近直立特厚煤层组“顶板-岩柱”诱冲机理及防控实践

Mechanism of rock bursts caused by “Roof-Rock pillar” in mining steeply-inclined and its prevention and treatment

  • 摘要: 乌东煤矿南采区近直立特厚煤层由于地质条件复杂及采煤方法的特殊性,使水平分段开采过程中动力灾害频发。为了降低冲击地压发生风险,以乌鲁木齐矿区乌东煤矿南采区B3+6,B1+2煤层为研究对象,综合运用现场调研、理论分析等方法,研究直立特厚煤层开采条件下冲击地压机理,分析近直立煤层顶板与煤层之间的结构并建立力学模型,对煤层间岩柱的稳定性进行研究。计算结果表明,顶板变形挤压和岩柱撬转的共同作用是导致B3+6煤层发生冲击地压的主要原因,它们为冲击地压的发生提供了高静应力条件,极大地增加了B3+6煤层发生冲击地压的可能性;顶板的断裂滑移破断和岩柱的局部破坏为B3+6煤层冲击地压发生提供了动力条件,该动力扰动与煤层高静应力的叠加是导致B3+6煤层虽浅埋深较浅却发生冲击地压的主要原因。基于分析结果并结合现场实践,开展顶板和岩柱超前预裂爆破卸压及岩柱地面爆破的综合卸压措施,现场实践表明,采取的防控方法能有效降低煤岩体应力集中和围岩活动强度,减小近直立特厚煤层冲击地压发生概率,为乌东煤矿近直立特厚煤层开采的冲击防控提供借鉴。

     

    Abstract: Due to the complexity of geological conditions and the particularity of mining methods, dynamic disasters occur frequently in the process of horizontal sublevel mining in the south area of Wudong Coal Mine.In order to reduce the risk of rock burst, this paper takes B3+6 and B1+2 coal seams in the south mining area of Wudong Coal Mine in Urumqi mining area as the research object.By means of field investigation and theoretical analysis, the mechanism of rock burst under the mining condition of vertical extra-thick coal seam is studied, the structure between roof and coal seam is analyzed and the mechanical model is established, and the stability of rock pillar between coal seams is studied.The results show that: the distribution of “induced rock burst events” in the mining process of B3+6 coal seam has obvious regional distribution, and the microseismic distribution in the roof and rock pillar area of B3+6 coal seam has obvious concentration phenomenon; The fracture, slip and rupture of roof and local failure of rock pillar provide dynamic conditions for the occurrence of rock burst in B3+6 coal seam, and the superposition of dynamic disturbance and high static stress of coal seam is the main reason for the occurrence of rock burst in B3+6 coal seam although it is shallow buried and shallow.Based on the results of the analysis and combined with field practice, the development of roof and rock pillars pre-splitting blasting pressure relief and rock pillars in advance ground blasting pressure relief measures, the prevention and control of field practice shows that adopting method can effectively reduce the intensity of stress concentration and activity of surrounding rock of coal or rock, reduce the probability of rock bursts occurred in nearly erect, thick coal seam, for the east mine nearly erect, the impact of the thick coal seam mining provides a scientific basis for prevention and control.

     

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