汾河特大桥大直径超深旋挖钻孔灌注桩施工技术

Construction technology of large diameter ultra-deeprotary bored piles at Fenhe Bridge

摘要:

蒙华铁路汾河特大桥桩基具有桩径大、钻孔深、地层复杂等特点。在施工过程中遇到了钻孔成孔后缩径、沉渣超标、钢筋笼位移等问题。通过认真分析探索，总结出了旋挖钻机在松散砂层施工条件下的泥浆配置方法、膨胀土缩径现象的处理措施、防止钢筋笼位移的有效工具，有效保障了工程质量、降低了施工成本，产生了一定的社会效益和经济效益。

Abstract:

The Fenhe Bridge pile foundation along Menghua Railway has such characteristics as large diameter, great borehole depth and complicated stratum. Many problems have been encountered in the construction such as borehole shrinkage, higher-than-standard settlements, rebar cage dislocation. By careful analysis and exploration, the method of mud preparation, the treatment measures of borehole shrinkage in expansive soil, and the effective tools to prevent dislocation of rebar cages have been developed for drilling in loose sand layers with rotary drilling rig, which not only ensured the construction quality, but also reduced the cost, achieving some social and economic benefits.