Thermo-hydro-mechanics of thawing permafrost: a phase-field framework with enriched modified Cam-Clay plasticity

This paper introduces a thermo-hydro-mechanical (THM) framework to model thaw consolidation in permafrost regions. By integrating internal energy degradation functions and a modified Cam-Clay model within a phase-field damage framework, the model focuses on simulating the simultaneous effects of phase change and particle rearrangement. The model integrates two distinct phase-field variables with the modified Cam-Clay plasticity framework. One phase-field variable monitors pore phase composition, while the other captures particle rearrangement. These variables are directly coupled to the constitutive model, providing critical data for updating the stress–strain relationship by accounting for particle rearrangement-induced softening and hardening effects due to volumetric deformation. The model converges to the modified Cam-Clay model when there is no phase change. This approach addresses a significant gap in existing models by capturing the associated microstructural evolution and plastic softening in thaw-sensitive soils. Validation efforts focus on experimental scenarios assessing both the mechanical impacts of thaw consolidation and the dynamics of phase transitions, particularly emphasizing latent heat effects. The results demonstrate the proposing model’s capability of handling complex behaviors of permafrost under thaw conditions, confirming its potential for enhancing infrastructure resilience in cold regions.