向家坝水电站坝基混凝土防渗墙研究及应用

Study and application of dam foundation concrete cutoff wall in Xiangjiaba Hydropower Station

向家坝水电站大坝为混凝土重力坝,河床部位存在由挠曲核部破碎带构成的复杂地质构造。为了满足坝基深浅层抗滑稳定、渗透稳定、承载力及变形控制要求,采用“扩大坝基+坝踵齿槽+深孔固结灌浆”综合处理方案,但河床泄水坝段坝踵部位仍保留约60m厚的Ⅳ~Ⅴ类挠曲核部破碎带岩体,其强度较低、遇水泥化、可灌性差,采用塑性混凝土防渗墙的防渗形式,成功地解决了工程软弱破碎岩体的渗透变形问题。本文对向家坝水电站坝基防渗墙的研究过程进行回顾,并对防渗墙的运行情况进行评价,可为类似工程建设提供技术参考。

The dam of Xiangjiaba Hydropower Station is a concrete gravity dam,and the riverbed contains a complex geological structure composed of a flexural core broken zone.The comprehensive treatment scheme of“expanding dam foundation+dam heel tooth space+deep hole consolidation grouting”is adopted in order to meet the anti-slip stability,seepage stability,bearing capacity and deformation control requirements in the dam foundation deep and shallow layer,but the 60m thick classⅣ~Ⅴdeflection core fracture zone rock is still retained in the dam heel area of the riverbed drainage dam section.It has low strength,which becomes mud in water with poor groutability.The plastic concrete cut-off wall seepage type is adopted to successfully solve the problem of the seepage deformation of the project weak broken rock.The study process of Xiangjiaba Hydropower Station dam foundation cutoff wall is reviewed in the paper,and the operation of cutoff walls is evaluated,which can provide technical reference for similar projects.