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突出厚煤层沿空掘巷煤柱留设宽度优化研究

Study on optimization of coal pillar width of gob-side entry driving in thick coal seam with gas outburst

  • 摘要: 突出煤层开采中存在开采时遗留过多煤柱与消突工程量投入巨大的问题,这和现阶段煤炭开采的理念有差异,合理的煤柱宽度以及安全的巷道布置范围不仅能保证煤炭合理安全的开采,还能提高煤炭资源的采出率、降低突出煤层中防突消突的投入量和工程量。以新集二矿1上煤230102工作面作为研究对象,采用理论分析和计算得出煤层开采过程中邻空煤体的应力分布规律以及极限平衡区宽度范围;采用钻孔测力计实测煤层开采过程中邻空煤体内垂直应力的变化情况,并结合数值模拟模拟工作面推进情况以及结合邻空、实体两侧煤体瓦斯含量确定了突出厚煤层采动卸压影响范围;基于FLAC3D软件模拟不同煤柱尺寸下巷道掘进的情况,结合卸压范围以及工程实践中关注的问题进而确定了合理的煤柱宽度。研究结果表明:①随工作面持续推进,在工作面邻空煤体内的支承应力随距采空区深度的递增呈现先增高至峰值后降低至原岩应力水平的规律,其支承应力峰值会出现在煤壁深入9.18 m附近;②在突出厚煤层开采中,邻空煤体0~25 m为卸压影响区,其卸压区和塑性区为邻空煤体0~9.5 m;③留设宽7~9 m煤柱时,能提高突出厚煤层煤炭资源采出率,降低突出厚煤层沿空掘巷消突工程量,利于巷道围岩控制,保证安全生产。

     

    Abstract: In the mining of outburst coal seams,there are problems such as excessive coal pillars left over during mining and huge investment in outburst prevention and elimination,which is different from the concept of coal mining at the present stage.Reasonable coal pillar width and safe roadway layout can not only ensure the reasonable and safe mining of coal,but also improve the recovery rate of coal resources and reduce the investment input and outburst prevention and elimination in outburst coal seams.Taking No.1 upper coal No.230102 working face of Xinji No.2 Coal Mine as the research object,the stress distribution law of adjacent empty coal body and the width range of limit equilibrium zone in the process of coal seam mining are obtained by theoretical analysis and calculation; The variation of vertical stress in adjacent empty coal body during coal seam mining was measured by borehole dynamometer,combined with numerical simulation of working face advancement and verification of gas content in adjacent empty coal body and the coal body on both sides of the entity,and then the influence range of mining pressure relief in outburst thick coal seam was determined; Based on FLAC3D software,the roadway excavation under different coal pillar sizes was simulated,and the reasonable coal pillar width was determined in combination with the pressure relief range and the issues concerned in engineering practice.The research results show that:① with the continuous advancement of the working face,the bearing stress in the coal body adjacent to the working face increases to the peak value first and then decreases to the original rock stress level with the increase of the depth from the gob,and the peak value of the supporting stress will appear near 9.18 m; ② In the mining of outburst thick coal seam,the adjacent empty coal body 0-25 m is the pressure relief affected area,and its pressure relief area and plastic area are the range of 0-9.5 m of adjacent empty coal body; ③ When the coal pillar is 7-9 m,it can improve the coal resource recovery rate of outburst thick coal seam,achieve the purpose of coal pillar stability and easy support,and reduce the amount of outburst elimination of roadway excavation along the gob in outburst thick coal seam,which is conducive to the control of roadway surrounding rock and ensure safe production.

     

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