长螺旋钻孔二次压灌混凝土成桩工艺在干性砂卵石地层中的应用

Application of Auger Drilling Secondary Pressure Fed Technology into Concrete Piles in Dry Sand and Gravel Formations

长螺旋钻孔压灌桩是近几年发展起来的比较实用便利的灌注桩施工技术,它主要适用于北方土质较硬地区,由于其成桩速度快、无需泥浆护壁而受到施工单位的欢迎,但同时也伴随着一些质量问题,尤其是在干性砂卵石地层中成桩钢筋笼插不到位的问题,已经成为这种工艺进一步推广的制约因素。为了解决这个质量问题,在原有施工工艺的基础上提出了二次压灌混凝土后插钢筋笼施工工艺。该技术是在传统长螺旋成孔压灌混凝土后插钢筋笼工艺的基础上总结出的新施工方法,并在多项实际工程应用中进行了验证,效果较好。

Auger drilling grouting pile is a more convenient and practical construction technology developed in recent years. It mainly applies to hard soil in northern area. It is well received by the construction company by its fast pile speed without slurry-supported. But at the same time accompanied by some quality problems,the most significant problem is the pile reinforcement cage can't insert properly in dry sandy pebble stratum,which has become a constraint to further promote of the technology. In order to solve this quality problem,we put forward reinforcing stell cage after the secondary pressure construction technology on the basis of the original construction technology. This is a new construction method summarized from the traditional pouring the concrete reinforcing cage after long spiral into pore pressure technology,and validated in a number of engineering practice,the construction effect is good.