乌江彭水水电站土石围堰防渗工程施工综述

Anti-seepage construction of earth rockfill cofferdam for Pengshui hydropower project on Wujiang River

乌江彭水水电站土石围堰防渗工程施工历经8个月之久,主要由于河床大孤石及两岸边坡开挖特大块石进入河床,架空严重,细颗粒料少等客观原因,运用高喷灌浆、塑性灌浆、灌注砂浆等多种方法,效果均不佳,围堰防渗无法闭气。经过4个阶段多种防渗处理方法,采取先堵漏后防渗补强的方法,终于解决了土石围堰闭气的最大难题,达到了防渗墙设计标准,经基坑开挖后表明,河谷底部仅有一处渗漏点,围堰防渗效果良好。

The anti - seepage construction of earth reckfill cofferdam lasted eight months for Pengshui hydmpower project on Wujiang River mainly due to boulders and extra big block stones excavated at both slopes entering into riverbed, with serious voids and little fine par＇tides. That does not achieve good effects by applying methods of jet grouting, plastic grouting and grouting mortar, and the anticofferdam can not be water tight. By anti - seepage treatments （i. e. firstly bloc/ring leakage paths, and then seepage reinfowement）, the most difficult problem was finally solved, attaining the design standard of cutoff wall. After excavation of foundation pit, it reveals that.the cofferdam has good seepage effect except only one leakage point left at the bottom of river valley.