Experimental and theoretical investigations into the formation of ice lenses in deformable porous media

Abstract

The aim of this paper is to increase the understanding of ice lens initiation and growth in freezing soil. A model describing the growth process of ice lenses in soils has been established. The model presented here, which considers a series of processes, including heat transfer, water migration, phase change, ice lens formation, soil deformation, is solved by the use of a transient finite element. The simulated results agree with the experimental data. Results show that: (1) Negative pore water pressure occurs in unfrozen areas, this result in the water transfers from the unfrozen zone to the frozen zone and substantial water was stored in the frozen zone which results in oscillation with in water content distributions. (2) Few segregation ice lenses appeared in the fast freezing section, several thin and discontinuous segregation ice lenses appeared in the transitional section, and thick ice lenses appeared in the third phase when the freezing front tended to be stable. (3) Both the consolidation process and the expansion process are in progress during the freezing process, due to the migration of unfrozen water. (4) The frost heave model is composed of two aspects: the coupled heat-mass transport and the growth of ice lens. Numerical modeling is able to represent the development of both the thermal field and ice segregation observed in the physical models.