Optimization Study on Drainage System for Canal of Middle Route Project of SNWT in Expansive Soil Area with High Groundwater Level

The seepage field regulation is important for the stability canal liner plate and slope for along the Middle Route of the South-to-North Water Transfer Project, especially for stretches excavated in expensive soil area with groundwater level. In order to analyzing the rationality and efficiency of seepage regulation measures comprehensively, a typical section was modeled, and the seepage field was simulated with the 3D finite element technology. The distribution of seepage field was analyzed and the seepage control measures were compared. The results show that water pressure on the underside of canal pavement would be reduced significantly by the measures, such as the measure of drainage cushion with drainage holes which open just when ground water level is higher than the canal water level, the measure with drainage cushion replaced by the drainage board. The differences among the two kinds of measure were compared. Their application conditions were discussed and proposed.