溪洛渡水电站上游围堰防渗体裂缝对渗流控制的影响

Seepage analysis for upstream cofferdam of Xiluodu hydropower station

采用固定网格有限元渗流分析方法 ,对溪洛渡水电站上游围堰防渗体发生裂缝等非常工况进行了三维全场渗流分析 ,并且提出了渗透坡降临界区的概念以评价围堰的渗透稳定性。计算结果表明 ,当防渗墙出现局部裂缝时 ,围堰的渗流量明显增大 ;在裂缝附近渗透坡降较大 ,但衰减较快 ,围堰渗流量和渗透稳定性与裂缝尺寸密切相关。

A fixed-mesh 3D FEM was used in the seepage analysis for upstream cofferdam of Xiluodu hydropower station when a crack born in the cut-off wall.A new concept called critical gradient area was presented to evaluate the seepage stability of the dam.According to the analysis results,the seepage discharge increase when the crack takes place,and the seepage gradient near the crack is large but become small a little far from the crack.Furthermore,the seepage discharge and stability was influenced by the size of the crack.