岩浆盖层下伏煤层物性特征与瓦斯突出灾变机制

Physical properties and gas outburst disaster induced-mechanism in coal seams underneath the magmatic sill cover

为研究岩浆盖层下煤层瓦斯赋存规律和动力灾害的特征,采用理论分析和工程案例验证的方法,分析了岩浆盖层条件下煤层变质程度、孔隙结构、瓦斯吸附解吸性能和瓦斯赋存特征,揭示了岩浆盖层对下伏煤层瓦斯动力灾害的控制作用机制。研究结果表明:煤层变质程度、孔隙结构发育程度和瓦斯吸附解吸性能与岩浆盖层的厚度和空间距离关系密切,一般随着岩浆盖层厚度的增加而单调增加,随着与岩浆盖层距离的增加而单调递减。岩床以盖层的形式圈闭煤层瓦斯,使得煤层瓦斯压力和瓦斯含量增加,在采掘作用下容易导致煤与瓦斯突出灾害的发生,并形成地面喷孔等复杂瓦斯动力灾害事故。

In order to study the gas occurrence law and dynamic disaster features of the coal seam underneath the magmatic sill cover,the theoretical analysis and engineering case verification method were applied to analyze the seam metamorphic degree,pore structure,gas adsorption and desorption performances and gas occurrence features under the condition of the magmatic sill cover. The control mechanism of gas dynamic disasters on the underlying coal seams by sill cover was revealed. The study results showed that the coal seam metamorphic degree,pore structure development degree and gas adsorption and desorption would have a closed relationship with the thickness and space distance of the magmatic sill cover. Generally they would be increased with the thickness of the sill increased and they would be decreased with the increasing of the sill space distance with coal seams. The sill would apply the cap rock to soundly seal the seam gas,thus,the seam gas pressure and gas content would be increased. A coal and gas outburst disaster would be easily occurred under the mining or excavating and a well blowout and other complicated gas dynamic disaster accidents would be occurred.