CFG桩复合地基空孔深度控制技术

Control on Hollow Bore Depth of CFG Piles Composite Foundation

针对基础埋深较深的建筑,当采用CFG桩复合地基时,CFG桩施工和基坑开槽施工先后顺序对整个工程建设的进度、安全、质量以及经济性都有着重要的实际意义。唐山某工程考虑项目整体部署,同时为了避免雨季基坑开槽后泡槽对CFG桩施工进度和安全性的影响,采用在现有地面首先施工CFG桩的方案。通过准确计算混凝土用量,选派有经验的人员控制停灰面,空孔最深达7.4m,将CFG桩保护桩长控制在0.7～1.5m,节省混凝土用量。同时通过精确放线,仔细调整钻杆垂直度,控制拔管速度,保证CFG桩成桩质量。

For buildings with deep foundation,when CFG piles composite foundation is used,the construction sequence of CFG piles and excavation of foundation pit is important to construction speed,engineering safety,engineering quality and economy.For overall deployment of the program,CFG piles are first constructed in an engineering with deep foundation in Tangshan,in order to avoid flood in foundation pit.In construction,the amount of concrete is accurately calculated and experienced workers is selected to control concrete pumping time.Length of protection pile is controlled ranging from 0.7 to 1.5 m,and hollow bore depth reached to 7.4 m at most,which saves large amount of concrete.Pile position is setting out precisely,verticality of drill pipe is adjusted accurately and speed of pulling drill pipe is slowed down.