AUTC project number: 309035
US Department of Transportation (RITA)
Department of Highways and Public Works, Yukon, Canada
The Alaska Highway, the only road connecting Alaska to the contiguous U.S., crosses large areas of permafrost-rich soils. Highway reconstruction in the mid-1990s damaged the organic layer that insulated and protected the surrounding permafrost. Since then, heat transfer through the road has been melting the ground ice. The thawing and settling ground has created dips, bumps, potholes, and cracks. Throughout the past 10 years, the climate has been relatively stable, but in the near future, climate warming will undoubtedly increase permafrost degradation and damage to the road. This project, an outgrowth of an earlier, completed AUTC project, will continue data collection along instrumented sections of the highway and lab testing of soil samples as well extensive data analysis and modeling. This summer's fieldwork included construction of a snow shed along one section of the highway embankment. By keeping the insulating snow off the ground surface, the soil is exposed to cold air flowing under it. This promotes convective heat transfers between cold air and the ground which is very effective for cooling, and for keeping permafrost frozen. Researchers also established a permafrost database and 3D cryostratigraphic model linked to a geographical information system that will allow evaluation of the mitigation technique's efficiency. Project results will help engineers in Alaska and western Canada mitigate damage to the Alaska Highway, as well as to other infrastructure that crosses ice-rich soils. Project researchers are working with the Yukon Highway Public Works Department to implement new designs for mitigation of the damage caused by melting permafrost. This project has also been the focus of study for Eva Stephani, a graduate student working on an interdisciplinary Master of Science degree in geomorphologic engineering.