Abstract: Abnormal water seepage has been found at the contact point between the volute section of diversion pipe and dam concrete of Wujiangdu hydropower station. The long term existence of water seepage would exert harmful influence on stability and safety of the hydraulic buildings, which is a serious
safety risk. Therefore, it is necessary to carry out investigation on the causes of water seepage and repairing measures immediately. By field exploration, construction data study, design and construction drawings query, seepage channel investigation and experiment (trichromatic method, Bernoulli theorem, and et al.), it is found that the leakage comes through the pipeline. In the process of repair, the unit maintenance period (no water in the steel pipe) is utilized. Ensuring the safety of staff and the unit, the exploration and maintenance inside the steel pipe is implemented and succeeded, worthy reference.

Key words: abnormal seepage within the dam, Bernoulli's theorem, data analysis, diversion pipe, volute

摘要： 乌江渡发电厂某台机组蜗壳段钢管与大坝混凝土接触处发现了异常渗水现象，坝内若长期存在异常渗水，对水工建筑物的稳定及安全有影响，属于严重安全隐患，需立即展开渗水原因排查并进行修缮处理。本次渗水处理通过现场勘探、历史施工资料研读、设计施工图纸查询、渗水可疑点排查实验（三原色法、伯努利定理等），分析各项所得数据，明确了渗水源为引水钢管内来水。处理修缮时，合理利用机组检修时段（钢管内无水），在保证人员及机组安全的前提下，通过引水钢管蜗壳段入人孔进入到钢管内部进行探查及维护。最终，渗水点成功修复，机组开机后不再渗水，成功消除了安全隐患。

关键词: 坝内异常渗水, 伯努利定理, 数据分析, 引水钢管, 蜗壳