大直径嵌岩桩旋挖钻成孔技术改进及应用

Improvement and Application of Drilling Technology for Large-diameter Rock-socketed Piles

珠海市某大桥3^(#)主墩基础设计为20根直径Φ2.5 m的钻孔灌注桩,为了充分利用旋挖钻、冲击钻成孔工艺的优点,提高施工效率和工程质量,桩基施工创新地采用旋挖钻、冲击钻组合成孔工艺,即旋挖钻成孔后,利用冲击钻对桩孔进行修整,最后利用泥浆反循环方法进行清孔,确保清孔彻底。实践表明,与钻孔灌注桩传统成孔工艺相比,该施工方法大幅提高了施工效率,减少了施工成本,有效地保证了桩基的施工质量。

The 3^(#)main pier foundation of a bridge in Zhuhai was designed as 20 drilling piles with a diameter of Φ2.5 m.To make full use of the advantages of rotary drilling and percussion drilling technology,as well as improve construction efficiency and project quality,the pile foundation construction innovatively used a combined hole forming technology of rotary drilling and percussion drilling.After rotary drilling the hole,the percussion drill was used to trim the pile hole,and to clean the holes thoroughly by the method of mud reverse circulation finally.Practice shows that this method greatly improved the construction efficiency,reduced construction costs,and effectively guaranteed the construction quality of the pile foundation,compared with the traditional hole-forming process of drilling piles.