study is to provide a comprehensive assessment of SWRC-derived soil-freezing curves for different types of soils under varying environmental conditions. An extensive set of data obtained from studies reported in the literature pertaining to thermally induced hydraulic properties of sand, silt, and clay soils from multiscale experiments was analyzed. In addition, in-house laboratory freeze-thaw experiments were performed using silty soil. The SFCs derived from the SWRC were in good agreement with the measured SFCs for sands, whereas significant discrepancies were noted for silt and clay soils. Intensified discrepancies were noted when the results from different experimental methods and changing boundary conditions were compared. A significant hydraulic hysteresis was observed and possible controlling mechanisms were explained. A reliable method to predict SFC from SWRC will enable accurate modeling of coupled heat transfer and water flow processes in the Arctic subsurface for sustainable built and natural environments.