超大逆作基坑地下连续墙变形分析

本文基于天津滨海新区某深基坑施工监测资料，对超大逆作基坑开挖过程中地下连续墙水平、竖向位移进行了分析。认识到，逆作基坑地连墙水平变形随开挖深度变化近似呈“弓形”分布，水平位移最大值出现的位置约为基坑开挖面以上1 /3 深度处，与顺作法位于基底开挖面附近区别较大。在竖直方向上，随着开挖深度不断加深，墙体的隆起值不断增加，但每步开挖后墙体隆起均有一定的滞后性，底层板浇筑后隆起趋于平缓。同时认识到基坑逆作法相对于顺作法具有变形小、整体性强的特点。

Analysis of underground diaphragm wall deformation in super-sized foundation pit by top-down construction method

Based on the monitoring data of a deep foundation pit construction in Tianjin Binhai New Area, this paper analyses the horizontal and vertical displacement of the underground diaphragm wall in the process of super-sized top-down method foundation pit excavation. According the analysis results, the horizontal deformation of the diaphragm wall in top-down method foundation pit, whose distribution is approximately shaped like a bow, changes over the depth of excavation. The maximum horizontal displacement varied significantly between top-down method foundation pit and down-top method foundation pit, occurring at about one-third of the pit depth from the foundation pit excavation surface and in the vicinity of excavation surface, respectively. The wall uplift values, on vertical orientation, increases continuously as the depth of foundation pit becomes increasingly deeper. However, it legs behind each stage of excavation to some extent and tends to be steady after pouring the bottom plate. In addition, the analysis results show that the top-down method has the features of small deformation and strong integrity in contrast with down-top method.