Study On Strata Behavior Regularity Of Contiguous Seams Mining Under Knife Pillar And Goaf

The near distance coal seam mining is different from the single coal seam mining.The selection method of the upper coal seam has different influence on the mining of the lower coal seam in the near distance coal seam,and the influence degree will increase with the decrease of the coal seam spacing.The mining of the coal seam under the pole pillar goaf has the characteristics of very small coal seam spacing and the mining effect of the residual coal pillar in the upper coal seam to the lower coal seam.Because the upper coal pillar mining with the cutter left after coal pillars of coal pillar,by the effect of stress concentration,and the roof of the lower coal rock structure,the relationship between support and surrounding rock,mining of the mine pressure behavior characteristics and roadway setting characteristics are all showing great difference.Wang Feng coal mine now mainly mining coal seam No.9,from the upper part of No.8 coal seam spacing is only 0.75 m,and the No.8 coal pillar mining residual coal cutter columns,is rich in resources,the use of "No.9 coal mining 9 8" combined layer caving mining,belonging to the scope of.This paper is based on the king coal mine mine as the research target,the physical and mechanical investigation and laboratory parameters measured information as a starting point,combining the theoretical analysis with simulation experiments in the No.9 coal seam mining stope underground pressure behavior connotation finally through expansion in the underground mine pressure observation further verify and enrich the stratabehavior features.The main research contents are as follows:1,through the theoretical analysis of the load characteristics of the residual coal pillar and the strength limit of the coal pillar,the stability of the coal pillar is discussed.2,investigate the distribution law of the coal seam to the bottom of the coal seam.3.The structure model of the overlying strata of the coal seam in the coal seam under the goaf is established.4.Based on the elastic mechanics,the structural model of the fixed beam and cantilever beam is established.5.According to the goaf with pillar under very close distance coal seam mining overburden rock movement,"a top loading layer of coal pillar has been connected with old top bracket" the whole structure is divided into two sub links in the coal pillar structure,and support reasonable support resistance is obtained.6.Based on the observation of rock pressure in the field,the law of ground pressure of fully mechanized top coal caving mining in fully mechanized sublevel caving mining area is further explored,which is basically consistent with the theoretical calculation.