Predictive Model for Saturated Hydraulic Conductivity of Thawed Fine-Grained Permafrost

Estimating the saturated hydraulic conductivity of thawed permafrost is relevant in many applications of cold region geotechnics but remains difficult due to changes in soil structure caused by freezing and thawing. These changes affect groundwater flow paths and result in distinct hydraulic behavior that is not captured by predictive models developed for unfrozen soils. As a result, the use of such models in thawed conditions may lead to underestimated conductivity values. This study presents a predictive model specifically developed for thawed fine-grained permafrost. Drawing on thaw consolidation theory and prior research, it relates hydraulic conductivity to cryostructure degradation, effective stress and soil compression. The model uses three index geotechnical parameters, a soil type indicator, a pore-ice proxy, and a soil compression parameter, to capture the distinct behavior of thawed permafrost. It is calibrated using empirical correlations and validated against historical laboratory data. Results show that the model provides reasonably accurate estimates of saturated hydraulic conductivity. A step-by-step example is included to support a practical application. Limitations include uncertainty regarding its use in unsaturated or partially frozen soils.