基于背向Brillouin散射监测混凝土应变

发布时间：2018-08-09 10:23

【摘要】：采用贴附法将一根玻璃纤维增强塑料(GFRP)单芯应变传感光缆埋设于钢筋混凝土试件的中间部位,对混凝土内部应变进行分布式测量。考虑在温度和外加应变的作用下,光纤中的背向布里渊(Brillouin)散射光将发生频移,使用光时域反射仪(OTDR)对反射光信号进行了分析。研究了混凝土凝固过程中应变的变化,结果表明:混凝土试件浇筑完成当天应变变化明显,应变变化趋势与试件内部温度相似,试件内部应变主要受水泥水化热的影响。试件凝固后,通过外力作用使得混凝土试件在纵向中心轴上产生平均宽度为6mm的裂缝。检测裂缝出现前后试件的应变变化,发现裂缝出现后试件内部应变明显变大,共发现3个应变峰值。通过应变峰值位置的分析,可判断裂缝的出现位置与方向。实验显示,利用背向Brillouin散射的分布式应变检测技术可较好地实现混凝土应变的分布式测量。
[Abstract]:A fiber reinforced plastic (GFRP) single core strain sensing cable was embedded in the middle part of the reinforced concrete specimen by the adhesive method to measure the internal strain of the concrete in a distributed manner. Considering the effect of temperature and applied strain, the backBrillouin (Brillouin) scattering light in optical fiber will be shifted frequently. The reflected light signal is analyzed by using the optical time domain reflectometer (OTDR). The strain variation of concrete during solidification is studied. The results show that the strain of concrete specimen changes obviously on the day of pouring, and the strain variation trend is similar to the internal temperature of the specimen, and the strain inside the specimen is mainly affected by the hydration heat of cement. After solidification, the concrete specimens have cracks with average width of 6mm on the longitudinal central axis by external force. The strain changes of the specimens before and after the cracks were detected. It was found that the internal strain of the specimens increased obviously after the cracks appeared, and a total of three strain peaks were found. The location and direction of the crack can be determined by the analysis of the peak strain position. The experimental results show that the distributed strain detection technique based on backscatter Brillouin can be used to measure the strain of concrete.
【作者单位】：昆明理工大学信息工程与自动化学院;
【基金】：云南省应用基础研究计划资助项目(No.2013FZ021) 昆明理工大学人才培养基金资助项目(No.KKSY201303044)
【分类号】：TU755

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