Investigation on the heat extraction capacity of the heat drain for thermal stabilization of embankments on thaw sensitive permafrost

Construction of transportation infrastructure often results in permafrost degradation and climate warming amplifies this phenomenon. Heat drains, based on wintertime natural convection, are a new mitigation technique designed to limit or avoid the thawing of permafrost. In winter, heat extraction is enhanced by the buoyancy-driven convection of the pore-air due to unstable air density in the heat drain. To monitor the efficiency of this technique, a heat drain was constructed in the shoulder of the Tasiujaq airstrip in Northern Quebec, Canada, in the summer of 2007. Thermistors were installed beneath the side slopes to measure ground temperatures. A good thermal performance was observed resulting in thermal stabilization of the underlying permafrost. A thermal model was developed based on the Tasiujaq experimental site characteristics and conditions. The model was also calibrated to the field data collected at Tasiujaq. A set of design charts were developed through the model and were successfully validated using the measured data from Salluit, Northern Quebec, Canada, where a heat drain was installed in 2012.