Hydraulic conductivity of frozen granular soils

Frozen soil barriers are used for the subsurface containment of liquid contaminants so as to prevent their migration before and during soil remediation. Questions concerning the imperviousness of a frozen soil barrier to liquid contaminants provided the impetus for this study. Hydraulic-conductivity measurements, using a conventional falling-head permeameter with close control on temperature, have been performed on a frozen gravelly sand for ice-saturation levels of 0-100%. The dry frozen soil (-10 degrees C), with decane (a nonaqueous liquid) as the permeant, has a hydraulic conductivity (K) about the same as the unfrozen soil would have for water. An increase in ice saturation with a decrease in the open pore space reduced the frozen soil conductivity. At full ice saturation, measured K-values were less than 10(-4) mm/s (10(-5) cm/s). Data show that a clay additive (bentonite) will help retain water so as to give a high degree of ice saturation in a granular soil. The effects of ice erosion in the frozen soil by water-soluble liquid contaminants and brines are introduced.