煤与瓦斯共采覆岩应力及渗透耦合特性实验研究

Experimental study on coupling of stress and permeability in overlying strata at longwall panel for efficient coal and methane co-extraction

为探索煤层开采过程中上覆岩体应力与其渗透性相互耦合特性,开展了煤与瓦斯共采相似模拟实验研究。采用柔性加载方式以及平面应变模型,模拟随工作面推进上覆围岩应力及渗透性的变化规律。结果表明:受采动影响,上覆围岩应力与渗透率变化呈现一定的分区特征。具体表现为,随采面推进,煤柱后方应力集中区域向远离采空区转移,应力集中系数降低,渗透率与压应力分布呈正相关关系;远离采空区向高位延伸方向,应力降低幅度有递减趋势,有明显应力拱向高位及广度扩展特征,当达到充分采动时,此特征趋于减弱;提出覆岩渗透规律具有"拱上梁"的假设特征,即在拱顶位置,渗透率有不升反降趋势。

In order to understand the coupling characteristics of stress and permeability in overlying strata, an analog experimental simulation was conducted to study the co-extraction of coal and methane in long＇wall coal mine. The ex- periment used a plane strain model and flexible loading to simulate the variation characteristics of stress in overly strata and permeability in advanced coal face. The results show that a partition tendency exists：with the coal face advancing, the concentration area of stress inside coal pillar removes away from the gob, the coefficient of concentration desceas- es, and the permeability and stress demonstrates a direct proportional relationship. The range of stress decrease experi- ences a tendency of slow in the direction from goal to high position. In addition, the stress arch expands vertically and horizontally at the same time, while it will recede at a fully extraction phase.