Permafrost conditions were characterized in detail between 2010-18 in preparation for major airport renovations and upgrading in 2018-19. Temperature profiles under asphalt pavement show warmer ground and faster, deeper, and longer thaw penetration than the shoulders and natural terrain, causing increased settlement underlying and adjacent to the asphalt surfaces. The newly acquired geoscientific data on the airport’s permafrost has oriented risk analyses and engineering design implemented during the recent improvements in order to develop a modern infrastructure that is better adapted to the impacts of climate warming. This information was integrated with a cost-benefit analysis and presented as part of the larger quantitative risk assessment that was performed. Risk evaluation is the combination, through multiplication, of, generally, three factors for a single danger: its hazard, consequence, and vulnerability. In the context of a quantitative risk assessment, the description is a limit state equation, which provides a definition of failure, either for ultimate or serviceability states. The probability of exceeding this failure limit is the hazard. The consequence is the cost of repairing the infrastructure damage and, possibly, the damage’s indirect effects on communities. Finally, the vulnerability is the degree to which the infrastructure is affected. Direct cost information came from earned value report data and the construction area calculations on the plans. Human and societal impact factors were determined from rubrics and conversations with stakeholders.
In 2017, researchers from Laval University conducted a quantitative risk analysis of the sensitivity of Iqaluit International Airport (YFB) to thaw settlement and permafrost degradation. Located in the city of Iqaluit in the territory of Nunavut, Iqaluit Airport is a hub for air transportation in the eastern Canadian Arctic. YFB has a 2,750-m runway and associated aprons and taxiways servicing the community of Iqaluit, Nunavut and outer lying Nunavut communities for which Iqaluit is the transit hub. It was built during the 1940’s, expanded with additional apron area and taxiways in the late 1950’s, 1970’s and 2010’s, and resurfaced and repaired repeatedly throughout the life of the infrastructure. As with most infrastructure in the Canadian Arctic, permafrost conditions were not investigated before construction. The uppermost layer of permafrost, known as the active layer, melts in summer with the depth of thaw dependent on the warmth of the summer. When the depth of thaw extends into ice-rich permafrost, the runway’s surface settles or cracks, requiring expensive repairs. Increasingly warm seasonal temperatures are causing the active layer to deepen thawing more subsurface ice, which brings more headaches for airport managers. To address knowledge gaps at the Iqaluit International Airport, scientists conducted geoscientific research of the airport’s permafrost conditions, its sensitivity to thaw settlement and the physical processes involved in the permafrost’s degradation. The research produced a quantitative risk analysis methodology utilizing geostatistics and reliability analysis methods and cost information to analyze the thaw settlement and soil bridge formation dangers within the embankment.