坚硬砂岩剪滑失稳引燃采空区瓦斯机制研究

Mechanism study on goaf gas ignited by shear sliding and instability of hard sandstone

为研究坚硬砂岩顶板断裂失稳过程中因破断岩块之间的摩擦效应而引燃采空区瓦斯的机理,以汝箕沟煤矿32213(1)综采工作面为工程背景,采用理论分析与室内试验的方法,对顶板发生剪切滑动失稳过程中的摩擦闪温以及瓦斯反应过程进行了研究。结果表明:工作面覆岩发生剪切滑移失稳时,一定条件下剪滑失稳带内会形成高温摩擦面并引燃其内以及周边的瓦斯。坚硬砂岩间摩擦速度v<6.0 m/s时,岩石内石英含量的高低对最高摩擦闪温影响不大;摩擦速度v>6.0 m/s时,最高摩擦闪温与砂岩内石英含量呈正相关。摩擦速度越大,摩擦面热量密度越高,点火能量越大,瓦斯越易被引燃。

In order to study the goaf gas ignition mechanism caused by the frictional effect between the broken rock blocks during the fracture and instability process of the hard sandstone roof,based on No. 32213（ 1）fully-mechanized coal mining face in Rujigou Mine as an engineering background,a theoretical analysis and in-door test method was applied to study the frictional flash temperature occurred in the shear sliding and instability process of the roof strata and the gas reaction process. The study showed that when the shear sliding and instability occurred in the overburden strata above the coal mining face,under the certain conditions,a high temperature friction surface would be formed within the shear sliding and instability zone and could ignite the gas within the zone and the surrounding area. When the friction speed between the hard sandstones was v〈6.0 m/s,the quartz content within the rock would not have a high influence to the highest frictional flash temperature. When the friction speed was v〉6.0 m/s,the highest friction flash temperature would have a positive correlation to the quartz content of the sandstone. When the friction speed was higher,the heat density on the friction surface would be higher,the ignition energy would be higher and the gas would be more easily ignited.