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    上保护层开采降压-减震-吸能效应与冲击地压防治技术研究

    Research on pressure reduction-shock absorption-energy absorption effectof upper protective seam mining and rockburst prevention and control technology

    • 摘要: 以雅店煤矿上保护层开采为工程背景,对上保护层开采条件下冲击地压防治原理进行研究。采用理论分析、数值模拟及现场实测等方法分析了上保护层开采后被保护层的顶板结构特征及围岩应力变化,揭示了上保护层开采冲击地压的防治原理。研究结果表明,保护层开采后顶底板岩层发生了变形、断裂、离层及膨胀变形等破坏,降低了被保护层工作面的围岩应力;改变了被保护层的顶板结构特征,降低了覆岩破断产生大能量震动的可能性,并形成了对矿震能量具有耗散作用的卸压结构体,对被保护层工作面起到了降压-减震-吸能的作用,降低了被保护层的冲击危险性。通过数值模拟对比,相对于非保护层开采而言,保护层工作面回采前巷道围岩应力降低了2.0~4.0倍,回采期间巷道围岩应力降低了2.3~3.5倍,有效降低了被保护层工作面采掘期间的围岩应力。通过现场试验验证,保护层开采后,最大水平主应力释放率为28.2%,垂直应力释放率为50.4%,最小水平主应力释放率为23.5%;相对于非保护层开采,保护层开采后被保护层的日微震总能量最大值、日微震总能量平均值、日微震总频次最大值和日微震总频次平均值分别降低了95.7%、92.2%、72.7%及65.4%,表明保护层开采能够有效降低被保护层巷道的围岩应力,降低微震能量及频次,防冲效果显著。

       

      Abstract: Based on the engineering background of upper protective seam mining in Yadian Coal Mine, the rockburst prevention and control mechanism under upper protective seam mining conditions was investigated. Theoretical analysis, numerical simulation, and field measurements were adopted to analyze the roof structure characteristics and surrounding rock stress evolution of the protected seam after upper protective seam mining, revealing the rockburst prevention principles of upper protective seam mining. The results indicate that the deformation, fracture, bedding separation, and dilatation of roof and floor strata induced by protective seam mining reduce the surrounding rock stress in the protected seam working face. Additionally, the roof structure of the protected seam is modified, decreasing the likelihood of high-energy vibrations caused by overburden fracturing and forming a pressure-relief structure that dissipates seismic energy. This mechanism achieves pressure reduction-shock absorption-energy absorption for the protected seam working face, effectively lowering its rockburst risk. Numerical simulations demonstrate that, compared to non-protective seam mining, the roadway surrounding rock stress in the protected seam decreased by 2.0-4.0 times before mining and by 2.3-3.5 times during mining, significantly alleviating stress concentration. Field tests verified that after protective seam mining, the maximum horizontal principal stress, vertical stress, and minimum horizontal principal stress were released by 28.2%, 50.4%, and 23.5%, respectively. Compared to non-protective seam mining, the maximum daily microseismic energy, average daily microseismic energy, maximum daily microseismic frequency, and average daily microseismic frequency in the protected seam decreased by 95.7%, 92.2%, 72.7%, and 65.4%, respectively. These findings confirm that protective seam mining effectively reduces surrounding rock stress, suppresses microseismic energy and frequency, and achieves significant rockburst prevention effects.

       

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