基于BOTDR的地裂缝分布式光纤监测技术研究

地裂缝的监测是防治地裂缝危害的一项重要工作。本文采用基于BOTDR的分布式光纤感测技术对已有地裂缝和潜在地裂缝进行了分布式监测，详细介绍了BOTDR分布式光纤感测技术原理和地裂缝分布式监测方法，并以无锡杨墅里地裂缝作为监测点进行了现场试验研究。研究结果表明：基于BOTDR的分布式光纤感测技术可十分有效地对地裂缝的变形进行监测； 采用定点布设的方法，可提高感测光纤的监测精度和量程，测量精度可以达到0.1mm； 2m长的定点间距，量程可达30mm； 通过网格化铺设感测光缆，可对一定区域内的多条地裂缝进行监测； 在同一方向上，不同点距的结合，可提高地裂缝监测的定位精度。

FIELD STUDY OF BOTDR-BASED DISTRIBUTED MONITORING TECHNOLOGY FOR GROUND FISSURES

The monitoring of ground fissures plays an important role in the prevention and control of the ground fissure hazard. In this paper, BOTDR-based distributed monitoring technology is used to monitor the development process of ground fissures. The principle of distributed optical fiber sensing technology and the distributed monitoring method are introduced. The field monitoring of ground fissures located in Wuxi is studied. The results show that BOTDR-based distributed monitoring technology can be effectively used to the deformation monitoring of ground fissures. Its monitoring accuracy and measuring range can be improved by the fixed-point layout of optical fiber. The monitoring accuracy can reach 0.1mm and the measuring range can raise 30mm. The multiple ground fissures within a certain area can be monitored by the gridded laying of optical fiber. The positioning accuracy of the ground fissure monitoring can be improved by setting up the different lengths between two fixed-points along the same direction.