三峡二期围堰填料参数的反分析

BACK ANALYSIS ON THE MATERIAL PARAMETERS OF THE SECOND STAGE COFFERDAM IN THE THREE GORGES PROJECT

二期围堰工程是三峡水利枢纽建设中的重要组成部分，在比较全面的实测资料基础上，对围堰填料进行参数敏感性分析；在试验资料的基础上确定了参数范围，采用复形法与有限元程序编制反分析程序，进行了参数的优化计算，确定出最适宜参数：最后根据最优参数对围堰进行了应力变形分析，结果表明围堰处于安全运行状态，计算结果与实测资料十分吻合．

The second stage cofferdam is one of the most important engineerings of the water conservancy construction in the Three Gorges Project. On the basis of the monitoring data, the sensitivity of material parameters of cofferdam is analyzed. The sensitive parameter to displacement of the cutoff wall can be selected as the parameters for back analysis. According to the tests, the ranges of parameter are confirmed. By use of optimum theory and finite element method, the back analysis program is developed, and the optimum parameter is found. Then, the stress and displacement of the cofferdam are computed and analyzed with the parameters. The results show that the cofferdam is safe in running state, and the computed results accord with monitoring data very well.