国内外学者对煤与瓦斯突出过程及机制进行了大量的研究,但使用的均是型煤试验,很少涉及地质构造对突出的影响,而且数据监测均未深入到煤体内部。基于相似模拟试验思想和地质力学模型试验新思路,在实验室搭建了综合考虑地应力、瓦斯压力及煤体结构的大型石门揭煤的煤与瓦斯突出试验平台。该试验平台包括试验箱体和反力架、液压加载系统、密封系统、试验监测系统;设计了线充气和面充气系统,用来模拟煤层的瓦斯赋存差异。同时,利用该试验平台进行了石门揭构造软煤的相似模拟试验,研究了石门揭构造软煤过程中煤岩应力和位移的变化规律,以及突出过程中煤层内瓦斯压力和声发射的变化规律。结果表明,在巷道开挖过程中,掘进工作面前方存在明显的应力集中,且越靠近构造软煤应力集中现象越明显;突出发生的瞬间,在突出点附近的位移产生了突变;在突出发生前,声发射信号有一次降低;掘进工作面前方煤岩体应力释放,煤体裂隙增大,为瓦斯的快速放散提供了条件。
Domestic and foreign scholars have made a lot of research on the process and mechanism of coal and gas outburst. Briquette was always used to test, but these tests rarely considered the influence of geological structures on outburst, and the data monitoring did not include the coal inside. On the basis of thoughts of the similar stimulation experiment and new ideas of the model test of geological mechanics, the experimental platform of coal and gas outburst for large coal uncovering by cross-cut in the laboratory was built. The geostress, gas pressure and structure of coal were considered. The test platform included test case, counter force frame, hydraulic loading system, sealing system and test monitoring system. Meanwhile, the line charging and plane charging system were designed to simulate the difference of gas in the coal seam. At the same time, the similar simulation test of tectonic soft coal uncovering by cross-cut was conducted in the laboratory. The variation laws of stress and displacement in the process of tectonic soft coal uncovering by cross-cut were studied. The gas pressure and acoustic emission in the process of outburst were also determined. The results show that the obvious stress concentration exists in surrounding rock ahead working face in the process of tunnel excavation. The closer to the tectonic soft coal is, the more obvious the stress concentration is. The displacement mutates near outburst point at the moment of outburst. Acoustic emission signal reduces once before outburst. The stress release of coal and rock in front of heading face provides the conditions for the crack increase and the rapid diffusion of gas.