西北口水库大坝右坝肩漏水成因分析

Analysis on Cause of Right Abutment Leakage for the Xibeikou Reservoir Dam

西北口水库大坝作为我国第1座百米级坝高的混凝土面板堆石坝被列入国家"七五"科技攻关项目,大坝投入运行以来,右坝肩即存在小股水流渗漏现象。通过对有渗漏观测记录以来的观测成果与库水位、降水量、时间的相关性分析,研究了西北口大坝右坝肩渗漏的成因。结果表明:西北口水库大坝右坝肩漏水的成因是①库区内右岸山体地表降水渗入山体经地质裂隙通道远距离汇流至右坝肩出溢点溢出;②右岸坝址区地表降水渗入地下汇流至右坝肩出溢点溢出。

Being the first 100m high concrete-faced rockfill dam in China,the Xibeikou reservoir dam is included in the national(seventh) 5yr-plan scientific and technologic key problem-tackling project.Ever since completion and operation of the dam,small leakage flows existed in right abutment.The cause of right abutment leakage in Xibeikou reservoir dam has been studied via analyzing the relativity of the available recorded observation results and the reservoir water level,the rainfall and the duration.It is clear that the cause of right abutment leakage includes:(1) the surface rainfall from the right bank mountain mass in reservoir area which has been infiltrated into the mountain mass and collected from a long distance through geologic fissures and paths to the effusion point of the right abutment to leak;and(2) the surface rainfall in right(abutment) area which has been infiltrated underground and collected to effusion point of the right abutment to leak.