复杂地质条件下钢板桩引孔施工技术研究与应用

Study and application of the construction technology of steel sheet pile guide hole under complicated geological conditions

为尽可能地节约基坑围护施工成本,解决在复杂泥岩卵石地带难以打入的施工难题,达到基坑安全生产、支护的要求,现提出一种预引孔+二次扫孔技术,即选择旋挖钻机作为引孔机械,配备0.8m和1.2m钻头各一个。先用直径0.8m钻头预引孔,至设计钢板桩底标高后,提钻并更换直径1.2m钻头,进行第二次扫孔。在进行下一次引孔时,为避免旋挖钻头碰撞钢板桩锁扣,首先在距离上一根钢板桩0.2m处采用直径0.8m钻头进行预引孔,然后后采用直径1.2m钻头紧贴上一根钢板桩进行二次扫孔,引孔后插打钢板桩并依次循环插打钢板桩。通过这项技术来解决复杂泥岩卵石地带钢板桩施工难题,为后续在渭河施工钢板桩提供参考案例。

In order to save the construction cost of the foundation pit enclosure as much as possible,solve the difficult construction problems in the complex mudstone and cobble zone,and meet the requirements of the safety production and support of the foundation pit,a technology of pre-pilot hole+secondary sweep hole is put forward,that is to say,the rotary drilling rig is selected as the leading hole machine,equipped with 0.8 m and 1.2 m bit respectively.First,the 0.8 m diameter bit is used to pre-guide the hole to the design of the bottom elevation of the steel sheet pile,then the 1.2 m diameter bit is picked up and replaced,and the second hole is swept.In order to avoid the impact of the rotary drilling bit on the lock catch of the steel sheet pile,a 0.8 m diameter drill bit was used at the distance of 0.2 m from the previous steel sheet pile,then,a steel sheet pile with 1.2 m in diameter was used to clean the hole twice,and then the steel sheet pile was inserted after the hole leading and then the steel sheet pile was inserted and driven in turn.Through this technology to solve the complex mudstone cobble zone steel sheet pile construction problems,for the subsequent construction of steel sheet pile in Wei River to provide a reference case.