Phase field modeling of freezing characteristics of saturated soil with different particle sizes

The unfrozen water content and its distribution are of importance to the macro mechanical behaviors of frozen soil. In this study, the phase field method was used to deeply investigate and model the evolution of the microstructure of different saturated soils during the freezing process. Particle size distribution and freezing point depression were considered in the simulation of freezing of the soil. The soil freezing characteristic curves of the soil with different particle sizes were well predicted by the phase field method. Moreover, the unidirectional freezing test was used to validate the proposed method. The simulation results successfully predicted the inhibition effect of soil particles on the spread of pore ice during the cooling process. A series of mesoscale characteristics can be well simulated, such as unfrozen water film, retardation effect of soil particles, nonhomogeneous freezing front, and isolated ice and unfrozen water. Our results provide a deeper insight into the freezing process of porous media, including the formation of pore ice, and the movement of the freezing front on a mesoscale.