Research On Monitoring And Recognition Of Electromagnetic Radiation In Abnormal Area In Front Of Hard Coal Driving Face

As the depth of coal mining continues to deepen,the conditions for the occurrence of deep coal and gas are becoming more and more complex.Ground stress and gas pressure continue to increase.Anomalous areas such as tectonic zones,broken zones,high-gas zones and high-stress zones are high-risk areas for dynamic disasters such as rock bursts and coal and gas outbursts,and the threat to coal mine safety is increasing.The abnormal area in front of the driving face mainly adopts the drilling method or geophysical detection methods,and the detection accuracy and timeliness need to be improved.Real-time monitoring and identification of the abnormal area in front of the driving face is an urgent problem to be solved.Therefore,it is very important to study a more efficient,convenient and safe method for monitoring and identifying abnormal areas in front of the driving face.In this paper,the hard coal driving face of high gas mines is combined with laboratory experiments and on-site data analysis.The experimental test analyzes the electromagnetic radiation law of gas-bearing hard coal fracture under stress,and analyzes the electromagnetic radiation response characteristics of abnormal area in front of the driving face.The research reveals the electromagnetic radiation precursor characteristics when the driving face is near the front abnormal area,determines the critical value of the electromagnetic radiation sensitivity index,and establishes a method for monitoring and identifying electromagnetic radiation in the front abnormal area of the coal mining site.The thesis achieved the following results:An experimental system for the failure of gas-bearing coal was established.The mechanical characteristics,gas seepage characteristics and electromagnetic radiation characteristics of gas-bearing hard coal under different gas pressure,effective confining pressure and loading speed were analyzed.It is found that the electromagnetic radiation signal and gas seepage in the process of gas-bearing hard coal failure are obviously critically slowed down.The rising trend of variance and autocorrelation coefficient reflects the precursor information of gas-bearing hard coal failure.The electromagnetic radiation signal of the abnormal area in front of the hard coal driving face is analyzed,and it is related to the gas concentration of the driving face,the critical slowing characteristics of the gas concentration,the cutting gas analysis index(K1),the cutting amount(S)and the Rayleigh wave advanced detection To compare the results.It is found that there is a corresponding relationship between the electromagnetic radiation signal and the abnormality of other indicators,and it will even lead the other indicators to respond to the front tectonic belt or gas anomaly area in advance.In-depth analysis of the abnormal electromagnetic radiation signal on site.Determine the electromagnetic intensity,electromagnetic intensity fluctuations and electromagnetic pulses as the sensitive indicators of electromagnetic radiation monitoring and identification in abnormal areas.Using the method of fuzzy mathematics,find the critical value of each index and carry out long-term on-site verification.An electromagnetic radiation monitoring and identification method suitable for the abnormal area in front of the driving face of the test mine has been formed.The efficiency and accuracy of monitoring and identifying the abnormal area in front of the coal mining face are improved.This paper has 61 figures,11 tables,and 121 references.