锦屏一级水电站大坝下游土石围堰基础涌水处理

大坝基坑围堰是保证大坝正常施工的重要临时建筑物。锦屏一级水电站大坝下游土石围堰在二道坝护坦基础开挖期间发生了基础覆盖层涌水,通过及时采取基坑渣料回填、对二道坝基坑下游开挖坡面实施反滤并压重、围堰坡脚基础加固及调整尾端护坦结构等措施,成功解决了围堰基础涌水及后续二道坝护坦设计和施工问题,保证了二道坝的安全运行。其施工经验可为类似水电工程围堰设计、施工提供借鉴。

Treatment of foundation inrush in downstream earth-rock cofferdam of arch dam of Jinping I Hydropower Station

The cofferdam for dam foundation pit is an important temporary structure to ensure the normal construction of the dam. During the apron foundation excavation of the auxiliary weir, inrush occurred to the downstream earth-rock cofferdam of Jinping I arch dam. By taking measures such as slag backfilling in foundation pit, anti-filtering and ballasting on excavated slope at downstream of the auxiliary weir foundation pit, reinforcing cofferdam slope toe, adjusting the structure of the rear apron and so on, we successfully solved the inrush and the problems in design and construction of auxiliary weir apron, which ensured safe operation of the auxiliary weir. It could provide reference for the design and construction of similar cofferdam projects.