Permeability analysis of a frozen unsaturated soil using Van Genuchten model and Fredlund-Xing model in soil vision

To measure permeability, one of Darcy's law's basic concepts is that the soil sample must be saturated. Traditional methods cannot be used to calculate the permeability of unsaturated soils because it does not follow Darcy's law. Two analytical models for estimating the permeability value for unsaturated soil have been proposed: Van Genuchten Model and the Fordland-Xing Model. For frozen unsaturated soils, such models use data from the soil-water characteristic curve to determine the necessary parameters. To provide a broad range of suction in this study, soil specimens were frozen-thawed (F-T) for different degrees of saturation, and soil water characteristic curves were formulated for all F-T cycles. For both models, the changes in fitting parameters and relative permeability with subsequent F-T cycles are discussed in this paper.