Study On Microseismic Monitoring And Prediction Of Rock Burst Surface In A 1000-meter Deep Well In Liaoning Mine

Rock burst is one of the most serious disasters in coal mining in the world.When it happens,the roadway of several meters to several hundred meters underground can be destroyed instantly,which seriously affects the safety environment of coal mining.This article in view of the current km deep coal mining in our country the status quo,combined with the country during the period of "difference" strategic planning on mine safety production,the methods of theoretical analysis and field engineering practice,a km deep impact earth pressure in liaoning mine as the main research object,according to monitoring the ground microtremor survey in coal mine actual situation,According to the monitoring results,the evolution law of surface microseismic events during mining is analyzed,and the maximum magnitude and types of rock burst in1000-meter deep Wells are studied.By Liao Ning three kilometers deep mining working face,a mine geological structure and mining process monitoring and early warning technique as well as their respective features that are characteristic of that analysis to the current km deep impact ground pressure mine using downhole source precursor information more comprehensive to identify a lack of sufficient theoretical basis and do not have universality and applicability,And the precursory information reflecting the impact risk is often extremely complicated and diverse.Compared with the traditional microseismic monitoring system,the surface microseismic monitoring system for 1000-meter deep mine percussive pressure is studied,including its hardware and software composition,monitoring station layout,station network,microseismic signal arrival time,location and magnitude calculation method,etc.The ground microseismic monitoring system is deployed and applied in a 1000-meter deep rock burst mine in Liaoning province.The results show that :(1)during mining,the distribution of microseismic events of different energy levels on the working face has zoning characteristics,and they are concentrated on the working face and the lateral goaf,and most of them are located in the coal body and roof strata vertically,indicating that the roof may be the main influencing factor of rock burst induced by the mine.(2)There is a positive correlation between the monthly advance degree,the number of microseismic events and the monthly total energy of microseismic events.In the month with a larger advance degree,the corresponding number of microseismic events and the monthly total energy of microseismic events are generally higher.Through real-time monitoring,it was found that the number of microseismic events and daily energy in the surface microseismic monitoring system showed an increasing trend in July,which gave an alarm to the mine.Suggestions were given to reduce the mining speed,strengthen the roadway support strength,and avoid increasing the mining speed after stopping production due to maintenance and other reasons.Based on the study of microseismic monitoring of rockburst surface,the risk prediction of rockburst based on microseismic monitoring is carried out.The main conclusions are as follows:(1)for the microseismic events of the surface monitoring system,there is a good positive correlation between the maximum single energy,the total energy of a day and the total frequency of a day,and 6.46E+06J and 5 times are the total energy of a day and the total frequency of a day respectively,which are the warning values of the surface microseismic monitoring system of the mine.(2)Through the study of the relationship between magnitude and frequency,it is concluded that there is a good linear relationship between the magnitude of impact events and the logarithm of occurrence frequency,and the fitting linear equation is 7)2) = 2.036-0.586.According to the fitting curve,the maximum seismic magnitude of rock burst is 3.47 under current mining conditions.(3)Through the moment tensor analysis of microseismic events,the failure types of the events are calculated,and the results show that the mixed failure events account for 42.90%,the shear failure events for 37.50%,and the tensile failure events for 19.60%.The failure types of high energy microseismic events are mainly mixed fracture and shear fracture,accounting for80.40%.The prevention and control of rock burst in this mine should pay more attention to shear type and mixed type,and adopt classified prevention and control measures,which provides a reasonable basis for scientific prevention and control in the future.