王家岭煤矿综放工作面上覆岩层运动规律及卸压区瓦斯抽采试验研究

Research on the movement law of overlying rock strata and gas drainageexperiment in fully mechanized caving face in Wangjialing Coal Mine

为实现低瓦斯高涌出矿井综放工作面安全高效开采,以王家岭煤矿为背景,结合物理相似模拟实验、UDEC数值模拟和微震监测,系统分析了王家岭煤矿综放工作面上覆岩层运动规律,在此基础上,开展了现场卸压区瓦斯抽采试验。研究结果表明:随工作面推进,煤层顶板上覆岩层垮落高度距煤层底板距离增大,离层裂隙距顶板距离增大,空洞高度减小;采空区两侧瓦斯运移通道的裂隙多于压实区的裂隙。初次来压前,采空区垂直应力随工作面的推进而降低;初次来压后,采空区垂直应力随工作面的推进而增大。在进、回风巷顶板,煤层、采空区顶底板共发生2 572个微震事件,工作面前方50 m范围内应力集中较大,应注意超前支护防范。12301工作面周期来压步距20~26 m,采动裂缝带高度90~110 m,周期来压4~6次。现场卸压区瓦斯抽采试验中,合理层位工作面瓦斯抽采量是其他层位工作面瓦斯抽采量的1.5倍,且工作面上隅角和回风流瓦斯浓度均小于0.8%,瓦斯治理效果显著。

In order to achieve safe and efficient mining of the fully mechanized caving face in a mine with low gas content and high gas emission,with Wangjialing Coal Mine as the background,combined with physical similarity simulation experiments,UDEC numerical simulation,and micro-seismic monitoring,the movement law of the overlying strata on the fully mechanized caving face in Wangjialing Coal Mine was systematically analyzed.On the basis,on-site gas drainage experiments were conducted in the pressure relief zone.The research results indicated that as the working face advanced,the distance between the direct roof collapse height and the coal seam floor,the distance between the separation layer crack and the roof both increased,and the height of the cavity decreased;there were more cracks in the gas migration channels on both sides of the goaf than in the compacted area.Before the initial weighting,the vertical stress in the goaf decreased with the advancement of the working face;after the initial weighting,the vertical stress in the goaf increased with the advancement of the working face.A total of 2572 micro-seismic events occurred on the roof of the intake and return air roadways,the coal seam,and the roof and floor of the goaf,and the stress concentration was significant within a range of 50 m in front of the working face,which needed more attention to advanced support and prevention.The average step distance of periodic weighting in the 12301 working face was 20-26 m,the height of the mining fracture zone was 90-110 m,and the periodic weighting occurred 4-6 times.In the on-site gas drainage test at pressure relief zone,the gas drainage amount of the reasonable level working face was 1.5 times that of the other level working faces,and the gas concentration in the upper corner of the working face and the return air flow was less than 0.8%,the gas control effect was significant.