Crack Formation in Soil Landfill Covers Due To Thermal Contraction

Abstract

Soil landfill covers in the northern United States experience ground freezing to depths of 2 m or more. During periods of decreasing winter temperatures, thermal contraction will increase tensile stresses creating the potential for crack formation. If elastic soil behaviour is assumed, a drop of only 2 or 3°C will generate significant tensile stresses. Climatological data examined for three locations, along with computed ground temperatures, show larger drops in temperature. Frozen cover soils are comparatively weak in tension. Cracks, once initiated, can propagate unstably through the frozen soil, and may extend deeper than the tensile stresses to which they owe their growth. Simple elastic soil behaviour used with thermal strains does not provide adequate information for predicting thermal contraction and crack formation. Information is needed on the thermal contraction behaviour of frozen soils, on the extent to which soil creep will reduce the tensile stresses, and on criteria suitable for preventing crack formation.