Finite volume simulation for coupled moisture and heat transfer during soil freezing

For simulation of one-dimensional soil freezing process using coupled moisture and heat transfer model, problems with constringency and non-necessary conditions in the current simulations are pointed out. A new full-implicit finite volume scheme is established, and the time step and discretization of special nodes are introduced. Freezing processes of silica flour and Zhangye loam column are simulated, and the results of temperature and moisture are in agreement with the experimental data. The results show that water redistribution happens mainly between unfrozen zone and freezing front because the water flow in frozen zone is negligible, and the water accumulation behind freezing front is intense while the freezing front is moving slowly. The medium columns with different penetrabilities differ in sensitivity to ice impedance factor, and the columns with higher penetrabilities such as the silica flour column are more sensitive to the impedance factor. When the water flow is negligible, the equivalent capacity model is obtained by simplifying the Harlan’s model, and its applicability for temperature calculation of soil freezing process with low moisture content is confirmed; for soil freezing process with high moisture content, the influence of water flow should be considered for temperature calculation.