桩基工程缺陷补桩施工技术研究

STUDY ON CONSTRUCTION TECHNOLOGY OF PILE FOUNDATION ENGINEERING DEFECT REPAIR

某高层写字楼工程由于桩基先行的钻孔灌注桩存在缺陷需要桩基补强处理,而大面积基坑已开挖至设计标高且部分基础垫层已施工。经过对工程地质的详细研究及对承压水水位进行二次勘探,各方确定采用局部回土补桩的方式进行桩基补强。补桩后经检测,工程桩极限承载力满足设计要求,100%小应变动测检测显示检测结果均为桩身完整。基于项目实践,在补桩施工过程中进行了回填土层厚度、钻孔灌注桩泥浆比重控制等方面进行了研究与实施,其经验可作为桩基工程发生缺陷时采取补强措施的参考。

In a high-rise office building project,due to the defects of the bored cast-in-place pile in advance of the pile foundation,the pile foundation reinforcement treatment is required,while the large area of foundation pit has been excavated to the design elevation and part of the foundation cushion has been constructed.After the detailed study of engineering geology and the secondary exploration of the confined water level,all parties decided to use the method of local backfill and pile reinforcement for pile foundation reinforcement.The ultimate bearing capacity of the engineering pile meets the design requirements after pile filling,and the 100%small strain test shows that the pile body is complete.Based on the project practice,this paper has carried out research and implementation on the thickness of backfill soil layer and the control of slurry proportion of bored pile during the construction of pile reinforcement,and its experience can be used as a reference for taking reinforcement measures in case of defects in pile foundation engineering.