某高层建筑桩基加固设计

Pile foundation consolidation design of a tall building

结合华南某超高层建筑桩基加固工程实例,分析了造成原桩基承载力严重不足的主要原因,给出该工程可采用 600有效桩长为30m的较短桩,按新旧桩数量比1∶3进行补桩的加固方案,详细介绍了桩筏基础加固的相关计算分析,包括原有桩承载力评估及取值、筏板底土分担比荷载的考虑、广东省《建筑地基基础设计规范》(DBJ 15-31—2016)减沉桩模式计算、中震下计算、三维有限元PLAXIS沉降计算等内容。计算结果表明,加固后基础的承载力可保持与原桩基础设计基本一致的较高安全度,建筑物的最终沉降量约为30mm,加固后的基础安全可靠。

Based on the pile foundation consolidation case of a super-tall building in south China,the main reasons which reduced the bearing capacity of the origin pile were analyzed. A suitable pile-raft foundation consolidation scheme for this project was proposed by adopting new shorter piles with diameter of 600 mm and effective pile length of 30 m. The ratio of original and new piles was 3 to 1. The relevant calculation and analysis of pile-raft foundation consolidation were introduced in detail,including the evaluation and selection of the original pile bearing capacity,consideration of the specific load shared by soil at the raft bottom,calculation of the mode of settlement reducing pile in Design code for building foundation( DBJ 15-31-2016) of Guangdong Province,calculation under fortification earthquakes,and calculation of threedimensional finite element PLAXIS settlement. The calculation results show that the bearing capacity of the consolidated foundation can keep a high degree of safety which is basically consistent with the design of the original pile foundation. The final settlement of the building is about 30 mm,and the consolidated foundation is safe and reliable.