超大荷载双套管试桩施工技术

Construction Technology of Double Casing Pile with Super Large Load

置地广场建设项目属于超高层建设项目,桩基用机械钻孔灌注桩,桩顶在地下16 m,最大的单桩承载力为21000 kN(极限值为42000 kN),设计对单桩抗压极限承载力试验结果精确度要求极高。由于项目没有对基坑底进行试桩施工及和试验条件,试桩的上端用双套管工艺,可以有效消除桩长上端的土体摩擦力影响试桩,由此外套管可以抵抗土体的侧压力、内套管可以确保桩身完整,避免桩长上桩身周边土体摩擦力影响试桩实际承载力,可使试桩实际承载力得到精确反映,为优化桩基设计提供了可靠的数据。

The landmark construction project belongs to the high-rise construction project,the pile foundation bored pile,the pile top in the ground 16 meters,the maximum bearing capacity of single pile is 21 000 kN（the maximum value is 42 000 kN）,bearing capacity design requirements of high precision test results of compressive limit of single pile. Because the project did not test and test conditions of pile construction and pit,pile top with double tube technology,can effectively eliminate the influence of friction of soil pile length at the upper end of the pile,the outer tube side pressure,can resist the soil within the casing can ensure the pile integrity,avoid pile length on the pile surrounding soil the influence of the friction pile actual bearing capacity,the actual bearing capacity of pile accurately,and provide reliable data for the optimization design of pile foundation.