采动裂隙煤岩体应力与瓦斯流动的耦合机理

Coupling mechanism of rock mass stress and gas flow in coal mining fissures

采用渗流力学理论分析方法,对煤层采动裂隙、采动应力与瓦斯流动的耦合作用进行了研究。对采动过程中煤层及其覆岩的裂隙,采动应力和瓦斯压力进行了现场实测,并对三者之间的相互影响作用进行对比分析。研究结果表明:采动影响下裂隙煤岩体的渗透率与裂隙宽度、裂隙贯通情况、裂隙不平整度、裂隙间距裂隙法向刚度和采动应力等有关,裂隙煤岩体瓦斯流动与其裂隙发育情况有着极其密切的关系,瓦斯渗透率与裂隙宽度呈正相关,与裂隙间距呈负相关。基于工作面煤层采动裂隙、采动应力与瓦斯流动耦合作用,依据裂隙煤岩体瓦斯渗流定律,构建了裂隙煤岩体采动应力-瓦斯渗透的力学模型,揭示了裂隙煤岩体的采动裂隙、采动应力与瓦斯流动的耦合机理。

Based on the analysis method from seepage mechanics,the coupling effect of coal-seam mining fissure,stress and methane flow was studied. The fissure of coal-seam and overlying rock,as well as mining stress and gas pressure were measured on site. Also,the interaction of these three parameters was comparatively analyzed. The results show that the permeability of cracked coal mass under mining is related to fissure width,connect situation,unevenness,spacing,normal stiffness and mining stress; methane flow in cracked coal mass is intimate to fissure development; and methane permeability is positively correlated to fissure width and negative to fissure spacing. Based on the coupling effect of mining fissure,stress and methane flow in front of working face,a mechanic model of cracked coal mass' mining stress and methane seepage was built. The model can provide the coupling effect of mining fissure,mining stress and methane flow in fractured coal-rock mass.