68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

DISEQUILIBRIUM PERMAFROST CONDITIONS ON NWT HIGHWAY 3

Session: Infrastructure Performance in Cold Regions / Performance des infrastructures en régions nordiques

Stephen Wolfe, Geological Survey of Canada, Natural Resources Canada (Canada)
Peter Morse, Geological Survey of Canada, Natural Resources Canada (Canada)
Ed Hoeve, Tetra Tech EBA Inc. (Canada)
Wendy Sladen, Geological Survey of Canada, Natural Resources Canada (Canada)
Steve Kokelj, Northwest Territories Geological Survey, Government of the Northwest Territories (Canada)
Lukas Arenson, BGC Engineering Inc. (Canada)

The thermal and physical states of permafrost in natural and developed settings along NWT Highway 3 are examined and implications of recent realignment between Behchoko and Yellowknife are discussed. Permafrost occurs in natural terrain beneath peatlands and forested fine-grained (glacio) lacustrine sediments. Natural and developed sites indicate surface warming especially beneath the highway embankment, which was straightened and reconstructed between 1999 and 2006. Fine-grained sediments are thaw-sensitive and ice-rich. The terrain could experience up to 1.3 m of settlement with thawing of the top 5 m of permafrost. Permafrost had aggraded into the old highway embankment comprised of fine-grained materials, but is unlikely to be sustained beneath the new highway embankment comprised primarily of blast rock.