沙湾水电站左岸坝肩“地窗式”防渗方案优化计算与分析

Optimal Simulation and Analyzing to "Lower Window" Type Seepage Control Scheme in Left Abutment of Shawan Hydropower Station

采用深度平均渗流模型结合2维立面渗流模型,对沙湾水电站左岸坝肩"地窗式"防渗方案进行了渗流量、渗流场及渗透坡降的计算;根据计算结果,对"地窗式"防渗方案进行了优化计算,提出了满足本工程防渗要求的阶梯型"地窗式"防渗体体型;计算结果表明沙湾水电站左岸坝肩采用阶梯型"地窗式"防渗体体型后,不仅可取消50m深防渗墙下施工繁琐的墙下帷幕灌浆3000余米,而且全封闭砼防渗墙可做成悬挂式,大大降低了防渗墙的最大深度和施工难度,还节约防渗墙900余米,其工程经济效益显著;本文方法对类似工程问题具有重要参考价值。

Combining depth-averaged numerical seepage flow model and 2-dimensional profile seepage flow model, seepage rate, seepage velocity field and hydraulic gradient of seepage control work in left abutment of Shawan hydropower station have been obtained. Based on the calculated results, the optimal simulation and analyzing to “Lower Window” type seepage control scheme has been done. And for the first time, a stepped “Lower Window” type cut-off wall is presented.The calculated results demonstrate that by using the presented stepped “Lower Window” type cut-off wall in Shawan Project, not only can 3 km-long grouting curtain be canceled, which are rather difficult to be constructed under 50 m deep cut-off wall, but also can diminish the construction difficulties by reducing the maximum depth and saving over 900 m length of the cut-off wall accordingly. The economic efficiency is remarkable and the presented method is of reference value to similar projects.