高混凝土面板堆石坝竖缝止水失效时坝前粘土铺盖防渗作用分析

为探讨某高混凝土面板堆石坝在强震等作用下竖缝止水失效时坝前粘土铺盖的防渗作用问题，采用饱和—非饱和渗流有限元法构建三维有限元模型，分析了不同竖缝失效后竖缝处渗透流量明显增大，粘土铺盖坡降增大，但均在允许范围之内，粘土铺盖在止水失效时起到了一定的防渗作用；随着粘土铺盖渗透系数的增大，粘土铺盖阻渗能力减弱，坝体浸润线逐渐升高至失效竖缝的顶端，浸润线抬升速度逐渐变缓，粘土铺盖渗透系数对整个坝体的防渗体系起到重要作用；在坝高100 m对应高程以下竖缝全长全失效情况下，若坝体浸润线高程渗透流量满足渗透稳定要求，就不必做防渗修补工作，面板坝仍能正常运行。

Anti-seepage Effect Analysis of Clay Blanket under Cases of Vertical Joints and Seal Failure for High Concrete Faced Rockfill Dam

To study the effect of clay blanket of high concrete faced rockfill dam on preventing seepage failure under high intensity earthquake or other factors with cases of vertical joints and seal failure, based on saturated and unsaturated theory, a three dimensional finite element numerical model was established. The result was found that under the condition of various vertical joints and seal failure, the seepage quantity and hydraulic gradient of clay blanket significantly increased, while both of them were within the allowable range. The clay blanket took some effect with cases of vertical joints and seal failure. With the increase of the permeability coefficient of clay blanket, the ability of permeability resistance reduced, the saturated surface rose to the top of vertical joints gradually and the speed slowed down at the same time, the permeability coefficient of clay blanket played an important part in the whole anti-seepage system of the dam. Under the condition of 100 m water seal failure, when the altitude of saturated surface and the seepage quantity meet the requirements of seepage stability, the high concrete faced rockfill dam could work without anti-seepage repairment.