Mechanism of thawing

Freezing–thawing phenomena have been studied at laboratory scale for decades with various techniques and test setups. In this study, a freezing–thawing laboratory apparatus was supplemented with a camera in order to get a better understanding of ice formation during the freezing period and ice melting during the thawing period. The results from three thawing tests with identical samples but different boundary conditions are presented here. Water intends to migrate upward even when the entire frozen part has been thawed. That would cause excess pore water pressure and softening of the soil after the thawing period as well. Upward water migration after the thawing period is due to changes in thawed soil properties such as permeability and fine particle redistribution. The rate at which thawing takes place is a very important factor for thawing conditions. Moreover, freezing condition, i.e. access to water, has a high impact on thawing soil. If the volume of ice lenses is sufficient, frozen soil would fluidize during thawing.