Formation and growth of multiple, distinct ice lenses in frost heave

Abstract

This paper presents a fully coupled thermo-hydro-mechanical (THM) modelwhich simulates frost heave in fully saturated soils. The model is able tosimulate the formation and growth of multiple distinct ice lenses. The basicequations of the system were derived using the continuum theory of mixtures,nonequilibrium thermodynamics, and fracture mechanics, considering skeletondeformation, water flow and heat transport. Central to this model is the coupledtransport of mass due to the temperature gradient across thefrozen fringe,whichacts as the main driving force of the phenomenon. The model is formulated interms of measurable physical properties and thus no ad hoc parametrization isrequired. In an ice-lens-free state, the system is solved as a continuum using thefinite element method (FEM). It is then locally treated as a discontinuous systemupon the formation of ice lens, by enriching the elements carrying the embeddedice lens(es) using the extended finite element method (X-FEM). The accuracyand efficiency of the proposed model has been verified using several laboratorytestsonDevonsiltsamplesatdifferentoverburdenpressuresandthermalbound-ary conditions. Shut-off pressures have been also estimated and compared withthe experimental results