Research On Surrounding Rock Control Technology Of Narrow Coal Pillar Gob-gob Driving In Chensilou Mine

The narrow coal pillar gob-side tunneling technology can improve the recovery rate of coal resources in mines.Because of its outstanding economic benefits and compact replacement,it is widely used in thin and medium-thick coal seams in my country.Narrow coal pillars are prone to plastic damage and lose their support,resulting in deformation and damage of the surrounding rock surface of the roadway,resulting in safety problems.This thesis takes the 21015 working face transport roadway of Chensilou Coal Mine as the research object,and comprehensively adopts the methods of field investigation,laboratory experiment,theoretical analysis,numerical simulation,industrial experiment,etc.,to study the reasonable width of the narrow coal pillar and the roadway support in the gob-cut roadway.care technology.The main research conclusions are as follows:(1)Using theoretical analysis and numerical simulation methods,the reasonable width range of narrow coal pillars in gob gob driving face 21015 working face was studied.Analyze the stress state and internal stress structure distribution of the coal pillar,and calculate the minimum value range of the narrow coal pillar width.Referring to the theoretical calculation results,6 different coal pillar width models of 2-10 m are designed,and the 6 different width models designed are simulated and analyzed by numerical simulation software.The results show that the smaller the width of the coal pillar,the higher the fracture degree of the coal pillar.The coal pillar is most seriously broken at 2m,but there is still a stress core area inside the 2m coal pillar,which can ensure the stability of the coal pillar and play a supporting role.When the width of the coal pillar increases,the internal stress core area of the coal pillar increases,the support stress of the coal pillar to the roadway increases,and the stability of the roadway increases.Decrease slowly at 10 m.Under the premise of ensuring safe production,to better improve the recovery rate of coal resources,after a comprehensive analysis of the stability of the surrounding rock of the roadway and changes in surface displacement,the coal pillar width range is determined to be 2-4m.(2)Using the method of engineering analogy and numerical simulation,the support scheme of gob-side entry for 21015 working face is designed.Based on the designed 2m coal pillar width,the support design for the surrounding rock of the working face transportation roadway is carried out.The length of the bolt and cable support and the range of the row spacing are determined by theoretical calculation,and the optimal and reasonable spacing of the bolt is determined by numerical simulation software.row spacing.Combined with engineering analogy,the roadway reinforcement support design is carried out,and the roadway support scheme is preliminarily designed.According to the designed support parameters,the support simulation analysis and verification of the transport roadway is carried out,and the support scheme of highstrength bolt + anchor cable + metal mesh + M steel belt + steel wire rope is finally determined for the surrounding rock of the roadway.(3)The industrial test of gob-side entry was carried out in the 21015 working face.The test results show that the gob-gob roadway with 2m narrow coal pillars is used in the transport roadway,and the roadway deformation under the support can meet the requirements of safe production,and the two gangs can provide stable support.The thesis has 106 figures,19 tables,and 69 references.