三峡二期上游围堰防渗工程若干问题的研究

二期上游围堰施工直接关系到三峡工程的总工期，工程量大，工期紧、施工强度高、防渗基础复杂是影响三峡工程施工成败的关键性项目之一。二期上游围堰在设计洪水时，库内蓄洪容积达２０亿ｍ＾３，万一失事，将造成工程及下游生命财产的重大损失，其重要性物技术复杂不是一般围堰工程所能比拟的，许多专家都指出：“二期围堰关键在防渗工程”。

Problems Related to the Impervious Works of the Second-stage Upper Cofferdam for the Three Gorges Project

The second stage upper cofferdam is one of the key items of work for the Three Gorges Project,having a direct influence over the general schedule of the Project. It is characterized with large quantity of work,short time for construction,high strength of coustruction as well as having a complicated foundation for its impervious works. The second -stage upper cofferdam was designed volume of flood of 2 billion m3,so it will bring about heavy losses to the Project itself and the lives and properties of people in lower reaches in case of failure. No any other cofferdam can stand comparison with the above -mentioned cofferdam in terms of significance and complexity in technology. Just as what so many experts pointed out,the crux of success for the second - stage cofferdam lies in the impervious works.