不同推速下综采工作面覆岩裂隙演化特征

Fracture evolution characteristics of overburden rock on fully mechanized mining face under different advancing speeds

为研究综采工作面不同推速下瓦斯运储区的演化特征,利用3DEC模拟软件进行模拟,分析了不同推速下采动覆岩裂隙分形维数演化规律。基于分形维数对卸压瓦斯运储区进行识别和划分,得到不同推速条件下的卸压瓦斯运储区分布及演化规律,并以此为依据优化了现场高位抽采钻孔的布置方式。结果表明,综采工作面覆岩裂隙分形维数整体随推进速度增大呈现出减小趋势,根据研究结果对试验工作面卸压瓦斯抽采钻孔进行优化设计。煤层回采期间,试验工作面高低推速区域抽采钻孔瓦斯体积分数最大均为30%以上,工作面、回风巷、上隅角瓦斯体积分数为0.18%~0.46%、0.2%~0.46%、0.25%~0.84%,均小于1%,表明了该布置方法更具合理性。

In order to study the evolution law of gas transportation and storage area under different advancing speeds on fully mechanized mining face,3DEC simulation software was used to simulate and analyze the evolution law of fractal dimension of mining overburden fracture under different advancing speeds.Based on the fractal dimension,the pressure relief gas transportation and storage area was identified and divided,and the distribution and evolution law of pressure relief gas transportation and storage area under different advancing speeds were obtained.The on-site high-level extraction drilling is optimized.The results show that the fractal dimension of overburden fracture on fully mechanized mining face decreases with the increase of advancing speed.According to the research results,the pressure relief gas drainage boreholes on the test face are optimized.During the coal seam mining,the maximum gas volume fraction of the extraction boreholes in the high and low advancing speed areas of the test working face is over 30%.The gas volume fractions of the working face,the return airway and the upper corner are 0.18%~0.46%,0.2%~0.46%and 0.25%~0.84%,respectively,which are below 1%,indicating that the layout method is more reasonable.