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针对混凝土结构裂缝难从理论上准确预测这一问题,本文基于预泵浦光时域分析(PPPBOTDA)的分布式光纤传感技术,借助模型试验,研究了利用该技术实现混凝土结构开裂辨识和发展状况监测的可行性,建立了混凝土结构开裂监测的经验模型。试验研究表明,光纤布里渊频移随着光纤温度的升高而相应的增加,二者呈一次线性关系,其温度系数为0.375 4MHz/℃;光纤布里渊频移峰值与混凝土开裂位置具有很好的对应性,且峰值的大小可表征出裂缝的宽度,光纤与裂缝正交时其应变系数为0.050 8 MHz/με。
According to the distributed optical fiber sensing technology of pre-pump optical time-domain analysis (PPPBOTDA), with the help of model tests, this paper studies how to identify and develop cracking of concrete structures by using this technique. The status of monitoring the feasibility of establishing an empirical model of concrete structure cracking monitoring. The experimental results show that the Brillouin frequency shift of optical fiber increases with the increase of optical fiber temperature, and the linear relationship between them is linear with a temperature coefficient of 0.375 4MHz / ℃. The Brillouin frequency shift peak of optical fiber has a Good correspondence, and the size of the peak can characterize the width of the crack, the fiber orthogonal to the crack strain coefficient of 0.050 8 MHz / με.