Assessment of the Physical and Mechanical Properties of Permafrost in Nunavik, Quebec, Canada: Fid-Bau Portal

Assessment of the Physical and Mechanical Properties of Permafrost in Nunavik, Quebec, Canada

Bilodeau, J.-P. / Verreault, J. / Doré, G.

Nunavik is a territory in Northern Quebec where 14 communities depend essentially on aerial transportation for their subsistence, economic development, and quality of life. Some airport runways built on permafrost in the late 80s showed worrying degradation signs only a few years after construction. The effect of runway embankments on the thermal regime at the embankment toes and where drainage is deficient, among other things, is well documented throughout the literature. These phenomena, as well as the general permafrost degradation, are amplified by climate changes, especially in northern regions. Because the permafrost degradation is worrying for transportation infrastructure, a project was undertaken to characterize the physical and mechanical properties of some permafrost soils in Northern Quebec, with the objective to assess their creep and thaw sensitivity. Frozen core samples were recovered at seven airstrips and two access roads, and undisturbed specimens were brought back to Laval University geotechnical laboratory. The samples from the most critical and representative study sites were subjected to basic geotechnical characterization along with triaxial creep. The creep tests allowed obtaining estimates of the creep rate for the soils at different deviatoric stress and temperatures. As for the thaw consolidation tests, they allowed estimating the settlements associated with a potential thawing of permafrost for various ice contents. The present paper focuses on the creep behavior. With the available ground thermal regimes and climate change scenarios, the results allow anticipating the thaw and creep settlements for some soils in Nunavik and can be used as part of a global adaptation strategy for infrastructure built on permafrost.