Determination Of Reasonable Size For Segment Coal Pillar And Roadway Support Technology In Fully Mechanized Face Of Changcun Coal Mine

Aiming at the problems of unreasonable width of coal pillars,large deformation of roadway surrounding rock and difficult support in transportation roadway section of N3-11 working face in Changcun Coal Mine,The optimum coal pillar width and support scheme are determined by field investigation,theoretical analysis and numerical simulation.The industrial test shows that the optimized coal pillar size and support scheme can effectively control the deformation of surrounding rock of roadway.The main conclusions of the paper are as follows:Based on the actual engineering geological conditions of Changcun Coal Mine and the elastic-plastic limit equilibrium theory,the theoretical formula for calculating the reasonable width of section coal pillar is established.According to the calculation,it is preliminarily obtained that the reasonable width of the coal pillar in the working face is 26.2~32.2m.Using FLAC3 D simulation software,the distribution of stress field,plastic zone and displacement field in Roadway with different pillar widths is studied.The results show that when the width of coal pillar is greater than 30 m,there is a stable elastic zone in the coal pillar,which can meet the requirements of maintaining roadway stability.Based on the analysis of influencing factors of deformation and failure of surrounding rock of roadway and combined with the specific engineering geological characteristics of N3-11 transport roadway,five kinds of surrounding rock control schemes of "strong bolt + anchor cable" combined support are put forward.The control effect of surrounding rock is compared and analyzed by numerical simulation,and the optimal support scheme is determined.The field industrial test results show that the optimized pillar size and support scheme can effectively control the deformation of roadway surrounding rock.The roof and floor approximation of Roadway after mining is about 346 mm,and the average roof and floor approximation is 269 mm,which meets the need of safe mining in working face.