Theory and application of a novel soil freezing characteristic curve

Abstract

Unfrozen water in frozen soil is a key factor for water migration, frost heave and thaw settlement under freeze-thaw cycles. The relationship between unfrozen water content and temperature in frozen soil is known as soil freezing characteristic curve. The integral form for a soil freezing characteristic curve was derived from the perspective of soil pore structure in this study. According to the relationship between pore radius and freezing temperature, using existed test data, a distribution function was basically determined. Then, theoretical expression of the soil freezing characteristic curve was proposed. The calculated results by the theoretical expression were in good agreement with the test data. The parameters of the soil freezing characteristic curve have clear physical meanings, and the theoretical expression is continuous at the point of initial freezing temperature. In order to apply the proposed theoretical expression to coupled hydro-thermal-vapor transfer model, the equation was substituted into a coupled hydro-thermal-vapor transfer model, and the numerical simulations for frozen soils were carried out. The simulated results illustrated the reasonableness of the proposed equation.