中文摘要：

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（PPP—BOTDA）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0．3754MHz／℃；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0．0508MHz／με。

英文摘要：

Theoretically,it is too difficult to predict the location and width of cracks is concrete structure accurately. Therefore, monitoring cracks of concrete structure is of great significance. Based on pulse-pre pump Brillouin optical time domain analysis （PPP -BOTDA）, the principle of distributed optical fiber sensing technology is discussed. By means of model test, this article studies the feasibility of using this technology to identify or monitor cracks in concrete structure, and an empirical model of crack monitoring in concrete structure is constructed. The experimental results show that the Brillouin frequency shift will increase linear by along with the rise of optical fiber temperature , and the temperature coefficient is 0. 3754 MHz/℃. According to the peak position of Brillouin frequency shift,the location of the crack can be determined,and the size of the peak indicates the width of the crack. When fiber and crack are orthog- onal,the strain coefficient is 0. 050 8 MHz/με.