支撑体软硬煤分层非同步变形诱发煤与瓦斯突出机理

Mechanism of coal and gas outburst induced by asynchronous deformation of soft and hard coal layer in the support body

大多数煤与瓦斯突出地点都存在软硬煤层同时存在的情况,软硬煤层同时存在时掘进面的非同步变形是煤与瓦斯突出灾害的显著特征。研究了软煤分层不同厚度下掘进面煤体受扰动的应力场、变形场演化规律,提出了煤与瓦斯突出支撑体模型,揭示了支撑体软硬分层非同步变形诱导煤与瓦斯突出机理。结果表明,支撑体的失稳过程是软煤分层失稳到整体失稳的动态发展过程,在高垂向应力和高水平构造应力的作用下,支撑体内软煤分层受扰动最早产生破坏变形,导致支撑体变薄进而导致硬煤分层垂向方向产生大的破坏变形,进一步导致硬煤分层和周围储能体失去连接,支撑体整体将会失稳。支撑体总体的失稳是突出启动的标志。基于支撑体模型揭示了煤与瓦斯突出发生发展的机制及各突出特征之间的内在联系,为煤与瓦斯突出的防治和监测预警提供了新的理论方法和依据。

Soft coal and hard coal layers exist simultaneously in most coal and gas outburst sites.Asynchronous deformation of driving face when soft coal and hard coal exist at the same time is an important characteristic for induce coal and gas outburst,but the research is not thorough enough.In this paper,evolution law of disturbed stress field and deformation field of coal body in driving face were researched under the different thickness of tectonic coal layer,and the model of coal and gas outburst support body was proposed,the mechanism of asynchronous deformation of the soft coal and hard coal layer induced coal and gas outburst was revealed.The results show that the instability process of support body is a dynamic development process from one point instability to the whole instability.Under the action of high vertical stress and level tectonic stress,the tectonic coal layer in the support body is the earliest to produce failure deformation,and leads to the failure of the raw coal layer,the failure of the raw coal layer body and loss connection between the energy storage body in the support,then the whole support will be destabilized.As a result,the support body becomes thinner,resulting in large damage deformation in the vertical direction of the hard coal stratification,and further leads to the loss of connection between the hard coal stratification and the surrounding energy storage body.The whole instability of the support body and the overall instability of the support body is a sign of the prominent start-up.The occurrence and development mechanism of coal and gas outburst and the internal relationship between the outburst omen were revealed based on the model of coal and gas outburst support body.A new theoretical method and idea basis was provided for the prevention and control of coal and gas outburst,monitoring and warning.