Strength of Frozen Soils and Tundra Travel Criteria
Abstract
Energy development on the North Slope of Alaska (an area of very limited roads) is dependent on winter exploration activities. The sensitive tundra environment dictates that most exploration takes place in the middle of winter, when snow cover and frozen soil conditions allow tundra traffic without adverse damage to the Arctic landscape. The current management protocols do not take into account the range of soil conditions and frozen ground characteristics. Management criteria require soils at 30 cm depth to be below - 5°C. Since establishment of this criteria, a number of meteorological and geotechnical data stations have been established on the North Slope. Soil temperature and unfrozen soil-moisture content data from a dozen monitoring stations in northern Alaska were examined along with laboratory determined temperature- and water-dependent soil strength values from the literature in order to estimate soil strength in the field as the soil temperature falls below freezing. Soil strength at temperature below 0°C depends on soil composition, salinity, and unfrozen water content. In general, bearing capacity of soils without salt changes sufficiently in the range of temperature from 0 to -1°C and very gradually with lower temperature. Soil composition and ice content are very important strength factors. The goal is to maximize permissible tundra travel time while minimizing environmental damage. If tundra travel restrictions, currently based on temperature and snow depth, would allow travel at slightly higher soil temperatures (and slightly higher soil water contents), the length of the tundra travel season could be increased, resulting in considerable economic benefit while maintaining environmental quality.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.C11C0522L
- Keywords:
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- 0700 CRYOSPHERE (4540);
- 0702 Permafrost (0475);
- 0704 Seasonally frozen ground;
- 0718 Tundra (9315);
- 0770 Properties