近距离煤层坚硬岩层破断影响因素分析

    Breaking Factors Analysis of Hard Rock in Close Distance Coal Seams

    • 摘要: 近距离煤层覆岩破断受到多次采动影响,与采高、层间距及岩体力学性质密切相关。在分析采高、层间距及岩体强度对覆岩破断影响的基础上,以晋华宫煤矿的近距离煤层赋存条件为背景,采用正交试验设计的方法,运用UDEC数值模拟软件,获得了近距离煤层覆岩破断演化规律及其采高、层间距及岩体强度对覆岩破断高度的影响。结果表明:开采7煤时,覆岩破断高度最大达到48 m,形态呈现拱形;随着8煤的开采,覆层裂隙进一步向上发育扩展,达到80 m,煤柱处裂隙向两侧横向扩展。同时利用极差分析法分析以上3个影响因素对覆岩破断高度的敏感程度,其由强到弱的顺序为:采高>层间岩体强度>层间距。

       

      Abstract: Overburden rock fracture of close distance coal seams is not only influenced by multiple mining, which is closely related with mining height, interlayer spacing and rock mechanics properties. Based on the analysis of effect of mining height, interlayer spacing and rock mass strength on overburden rock fracture, taking the coal occurrence condition of close distance coal seam group in Jinhuagong Coal Mine as the background, using the method of orthogonal experimental design and UDEC, the overburden rock fracture evolution law of close distance coal seam group and the effect of mining height, interlayer spacing and rock mass strength on overburden rock fracture height are obtained. The results show that the biggest mining fracture height is up to 48 m with arched when coal 7 is mined; as coal 8 is mined, overlying rock crack extends and develops upward and is up to 80 m; the cracks on both sides of the pillar extends to transverse at the same time. The range analysis is applied to analyze the three factors to the sensitive degree of the development of highly fractured zone. The principal factors in sequence would be the mining height, the rock mass strength between the seams and the distance between seams.

       

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