Vapour transfer in the freezing soils – physical phenomena of the frost heave

Abstract

Study of the hydraulic conductivity in the freezing soils and the frost heave mechanism started as far as in the 30’s of the last century and even earlier. However explanation of frost heave mechanism with hydraulic conductivity is fundamentally wrong approach which leads to the complication in the calculations and the predictions of frost heave. The presented work explains the detailed description of the moisture migration in a gas phase within the freezing porous media and gives the mathematical modelling based on the phase transitions of moister as water–gas–water-ice. The proposed method is based on the thermodynamically and phases equilibrium and allows to determine the speed of the mass transfer in the freezing media. The calculations were shown in an example of the experimental testing data. The obtained results admit the strong relationship of the frost heave and air void volume. They also emphasize the impact of soil density, void ratio and moisture content on the amount of built ice in the freezing zone of the soil.