古河槽深覆盖层渗流控制措施

Seepage control measures for ancient river channel on deep overburden layer

新疆某水电站工程左岸V级阶地以下分布有3条古河槽,蓄水后左岸存在渗漏问题.采用三维有限元法对坝址区左岸渗流场进行计算分析,评价古河槽砂卵砾石层和副坝的渗透稳定性,并提出了渗流控制措施建议.计算分析表明,1号古河槽仅采用表层黄土进行防渗的方案不能满足渗透稳定性要求,需要增设粘土铺盖或混凝土面板.根据本工程的实际情况,建议采用混凝土面板方案F5,此时砂砾石层的最大渗透坡降为0.101 2,3条古河槽总渗透流量为670万m3/年,可以满足渗透稳定和渗流量的要求.

Three ancient river channels are distributed under V terraces of right bank of a hydropower station.After storage,the left bank exhibits leakage.A 3D finite elements is adopted to calculate seepage field of left bank and evaluate seepage stability of the ancient river bed sand and gravel layer and auxiliary dam.Some seepage control measures are proposed.The result shows that for the ancient river channel #1 surface loess measure can not satisfy requirements of seepage stability.Clay blanket or concrete panels supplement is necessary.According to the project actual situation,the scheme of concrete panels F5 is proposed,while the maximum permeability slope of gravel layer is 0.101 2.Total seepages of the three ancient river channels are 6.7×106 m3 in years that can satisfy seepage stability and seepage.