水分迁移对高山草甸区非冻结路基土的影响

高山草甸区域内道路冻胀、翻浆等病害大量发生,水分迁移是产生冻胀翻浆病害的主要原因.为了研究初始含水率、细颗粒含量及入流通量对非冻结路基土中水分迁移的影响.依托拉妥至芒康公路改建工程,进行室内试验.结果表明:当土体处于最佳含水率时,不同细颗粒含量的土样毛细水上升高度不同;在一定细颗粒含量范围内,土体总入流量及入流通量随细颗粒含量的增加而增大;当初始含水率为11％时,细颗粒含量为19％的土样总入流量随时间变化曲线表现为"S"形,而细颗粒含量为22％的土样却表现为拱形,说明土样总入流量随时间变化曲线随着细颗粒含量的增加,土样同样出现滞后现象.土体总入流量及入流通量与初始含水率成反比,总入流量随时间变化曲线由拱形变化为"S"形.结果表明高山草甸区的最低路基填筑高度控制在1.5 m以上,能有效防治路基冻胀翻浆.研究成果可对西藏高山草甸区公路建设与养护提供科学的依据和指导意义.

Effects of moisture migration on non-frozen subgrade soil in alpine meadow area

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.