Coarse-grained soil is generally used in cold-regions infrastructure to mitigate the frost damage to engineering because of its non-frost heave susceptibility; however, in certain cases, coarse-grained fill has been observed to experience frost heave under hydraulic pressure. To reveal the mechanism of hydraulic pressure on coarsegrained soil frost heave, a model was developed to describe the frost heave in coarse-grained soil, incorporating the migration of external water to ice lenses through an unfrozen water film under hydraulic pressure, then the model was validated using published results. Subsequently, based on the validated model, the influence mechanism of hydraulic pressure and fine content on coarse-grained soil frost heave were analyzed. The calculation results demonstrate that the hydraulic pressure aggravates frost heave by increasing the pore water pressure gradient in the unfrozen water film. Additionally, frost heave rate increases with fine content because of the thickening of the film, which facilitates water flow and ice segregation. Furthermore, gray correlation analysis demonstrated that the impact of hydraulic pressure on frost heave in coarse-grained soil is more significant than that of fine content. Finally, the study discusses frost damage that occurred in high-speed railway subgrade and proposes the preventive measures.

来源平台：TRANSPORTATION GEOTECHNICS