The3D Electromagnetic Radiation Detection System Research For Coal And Gas Outburst

Coal has been an important foundation of our economic and socialdevelopment of the national economy. But we also have to be clearly seen,mostly from coal mine accidents occur every year in our country。All theaccidents caused huge casualties and economic losses because of thecomplexity of coal mining environment. Coal and gas outburst accident is themost serious accident during all the coal mine accidents, accounting for over30%of the total coal mine accidents. Especially in recent years, the miningdepth is getting deeper and deeper and the mining environment is more andmore complex and capricious, so that the probability and the intensity of thecoal and gas outburst accident and the economic losses would obviouslyincrease. Research shows that this kind of accident phenomenon was notaccurately predicted because the technology used in coal and gas outburstprediction is still static prediction method (traditional ways such as cuttings orusing the initial speed of borehole gas emission or cuttings gas descriptionindex to predict coal and coal and gas outburst, etc.). Drill cuttings methodand parameter determination have to take up work time and space and theirquantity is large. Additionally, the predicted operation time is longer and it hasa certain influence on the production. The cost is also higher. In addition, theaccuracy of this kind of static method is not high and it is easily affected byartificial and coal rock mass structure, the stress distribution and instability. In recent years, hundreds of gas outburst accidents emerged due to the predictorhas not exceeded the thresholds. The thesis aims to introduce a3Delectromagnetic radiation prediction system based on the model of AR modelwhich can predict coal and gas outburst. The3D electromagnetic radiationprediction system is a kind of system which has many advantages: forecast inreal-time, non-contact and no geographical restrictions, etc, and it also cansolve the deficiency of the existing gas drilling prediction, such as non-global,non-real time,.non-dynamic and high cost.The main content of this thesis include the following parts:（1）.Study the propagation rules and characteristics of electromagneticradiation signal when coal and gas outburst in order to analyze the feasibilityof monitoring coal and gas outburst based on the electromagnetic radiation.（2）.In order to achieve the overall requirements of coal and gas outburstprediction system and achieve the desired function, the overall framework ofthe system was designed. Meanwhile, for the requirements of rapid andaccurate of the coal and gas outburst prediction, we design a three mutuallyperpendicular space dipole antenna sensor to detect electromagnetic radiationsignal. Besides, this system fulfills the process of the sensing electromagneticradiation signal through mixing, amplification, filtering and analog-to-digitalconverter by using the principle of Super-heterodyne receiver. Based on theabove, this thesis studies the principles of data collection thoroughly from theperspective of theory and technology. (3) Introduce the structure of the monitor system in details. The monitorsystem includes two parts: signal collection and data analysis and processing.The signal collection circuit consists of super-heterodyne receiver circuits, RFfront-end circuit, amplifier, band-pass filter, and A/D converter circuit andsome other components; while the data analysis and processing hascomponents such as the amplifier, A/D converter, real time processor, digitalsignal processor, FPGA, memory, and microprocessor, etc. Besides, themonitor can connect to the computer through the data communication devicewhich composed of fiber-to-USB device, so that the collected data can beuploaded to the software in a computer system for further analysis, processing,and predicting.(4) Through an initial hardware and software debugging to the coal and gas3D electromagnetic radiation prediction system designed in this paper, theresults showed that: the system is operating normally and can achieve areal-time data collection and dynamic prediction, and can further achieve thedesired functional requirements.