条形深基坑对临近大直径管线的影响分析

Analysis on Influence of Strip-type Deep Foundation Pit on Adjacent Large-diameter Pipeline

借助上海某下立交工程,分析条形深基坑开挖对临近大直径管线影响,可知围护结构宜采用直径1 000 mm钻孔咬合桩,较大的围护刚度对控制基坑变形作用明显。污水管竖向位于坑底附近,水平方向处于基坑理论破裂角之外时,主要发生开挖面的水平位移;污水管竖向位于坑底之上,竖向处于基坑理论破裂角范围内时,位移值相比较大,矢量方向指向坑脚;污水管竖向位于坑底以上,竖向处于基坑理论破裂角外时,总位移方向指向坑脚。通过分析,得出管道与基坑水平距离、管道覆土埋深是管道变形的主要影响因素(除基坑工程本体以外),管径为次要因素。可为以后类似工程提供参考。

Taking an underpass project of Shanghai as an example, the article analyzes the influence of excavating the strip-type deep foundation pit on the adjacent large-diameter pipelines. The diameter 1000 mm of drilling bitten pile is suitable to use for the enclosure structure. The larger enclosure rigidity is obvious for the control of the deformation of foundation pit. When the sewage pipe is vertically located near the bottom of pit, and horizontally located outside of the theoretical fracture angle of foundation pit, the horizontal displacement of excavation surface will mainly happen. When the sewage pipe is vertically located on the bottom of pit, and vertically located within the range of the theoretical fracture angle of foundation pit, the displacement value is relatively larger and the vector direction points to the pit foot. When the sewage pipe is vertically located on the bottom of pit, and vertically located outside of the theoretical fracture angle of foundation pit, the total displacement direction points to the pit foot. The analysis of influence factors shows that the horizontal distance of pipeline and foundation pit, and the earthing burial depth of pipeline are the main influence factors of the pipeline deformation(except the foundation pit engineering itself), and the pipe diameter is the secondary factor, which can be referred for the similar projects.