Frost Penetration and Thermal Regime in Dry Gravel

The depth of frost and ground temperatures were monitored on a regular basis between 1983 and 1985 at 12 locations in Tumbler Ridge, British Columbia. The soil is dry gravel which has a moisture content of 1.5 to 4%. The maximum depth of frost recorded was 3.98 m for a winter having 1,430 ° C‐days. Back calculation using the Stefan equation yielded n factors relating air and ground freezing indices to be generally within the range of those quoted in the literature. However, in heavily traveled cleared roadways, the value of n was higher than that reported in the literature. Values of unfrozen thermal diffusivity were calculated from both the temperature dissipation with depth and the time lag that the maximum temperature was recorded with depth. The results of these analyses compare well with typical values quoted in the literature for dry gravel.