A model of segregation frost heave for saturated soil freezing under overburden pressure

To study the inhibition mechanism of overburden pressure on water migration in freezing soil, the pressure-suction coexistence state of film water is analyzed, and it is found that the main function of ice pressure is to offset and balance the theoretical suction. Under the combined action of ice pressure and theoretical suction, the surface adsorption force that drives water migration is produced. Based on this, the mechanical model of the pressure-suction coexistence state is introduced into the frozen fringe theory, and it is found that as the overburden pressure increases, the surface adsorption force gradually increases, while the total permeability coefficient of the frozen fringe decreases according to a high-order power function. Given this, a theoretical model of segregation frost heave under pressure is established and an explicit equation for the water migration velocity is given. Finally, a frost heave loading test is performed on saturated silt under open-system conditions, and the main parameters of the test process are substituted into the explicit equation for water migration velocity, the results showed that the calculated value of the model is completely consistent with the experimental value, thus verifying the correctness of the model. In summary, the proposed model has important theoretical value and practical significance for improving the existing frost heave theory.