Abstract:In the alpine meadow area, road frost heaving, tumbling and other diseases occur in large quantities, and moisture migration is the main cause of frost heaving and turbulence. To study the effect of initial moisture content, fine particle content, and inflow flux on moisture movement in non-frozen subgrade soil. In this paper, laboratory tests are carried out on the basis of the reconstruction project of Latuo-Mangkang highway. The experimental results show that when the soil is in the optimum moisture content, the capillary water rising height of soil samples with different fine particle content is different; Within a certain range of fine particle content, the total inflow and inflow flux of soil increase with the increase of fine particle content; When the initial moisture content is 11%, the total inflow of soil samples with 19% fine particle content changes with time in S shape, while the fine particle content shows S shape. However, the soil sample with 22% particle content is arched, which shows that the total inflow curve of soil sample with time increases with the increase of fine particle content, and the soil sample also appears lag phenomenon. The total inflow and flux of soil are inversely proportional to the initial moisture content, and the curve of total inflow changes from arch to S shape with time. The results show that the minimum filling height of roadbed in alpine meadow area is more than 1.5 m, which can effectively prevent frost heaving and frost boiling. The research results can provide scientific basis and guiding significance for highway construction and maintenance in alpine meadow area of Tibet.