Optimization of Coal Pillar Width in the Mining of the Foot Wall of Faults Under the Mined Out of Upper Wall
Under the influence of faults and mining,the coal pillars width on the fault side of the foot wall working face restricts the safe and stable production of the working face.Based on the engineering background of the 203 foot wall working face in the second panel of Huangling Coal Mine,a combination of theoretical analysis,numerical simulation,and similarity simulation was used to study the relationship between the load above the fault side coal pillar and the size of the coal pillar after the upper working face was mined out.The displacement,stress evolution,and plastic zone distribution characteristics under the coal pillar widths of 30,26,22,20,13,and 6 meters were revealed,and the overburden structure characteristics with coal pillar width of 30 meters were analyzed.Through comprehensive analysis,the reasonable coal pillars width in the working face was optimized.The results show that when the upper working face is mined out,under the influence of fault and mining,with the decrease of coal pillar width,the load above the coal pillar on the fault side of the foot wall working face is divided into load reduction zone,load transition zone and load stability zone.When the coal pillar width is 30 m,the high rock layer on the fault side of the foot wall working face separates,and the stress concentration degree above the coal pillar is greater than that on the other side,with strong bearing capacity and high stability.When the coal pillar width is reduced to 22 m,the maximum subsidence and stress concentration of the roof near the fault side increase significantly,and the plastic failure of the coal pillar begins to occur,and the bearing capacity gradually weakens.When the the coal pillar width is reduced to 13 m,the plastic zone on the fault side develops towards both ends and above the working face to connect the coal pillar,resulting in poor stability of the coal pillar.When the coal pillar width is reduced to 6 m,the maximum subsidence and stress concentration of the roof on the fault side continue to increase,and the plastic zone continues to develop.Through similar simulation test,it is found that when the coal pillar width is 30 m,the roof collapses and fills the goaf,and there is no obvious change above the coal pillar on the fault side of the foot wall working face.Through comprehensive analysis,it is determined that the reasonable coal pillar width on the fault side of the foot wall working face is 18-22 m,which can improve the recovery rate of the working face and ensure safe production of the working face.
Mined out of upper wallMining of foot wallCoal pillar on the fault sideCoal pillar width
万方数据
维普
