Study On Optimization Design Of Section Coal Pillar In Shallow Coal Seam

As one of the main coal production bases in China,Shaanxi and Inner Mongolia coal producing area mainly mines shallow buried thick coal seam near horizontal.Its severe mine pressure behavior characteristics lead to many problems in coal pillar setting in working face section under this condition.Therefore,it is of great significance for safe,efficient and green mining to reasonably reserve section coal pillar.Taking 308 and 306 working faces of Shuangshan coal mine as the research background,this paper studies the mining stress distribution law of section coal pillar in 308 working face by field measurement method,and studies the reasonable reserved size of section coal pillar in 306 working face by means of theoretical calculation,laboratory test,numerical simulation and field test.The results are as follows:(1)Under the condition of secondary mining,the movement of coal body in the 0?1m range of the shallow part of the coal pillar is the most intense,followed by the movement of coal body in the 2.5?3m range of the deep part,and the width of the plastic zone inside the coal pillar is 5m,so there is optimization space for the coal pillar.(2)Based on the limit equilibrium theory and BP neural network algorithm,the reasonable reserved size of coal pillar in 306 working face of Shuangshan coal mine is calculated theoretically.The calculation results show that the reasonable reserved size of coal pillar should be between 10.8m and 12.1m.(3)According to the numerical simulation results of different coal pillar width of 9?15m,the reasonable reserved size of coal pillar in Shuangshan coal mine is determined to be 11.5m.The analysis of numerical calculation results of 11.5m coal pillar size in advance working face without support shows that the development range of surrounding rock plastic zone within 5m in advance is maintained between 2.3m?4.6m,so it is necessary to further improve 11.5m coal pillar height by strengthening support The stability of the surrounding rock of the roadway is improved.(4)Through theoretical calculation,numerical simulation,field measurement and other means,the support parameters and construction process parameters of Mining Roadway after optimization of coal pillar are explored,and the support parameters of 306 working face are determined.In the process of field application,through the analysis of the surface displacement,deep displacement and bolt(cable)stress characteristics of the roadway,it is found that the optimized roadway support parameters effectively solve the serious problem of roadway rib spalling,and the roadway deformation is less than 10%of the overall section,which can meet the needs of mine safety production,and reasonably improve the coal resource recovery rate.