三峡二期围堰工程几个问题的研究及实践

三峡工程二期围堰是三峡工程最重要的临时建筑物之一，大江截流水深大，流量大；防渗墙深度大，工程量大，工期紧，且还要穿过各种复杂地层，通过试验，研究，采取有效地对策确保大江安全，顺利截流，基坑按三峡总工期目标要求抽干，检查渗漏量仅为设计估计量的1／10。

Study on Some Problems of Stage Ⅱ Cofferdam for Three Gorges Project and Practice

Stage II cofferdam is the most important one of temporary structures for the Three Gorges Project. For rover closure of the Yangtze River the water depth in the river is large , so is discharge. The cutoff wall of the cofferdam has large depth, large quantity, tight construction schedule and passing through all kinds of strata. Through testing study and taking effective measures,The safety of the principal channel of the river, and its clusere can be reached. The foundation pit of stage II has been drained. The master schedule of Three Gorges Project has been ensured. The water leakage of the cofferdam is only one-tenth of the allowable design value.