岩溶发育区域钻孔灌注桩施工案例分析

A Case Study of Cast-in-Place Pile Construction in Karst Developed Region

武汉市某高层住宅项目位于岩溶发育区域。桩基施工前,采用数值分析的办法,对整个场区岩溶发育程度、溶洞洞顶埋深、溶洞洞顶高度进行分析,并找出整个场区的岩溶地下水运移主通道,据此进行桩基设计,确定施工方法,合理安排施工顺序。介绍了岩溶发育区域钻孔灌注桩施工方法,对采用块石黏土水泥筑壁工艺以及注浆法等成功的工程经验进行了说明,并对溶沟、溶槽区域未采用块石黏土水泥筑壁工艺而造成桩顶砼面下降的质量缺陷教训进行了总结。从施工结果可以看出,工程桩基的成桩质量得到了有效控制,除个别桩头出现下降需要接桩外,其余的桩均达到了设计要求。

A high-rise residential project in the Wuhan City is situated in a karst developed region. Before the pile foundation construction,the numerical analysis has been used to carry out analysis for whole site karst development level,karst cave top buried depth and cave height,as well as site main groundwater migration channel. In view of the above carried out pile foundation design,determined construction method,reasonable arrangement of construction sequence. The karst developed area cast-in-place pile construction method has been introduced; successful engineering experiences of block stone clay cement walling technology and grouting method explained. Summed up lessons on pile top concrete surface descent quality defects from without block stone clay cement walling technology used in karren,solution groove areas. From construction result can be seen,project pile foundation piling quality has been effectively controlled,except very few pile top descent need to be extended,the rest piles are all meet the design requirements.