Calculating capillary pressures in frozen and ice-free soils below the melting temperature

Abstract

Approaches to calculating capillary pressure in frozen and ice-free soils below the melting temperature are surveyed. Three methods for calculating capillary pressure in frozen porous media are presented and compared. Except at very low temperatures all give comparable results. The effect of changes in the ice–melt interfacial tension on the soil freezing curves are expected to be trivial since the relative decrease in ice–melt interfacial tension becomes appreciable only at temperatures at which unfrozen water contents become vanishingly small. The thermodynamic relationships and formulas are presented to estimate the capillary pressure for unfrozen water in ice-free soils.