综采工作面卸压瓦斯运储区演化推进速度效应研究

    Study on advancing speed effect of pressure relief gas transport and storage area evolution in fully mechanized mining face

    • 摘要: 为研究综采工作面不同推进速度下瓦斯运储区演化规律,基于煤矿工程概况,利用FLAC3D模拟软件进行模拟,分析了覆岩采动推进速度效应;采用多种方法对卸压瓦斯运储区进行联合判别,得到不同推进速度条件下卸压瓦斯运储区分布及演化规律;以此为依据,优化现场高位抽采钻孔。结果表明:综采工作面煤层开采后,垂直应力分布大致呈对称梯形,推速加快,垂直应力分布转变为左高右低抛线形;采空区覆岩下沉量及塑性破坏高度随推速增加而减小;卸压瓦斯运储区高度随推进速度增加而降低,卸压瓦斯运储区位置向采空区中部集中;试验工作面卸压瓦斯抽采钻孔优化后,试验工作面高低推进速度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%,布置方法更具合理性。

       

      Abstract: In order to study the evolution law of gas transportation and storage area under different advancing speed of fully-mechanized working face, based on the overview of coal mine project, we analyzed the effect of overburden mining advancing speed by using FLAC3D numerical software for simulation, and used various methods to jointly discriminate the unloading gas transportation and storage area, obtained the distribution and evolution law of unloading gas transportation and storage area under different advancing speed conditions. Based on this, we optimized the high level extraction drilling in the field. The results show that after the coal seam mining in the fully mechanized mining face, the vertical stress distribution roughly follows a symmetrical trapezoidal shape, and the advancing speed is accelerated. The vertical stress distribution changes into a left high right low throw line; the subsidence amount and plastic failure height of the overlying rock in the goaf decrease with the increase of advancing speed; the height of the unloading gas storage area decreases with the increase of the advancing speed, and the location of the unloading gas storage area is concentrated towards the middle of the goaf; after optimizing the pressure relief gas extraction drilling holes in the experimental working face, the maximum gas volume fraction of the extraction drilling holes in the high and low advancing speed areas of the experimental working face is above 30%. The gas volume fractions in the working face, return air roadway, and upper corner are 0.18%-0.46%, 0.2%-0.46%, and 0.25%-0.84%, all less than 1%, making the layout method more reasonable.

       

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