FROST HEAVE DUE TO ICE LENS FORMATION IN FREEZING SOILS .1. THEORY AND VERIFICATION

A frost heave model which simulates formation of ice lenses is develop ed for saturated salt-free soils. Quasi-steady state heat and mass flo w is considered. Special attention is paid to the transmitted zone, i. e. the frozen fringe. The permeability of the frozen fringe is assumed to vary exponentially as a function of temperature. The rates of wate r flow in the frozen fringe and in the unfrozen soil are assumed to be constant in space but vary with time. The pore water pressure in the frozen fringe is integrated from the Darcy law. The ice pressure in th e frozen fringe is determined by the generalized Clapeyron equation. A new ice lens is assumed to form in the frozen fringe when and where t he effective stress approaches zero. The neutral stress is determined as a simple function of the unfrozen water content and porosity. The m odel is implemented on an personal computer. The simulated heave amoun ts and heaving rates are compared with experimental data, which shows that the model generally gives reasonable estimation.