Liquid water–vapour migration tracing and characteristics of unsaturated coarse-grained soil in high-speed railway subjected to freezing and different load types

Abstract

Unsaturated coarse-grained soil (CGS) is typically used as fillings in high-speed railway subgrade. Herein, the frozen depth, external water intake, water content distribution, liquid water migration height, and frost-heaving process were investigated in vapour migration and liquid water–vapour migration modes. Liquid water–vapour migration characteristics under gravity, static load, and dynamic load were compared. Vapour migration is dominant in the CGS external water intake; vapour affects the frozen zone of CGS specimens. The frost-heaving duration under dynamic load is longer than under gravity and static load. More attention should be paid to the frost heaving induced by vapour migration.