F1 Fault Zone Of Changheng Coal Mine Mechanics Test And Numerical Analysis Of Reasonable Setting Of Coal Pillar

The reasonable setting of waterproof coal pillar near fault is related to the extraction rate of coal resources.If set waterproof coal pillars near fault can ensure safety production of the mine and the maximum exploitation of coal resources,it is adhering to social purposes and philosophy of the "people-oriented,science and technology mining,safe and efficient and reduce the loss of resources,take sustainable development".The setting method of waterproof coal pillars near fault is more and more.Due to occurrence condition of fault differs from one another,choose a variety of methods to study according to different working conditions and their specific occurrence conditions.As F1 fault near 9102 working face in Changheng coal mine as the research object.Firstly,in order to clear mechanical and hydraulic properties of F1 fault zone,construct four borehole at wind lane near F1 fault in 9102 working face such as top 1,top 2,bottom1,bottom 2 and get rock samples.Rock samples need done rock mechanics and water property test,and water property includes moisture content,water absorption,permeability,expansion and disintegration of resistance.Results show that the F1 fault zone is mixed accumulation of fault breccia,fault gouge and mylonitic rocks,and it has the characteristics of "loose,scattered,soft and weak".The average moisture content is 2.53%.The average permeability coefficient is 0.35cm/s.It belongs to the "strong water permeability" type of rock.The average inflation rate is 0.656%.Most of the soft rock sample is broken,and they would disintegrate under water and faster.The stability of most rocks is bad,as their argillization degree is higher under water,they belong to unstable rock.Secondly,the change of mining pressure,displacement and plastic zone of the surrounding rock and the fault with different face advance distance is studied by FLAC^3D software simulation method.Results showed that mining pressure,displacement and plastic zone of the surrounding rock and the fault increased with the increase of the goaf area.Because the mining pressure,displacement and plastic zone in the middle of the working face are larger than in the end of the working face,the reasonable setting of waterproof coal pillars near fault should draw on the range of destruction in the middle of the working face.The depth of the damage bottom is 19 m and the plastic destruction area is small in the fault zone,when the mining face is advanced by 140 m,this time the plastic destruction zone of the bottom does not reach the fault zone.the interface displacement between the upper and lower of the fault is 0.005 dm,so the fault is not activated,and thewaterproof coal pillar near fault is set to 45 m.Again,the width of the waterproof coal pillar near fault is designed by the coal pillar elastic-plastic partition method with the elastic-plastic limit equilibrium theory,the material mechanics theory and the lithology of the fault zone.In this way,the width of the limit equilibrium zone of the coal pillar is14.27 m,and the width of its elastic zone is 28.23 m,and the width of the influence zone of fault is 6.88 m,and the sum of the three is 49.38 m.To ensure the safe mining of the working face,the reasonable width of F1 fault waterproof coal pillar is set to 50m.