龙凤水电站闸基渗流稳定分析

Research on the Seepage Stability of Sluice Foundation of Longfeng Hydropower Station

针对地基渗透性强可能导致闸基渗透破坏的问题,龙凤水电站在泄洪闸段上游设置了垂直防渗墙,并深入基岩形成封闭的防渗体系。利用Ansys软件建立了三维渗流模型,分析了有垂直防渗墙和没有防渗墙情况下的闸基渗流特性,结果表明:无防渗墙情况下,闸基以下渗透坡降均匀分布,上游铺盖和下游逸出点达到最大且均远大于沙卵砾石的渗透坡降允许值,极易发生渗透破坏,且水头在底板处只折减约87.0%,导致出逸点渗透坡降值较大;有防渗墙情况下,泄洪闸下游出逸点的坡降值较小,所有水头折减发生在防渗墙部位,冲沙闸段下游出逸点的渗透坡降较小,且所有的水头折减发生在底板处,可以控制整个闸段的渗透破坏,说明实施防渗墙是必要的。

As the high permeability foundation may lead to the seepage failure of sluice foundation, Longfeng Hydropower Station built vertical cut- off wall in the upstream of sluice and formed closed seepage contrul system deeply into the bedrock. The paper built three-dlmensional seepage mod- el by applying the software of ANSYS and analyzed the seepage characteristics of sluice foundation with and without cut-off wall. The rosults show that, in the absence of cut-off wall, seepage slope distributes evenly under the sluice foundation, and reaches the maximum at the blanket upstream and escape point downstream which is far bigger than the allowable value of sand and may happen seepage failure easily. Hydraulic head reduces only 87.0% at the base plate which leads to the seepage slope value of escape point is bigger. With eut-off wall, seepage slope value of escape point in the downstream of floodgate is smaller and the reduction of all hydraulic head occurs al the parts of cut-off wall. Seepage slope value of es- cape point in the downstream of flushing sluice is smaller and the reductinn of all hydraulic head occurs at the base plate, which can control seepage failure of the whole sluiee section, showing building cut-off wall is necessary.