A mathematic model for the soil freezing characteristic curve: the roles of adsorption and capillarity

The relationship between the unfrozen water content in frozen soil and negative temperature is defined as the soil freezing characteristic curve (SFCC). The SFCC plays a crucial role in understanding the hydrothermal migration, frost heaving and constitutive relations of frozen soil. The mechanism of the SFCC is less understood, especially in the low-temperature range. Considering the adsorption and capillary action between soil particles and the ice interface, a new SFCC model for saturated frozen soil is proposed from the pore scale. The predicted results of the model show that the unfrozen water content gradually decreases with the increasing particle radius at the same temperature. The SFCC of monodisperse silica microspheres and quartz sand samples were tested based on nuclear magnetic resonance technology. The experimental results were compared with the mathematical model, which showed that the new SFCC model is in good agreement with the experimental results. The new model has a clear physical meaning and can provide a theoretical basis for understanding the phase change process in frozen soils, which is of great significance to the application of the proposed model.

Automated summary

The soil freezing characteristic curve (SFCC) is crucial for understanding the hydrothermal migration, frost heaving, and constitutive relations of frozen soil. A new SFCC model was proposed based on the adsorption and capillary action between soil particles and the ice interface, which showed a good agreement with experimental results. The model provides a clear physical interpretation and theoretical basis for understanding the phase change process in frozen soils.