苗尾水电站上游围堰三维渗流场分析及基础防渗方案研究

苗尾水电站上游围堰具有堰高、心墙土工膜承受的水头高及地质条件较为复杂等特点.采用非均质土统一的饱和-非饱和土渗流控制方程,对苗尾水电站上游围堰进行了渗流场三维有限元分析,并对不同基础渗控方案进行了对比;同时针对复合土工膜与防渗墙连接处应变集中拉脱以及防渗墙可能出现的施工缺陷等极端情况进行了分析.得出了不同基础帷幕灌浆深度及防渗体缺陷条件下各关键性的渗透指标,为围堰的技术经济设计决策及基坑抽排方案选定提供了参考.

Research on Three-dimensional Seepage Field and Seepage Control Schemes of Upstream Cofferdam for Miaowei Hydropower Station

Miaowei hydropower station upstream cofferdam is characted with its height, geomembrance core wall under high water head and complex geological condition. Based on the uniform saturated-unsaturated seepage control equation for non-homogeneous soil, three dimensional finite element method is used to analyze the seepage field for Miaowei hydropower station upstream cofferdam. Different seepage control schemes for cofferdam foundation are compared. Many impervious defect cases such as composite geomembrane tension crack in the junction and cut-off wall split are also calculated. The key seepage indices for different depths curtain grouting and defect are obtained. The results can be for reference in the techno-economic design and drainage system selection.