Thermal Regime of Highway Embankments in the Arctic: Field Observations and Numerical Simulations

There is limited understanding of how frozen fill compacted below freezing air temperatures affects the performance of highway embankments in the Arctic. Fill material needed to construct embankments is typically obtained from borrow sources potentially containing high ice content that makes compaction challenging. Embankment test sections along the recently constructed Inuvik-Tuktoyaktuk Highway (ITH) in the Northwest Territories, Canada, were constructed with frozen fill material and instrumented with thermistor strings to monitor temperatures at different locations within the embankment and the foundation soil. Thermal modeling was carried out using a commercially available finite-element software applying (1) thermal modifiers available from the literature and (2) available climate parameters from weather stations and satellite data for a surface energy balance model calibrated with recorded field data. Thermal model results for the 3-year monitoring period show good agreement with recorded field data for both modeling approaches. With climate change being an important consideration for embankment design, construction, and maintenance in the Arctic, climate modeling scenarios provided by the Canadian Centre for Climate Modelling and Analysis (CCCma) were used to evaluate thermal resilience under near-term and long-term conditions. The results confirm that the design of embankments and maintenance operations need to consider impacts of near-term and long-term climate change in order to maintain the thermal stability of these embankments and to provide adequate resilience against permafrost degradation.