摘要
针对盾构推进前方障碍物(废弃灌注桩)埋深大、土体易坍塌及周边环境变形控制要求高等特点,在比较不同清障方法的基础上,选用全回转机全套管跟进钻孔进行无损清障。工程实践表明:被清除桩桩孔周边管线最大沉降为5 mm,差异沉降为2 mm,满足管线变形控制要求;盾构隧道以上6 m之内的旧桩孔内采用了水泥掺量30%的水泥土充填,其强度既能保证盾构正常向前推进,又能避免推进过程中隧道上部的桩孔土体塌陷。成果可为城市轨交清障工程提供借鉴与参考。
Aiming at the characteristics of large burial depth of obstacles(abandoned cast-in-place piles),easy collapse of soil and high requirement of surrounding environment deformation control in front of shield driving,on the basis of comparing different barrier clearance methods,the full rotary drilling rig is selected to carry out follow up drilling holes for non-destructive barrier clearance.The engineering practice indicates that the maximum settlement of the pipeline around the pile hole is 5 mm and the differential settlement is 2 mm,which meets the requirement of pipeline deformation control;the old pile holes within 6 m above the shield tunnel are backfilled with 30%cement and soil,whose strength can not only ensure the normal advance of the shield,but also avoid the collapse of the pile holes in the upper part of the tunnel during the advance.The results can provide reference for urban rail transit barrier clearance project.
作者
钱德良
QIAN Deliang(Zhongyifeng Construction Group Co.,Ltd.,Suzhou,Jiangsu 215131,China)
出处
《建筑施工》
2019年第11期1966-1968,共3页
Building Construction
关键词
桩基
无损清障
全回转钻机
回填
变形控制
pile foundation
non-destructive barrier clearance
full rotary drilling rig
backfilling
deformation control
