Estimating Thaw Settlement of Highly Organic Permafrost

Organic soils in permafrost regions pose a significant challenge for engineers and planners due to their high compressibility and time-dependent settlement properties. This study characterizes the thaw-settlement behavior of highly organic soils using laboratory and field data from Canadian permafrost regions. The study compares the index properties of these soils with mineral soils and discusses the application of various easily determined index properties to predict the parameters that characterize the thaw settlement of peat samples. Water content was identified as the most reliable predictor of the compression index and thawed void ratio, which are critical parameters in calculating settlement. We illustrate how these models can be used to calculate different components that contribute to the total settlement of peat, including initial thaw strain due to the presence of excess ice, primary consolidation, and secondary compression. The results will help planners and designers estimate anticipated settlement, design and plan more effectively for new developments under changing climate conditions, reduce maintenance costs, and improve safety and serviceability.