A comparison of hydraulic conductivities, permeabilities and infiltration rates in frozen and unfrozen soils

In order to protect water resources, fuel-storage facilities in Alaska are required to provide secondary containment for fuel spills. Secondary containment generally consists of a lined catchment basin. The lining must have a hydraulic conductivity of less than 1e−6 cm/s [ADEC, 1996. Alaska Department of Environmental Conservation Division of Spill Prevention and Response Industry Preparedness and Pipeline Program. “Sufficiently Impermeable Secondary Containment Systems.” March 11: 19 pages.]. es of studies were conducted to evaluate the potential for frozen soil to serve as a secondary containment lining for fuel storage facilities in Alaska. Laboratory tests quantified hydraulic conductivities, permeabilities and fuel infiltration rates for three soil types collected at a fuel storage facility in Bethel, Alaska. Two of the soils, organic-rich silty sand and sandy silt, represented indigenous soil at the site. The third type, silty sand, was fill material imported to the facility from a nearby materials source. en and frozen soil samples were placed in cast acrylic permeameter columns. Tests performed on unfrozen samples were conducted at room temperature (19.8 to 24.0 °C). In unfrozen soils, fuel-infiltration rates were similar at the three volumetric moisture contents tested, 15%, 30% and saturation. Tests for frozen samples were conducted in a cold room at −4 °C. Fuel-infiltration rates in the frozen soils decreased as ice-saturation increased. Hydraulic conductivity, permeability and infiltration rates for ice-rich soils were approximately 1e−9 cm/s, 1e−13 cm2 and 1e−8 cm/s, respectively.