Formation and evolution of pore ice in saturated soil with consideration of freezing point

The distribution and evolution of pore ice are essential for the thermal-hydro-mechanical properties of frozen soil. This study proposed a lattice Boltzmann model to explore pore ice formation and evolution. The particle random distribution method was used to generate complex soil structures, and the generalized Clapeyron equation and pre-melting theory were used to calculate the freezing temperature distribution for capillary and bound water. The model incorporated the effects of particle size distribution and pore structure on freezing behavior, providing a novel approach for simulating the ice-water phase transition in frozen soil. The simulation results were validated against experimental data, with squared correlation coefficients of 0.961–0.946 for sand and silt loam in homogeneous freezing. For one-dimensional freezing, the coefficients were 0.87, 0.94, 0.90, and 0.84 at temperature boundary conditions of ‐2, ‐3, ‐4, and ‐5 °C, respectively. The homogeneous freezing process consisted of three stages: supercooling, rapid freezing, and slow freezing, with early stages influenced by pore structure and later stages governed by particle surface adsorption forces. The results indicate that the model effectively captured the mesoscopic characteristics of pore ice formation and evolution in soil, revealing the fundamental interaction mechanisms.