急倾斜特厚煤层采场结构失稳探测分析

Detection and analysis of stope structural instability in steeply inclined and extra-thick seam

运用地质雷达、锚杆应力计、微震在线监测系统等多元监测手段,对某矿北采区+575水平45#煤层西翼工作面,覆岩结构、采场应力、采场煤岩体内能量以及巷道围岩破损程度进行监测分析。监测结果表明:采场顶板岩体整体完整,裂隙发育程度差;而煤体裂隙发育,部分区域破碎严重;采空区内垮落的煤岩块呈松散态,并在局部形成顶板悬空区;采场顶板巷内应力值明显高于底板巷;超前工作面0m～40m范围内,巷道支护系统所受载荷整体偏高;且在超前工作面8m～30m范围内,应力值由50kN～60kN骤增至91kN～109kN,应力峰值出现在7m～8m范围内。且随工作面的推进,采场煤岩体内微震大事件数与总释放能量整体呈骤增—骤减—骤增的趋势,且在总释放能量骤增过程中,持续时间短,单事件释放能量高。

By means of multiple monitoring means such as ground penetrating radar,bolt stress gauge and microseismic on-line monitoring system,this paper monitors and analyses the overburden structure,stope stress,energy in stope coal and rock mass and the damage degree of surrounding rock of roadway in the west Wing of 45#coal seam at+ 575 level in the north mining area of a mine.The monitoring results show that the roof rock mass of the stope is integral and the development degree of the cracks is poor,while the cracks of the coal body are developed and some areas are severely broken.The collapsed coal and rock blocks in the goaf are loose and form a roof suspended area locally.The stress value in the roof roadway of the stope is obviously higher than that in the floor roadway.The load on the roadway support system is higher in the range of 0 m^40 min the advance working face.Within the range of 8 m^30 min advanced working facce,the stress value increases suddenly from50 kN ~ 60 kN to 91 kN ~109 kN,and the peak stress appears in the range of 7 mto 8 M.With the advancing of the working face,the number of major microseismic events and the total released energy in the coal and rock mass of the stope show a trend of sudden increase-sudden decrease-sudden increase.And in the process of the total released energy,the duration is short and the single event released energy is high.