外海钢管斜桩嵌岩混凝土芯柱成孔技术

Drilling technology of concrete core column of offshore inclined rock socketed steel pipe pile

在外海无掩护孤立墩施工环境条件下,灌注桩斜向成孔一直是施工难点。分析斜桩嵌岩混凝土芯柱在硬度较高岩层中成孔时存在的钻孔偏位、坍孔、钻孔进尺缓慢等施工难点及原因。采取针对性措施:选用气举反循环回旋钻机、采用采用牙轮滚刀钻头、钻杆中部加设导向装置、采用海水制浆泥浆护壁、合理调整钻压钻速等参数,成功克服了此类条件下灌注桩斜向成孔施工中的难点问题,形成外海斜桩嵌岩成孔技术,为同类工程提供借鉴。

Inclined hole forming of isolated pier pile has always been a construction difficulty problem in the open sea. This paper analyzes the construction difficulties and reasons of inclined rock-socketed piles concrete core such as drilling deviation,hole collapse and inefficiency during drilling construction in hard rock. Targeted measures are taken:selecting air lift reverse circulation rotary drilling machine and cone bit,assembleing the guide device in the middle of drill pipe,using sea water slurry supporting,reasonably adjusting the drilling pressure and drilling speed and other parameters,which successfully overcome the aforementioned difficulties. Thus the technology of rock socketed hole forming of offshore inclined pile is formed to provide reference for similar projects.