隧道健康诊断BOTDR分布式光纤应变监测技术研究

布里渊散射光时域反射监测技术是一项新型的光电监测技术,它利用布里渊散射光的光谱技术和光时域测量技术,可对沿光纤的轴向应变进行分布式监测,并具有分布式、长距离、精度高和耐久性长等特点。首先介绍了该监测技术的原理和特点,并以南京市鼓楼隧道健康诊断为例,介绍了该技术应用于该隧道变形监测以及监测的方案,讨论了隧道内环境因素如温差和振动等对监测结果的影响,验证了监测系统的灵敏性,最后对隧道的变形监测结果进行了分析,给出了鼓楼隧道的健康诊断。研究成果表明:该技术应用在隧道安全监测和健康诊断中是十分可行的,也是十分有效的。

STUDY ON BOTDR-BASED DISTRIBUTED OPTICAL FIBER STRAIN MEASUREMENT FOR TUNNEL HEALTH DIAGNOSIS

The Brilliouin optical time domain reflectometer(BOTDR) is a newly developed measurement and monitoring technique,which utilizes Brilliouin spectroscopy and optical time domain reflectometer to measure strain generated in optical fibers and distributed in the longitudinal direction. Hence,the BOTDR has the characteristics of distributed measurement,long distance,high precision and durability. In this paper,the basic principle and features of the BOTDR are briefly introduced;and taking Nanjing Gulou Tunnel as a case,the technical and monitoring schemes of BOTDR are presented;the installation of sensing optic fiber and the temperature compensation method are introduced;the influence of environmental factors such as temperature and vibration on the measurement results is discussed. Finallyt,he monitoring results of the tunnel are analyzed and the health diagnosis is given. The monitoring achievements demonstrate that the BOTDR is a feasible and powerful technique for the strain measurement and health diagnosis of the tunnel engineering.