Warming and its effects on foundations for northern infrastructure

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Construction of civil engineering infrastructure in northern Canada usually removes vegetation cover, affects snow cover, increases heat transfer, changes drainage pattern, and therefore contributes to thawing of permafrost. Climate warming also contributes to thawing of permafrost. Thawing, either as a result of climate warming or construction activities, can produce large settlements and serviceability issues for buildings, airport runways, railway beds, highway embankments, river crossings, and hydroelectric facilities. Thawing permafrost and expanding infrastructure systems require improved designs, construction, and maintenance. Understanding the stress-strain characteristics of warming soils is essential in predicting the performance of foundations, and subsequently in mitigating failing foundations for northern infrastructure. This research will use laboratory testing methods to investigate the effects of temperature on mechanical, thermal, and flow properties of soils. Particular emphasis is placed on highly plastic clays and peats found frequently in northern Canada. Predictive tools in climate warming developed by scientists will be used in predicting ground temperatures and their effects on soil properties and foundation performance. The research will develop conceptual numerical models to simulate the warming effects on soil properties. Laboratory testing and numerical modeling techniques will be used as a means of explaining monitored field behaviour. Two available instrumented test sites provide a database of field performance and allow validation of the newly developed numerical model. The research will predict and mitigate excessive deformations and instabilities of northern infrastructure using validated and fine-tuned numerical models. It will develop mitigation measures for consideration in future design guidelines, which will include adaptation strategies for infrastructure impacted by climate change. This research is important and relevant for climate change 'impacts and adaptation strategies' for northern infrastructure and the delivery of 'clean' energy from northern to southern markets.