桩撑支护体系施工全过程桩身弯矩演化与分析

Evolution and Analysis on Pile Bending Moment in Pile Bracing Strut Support System during the Whole Construction Process

在基坑支护设计中,现有的计算方法很难真实地反映桩撑支护体系在实际开挖和主体结构施工过程中排桩内力的分布与演化规律。因此,依托郑州市轨道交通1号线二期河工大地铁车站实例基坑工程,通过实测基坑开挖和主体结构施工过程排桩钢筋应力,反算得到各个工况下的桩身弯矩。分析桩撑支护体系中排桩在施工全工程中弯矩的分布和演化规律,发现桩身弯矩在主体结构施工和支撑拆除阶段会发生重新分布。将支护排桩弯矩实测值与计算值进行对比,发现实测值略小于增量法计算结果,而经典法结果相差较大,说明对于桩撑支护体系增量法计算结果更为经济合理。

The existing calculation method is difficult to reflect the distribution and evolution of internal pile force in pile bracing strut support system in the actual excavation process. Based on the measured reinforcement stress of the pile in the subway station excavation engineering in Zhengzhou,pile bending moment was reversed. The distribution and evolution of pile bending moment in a pile bracing strut support system were analyzed,and it’s found that the pile bending moment would be redistributed in the construction of the main structure and the support demolition stage. The measured values of the pile bending moment were compared with the calculated values. It’s found that the measured values were slightly smaller than the calculated values of the incremental method,while they were quite different from the classical method. It shows that it is more economical and reasonable to use an incremental method to calculate the pile bracing strut support system.