大规模“一柱一桩”施工精度控制关键技术

上海市某污水处理厂工程一体化箱体基坑面积约12.3万m2,典型基坑深度17.5 m,逆作法施工。其中灌芯500×16钢管立柱数量达1861根,采用一柱一桩法施工,立柱桩基直径1 m。钢管立柱设计定位误差不大于5 mm,垂直误差不大于1/500。工程中采用桩顶扩径、桩底后注浆、校正架调垂等施工工艺,保证了大规模“一柱一桩”钢管立柱的稳定性和施工精度,最终钢立柱垂直度合格率达98.3%。为类似的逆作法一柱一桩工程施工提供参考和借鉴。

Key Technology of Construction Precision Control of Large-scale "One Column One Pile"

The area of the integrated box foundation pit in a wastewater treatment plant project of Shanghai is about 123000 m2.The typical foundation pit is 17.5 m deep and is constructed by the reverse method.There are 1861 filling-coreΦ500×16 steel pipe columns construed by the"one column one pile"method in the project.The diameter of column pile foundation is 1 m.The design positioning error of steel tube column is not larger than 5 mm,and the vertical error is not larger than 1/500.The construction technologies of pile top expanding,post pouring at pile bottom and straightening frame adjustment are adopted in the project in order to guarantee the stability and construction precision of the large-scale"one column one pile"steel tube column.Finally,the perpendicularity acceptability of steel column is up to 98.3%,which can be referred for the construction of the similar"one column one pile"projects by reverse method.