Modeling thermal conductivity of soils during a freezing process

Thermal conductivity of soils is a key parameter in determining the heat transfer and temperature field in thermal engineering. This paper developed a thermal conductivity model of soils with a consideration of the thermo-hydro-deformation interaction during a freezing process. The model was proposed based on the concept of normalized thermal conductivity, and integrated the temperature, volumetric unfrozen water content, porosity, mineralogy, solid particle type and frost heave. Then, the steps to calculate thermal conductivity of soils during a freezing process were illustrated. Additionally, compared with the other two widely used empirical models, i.e., model based on the apparent heat capacity method and model based on the Heaviside function, the proposed model was more effective and reasonable, while the other two models had some limitations in calculating thermal conductivity of soils during a freezing process. Moreover, the proposed model was comprehensively verified by the 32 soil samples, and the good agreements between the measured and model-calculated thermal conductivities of soils confirmed that the proposed model can be used to calculate the thermal conductivity of soils in the numerical simulations, and could also well reflect the effect of phase transition of water-ice on thermal conductivity of soils during a freezing process.