万家口子水电站岩溶发育特征及工程处理措施

Karst Development Characteristics and Engineering Treatment Measures of Wanjiakouzi Hydropower Station

万家口子水电站坝址建基岩体全部为石灰岩透水岩层构成,溶洞、溶蚀裂隙发育,深部发育连通性好,溶蚀透水带、坝基溶蚀断层带分布范围广,深度大,存在管道性渗漏和坝基变形稳定等问题。工程施工针对坝基断层带,采取了开挖回填、深孔高压固结灌浆和传力洞置换等综合处理措施;针对深部岩溶,设计帷幕穿过深层岩溶透水带底界处理。大坝建成运行监测结果表明,大坝运行正常,基础处理方案合适,防渗设计合理,岩溶地质问题工程处理措施是成功的。

The foundation rock mass of Wanjiakouzi Hydropower Station dam site is all composed of limestone permeable rock stratum,with developed karst cave and dissolution fissure,well developed connectivity in the deep part,the corrosion permeable zone and the dam foundation corrosion fault zone are widely distributed and deep,there are problems such as pipeline leakage and dam foundation deformation stability.According to the fault zone of dam foundation,comprehensive treatment measures such as excavation and backfilling,deep hole high-pressure consolidation grouting and transfer tunnel replacement are taken in the project construction.For deep karst,the curtain is designed to pass through the bottom boundary of deep karst permeable zone for treatment.The monitoring results show that the dam operates normally,the foundation treatment scheme is suitable,the seepage control design is reasonable,and the engineering treatment measures for karst geological problems are successful.