大直径灌注桩桩端后注浆技术在某高层建筑中的应用

Application of post grouting technology at pile end of large diameter cast-in-place pile in a high-rise building

为节省工程造价,优化基础设计,充分发挥地基承载能力特性,在对某高层建筑大直径灌注桩全面施工前的试验桩阶段中,采用埋设桩身应力计的方式,测定桩身内力及桩端阻力,对常规工法施工与采用桩端高压注浆这两种不同施工工艺下桩基承载能力进行对比,分析两种施工工艺下灌注桩的承载能力特性。对比分析结果表明:桩端注浆能明显提高桩端土的端承力及注浆断面以上一定范围内的桩侧摩阻力,进而提高单桩竖向承载力,可为桩基设计优化提供依据。

In order to save the project cost and optimize the foundation design and give full play to the characteristics of foundation bearing capacity.The pile internal force and pile end resistance are measured by embedding pile stress meter in the test pile stage before the full construction of large-diameter cast-in-place pile of a high-rise building.The bearing capacity of pile foundation under two different construction processes of conventional construction method and pile end high-pressure grouting is compared.The bearing capacity characteristics of cast-in-place pile under the two construction processes are analyzed.The comparative analysis results show that pile end grouting can significantly improve the end bearing capacity of pile end soil and pile side friction within a certain range above the grouting section so as to improve the vertical bearing capacity of single pile.It provides a basis for pile foundation design optimization.