感潮河道内岩溶发育地区的超大直径桩基施工要点

Key Construction Points of Super Large Diameter Pile Foundation in Karst Developed Area of Tidal River

目前,岩溶地区桥梁桩基的设计与施工方法已成为我国桩基研究的一个发展方向,通过采用“预注浆+钢护筒护壁”预处理技术+多直径钻头扩孔钻进技术,有效充填溶洞裂隙,提高桩基周边地层强度,增加桩基承载力,加之钻进过程中通过钻头更换,避免造成设备卡钻、缩颈现象,有效提高钻头使用寿命,缩短终孔时间,属于一种复合型桩基施工技术。

At present,the design and construction method of bridge pile foundation in karst area has become a development direction of pile foundation research in China.By adopting the pretreatment technology of“pregrouting and steel barrel wall protection”and multi-diameter bit reaming drilling technology,the karst cave fissures can be filled effectively,the stratum strength around the pile foundation can be improved and the bearing capacity of the pile foundation can be increased.In the process of drilling,the replacement of drill bit can avoid stuck and necking of equipment,effectively improve the service life of drill bit and shorten the final hole time,which is a kind of composite pile foundation construction technology.