Study On Evolution Law Of Mine Earthquake Under Different Mining Methods In Large Dip Angle And Extra Thick Coal Seam Of Huayan Coalfield

Rock burst is a kind of coal and rock dynamic disaster,which causes serious harm to mine safety production.Rock burst is induced by mine vibration load.Different mining methods have different responses to surrounding rock breaking motion,different degrees of accumulated energy release,and different laws of mine vibration behavior.Based on the conditions of inclined coal seam in Huayan coalfield,this paper studies the evolution law of mine seismic activity under the conditions of horizontal sublevel caving mining method and longwall caving mining method,and makes a comparative analysis,which is of great significance for the prevention and control of rock burst in Huayan coalfield.Coal seam 5 of Huayan coalfield is extra thick coal seam(Dongxia coal mine is called 6 coal seam,which is actually the same coal seam.In this paper,the 6 coal seams mentioned are all 5coal seams of Huayan coalfield),and the dip angle of some coal seams reaches 20 ? 50 degrees.Yanbei coal mine is adjacent to Dongxia coal mine.When the coal seam extends to Dongxia coal mine,the coal seam bifurcates.Yanbei coal mine adopts horizontal sublevel mining for super thick seam with large dip angle,while Dongxia coal mine adopts inclined sublevel mining.The mining depth is more than 600 m.A large number of mine tremors appeared in the process of mining in both mines,but the energy size and frequency distribution of mine tremors are obviously different.According to the seismic data of 37121-1 working face in Dongxia coal mine and 150214 working face in Yanbei coal mine measured by field microseismic system,the statistical analysis shows that: during the whole mining period,the number of mine tremors in 150214 working face with horizontal sublevel mining is far less than that in 37121-1 working face with inclined slicing mining,but the total energy of mine tremors is higher than that in the latter,and the fifth power large energy mine tremors occur in the working face In the initial stage,in terms of spatial distribution,the mine tremor of 150214 working face is mainly distributed in the roof side,while the mine tremor of 37121-1 working face is mainly distributed in the floor side.Different mining methods lead to different structural characteristics of the roof and floor,which is the fundamental reason for this difference.In addition,geological factors such as mining depth,dip angle,coal thickness change and mining technology factors such as mining intensity and mining influence also have an important impact on the difference of mine earthquake distribution.This paper carries out a more detailed analysis on these aspects.The numerical simulation shows that the subsidence of stress and displacement on the roof side of 150214 working face with horizontal sublevel mining is larger than that on the floor side of 37121-1 working face with inclined sublevel mining,which proves that the distribution of mine earthquake accords with the actual situation.According to the study of time-space distribution and numerical simulation of mine earthquake,combined with the actual situation,the monitoring technology and anti impact measures of two working faces are put forward,and the impact risk area is divided.This paper has 50 figures,21 tables and 85 references.