Robust computational modelling of the coupled thermal, hydraulic, and mechanical behaviour of soil during freezing and thawing is important for permafrost engineering and the design of artificial ground freezing [1]. The processes of freezing and thawing of soil involve phase change that results in significant non-linearities due to rapid change in the soil's thermo-physical properties and the release of latent heat of solidification. These complexities are rather difficult to be accurately addressed in computational models that are based on local (differential) approaches [2]. We will present a non-local formulation based on peridynamics framework to model the freezing and thawing processes in unsaturated soil systems (three phase system). The model considers three fundamental conservation laws: mass conservation of water, energy conservation, and linear momentum conservation [3]. These equations are complemented by constitutive relationships that account for changes in soil properties. The developed peridynamic coupled framework and its numerical implementation are discussed. We will present the systematic verifications and validations to demonstrate the accuracy of numerical implementations and the theoretical framework. We will describe the application results of the model for the case of a laboratory test involving heat and water transfer. It is demonstrated that our proposed peridynamic model provides a robust computational framework to study the coupled processes including the water flow, heat transfer, and mechanical deformations and effectively captures the dynamics of phase change fronts and the evolution of soil properties [1,3]. REFERENCES [1] P. Nikolaev, A.P. Jivkov, L. Margetts & M. Sedighi (2024). Non-local modelling of freezing and thawing of unsaturated soils. Advances in Water Resources, 184, 104614. [2] P. Nikolaev, M. Sedighi, A.P. Jivkov & L. Margetts (2022). Analysis of heat transfer and water flow with phase change in saturated porous media by bond-based peridynamics. International Journal of Heat and Mass Transfer, 185, 122327. [3] P. Nikolaev, A.P. Jivkov, L. Margetts & M. Sedighi (2023). Analysis of soil behavior under freezing and thawing conditions. Symposium on Energy Geotechnics 2023, 1-2.