考虑非饱和区的复合土工膜防渗坝渗流分析

Seepage Analysis of Composite Geomembrane Earth-rock Dam Considering Unsaturated Zone

针对传统的渗流分析主要考虑饱和区的渗流而不考虑非饱和区的渗流存在一定的安全隐患问题,基于饱和—非饱和渗流理论,结合复合土工膜防渗坝设计了四种不同的水位组合,分别计算了饱和渗流量及饱和—非饱和渗流量,并分析了正常蓄水位下考虑与不考虑非饱和区的渗流速度场等变化规律。结果表明,考虑非饱和区后单宽渗流量有了明显下降,出溢点的渗流溢出坡降变小,且渗流路径变的较为陡直,靠近上游部分区域的渗透坡降相对较大,水压力在土工膜中的降低相对减小。

Some certain security issues may exist for traditional seepage analysis mainly considering the saturated zone seepage and not considering the unsaturated zone seepage. Based on the saturated-unsaturated seepage theory, this paper designs four different combination of water level by considering composite geomembrane impervious dam. And then, the saturated seepage flow and saturated-unsaturated seepage flow are calculated, respectively. Finally, under the normal wa- ter level, the velocity field variation is analyzed whether the unsaturated zone seepage is considered or not. The results show that after considering unsaturated zone seepage, flow per unit width has a significantly decline; the seepage overflow slope of overflow point is decreased obviously; the seepage path becomes relatively abrupt; seepage slope near the upstream part of the area is relatively large; the fall of water pressure in geomembrane is relatively reduced.