巨厚火成岩下采动应力演化规律与致灾机理

摘要

To find out the reason why coal and gas outburst（CGO） occurred in the Ⅱ102 mining area,the geological and mining conditions,gas geology and outburst characteristics were analyzed.A numerical model with universal distinct element code was built to study the evolvement law of mining-induced stress（MIS） under 140-m-thick extremely thick igneous rock（ETIR） with the purpose of explaining the occurrence of the disaster in the viewpoint of MIS coverage.The results indicate that the ETIR which is 170 m above the coal seam doesn＇t break in the span of 370 m,and the coverage of MIS increases to 310 m which is three times of that without ETIR.The factor of MIS increases to 1.7 in the roadway 180 m away from the goaf,which proves that MIS is the main power for the CGO when excavating in the roadway of Ⅱ1026 working face under ETIR.%为确定海孜煤矿Ⅱ102采区内煤与瓦斯突出灾害原因,综合分析了采区地质开采条件、突出点瓦斯地质特征及突出特征,采用UDEC软件模拟研究了均厚140 m火成岩下开采时的采动应力演化规律,从采动应力影响范围的角度解释了此次动力灾害的原因。研究结果表明：距煤层170 m的巨厚火成岩在累计采宽370 m时仍然不发生破断,导致采动应力影响范围增大至310 m,为不存在火成岩时的3倍;受火成岩影响,采空区边界外180 m处应力集中系数高达1.7,在此处进行Ⅱ1026工作面机巷掘进时,采动应力成为煤与瓦斯突出的一个主要动力源。