| The coal mine roadway collapse problem is very common and its damage is very serious. It also seriously endangers people’s lives and property safety. Therefore, it is necessary for the health monitoring of coal mine roadway roof to achieve early collapse warning. Optical fiber sensing technology has developed rapidly in recent years and its application is more widely. It has several significant advantages, such as high sensitivity, intrinsic safety, high temperature resistance, corrosion resistance, anti-electromagnetic interference, stable performance, etc. It can be used to measure pressure, temperature, displacement, acceleration, humidity and other physical quantities. Its intrinsic advantages also make it more suitable for safety monitoring of coal mine. It has attracted increasing attentions in coal mine safety monitoring field. Based on the above discussion and analysis, a new type roof separation displacement sensor with large range was design and a roadway roof monitoring system based on fiber grating technology was establish in this thesis, which could be used to achieve early stability safety warning and prevent the accidents of coal mine roadway collapse by monitoring the displacement of roadway roof. It has very important practical significance for coal mine safety production.In this thesis, the roadway roof monitoring system based on fiber grating technology is studied through theory and experiments. The main research contents including:(1) Theoretical studies and simulation analysis are conduct on the characteristics and mechanism of roadway roof accidents. The finite element software was used to build different types of mine roadway models and analysis the stress and deformation of roadway roof by simulation. The deformation mechanism of roadway roof can be found through these research. It can also show the maximum force and deformation distribution point of the roadway roof.(2) A new sensing method suitable for mine roadway is proposed based on the basic theory of optical fiber sensing. A large range roof separation displacement sensor is designed based on FBG The key part structural parameters of sensor and their impact on sensor performance are analyzed to determine the structure and form of the sensor.(3) The roadway roof experimental model was designed, which can be used to simulate the actual circumstances of coal mine roadway roof under laboratory conditions. The PC software for roadway roof condition monitoring was designed, which can be used to achieve remote monitoring and measurement.(4) The roadway roof condition monitoring system based on fiber grating technology is designed and built. The monitoring system is applied to the design experimental model of roadway roof. The experiments to measure the roof separation displacement are carried out. By calculating the experimental data, the sensing characteristics are analyzed. The final displacement measurement range is 50mm, the resolution is lmm and the sensitivity of system is up to 23. 1pm/mm.The roadway roof condition monitoring system design in this thesis achieves the desired design requirements. It can monitor the status of roadway roof effectively in real time. It also provides a practical approach to predict the roadway roof accident. The roadway roof condition monitoring system designed in this thesis should be considered to applying in practical engineering occasion in future research. Promote its practical application to achieve large-scale production and field testing, which can provide technology and methods for real-time monitoring and forecasting of roadway roof accident in the practical engineering. |
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