Water Redistribution in Partially Frozen, Saturated Silt Under Several Temperature Gradients and Overburden Loads

The flux of water and the resultant formation of discrete ice lenses were studied in samples of New Hampshire silt which were saturated and then frozen under different temperature gradients and overburden pressures. A dual energy gamma scanning system was employed to locate the position of the growing ice lens relative to the freezing front. Parameters controlling water flow and the location of the ice lenses were employed to evaluate theories that have been proposed to describe the mechanisms of ice lens formation. The capillary theory was employed to locate the freezing front. However, the ice lenses were found to be located 0.2–0.4 cm behind the freezing front, which is inconsistent with the location of the ice lenses predicted by the capillary theory. Neither the hydrodynamic theory, nor the secondary frost heaving theory account for the redistribution of overburden pressure between soil particles, ice, and water. These theories cannot be employed to predict the location of the ice lens relative to the freezing front until overburden pressure effects are incorporated into the theory.