Pore‐Morphology‐Based Estimation of the Freezing Characteristic Curve of Water‐Saturated Porous Media

Abstract Assessment of freezing effects on soil requires estimating the soil freezing characteristic curve (SFCC)—the variation of unfrozen water content with temperature. The existing methods for obtaining SFCCs often involve either costly experiments or heuristic inference from water retention data. Here, we propose a pore‐morphology‐based method for simple and efficient estimation of the freezing characteristic curve of water‐saturated porous media, whereby the pore‐scale configurations of water and ice phases are simulated in a digital image of porous microstructure. Idealizing the pore space as a system of overlapping spherical pores, the method simulates the freezing process with the Gibbs‐Thomson equation that can consider freezing‐point depression—a decrease in the freezing point due to spatial confinement—based on thermodynamics. For validation, we apply the proposed method to estimate the SFCC of a field soil for which the experimental freezing characteristics data are available. Results show that even with a digital pore image extracted from a surrogate discrete‐element packing of the soil, the proposed method provides an SFCC very close to the experimental data. Key Points A pore‐morphology‐based method is proposed to estimate the freezing characteristic curve of water‐saturated porous media The Gibbs‐Thomson equation and the sphere insertion method are combined to incorporate freezing point depression The proposed method is validated against experimentally measured freezing characteristic data of a field soil