应用复合土工膜处理合水水库坝基岩溶渗漏

Applying Complex Geomembrane to Treating Karst Seepage of Dam Foundation of Heshui Reservoir

合水水库由于坝基石灰岩溶渗漏，致使水库自1960年建成运行以来，先后多次发生坝后涌流浑水和跌窝，威胁水库工程安全。其间虽曾采用灌浆、观前抛上和坝后压渗等工程处理措施，但效果欠佳。经多方案比较后，于1994年冬采用库内铺设复合土工膜防渗处理。据第一期工程竣工后蓄水监测，当库水位低于第一期铺膜顶部高程时，防渗效果达86．96％；但当库水位超过铺膜顶部高程时，渗流量将随库水位升高而逐渐增大泅此有待续建第二期铺膜工程。

Because the karst seepage of dam foundation of Heshui reservoir, the piping and droppits phenomena occurred many times since the reservoir had been constructed in 1960. The security of the reservoir is threatened. At that time, the following engineering treatment measures have been adopted: grouting, throwing soil at the front of the dam, pressing seepage at the dam toe, and etc.. But the effectiveness of these measures are far from good. In winter 1964, through alternative comparison the complex geomembrane laying in the reservoir has been adopted to prevent seepage. According to the monitoring impounding after the first stage of geomembrane works has performed, the anti-seepage effectiveness reached 86. 46% when the reservoir level was lower than the elevation of geomembrane topl but when the reservoir level was higher than the elevation of the geomembrane top, the seepage flowrate increased followed the rising of reservoir level. Therefore the second stage of geomembranc works will be cons tructed.