| Tunnel fire hazard will often cause great economic losses and significant casualties, accurate and real-time monitoring of tunnel temperature and make early predictions about what might happen can provide the basis for the safe operation of the tunnel. The good performance of the distributed optical fiber sensor has a unique advantage in the tunnel temperature monitoring, but distributed Raman temperature sensor for temperature measurement with a certain margin of error, which determines its functional limitations. And the fiber Bragg grating sensor is a point type sensor which is different from the distributed Raman temperature sensor, It has the advantage of good stability and sensitivity of the measuring point, and can compensate the error of the temperature measurement of the distributed optical fiber. According to the characteristics of the two kinds of sensors, proposed a system of distributed optical fiber temperature measurement with temperature compensation, binding fiber tunnel monitoring and management system of Mountain Slope Tunnel of the site layout, realizes the real-time monitoring of the mountain slope tunnel temperature field and improve distributed optical fiber in tunnel temperature measurement accuracy, making it in the tunnel fire early warning, can reduce the loss to the lowest. The main contents of the study include the following aspects:(1) Firstly discusses the distributed Raman temperature sensor and fiber Bragg grating temperature sensor working principle, and then completed the selection of two kinds of sensing system in the mountain slope tunnel field measurements required components, and the distributed Raman temperature sensor and fiber Bragg grating temperature sensor temperature measurement and analysis, finally fusion characteristics of two kinds of sensing system presents a with temperature compensation of distributed optical fiber temperature measurement system, and the temperature of the optical fiber sensor test measurement analysis and compensation.(2) Based on the B/S (Browser/Server) mode of the fiber Bragg grating remote monitoring system, the system of data communication is designed, including system function analysis, use case design and database design. Fiber Bragg grating temperature sensor and distributed Raman temperature sensor data were transmitted to the host computer through the serial port and the network port, the monitoring system will collect the data into the database.(3) In combination with the practical situation of mountain heart slope of the tunnel, the layout of the related devices technical indicators and selection criteria are discussed, the heart mountain slope tunnel site layout is as follows:distributed optical fiber channel 2 road, optical fiber Bragg grating sensor for 3 road, tunnel wiring for the horizontal direction. Spatial resolution of distributed optical fiber for 3 m, measuring distance is 8000 m, the tunnel length of 680 m, the distance of two adjacent optical fiber Bragg gratings is 60 meters,11 per channel layout along the optical fiber Bragg grating sensor optical fiber Bragg grating. Draw the sensor installation diagram and mountain slope section layout diagram, the tunnel internal layout of the actual situation of the performance is more intuitive, and finally put forward a scheme of optical fiber sensing network tunnel, by reading the data in the database, which can realize the collected data and compensation after data displayed in the browser interface, by querying the sequence diagram of the remote monitoring system, can be real-time monitoring of temperature in the tunnel, the system working conditions and the experimental results verified the reliability and stability of the system design, can realize remote monitoring of tunnel temperature. |
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