A Coupled Thermo-Hydraulic Transfer Model for Soil Freezing

Frost heave is a common challenge in cold regions, threatening infrastructure stability. Despite decades of research, numerical simulation remains difficult due to the complex nature of coupled processes. This study presents a coupled thermo-hydraulic model for soil freezing, developed within the framework of unsaturated soil mechanics. The model uses suction and temperature as primary variables and incorporates a method to estimate ice content. It employs a soil freezing characteristic surface (SFCS), previously developed in related work, to calculate unfrozen water content as a function of both suction and temperature in partially frozen soils. The model is implemented in COMSOL for both closed and open systems and effectively simulates liquid water migration driven by suction gradients. Validation against experimental data shows good agreement in predicted temperature and total water content. This study provides a unified framework for modeling soil freezing processes and enhances the predictive capability of numerical simulations in cold regions.