扩底钻孔灌注桩在软土地基加固中的应用

青草沙5号沟泵站工程是上海青草沙水源地原水工程三大主体工程中的1个子项,开挖深度为21.2 m,采用扩底钻孔灌注桩对泵站基坑底下的软土地基进行加固。介绍了扩底钻孔灌注桩施工的全过程及施工注意事项。工程选用特别设计的MRS800型钻头,优化工艺,运用新材料玻璃钢夹砂管,控制了扩底、成孔的质量。优良的桩基质量为后续超大深基坑开挖打下扎实的基础,同时也为上海软土地基使用扩底钻孔灌注桩积累了经验。

On Expanded-base Cast-in-situ Bored Pile Applied in Soft Soil Foundation Strengthening

Qingcaosha No.5 trench bumping station project is a sub-one of three main projects of Shanghai Qingcaosha Water Source Area Raw Water Project with the excavation depth of 21.2 m.Expanded-base cast-in-situ bored pile is adopted to strengthen the soft soil foundation below the bottom of the pumping station foundation pit.The whole procedures and construction cautions of the pile are introduced in detail.The special designed MRS800 drilling bit is chosen for this project to optimize the process and new material glass reinforced plastic sand pipe is used to control the quality of baseexpanding and pore-forming.Great pile foundation quality can provide great base for later super-large deep foundation pit excavation,and meanwhile can accumulate experience in using expandedbase cast-in-situ bored pile in Shanghai soft soil foundation area.