动压巷道区段煤柱合理留设宽度研究

Study on reasonable width of coal pillar in dynamic pressure roadway

为了确定受工作面采动压影响下的区段煤柱尺寸,提高煤炭资源采出率,以付村煤矿3上403,405巷道为背景,采用理论计算和数值模拟的方法,建立了考虑中间主应力影响的三维离散元模型,探讨了支护参数优化后煤柱宽度分别为3、5、7、9、11m下的巷道围岩变形和支承压力分布规律。研究结果表明:理论计算得到煤柱留设尺寸应为3.25~3.85m;数值分析显示沿空侧煤帮变形量随煤柱的宽度的增加先减小后增大再减小,在煤柱宽度为5m时达到最小值;煤柱内的支承压力呈单峰分布且峰值大小且随煤柱宽度的增大而增大,煤柱宽度小于5m时峰值应力小于原岩应力;动压巷道可以留设在距离煤帮0~6m的应力降低区内,区段保护煤柱最优宽度为3.0~5.0m。经现场实践,在高预应力让压锚杆支护体系下留设3m煤柱,取得了良好的围岩控制效果,为类似情况下合理煤柱宽度的选择提供参考。

In order to determine the size of the section coal pillar under the influence of the working face mining pressure and to increase the coal production efficiency,this paper takes the No.403,405 lane of No.3 Coal mine in the Fucun Coal Mine as a case.On the basis of theoretical calculation and numerical simulation,a three-dimensional discrete element model which takes the influence of the middle stress into account is built.After optimization of the supporting parameters,the distribution of surrounding rock deformation and supporting pressure of the roadway with the coal pillar widths of 3,5,7,9,and 11 m are discussed.The research results show that the theoretical measurement of the coal pillar retention should be 3.25 to 3.85 m.The numerical analysis shows that the deformation of the coal seam along the empty side decreases first and then decreases with the increase of the width of the coal pillar,and reaches a minimum when the coal pillar width is 5 m.The bearing pressure in the coal pillars has a single peak distribution and the peak size increases with the increase of the coal pillar width.When the coal pillar width is less than 5 m,the peak stress is smaller than the original rock stress.The surrounding rock control of dynamic pressure roadway can be left within the stress reduction zone of 0 to 6 m,and the optimal size of section protection coal pillar is 3.0 to 5.0 m.In a field practice,the 3 m coal pillar is placed under the high pre-stressing pressure anchor support system,which has a good surrounding rock control effect,and it provides a reference for the selection of reasonable coal pillar width under similar conditions.