The mechanism analysis of micro frost heave coarse-grained filling material in the high-speed railway

Lots of high-speed railway subgrades have been built in the severely cold region in China. The water-proof and drainage system with frost heave prevention structure and micro frost heave coarse-grained filling material with good frost-resistance performance have been widely used in these regions, which can generally solve the problem of high-speed railway subgrade frost heave in the seasonally frozen region. However, the long period monitoring of high-speed railway subgrade indicates that there are still some frost heave problems existing in the seasonally frozen region and this can cause the irregularity problem to the high-speed railway lines which cannot be totally ignored. A new experimental system has been built, which can investigate the frost heave characteristic, the permeability and the water retention capacity of coarse-grained soil. The influence of the fine particles filling material, the permeability and the water content to the frost heave deformation have been tested and analyzed. The water retention ability of different soil is also analyzed. Based on the characteristic of water movement of subgrade in the frozen period and the interactive affection among the water, ice and soil particles; the frost heave development mechanism of micro frost heave coarse-grained filling material is discussed. This achievement can provide scientific evidences, in order to optimize and improve the frost heave prevention filling material and structure.