特大圆环支撑深基坑变形特性的三维数值分析

3D Numerical Analysis on Deformation Properties of Deep Foundation Pit with Superlarge Arch Brace

以某特大圆环支撑深基坑工程为背景,采用有限元分析软件MIDAS/GTS,对深基坑特大圆环支撑体系的变形特性进行了系统的三维数值分析。通过与地下连续墙的水平侧向变形和墙顶沉降实测数据进行对比分析,表明采用GTS软件进行特大圆环支撑深基坑工程的三维动态施工模拟分析是可行的;研究了不同土体开挖次序下、不同工程地质条件下特大圆环支撑深基坑地下连续墙的水平侧向变形特性,结果表明:土体开挖过程,地下连续墙的水平侧向位移存在显著的位移回弹效应,且随着基坑开挖深度的增大而增强,非对称开挖明显强于对称开挖,采用对称开挖比非对称开挖能显著减小软土地层地下连续墙的水平侧向位移。

Taking a deep foundation pit with superlarge arch brace as the background, the deformation properties of superlarge arch brace system of deep foundation pit are analyzed by finite element software MIDAS/GTS. It shows that analysis on the foundation pit with arch brace system by GTS is feasible through comparison of the analysis result with measured data including horizontal deformation of diaphragm wall and settlement of the top of diaphragm wall; the deformation properties of diaphragm wall of deep foundation pit with superlarge arch brace in different excavation order and in different geological conditions were studied, the results indicate that： in soil excavation, there exits sig- nificant displacement spring back effect in horizontal deformation of diaphragm wall which is enhanced with the in- crease of excavation depth of foundation pit, and in the asymmetric excavation is stronger than that in the symmetric excavation. Using symmetric excavation can significantly reduce the horizontal deformation of diaphragm wall com- pared with using asymmetric excavation in soft soil stratum.