The flux of water and the resultant formation of discrete ice lenses were studied in samples of New Hampshire silt which were saturated and then frozen under different temperature gradients and overburden pressures. A dual energy gamma scanning system was employed to locate the position of the growing ice lens relative to the freezing front. Parameters controlling water flow and the location of the ice lenses were employed to evaluate theories that have been proposed to describe the mechanisms of ice lens formation. The capillary theory was employed to locate the freezing front. However, the ice lenses were found to be located 0.2–0.4 cm behind the freezing front, which is inconsistent with the location of the ice lenses predicted by the capillary theory. Neither the hydrodynamic theory, nor the secondary frost heaving theory account for the redistribution of overburden pressure between soil particles, ice, and water. These theories cannot be employed to predict the location of the ice lens relative to the freezing front until overburden pressure effects are incorporated into the theory.
Heaving tests were conducted with 2–4, 4–8, and 8–16 µm soil fractions in special apparatus in which sliding friction (during heaving) was eliminated by confining the specimen as in standard triaxial test apparatus. Maximum pressures developed by heaving exceeded those computed by a primary heaving model (using air intrusion data) by factors as large as 3 to 6. Maximum pressures and rates of heave at constant pressures depended on temperature gradient and were maximal at gradients between 1 and 3C cm‐1.Comparisons with simplified transport equations for a frozen fringe adjacent to a growing ice lens (the characteristic feature of secondary heaving) indicate that pore ice in the frozen fringe contributes to water transport for lens growth but this may be offset by plastic counter‐flow of ice at large temperature gradients, accounting for the gradient‐dependent maxima.Results were interpreted as supporting the concept of secondary heaving.
Nous avons suivi durant la p6riode normale dc gel l'dvolution des profils hydriques ct thermiques dans un luvisol gris brun. Les calculs prenant en compte la d6formation du systeme de coordonn6es ont 6t6 r6alis6s pour obtenir des estim6es exactes du d6place-ment vertical de la surface du sol et de la pdn6tration de I'isotherme de 0' C. Les auteurs passent en revue les probldmes li6s d la collecte des donn6es n6cessaires pour 6prouver les moddles math6matiques du transpolt jumel6 de l'eau et de la chaleur dans les conditions normales de terrain.The redistribution of soil water due to freez-process is the development and testing of an ing conditions is of concern to agricultural-appropriate mathematical description. The isti, engineers and geomorphologists. An second type of study involves applying the ability to predict aciurately the freezing-mathematical description to field conditions' induced redistribution of water and heat, and Much of the research on heat and water the subsequent displacement of objects on or flow in tireezing soils has been of the first type beneath the ground surface, is the goal of discussedabove(e.g. Everett 1961;Williams scientists with interests as diverse as winter-1968;Penner 1967;Miller 1978 1974-1975 and lgt5-1916. Soil temperatures were measured using precision thermistors (10 000 ohm at 20"C) which were individually calibrated prior to installation.Thermistors were waterproofed and placed at depths of O, l, 2,5, 10, 15, 20,25,30, 50, 75, 100, 150, 200 Measurements were made on a weekly basis in [1914][1915] and every 2 to 3 days rn 1975-1916. Soil heave or displacement of the ground surface was estimatecl from moisture and temperature profiles. In addition, displacement was measured directly at one location at the edge of the site using a heavograph (Fahey 1973 Dec.2,1975 Dec. 17, t975 Dec,23,1975 Dec.3l ,1975 Jon. 7,1976 Feb. 4
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