On-line Health Monitoring Of High-speed Railway Track Based On Φ-OTDR

Distributed optical fiber sensing technology has many advantages,such as high sensitivity,easy deployment,anti-electromagnetic interference and so on.With the continuous improvement of key technologies,it is rapidly advancing to the practical stage.Phase-sensitive optical time-domain reflectomete(Φ-OTDR)is a very characteristic distributed optical fiber sensing technology.Its non-contact detection ability makes this technology become a research hotspot in the field of distributed sensing in recent years.In this paper,Φ-OTDR is introduced into the field of health monitoring of high-speed railway,and the potential vibration safety hazards between wheels and rails at high-speed operation of high-speed railway are monitored and studied,in order to replace the traditional methods of manual inspection with high cost and efficiency and point sensor monitoring.High-speed rail has the characteristics of closed operation,and the construction standard is very strict.The construction cost is very high by laying additional optical cables.This is also an important reason why other distributed optical fiber sensing technology has been unable to land in the field of health monitoring of high-speed rail.According to the non-contact detection capability of Φ-OTDR,this paper takes the existing communication optical cable as the sensing medium,and through the analysis and comparison of the characteristics of the inherent vibration modes of high-speed rail after being impacted by trains,realizes the long-distance on-line real-time monitoring of high-speed rail safety.This technology will greatly reduce the landing cost of distributed optical fiber sensing technology.Firstly,based on the actual characteristics of high-speed rail health monitoring,this paper presents a Φ-OTDR high-speed rail health monitoring scheme based on existing optical cable.Then,aiming at the problem of reducing the coupling efficiency between optical fiber and rail,the detection sensitivity of the sensor system is improved from three aspects:polarization noise suppression,micro-disturbance quantitative detection and natural resonance frequency analysis.Finally,the health monitoring of high-speed rail is realized by image processing algorithm.Under the support of the above technology,through improving the prototype of the laboratory,field experiments were carried out on some typical railway scenes,and a database of the inherent resonance frequencies of rails was established.The database can be continuously compared and updated in future detection.Based on the existing optical cable Φ-OTDR high-speed rail health monitoring technology,the cost of landing of the technology can be further reduced by large-scale networking in the later stage.I believe that with the further maturity of the technology,it will become another powerful means of high-speed rail health monitoring and escort for the healthy operation of high-speed rail in China.