急倾厚煤层综放开采顶煤超前预裂爆破技术

Advance Pre-Cracking Blasting Technology of Roof Coal for Fully Mechanized Top Coal Caving Mining in Steep Inclined Thick Seam

急倾厚煤层综放开采中顶煤充分软弱化才能有效放出,但充分实施超前预爆弱化顶煤工艺有潜在危险,为实现安全高效综放开采,确定合理预爆工艺参数,提高顶煤破碎度,基于现场煤层赋存环境与开采条件分析,采用数值模拟和钻孔窥视等方法,剖析了顶煤预裂爆破后顶煤应力分布规律与顶煤破碎程度。结果表明:爆破松动范围为1.2m,爆破孔排距为4.5～5.0m,节理裂隙网络分布与演化符合S形分布规律,煤层透气性得到提高,工作面矿压显现不剧烈,超前支承压力分布范围向工作面内移,应力集中区域范围明显减少,实现了安全开采。

In the fully mechanized top coal caving mining in the steep inclined thick seam,the top coal could be caved only when the top coal was fully weakened.But there would be dangers in potential when the top coal advance pre-blasting weakening technique conducted.In order to have a safety and high efficient fully mechanized top coal caving mining,to rationally set up the pre-blasting technique parameters to improve the breaking of the top coal,based on the analysis on the site seam deposit environment and mining conditions,the numerical simulation and the borehole peep were applied to analyze the top coal stress distribution law and the top coal breaking degree after the pre-cracking blasting of the top coal conducted.The results showed that the blasting releasing range was 1.2 m,the raw of the blasting boreholes was 4.5～5.0 m,the joint crack network distribution and evolution could meet the S type distribution law,the permeability of the seam was improved and the strata pressure behavior of the coal mining face would not be serious.The advance support pressure distribution range would be forward to the coal mining face and the stress concentration zone range was obviously reduced to have a safety mining operation.