顶管工作井围护开挖过程的FLAC^(3D)模拟

FLAC^(3D) Modeling of the Excavation Process of Work Well for Pipe-Jacking

针对典型的圆形顶管工作井,采用三维有限差分程序FLAC3D法,建立了数值模拟模型,研究了圆形顶管工作井分步开挖引起的土体水平位移及水平应力变化,以及围护结构所受水平应力的分布特征.研究表明:圆形工作井井壁从地面向下6 m范围内的土体发生了圆弧滑移破坏,最大位移发生于工作井从地面向下8~12 m的范围内,最终形成中间大,两端小的形状;井壁土体水平应力随开挖深度变化较小,围护结构所受水平应力较小,有效地发挥了其功效;三维有限差分法能较好地模拟顶管工作井的施工动态,模拟结果也为类似工程地质条件下圆形顶管工作井的施工提供了重要的参考.

This paper used the three dimensional finite difference program,FLAC3D,to establish a model for the circular work well for pipe-jacking.It studied the variation of the horizontal displacement and stress resulted from the step by step excavation of the circular work well for pipe-jacking,and the characteristics of the horizontal stress on the frame bracing structure.The results showed that circular failure occurred within the wall of the well from the surface to the depth of 6 m,the maximum horizontal displacement took place within 8 m to 12 m from surface to the bottom,the horizontal stress slightly varied with depth and the horizontal stress on the frame bracing structure was small,the three dimensional finite difference program,FLAC3D,was effective in modeling the excavation process of the work well for pipe-jacking and the modeling results can be used as the important reference for the construction of work well for pipe-jacking under the similar geological conditions.