Initial Performance of a Thermopile Foundation for a Building in Inuvik

摘要

The initial ground temperature response for the first building supported on a thermopile foundation in Canada is reviewed. The building is the RCMP detachment in Inuvik, NT. Challenging geotechnical ground conditions at the site that influenced the selection of the foundation type included an up to 3 m thick unfrozen zone (talik) below the active layer, up to 10 m thick ice and ice-rich soils, and warm permafrost temperatures. At the time of design, it was not known if water flowing through the talik would impede foundation freeze-back. The structural design of the building proposed a total of 128 piles in five pile loading groups with variable pile spacings. These were consolidated into three design groups for geotechnical design, which considered projected climate warming for a design life of 50 years. Four thermistor cables were installed to permit ground temperatures to be measured, and the data is being collected with dataloggers. The first four years of data is summarized. It shows that the thermopiles have cooled the ground more than what was predicted during the design, which was intentionally conservative, due to the precedent-setting use of this technology in Canada. Two significant practical implications from this review are that the observed cooling suggests that this foundation type will be resilient to climate change and the performance data being collected data will permit future designs to be optimized.