急倾斜上保护层开采瓦斯越流固-气耦合模型及保护范围

Model of gas leak flow coupled solid and gas for exploiting of steep-inclined upper-protective layer and its protection scope

开采保护层是防治煤与瓦斯突出最有效的措施之一,其关键是保护范围的合理确定。针对急倾斜多煤层上保护层开采有效保护范围的划定问题,基于煤层瓦斯越流理论,根据煤岩层变形与瓦斯渗流的固-气耦合作用,建立了瓦斯渗流场方程和煤岩体变形场方程,得到了急倾斜上保护层开采瓦斯越流固-气耦合数学模型。以南桐矿区某矿上保护层开采为实例,通过多物理场耦合系统,建立了该矿上保护层开采瓦斯越流几何模型并进行数值计算,获得了上保护层工作面开采后被保护层瓦斯压力的分布规律,确定了上保护层开采的卸压保护范围。数值计算与现场考察试验结果具有一致性,由此验证了数值计算的合理性。研究结果可以对现场保护范围的划定及卸压瓦斯抽放等提供理论指导,具有实际工程意义。

Exploiting protective layer is one of the most effective measures for control of coal and gas outburst; and the key problem is to locate the protection scope exactly. Aimed at the problem of locating the protection scope for the exploiting of steeply clined upper-protective layer, based on the theory of gas leak flow and the coupling effect between deformation of coal ＆ rock and gas seepage, the methane gas seepage field equation and coal ＆ rock deformation field equation are established; and then the mathematical models of gas leak flow coupled solid and gas of steeply clined upper-protective layer are also established. Taking a coal mine in Nantong mining area for engineering example, by using multi-physical field coupling system for numerical calculation of the model, the law of gas pressure distribution in protected layer is gained after protective layer was mined. Furthermore, the pressure-relief scope of protective layer mining is also obtained. It is shown that the protection scopes of numerical simulation are basically closed to the results of practical test. Therefore, this study results can provide theoretical guidance for locating protection scope and are of great significance for practical matters.