State-of-the-art report — frost action in soils

Abstract

Several theories have been employed to describe the mechanism of frost heave and ice lens formation in soils. In the early seventies, the capillary theory, visualizing ice lens growth at the frost front in non-colloidal soils, has been invalidated by experimental evidence. This led to models in which ice lens growth takes place behind the frost front. Experimental confirmation of this concept was presented at several occasions. Simultaneously, numerical simulation of these models was attempted. In some of these, advanced finite-element and finite-difference techniques were employed.In these recent approaches, mass movement for ice lens growth takes place in a zone of frozen soil. This movement is facilitated by the presence of liquid water films between the pore ice and the pore wall. Coupling of heat and moisture movement in this zone is achieved by employing a generalized form of the Clausius-Clapeyron equation.Some qualitative and numerical models now include the effect of overburden load on the heaving process. Different approaches are followed to predict the effect of overburden load on the pressures in pore liquid and pore ice. In this paper various laboratory tests for frost-heave susceptibility, in use or proposed in recent years, are summarized. A major difference among them is, that either a constant frost penetration rate or a step change in surface temperature is applied. In recent publications it is concluded that net rate of heat extraction is the independent variable in the frost-heave process and should be standardized in laboratory tests.