地铁深基坑变形监测分析

以某地铁深基坑围护结构为背景，采用现场监测数据与Origin数据分析软件相结合的方法，对灌注桩桩体水平位移、地表沉降量的变化规律进行了研究。发现灌注桩桩体水平位移变形曲线由“悬臂型”向“抛物线型”发展，且桩体最大水平位移的位置随基坑开挖深度增大而下移；地表沉降变形曲线呈“凹槽型”分布，沉降最大值发生在临近基坑土方开挖完成阶段，且最大沉降点位于坑壁外12 m处，工况Ⅱ，工况Ⅲ，工况Ⅴ的开挖对地表沉降影响较大。

Deformation Monitoring and Analysis of Subway Deep Foundation Pit

For the retaining structure of a subway deep foundation pit, the change rules of the horizontal displacement of the bored piles and the ground surface settlement were studied by use of field monitoring data with Origin data analysis software. It was found that the horizontal displacement deformation curve of the bored pile developed from cantilever-shape to parabola-shape, and the position of maximum horizontal displacement went down with the increasing depth of excavation; the settlement deformation curve of ground surface presented concave groove shape, and the maximum subsidence arose in the stage close to the completion of deep excavation and 12 m away from the foundation pit wall. The excavation under the Condition Ⅱ, Condition Ⅲ and Condition V has great impact on the ground surface settlement.