非稳定渗流条件下含类泥质互层面板堆石坝稳定性分析

Stability Analysis of CFRD with Muddy Interlayer Subjected to Unsteady Seepage

国外某水电站混凝土面板堆石坝施工期间,坝体分层碾压时层面形成类泥状物质,因无法彻底清除,从而导致堆石区80cm/10cm的互层。为分析类泥质互层对面板堆石坝坝坡稳定性影响,建立了含类泥质互层三维坝体渗流及二维坝坡稳定性分析模型,分析了非稳定渗流条件下坝体渗流场,研究了渗流作用下坝坡的稳定性。结果表明,蓄水及泄放洪期,类泥质互层对坝坡稳定性影响较大;滑弧底部基本是沿着类泥质夹层层面滑出;泄放洪期,水位骤降引起内水外渗,易导致坝坡失稳,因此提出控制水位下降速率以保证坝坡稳定性。

During construction of concrete faced rockfill dam for a certain hydropower station abroad,argillaceous mud come out on the rolled layers which can not be cleaned leads to 80cm/10 cm alternation in the material zone.In order to study the impact of muddy interlayer on dam slope stability,three-dimensional seepage model and two-dimensional slope stability model with muddy interlayer is established.And then seepage filed of dam body is analyzed under unsteady seepage conditions.The stability of dam body is studied under seepage conditions.The results show that the impact of muddy interlayer on the dam slope stability is great during storage and flood discharge;the bottom of slip circle is slide along the muddy interlayer on the whole;on account of the changes in seepage field in the material zone delay in period of reservoir water level drawdown,the stability of upstream dam slope can not be assured;the speed of drawdown should be controlled to ensure the stability of the dam slope.