摘要
某工程的桩基钻孔灌注桩在低应变动测后,发现55%左右的承压桩在桩顶以下8～9 m处存在缺陷。对照设计和现场施工情况,分析问题产生的原因,判定主要是由于基坑开挖,坑底土体反弹拉裂了这部分桩。处理采用动力复位和基础加强两种措施。动力复位处理后作高应变动测检验,检验结果认为缝隙基本闭合,缺陷得到改善。进而提出了对钻孔灌注桩施工的要求以及关于计算基坑坑底反弹对桩影响的思考。
Drilling piles were used in the foundation of a project in Shanghai.Based on the low-strain-dynamic-survey results,defects were found from 8 m to 9 m depth on bodies of nearly 55 percent of the compression-load-bearing drilling piles.The reasons were analysed according to the design condition and construction situation.Rebounding of soil body which produced by the foundation ditch excavation was the main reason to make the piles crack.Dynamic resetting and foundation strengthening were employed to deal with the defects.It was proved by the high-strain-dynamic-survey,which was carried on piles after dynamic resetting,that the cracks on these piles were closed.Specifications were proposed for constructing of drilling piles to avoid the crack of piles.Proposals to calculate the rebounding of foundation and its effects on drilling piles were also presented.
出处
《结构工程师》
2011年第4期104-108,共5页
Structural Engineers
关键词
坑底反弹
桩身断裂
桩身检测
动力复位法
rebounding of the foundation
shaft breakdown
shaft detection
dynamic resetting
