Mechanico-Empirical Model for Thaw Strain of Fine-Grained Soils Considering Soil Type and Applied Load

This paper presents a mechanico-empirical model for predicting the final thaw strain resulting from the volume change caused by ice to water phase change and the compression of the ground as a result of consolidation in fine-grained permafrost. The model is developed from an advanced conceptual framework for thaw consolidation. It derives the necessary hydro-mechanical soil parameters from empirical correlations using standard index properties (clay content, liquid limit, and median grain size of the fine fraction). A significant advantage of this approach is the direct incorporation of both soil type and applied load as input parameters. The model explicitly calculates the components of thaw strain (phase change, excess water expulsion, and soil skeleton compression), which allows it to differentiate the behaviors of ice-rich and ice-poor soils. It also captures swelling upon thawing in dense, ice-poor soils under low pressures. The model's robustness is confirmed through validation against a comprehensive dataset of over 200 thaw consolidation tests on natural permafrost from northern Canada, demonstrating a strong agreement between predicted and measured strains across diverse soil types and stress levels.