Study on multidimensional frost heave characteristics and thermal-hydro-mechanical predictive model

The multi-dimensional estimation of frost heave deformation is crucial for predicting soil deformation and the pressure generated during the freezing process. This study offers a comprehensive review and analysis of frost heave characteristics in the heat flow direction and the transverse direction to it. Based on the frost heave test results, an innovative method for calculating the anisotropic parameter has been introduced. This method includes only two parameters: one reflects the more pronounced characteristic of frost heave in the direction of heat flow, and the other represents the sensitivity of anisotropic parameters to constraint stress. Through comparative analysis with experimental results, this method can effectively express the evolution of the anisotropic frost heave with changes of the confining stress in different directions. Then, a combined thermal-hydraulic-mechanical coupling model is established, offering a way of applying the improved model. The coupling model can predict significant frost heave under conditions of sufficient water supply and effectively captures the frost heave characteristics under various temperature and stress boundary conditions. This research contributes significantly to predicting frost heave deformation in low-temperature natural gas pipelines and calculating the frozen soil pressure exerted on the pipelines.