基于BOTDA的PHC桩挠度分布式检测研究

A Study on Distributed Measurement of PHC Pile Deflection Based on BOTDA

针对预应力高强混凝土(PHC)管桩桩身在水平荷载作用下挠度大小和分布的检测困难,介绍了基于布里渊光时域分析技术(BOTDA)的桩身挠度检测方法;设计了管桩平推模型试验,推导出了管桩在水平荷载作用下的挠度计算公式;通过模拟和实测数据对比,分析了BOTDA用于PHC桩挠度检测的可行性与准确性,获得了PHC桩在水平荷载作用下的变形规律;结合具体工程,对该方法用于PHC桩身在水平荷载作用下挠度测量的可行性进行了验证。研究结果表明:BOTDA用于PHC桩挠度的检测与监测具有明显的优势,其分布式检测的特点,可以准确获得水平荷载对PHC桩的影响深度和挠度分布;该方法操作简便,性价比高,感测光纤耐久性好,可对桩身挠度分布进行精细化检测与监测,值得在桩基检测与监测中应用推广。

Under the horizontal load,it is difficult to detect the size and distribution of prestressed high concrete pile（PHC pile）deflection.This paper introduces the pile deflection method based on Brillouin optical time domain analysis（BOTDA）.A model test about piles flat pushing was designed,and the deflection formula of the pile under the horizontal loads was deduced.Through comparing the simulation and the measurement data,the feasibility and accuracy of the PHC pile deflection detector based on BOTDA was analyzed and the deformation of PHC pile was gained.Applying to project,the feasibility of the method used to measure PHC pile deflection was verified.The result shows：the advantage of PHC pile deflection detection and monitoring by BOTDA sensing technology is obvious;the technology has the characteristic of distributed detection,and can accurately obtain the impact depth of PHC pile under the horizontal loads and its deflection distribution.The method is simple and cost-effective,and sensing fiber is durable.The fine detection and monitoring of pile deflection distribution can be achieved through the technology.It is worth of application and promotion in the detection and monitoring of the pile.