Similarity of soil freezing characteristic and soil water characteristic: Application in saline frozen soil hydraulic properties prediction

Abstract

Accurate prediction of hydraulic properties in frozen soils is of importance for the role of frozen soil water dynamics in cold region water cycles. Furthermore, the existence of solute is known to complicate the water, heat and solute transport in frozen soils. To predict hydraulic properties in saline frozen soils more accurately, experiments on soil water characteristic curves (SWCCs) and soil freezing characteristic curves (SFCCs) were conducted under five solute types combined with five solute content levels. Results showed that, under low salinity conditions (e.g., no higher than 1.0% g/g dry soil), the conversion of SFCCs to SWCCs (or SWCCs to SFCCs) was possible by using generalized Clausius-Clapeyron equation (GCCE). The combination of these two curves could predict more reliable hydraulic parameters for the compensation in experimental data ranges. Comparison of the combining method with other direct or indirect experimental results indicated that accurate and integral θl − h relationships could result in accurate estimation in hydraulic parameters in frozen saline soils. This study has proposed an improved method for predicting hydraulic parameters in saline frozen soils, and more validation work with experiments under various soil and solute conditions is needed before incorporating it into frozen soil properties predicting frameworks.