黄壁庄水库副坝的防渗与观测分析

由于黄壁庄副坝的坝基是滹沱河的古河床,坝体多处直接与出露的砂层接触,基础深处是砂卵石层及副坝施工又存在种种缺陷等原因,运用40多年来,管涌渗漏严重,使防洪安全问题十分突出.为确保防洪安全,1999-2002年对副坝实施了垂直防渗处理,防渗墙由坝顶打至基岩,施工中又埋设了仪器进行观测.实测结果表明,防渗墙前及墙后水位差达到14～27 m,防渗墙后的水力坡降接近0,防渗墙的防渗效果是明显的,从而使副坝的管涌、流土问题获得解决.本文利用有关水文地质资料分析副坝出现险情的原因,从理论方面回答为什么必须进行副坝加固的问题,同时,又从施工观测得到加固后的水文渗透资料获得证明,采用冲击钻造孔的防渗墙,对消除副坝存在的险情起到了积极的作用.

Anti-Seepage Observation and Analysis of the Secondary Dam of Huangbizhuang Reservoir

As the foundation of the secondary dam locating in the ancient bed of the Hutuohe River, many places of the dam body directly touched the outcrop sand layer, and some defects were found during the secondary dams construction. Horizontal anti-seepage treatment was implemented from 1999 to 2002, seepage cutting wall was built from crest of the dam till bed rock. Field test results showed that seepage cutting wall was effective, the different water level gaps between the front and the back of seepage cutting wall ranged from 14 to 27m, and hydraulic gradient was nearly to zero.