季节冻土区高速公路路基土中的水分迁移变化

Water Migration and Variation in the Subgrade Soils of Expressway in Seasonally Frozen Ground Regions

在季节冻土区,路基水分迁移变化是道路冻害最积极活跃的因素.在路堑段,不管地下水位埋深大小,冻结期间水分都向路基上部路床迁移,但其特征有所不同.线路气候条件和路基土质条件都对水分竖向的迁移和冻胀大小有重要影响.这种竖向迁移,导致路基上部土层产生强烈冻胀作用.水分的它向迁移(包括路肩坡面、失效的排水沟、路面裂缝和中央隔离带等)也可能是产生道路冻害的不可忽视的因素.道路修建以后,其路基土的干湿状态可能比当初设计状态严重恶化,从而产生冻害.

Water migration and variation in subgrade soils is the most active and live factor to the road frost damage in seasonally frozen ground regions. No matter how deep groundwater level is, groundwater may migrate to the upper subgrade at a cutting in freezing period with different extent. Climatic conditions of the road and properties of the subgrade soils all have a strong influence on the vertical migration amount of moisture and the extent of frost heave. It is the vertical migration that causes strong frost heave in the upper subgrade. Other migrations of moisture (including in the slope surface of shoulder, the disabled drain ditch, the crack of pavement, the central isolation strip and so on) may also be the assignable and important factors to lead frost damage to the road. The dryness of the subgrade soils will deteriorate seriously after the road is completed, leading to frost damage.