井上下多层复合采空区漏风运移相似模拟实验研究

    Experimental study on similarity simulation of air leakage and transport in multi-layer composite goaf above and below the shaft

    • 摘要: 在多层复合煤层开采过程中,下部煤层开采造成了上部采空区严重漏风,加剧了采空区残余煤体的自燃。为了防止煤炭自燃与瓦斯爆炸耦合灾害的发生,采用相似物理模拟实验进行煤矿采空区漏风运移规律研究,设计了多层复合采空区模拟系统,结合补连塔煤矿22310工作面情况,分别采用抽出式和压入式2种通风方式,控制风量为4.4×10−3、5.9×10−3、7.4×10−3 m3/min条件下进行模拟实验,得到了不同通风方式下采空区氧气体积分数的分布规律,以及多层复合采空区煤自燃危险区域空间的分布规律。结果表明:压入式通风氧气体积分数影响面积较大,走向和倾向均有较高的氧气体积分数,影响高度距底板0.5 m以下;而抽出式通风对采空区氧气体积分数的影响涉及最顶层,表现为局部影响,氧气体积分数等值线分布呈现“漏斗形”。

       

      Abstract: During the mining process of multi-layer composite coal seams, the mining of the lower coal seam causes severe air leakage in the upper goaf, which exacerbates the spontaneous combustion of residual coal in the goaf. In order to prevent the occurrence of coupled disasters of coal spontaneous combustion and gas explosion, similar physical simulation experiments were conducted to study the law of air leakage and transportation in coal mine goaf. A multi-layer composite goaf simulation system was designed. Based on the situation of 22310 working face in Bulianta Coal Mine, simulation experiments were conducted using two ventilation methods: extraction type and pressing type, with controlled air flow rates of 4.4×10−3, 5.9×10−3, 7.4×10−3 m3/min. The distribution patterns of oxygen volume fraction in the goaf under different ventilation methods and the spatial distribution law of coal spontaneous combustion risk areas in multi-layer composite goaf were obtained. The results show that the impact area of oxygen volume fraction in press-in ventilation is relatively large, with high oxygen volume fraction in both direction and inclination, and the impact height is below 0.5 m from the bottom plate; the impact of the extraction type on the oxygen volume fraction in the goaf involves the top layer, manifested as local effects, and the distribution of oxygen volume fraction contour lines presents a “funnel shape”.

       

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