南水北调中线工程中渗流调控是保障渠坡及衬砌板稳定的关键。为全面分析高地下水地区挖方渠段渗流调控措施合理性及优化的效果,针对典型渠段建立渗流模型,通过三维有限元数值模拟,研究渠道渗流场分布规律,比较不同措施的调控效果。结果表明:排水垫层结合逆止阀、排水板结合逆止阀、排水板结合衬砌板透水缝等3种排水措施都能有效降低渠底衬砌板下扬压力。最后比较了上述3种措施的差别,讨论了应用条件,提出了相应的建议,对类似工程有借鉴意义。

Seepage field regulation is crucial for the stability of canal slope and liner plate along the middle route of the South-to-North Water Transfer Project, especially for stretches excavated in expensive soil area with high groundwater level. In this article, the seepage field of a typical section was simulated with 3-D finite element technology to investigate into the rationality and effectiveness of seepage regulation measures comprehensively. The distribution of seepage field was analyzed and the seepage control measures were compared. Results show that the uplift pressure on canal pavement would be reduced significantly by drainage cushion with drainage holes opening only when groundwater level is higher than the canal water level, by drainage cushion replaced by drainage board, and by drainage holes replaced with permeable joints of liner plate in addition. The differences in the three measures were compared, and their application conditions were discussed and corresponding suggestions were given.