Seasonal deformations under a road embankment on degrading permafrost in Northern Canada

Permafrost degradation is a major concern in cold regions that are warming because of climate change. To assist in understanding the process, ground temperatures, lateral and vertical deformations and groundwater pressures were measured for 6 years under a road embankment in northern Manitoba, Canada. The road surface requires ongoing maintenance due to irregular settlements. The field data allowed the calibration of numerical modelling that related deformations to ground temperatures. It confirmed the presence of remnant permafrost under the centre of the embankment, but none under the midslope or toe. This 'frost bulb' plays an important role in the ground thermal regime, the groundwater pressures, the observed deformations and, ultimately, necessary road maintenance.