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采用FLAC3D和理论分析研究了龙门塔矿8#煤层残余煤柱底板下主应力差分布规律,结果表明:1煤柱边缘主应力差呈45o向底板扩散,距离煤柱越远扩散范围越广且逐渐衰减;2煤柱较窄时,中线和边缘主应力差影响深度浅,煤柱增大到中部具有弹性核时,底板主应力差变化和影响深度较大,当煤柱宽度足够大时,中部趋于原岩应力;3中线处、煤柱边缘处主应力差呈负指数规律向深部衰减;4同一水平面上,主应力差呈马鞍状分布;5煤柱宽度增加,煤柱中线处和边缘处主应力差先增大后减小,但煤柱边缘主应力差峰值位置先减小后增大。认为:1内错布置可以避开主应力差峰值,巷道处于低主应力差环境;2内错足够距离可避开较大的主应力差变化率。9207胶带巷内错20 m,其承受平均主应力差小于1.5 MPa,两帮最大相对移近速度6 mm/d、顶底最大相对移近速度7 mm/d,10 d实现自稳,两帮相对移近量87 mm,顶底相对移近量97 mm。
Using FLAC3D and theoretical analysis, the main stress distribution law of the residual coal pillar floor in 8 # seam of Longmen Tumu Coal Mine was studied. The results show that the main stress difference at the edge of No.1 coal pillar spreads to the bottom plate at 45o, When the size of coal pillar is large enough, when the coal pillar is narrow, the influence of the main stress difference between the center line and the edge is shallow. When the coal pillar is enlarged to have the elastic core in the middle, the variation of the main stress difference of the floorboard and the influence depth are larger. The middle part tends to the original rock stress; 3, at the midline, the main stress difference at the edge of coal pillar declines to the deep with negative exponential law; 4, the main stress difference is saddle-like distribution on the same level; The principal stress difference at the edge first increases and then decreases, but the peak position of the principal stress difference at the coal pillar edge first decreases and then increases. It is considered that: 1 Internal stagger arrangement can avoid the peak value of main stress difference, and the roadway is in low main stress difference environment; 2 The internal error enough distance can avoid large change rate of main stress difference. 9207 tape lane error 20 m, the average primary stress to withstand the difference is less than 1.5 MPa, the maximum relative moving speed of two gangs near 6 mm / d, top and bottom maximum relative moving speed of 7 mm / d, 10 d to achieve self-stability, two gang Relatively moved to the amount of 87 mm, the top and bottom relative to the amount of 97 mm.