胡家湾渡槽拱墩基础灌注桩施工技术研究

Construction Technology for Cast-in-place Piles of the Arch-pier Foundation in Hujiawan Aqueduct

胡家湾渡槽为连拱支撑结构,进出口拱座各设20根桩径为1.0 m、桩孔深12~14 m的抗滑桩,1~5号中墩下设计8~9根长7~28 m不等的支撑桩,桩基为不完整灰岩,且溶沟溶槽发育,局部还夹杂孤石和充填型溶洞,岩体含量低于土体含量。针对强烈发育的地质情况,确定了旋挖钻和冲击钻组合的灌注桩施工方案,编制了详细的施工方案和实施措施,顺利解决了灌注桩的施工难题,取得了良好的工程质量,可供同类工程借鉴。

Hujiawan aqueduct is a multi-arch support structure.Twenty anti-slide piles with the diameter of 1.0 m and the pile hole depth of 12~14 m are installed under the entrance and exit arch abutment of the aqueduct.Also,eight to nine supporting piles with the length of 7~28 m are arranged under the 1#~5#middle piers.The pile foundation is incomplete limestone,with developed karst channels and grooves and local inclusions of solitary stones and filled karst caves.The rock mass content is even lower than the soil content.Considering the geological conditions with strongly developed karst,a construction scheme of the cast-in-place piles using the combination of rotary drilling and impact drilling is proposed.Detailed construction plans and implementation measures are prepared,which successfully solve the construction difficulties of the cast-in-place piles and achieve satisfactory construction quality.The technology can be useful reference for similar projects.