Research On Reasonable Width And Stability Of Section Coal Pillars In Deep Fully Mechanized Caving Mining

The Binchang mining area in Shaanxi Province is the main mining area of Huanglong Coalfield,a large coal base.The 4#coal seam is mainly mined.The buried depth of the coal seam is 500?1000m,the thickness is 4?26m,the occurrence conditions are complicated,and the disasters are coupled and superimposed.In order to ensure safe and efficient production in mines,increase resource recovery,and protect the stability of surrounding rock in mining roadways,it is particularly important to carry out research on the reasonable width and stability of coal pillars.Based on the engineering background of 402102 working face in Binchang Hujiahe Mine,using rock mechanics experiment,theoretical analysis,numerical simulation and field measurement research methods to carry out research on the reasonable width and stability of coal pillars in deep mining fully mechanized caving face,the following results have been achieved:Firstly,based on the results of on-site geological surveys and coal rock mechanics tests,accurate coal rock mechanics parameters are obtained,combined with acoustic emission monitoring,the acoustic emission characteristics of the failure process of uniaxial loading are analyzed,and the mechanical properties of coal rock damage and failure are clarified.It lays the foundation for the design of coal pillar size considering the strength of the coal body.Secondly,the limit equilibrium theory is adopted to establish the coal pillar lateral supporting pressure mechanical model,and the coal pillar failure width affected by mining is 16.04m.The reasonable width of the bearing coal pillar is 44.04m,and the surrounding rock stability is good.The width of the yielding coal pillar is 14?16m,and there is no elastic core area.Furthermore,FLAC3D is used to numerically simulate the stress distribution law of coal pillars of different widths to explore the stability of the surrounding rock of coal pillars with different widths.When the width of coal pillars is less than 15m,there is no elasticity.The core area has a certain bearing capacity when the width is 20?40m,and when it is greater than 40.0m,the stress tends to be stable,and the continuous increase of the width will not play a decisive role in the stability of the coal pillar.Finally,Carry out on-site measurement and analysis of coal pillar stability,obtain the stress distribution law of coal pillar surrounding rock,comprehensive theoretical calculation and numerical simulation results,and put forward a reasonable coal pillar width optimization suggestion,that is,the design of the section coal pillar width of 40m is more reasonable,which can ensure the coal pillar On the basis of the stability of the surrounding rock,the coal resource recovery rate is improved,and it is more reasonable to adopt a narrow yielding coal pillar less than 10m between the discharge lane and the air return lane.At this time,there is no elastic zone in the coal pillar,which can alleviate the phenomenon of dynamic manifestation.The research results can provide references for the design and stability analysis of coal pillars in Hujiahe Coal Mine.It also has a certain reference value for the study of reasonable coal pillar widths in similar conditions.