Freezing–Thawing Model for Soils and Rocks

Abstract

A coupled model of freezing–thawing of saturated porous materials, such as soils and rocks, is presented. The formulation is based on fundamental laws of continuum mechanics, i.e., conservation of mass, momentum, energy, and on mixtures theory. The problem is first tackled by ignoring irreversible phenomena like soil or rock damage. Therefore it is assumed that the phenomenon of freezing or thawing is governed by the theory of thermodynamics of reversible processes. It is shown that under certain assumptions the energy balance equation may be simplified to an equation with the unknown temperature only. This is a significant result since temperature is an easily measured parameter during an experiment. Subsequently, the heat flow equation is implemented into a one-dimensional finite element code that takes into account the change of phase of pore water during freezing. Finally, it is shown that the model may be used for the analysis of preliminary thawing experiments on a porous sandstone.