Research On FBG Sensor In Coal Mine Roadway Structure Monitoring

In recent years, coal mine is excessive mined, the depth of coal mining is increasing, the geology of the coal mining area is more and more complicated, to ensure safe production of coal mine is a priority for all. The main coal mine safety accidents include coal mine roadway roof abscission layer lead to high density of gas appeared in the process of the excavation of coal mine, coal mine pressure imbalance cause the original supporting structure be damaged. Therefore, how to guarantee the safety of production area, how to achieve that eliminate people or hidden security danger existing in the coal mine areas safely and timely and effectively has been paid great attention in each coal mine. To ensure the safety of coal mine production, reduce the safety accidents occurred in the coal mining process, increase the reliability of the safety in production, they all can make a great help to guarantee the safe of miner’s life and the economic benefit of coal mine.Fiber Bragg grating sensors applied in this project to realize the monitoring of coal mine roadway roof abscission layer and two sides of roadway surrounding rock pressure. Fiber Bragg grating displacement sensor has the many advantages which the traditional sensors do not have, such as fiber Bragg grating sensor has a light weight, strong ability to resist electromagnetic interference, high precision and intrinsically safe characteristics, these advantages overcomes the traditional sensor limitations on the use of regional problems. Install the FBG sensor and earth pressure sensor in the monitoring area, due to the large information transmission characteristics of fiber, it can achieve24-monitoring in the monitoring area, and timely grasp the roadway roof coal mine and the tendency of the two sides of roadway surrounding rock pressure, to forecast the development trend of roadway in monitoring area, timely warning the constructors in this area.Based on the Huaibei mining Zhu Xianzhuang south second air shaft upper yard as the roof abscission layer of coal mine roadway surrounding rock pressure monitoring and project background, research the application of FBG sensing technology in coal mine roadway monitoring. Mainly includes the following several works: cl. Research and analyze the sensing structure, sensing model and sensing principle of the fiber Bragg grating displacement sensor and soil pressure sensor, using the transmission characteristics of fiber to form fiber sensing network with fiber Bragg grating sensors, realize long-term real-time online monitoring of the displacement of coal mine roadway roof and the two side pressure of roadway surrounding rock.2. Research and analyze the disease situation of coal mine, and the influence to the displacement of coal mine roadway roof abscission layer and two sides pressure of roadway surrounding rock when blasting construct, research and analysis the monitoring data of mutation. Meanwhile, the structure by differential displacement sensor is to eliminate the influence of temperature on the sensor.3. In view of the existing equipment can not meet the requirement of the coal mine explosion-proof of equipment, the existing market sales of the PLC flameproof switchgear to be modified, the fiber Bragg grating demodulation devices and optical switch module are installed in modified flameproof switchgear, to meet the coal mine explosion-proof requirements for equipment.4. Due to the down hole lighting electricity ordinary use127V voltage, it can’t satisfy the use of existing equipment, through the installed inverter in the explosion-proof switch cabinet, to switch the down hole calls using the127V lighting electricity into220V voltage through the inverter, which the equipment can be normal used,to ensure the normal operation of the system.5. Use the finite element analysis software to simulate the change of coal roadway surrounding rock before and after the excavation, analysis the distribution of displacement field, stress field distribution strength, shear strength field distribution before and after the excavation, through the simulation analysis of and comparison between the numerical and monitoring period of data to verify the reliability of the finite element analysis software simulation values.