Research on Relationship between Unfrozen Water Content in Soil and Temperature

The balance equation of ice and water chemical potential was built by taking advantage of the thermodynamic principle for the physicochemical characteristics of water solution. Moreover, the formula of water freezing in different pore sizes was deduced according to the pore distribution characteristics of soil under the assumption of the ideal ice-forming model. In this process, the principle of effective stress was introduced to build the relationship between unfrozen water content and temperature in low temperature. Based on this, a general equation to determine water freezing in soils at different temperatures was proposed. Besides, the rationality and accuracy of this equation have been proved through experimental verification. The results show that the unfrozen water content decreases with freezing temperature exponentially. The increase of the external load and the increase of salt content will cause the curve of unfrozen water content-temperature to move rightward in the coordinate, while the decrease of soil pore sizes results in the anticlockwise rotation of the unfrozen water content curve. The ice crystal in the pores in the soil delays the process of water freezing and the impact of ice crystals on water freezing is increasingly obvious with the decrease of pore size. © 2018, Department of Journal of the China Railway Society. All right reserved.