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回采速度对厚煤层综采工作面冲击显现的影响

Effect of mining speed on bump manifestation offully-mechanized mining face in deep and thick coal seam

  • 摘要: 为了确定蒙陕地区纳林河二号井31102工作面在防冲条件下的合理推采速度,通过理论分析、现场实测等方法,探讨了31102工作面回采速度与微震、煤体应力监测数据、冲击显现、上覆岩层运动规律的关系,结果表明:回采速度与微震事件总能量、频次存在正相关性;强推采速度造成覆岩能量积聚来不及释放,从而造成应力监测系统曲线出现突变,易出现动载;生产班内微震数量和能量明显高于非生产班,一般情况下生产班微震数量和能量是非生产班的3~5倍。
    应保证回采速度稳定,推进度最大变化量不应超过5刀/d;当回采速度保持在较快速度或变速时,采场上覆岩层运动呈现滞后性,当推采距离超过岩层垮落极限时,上覆岩层将发生大厚度整体回转下沉,导致采场围岩压力短时间内大幅度升高,容易诱发冲击。在推进度剧烈变化期,特别是在由高转低阶段,易出现冲击,滞后时间为1~3d。通过对31102工作面合理回采速度的研究,有效保障了工作面的安全回采。

     

    Abstract: In order to determine the reasonable mining speed of 31102 working face of Nalinhe No.2 well in Inner Mongolia and Shaanxi area based on scour-proof condition, the correlation between mining speed of 31102 working face and microseism, coal stress monitoring data, impact appearance and movement law of overlying strata is discussed through theoretical analysis and field measurement. There is a positive correlation between mining speed and the total energy and frequency of microseismic events; the overburden energy accumulated by strong mining speed can not be released in time, resulting in sudden change of stress monitoring system curve and dynamic load; the number of microseisms in production class is obviously higher than that in non-production class, and the number of microseisms in production class is usually non-production class. The number of production shifts is 3 to 5 times, and the energy statistics of production shifts is about 3 to 5 times that of non-production shifts. The site has strengthened the management of working face personnel during the production shift, strictly enforcing the restriction measures within the advanced influence range of 300 meters in front of the work; during the period of drastic change in the advance degree, especially in the period from high to low, the impact is easy to occur, the lag time is 1~3 days, and the maximum change should not exceed 5 knives; while working face mining work is maintained. When the mining distance exceeds the collapse limit of the strata, the overburden strata will rotate and subside in a large thickness, which will lead to a large increase of the surrounding rock pressure in a short time and easily induce impact. The mining speed of 31102 working face should be stable and avoided. The maximum change is not more than 5 knives without large change of propulsive degree. If the propulsive degree is zero on the same day, low-speed and stable increase of mining speed should be considered when mining again. Through the study of reasonable mining speed of No.31102 working face, the safe mining of working face is effectively guaranteed

     

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