狭小空间大直径钻孔桩机械化快速施工技术研究

Research on Mechanized Rapid Construction Technology of Large Diameter Bored Pile in Narrow Space

为解决暗挖地铁车站砂卵石地层钻孔桩狭小空间内施工成孔难、成桩速度慢和质量难以控制等问题,本文结合新建M16线二里沟车站大直径钻孔桩施工,研发出配以高频振动功能液压冲击钻头的全液压履带自行式反循环钻机,总结形成"反循环钻孔+桩底后注浆"的砂卵石地层导洞内大直径中桩施工工艺,解决了狭小空间内大直径桩基钻头损耗严重、堵管频率高及成孔垂直度偏差大等问题,提高了成孔质量和效率,可为类似工程提供参考。

In order to solve the problems of difficult hole forming, slow pile forming speed and difficult quality control in the narrow space of bored pile in sandy pebble stratum of underground excavation subway station, this paper combines with the construction of large-diameter bored pile in Erligou Station of new M16 line to develop a full hydraulic crawler self-propelled reverse circulation drill equipped with hydraulic impact bit with high-frequency vibration function, and summary the construction technology of “reverse circulation drilling+post grouting at pile bottom” applied to large-diameter medium pile of single-layer pilot tunnel in sandy pebble stratum. The construction technology solves the problems of serious loss of drill bit, high pipe plugging frequency and large deviation of hole perpendicularity of large-diameter pile foundation in narrow space, improves the hole forming quality and efficiency, and provides reference for similar projects.