Alaska Highway Case Study: Heat Transfer, Permafrost Degradation, and Transportation Infrastructure Stability
The Alaska University Transportation Center (AUTC) of the University of Alaska, Fairbanks, has supported multiple projects to research measures to reduce permafrost thaw and the resulting impacts to roads, specifically along the Alaska Highway (the only road connecting Alaska to the continental U.S.). Structural damage occurs when the permafrost under road infrastructure thaws. Thermal modeling demonstrates that the stability of permafrost below roadways and embankments is greatly affected by surface temperatures of roadways, and it has therefore been predicted that as the climate warms, permafrost degradation will be a major issue for the design and maintenance of roads in Alaska.
The Alaska Highway crosses large areas of permafrost-rich soils, and heat transfer through the road melts underlying permafrost. Thawing permafrost causes dips, bumps, potholes, and cracks in roads. Between 2009 and 2011, an AUTC research team collected data along sections of the Alaska Highway, using thermal monitoring of permafrost, and monitoring of surface drainage and snow dynamics to develop measures to reduce thawing of permafrost underlying roads. The fieldwork included construction of a snow shed along one section of a highway embankment. (Similar to a tunnel, a snow shed is a wooden structure that provides a roof over a road embankment to block out precipitation that increases surface temperatures of roadways causing underlying permafrost to melt). By keeping the insulating snow off the ground surface, the soil is exposed to cold air flowing over and under it, encouraging permafrost to stay frozen.
From this data collection, a permafrost database was established, as well as a 3D cryostratigraphic model (modeling of the structures formed by the amount and distribution of ice or permafrost), which was linked to a geographical information system (GIS). Along with thermal data, the database and the cryostratigraphic model allows researchers to evaluate how well adaptation measures reduce surface damage. The model is being used by AUTC and the Yukon Highway Public Works Department to develop strategies for mitigating damages to roads from melting permafrost.
This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on February 2, 2015.
Publication Date: 2011
- University of Alaska Fairbanks
- Academic research paper
- Case study
- Modeling tool
- Air temperature
- Permafrost melt