Thaw consolidation of two-layer frozen soils considering self-weight: An analytical model

Amid global warming, thaw settlement from permafrost degradation is a major cause of infrastructure damage in cold regions. Understanding the thaw consolidation behavior of frozen soil is crucial for the safe construction, operation, and maintenance of infrastructure in these areas. However, previous analytical studies have primarily focused on homogeneous frozen soil structures, neglecting the analysis of the effect of self-weight. This study develops a novel analytical model for thaw consolidation in layered frozen soil, considering self-weight. The model integrates heterogeneous soil consolidation dynamics with the moving boundary conditions resulting from thawing processes, and the corresponding transient solution is derived by applying the Stieltjes integral and Gauss error function. Based on this solution, the effects of soil heterogeneity, thaw consolidation, and self-weight were investigated. Results reveal that (1) soil heterogeneity in thaw-consolidation models can significantly affect the prediction of excess pore pressure; (2) excess water from thawing can lead to pore pressure accumulation and low consolidation ratio, which causes safety issues; (3) assumptions neglecting soil self-weight tend to underestimate pore pressures over 35 % and overestimate consolidation ratios over 40 %. This work provides a preliminary assessment tool for thaw-consolidation of heterogeneous frozen soils, which is important for engineering design in cold regions.