Cracks are the most common lesion in water-wading structures such as dams and sluices, which have an important impact on the durability of concrete materials and the safety of structures. The emergence of cracks is also regarded as a precursor to the destruction of buildings. However, the randomness and concealment of cracks are strong, which bring great difficulty to real-time and accurate capture. This paper focuses on Pulse Pre-Pump Brillouin Optical Time Domain Analysis (PPP-BOTDA) and studies the principle and realization method of PPP-BOTDA optical fiber sensing for concrete structure strain. On this basis, several groups of monitoring experiment for crack initiation location and propagation process of concrete structures are carried out. In the paper, the relationship between force-light-opening is studied and the influence of angle between optical fiber and crack on monitoring results is analyzed. Finally, a monitoring model for concrete cracks based on optical fiber strain sensing is constructed.

裂缝是大坝、水闸等涉水结构中最常见的损伤，对混凝土材料的耐久性和结构的安全性具有重要影响。裂缝的出现也被认为是建筑物破坏的先兆。但裂缝的随机性和隐蔽性强，给实时准确捕捉带来很大困难。本文以脉冲预泵布里渊光时域分析（PPP-BOTDA）为研究对象，研究了PPP-BOTDA光纤传感混凝土结构应变的原理和实现方法。在此基础上，开展了多组混凝土结构裂纹萌生位置及扩展过程监测实验。在论文中，研究了力-光开度的关系，分析了光纤与裂纹夹角对监测结果的影响。最后，构建了基于光纤应变传感的混凝土裂缝监测模型。