深厚覆盖层深大基坑渗流控制

Seepage control of deep/large foundation pit on the deep covering layer

介绍了深厚覆盖层深大基坑渗流研究的背景和现状，结合金沙江上某水电站深厚覆盖层上深大基坑工程设计实例，进行了基坑一围堰系统渗流场随防渗墙深度加深、以及随覆盖层各层渗透系数降低而变化的规律研究。结果表明，斜心墙或防渗墙渗透系数为1e-5cm／s时，渗流场已能得到良好控制；建议该工程将防渗墙打到98m深以全封闭覆盖层渗流路径。

The background and current situation of study on seepage control of deep/large foundation pit on the deep covering layer were introduced, and the rules of change in seepage field of foundation pit-cofferdam system along with the deepening of impervious wall and the reduction of permeability coefficient of all components layers of the covering layer were studied, in combination with the project case of deep/large foundation pit on the deep covering layer of one hydropower station in Jinsha River. The results showed that the seepage field can be better controlled when the permeability coefficient of sloping-core wall or impervious wall is 1 × 10^- 5cm/s; it is suggested that the impervious wall is dug to the depth of 98m so as to fully seal the seepage route of the covering layer.