中风化岩层地质条件下的旋挖扩底钻孔灌注桩施工技术

某项目桩基设计为有扩大头的钻孔灌注桩,且在深度范围内涉及的土层大部分为中风化岩层。以此为例,通过对土层特性、机械成孔、扩底及干作业施工的技术可行性分析,选择了适用于不同土层的钻头和扩孔用钻头。实践证明,在中风化岩层中的灌注桩采用旋挖钻机成孔并扩底施工的方法可行。总结的分析结论可为类似项目在中风化砂岩土层地区的施工提供参考。

Construction Technology of Rotary Drilling Bored Pile with Expanded Bottom Under Geological Conditions of Moderately Weathered Rock Stratum

The pile foundation of a project is designed as a bored pile with enlarged head,and most of the soil layers involved in the depth range are moderately weathered rock stratum.Taking this as an example,through the technical feasibility analysis of soil layer characteristics,mechanical hole forming,expanded bottom and dry operation construction,the drilling bit suitable for different soil layers and the drilling bit for hole expanding are selected.It is proved that the method of hole forming and expanded bottom by rotary drilling rig is feasible for the construction of cast-in-place pile in the moderately weathered rock stratum.The analytic conclusion can provide a reference for similar projects in the construction of moderately weathered rock stratum area.