施工及运行期三峡二期围堰防渗墙有限元分析

三峡工程二期深水高土石围堰，是三峡工程的关键工程之一，二期围堰堰体特别是防渗墙体的应力变形，是衡量围堰安危的重要指标．本文针对现场施工工况，对三峡二期围堰塑性混凝土防渗墙进行了应力变形有限元计算分析．根据塑性混凝土龄期选择相应的模型参数，考虑施工、运行时上下游水位变动对墙体应力状况的影响，得到了一些有意义的结论．计算结果表明，从防渗墙体应力和应力水平看，三峡二期围堰在施工和运行阶段是安全的；上下游水位变动对防渗墙水平位移有较大的影响，随着上游水位升高和基坑进一步抽水，墙体水平位移将会加大．

FEM Analysis on Cutoff Walls of Second Stage Cofferdam in TGP

The second stage earth-rockfill cofferdam is one of the key projects of Three Gorges Project, and the stresses and deformations of cofferdam, especially those of cutoff wall, are important indexes of cofferdam safety. According to the actual construction condition, the cofferdam of TGP was analyzed by finite element method- The stresses and deformations of cutoff wal1s were listed and discussed in this paper. The calculation results show that the cofferdam of TGP is safe during construction and operation period, and the horizontal de-formation will be larger with the increase of upstream water table and decrease of downstream water table.During the operation peried, monitoring on stresses and deformations of cutoff wall should be performed, and measured value should be analyzed timely.