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煤柱型冲击地压类型、发生机理与防治对策研究

Research on the type and occurrence mechanism and prevention of coal pillar rockbursts

  • 摘要: 煤柱型冲击地压是近年我国煤炭开采过程中发生的典型冲击地压类型,如何总结煤柱型冲击地压的工程尺度破坏特征、揭示冲击失稳发生机理以及制定科学精准的防冲对策,成为煤矿科技工作人员面临的难题。采用现场调查、理论分析、现场监测等方法对我国煤矿3类典型煤柱型冲击地压事故的工程特征和冲击显现特征进行分析,将当前我国煤柱型冲击地压分为应力叠加型冲击地压、切割蠕变型冲击地压和整体失稳型冲击地压3类。分别建立了3类煤柱型冲击地压发生机理的力学模型,揭示了3类煤柱型冲击地压的发生机理,提出了3类煤柱型冲击危险的评估方法和防治对策。其中应力叠加型冲击地压的发生机理为施加在煤柱上的叠加应力超过煤体发生冲击失稳的临界值,煤柱在细微扰动或无条件扰动下发生冲击失稳;整体失稳型冲击地压的发生机理为煤柱弹性承载区煤体承担的载荷超过了其极限承载能力,弹性承载区煤体引发冲击并导致煤柱浅部煤体发生大面积破坏;切割蠕变型冲击地压的发生机理为煤柱在长期高应力状态下支撑能力缓慢降低导致载荷向弹性承载区转移,当弹性承载区煤体载荷超过发生冲击失稳临界值时,将发生大范围煤体冲击失稳。由于我国矿井开采条件复杂,实际生产期间还会遇到很多具有隐蔽性的煤柱型冲击类型,因此在现场冲击地压防治工作中,需要加强对这些隐蔽性煤柱型冲击风险的判识和防治工作。

     

    Abstract: Coal pillar rockburst is a typical type of rockburst occurring in coal mining in China in recent years. How to summarize the engineering scale damage characteristics of coal pillar rockburst, reveal the mechanism of rockburst instability and formulate scientific and accurate anti-burst measures has become a difficult problem for coal mine science and technology personnel. The engineering characteristics and burst manifestation characteristics of three types of typical coal pillar burst accidents in China's coal mines are analyzed using field investigation, theoretical analysis and field monitoring, and the current coal pillar type burst in China is classified into three types: ground pressure superimposed type, cut creep type and overall destabilization type. The mechanical models of the occurrence mechanism of the three types of coal pillar burst are established respectively, the evaluation methods and prevention countermeasures of the three types of coal pillar burst hazards are proposed, and the occurrence mechanism of the three types of coal pillar burst is revealed. The mechanism of superimposed ground pressure type is that the superimposed stress applied to the coal pillar exceeds the critical value of the coal mass for burst instability, and the coal pillar is destabilized by minor or unconditional perturbation; the mechanism of overall instability burst is that the load borne by the coal body in the elastic bearing zone of the coal pillar exceeds its ultimate bearing capacity, and the coal body in the elastic bearing zone triggers the burst and causes the coal body in the shallow part of the coal pillar to fail extensively. The mechanism of cut creep rock burst is that the load transfers to the elastic bearing area due to the slow decrease of supporting capacity of coal pillar under long-term high stress, and when the load of the coal body in the elastic bearing area exceeds the critical value of burst, a large-scale coal body impact destabilization will occur. Due to the complex mining conditions in China, there are many hidden types of coal pillar bursts encountered during field production, therefore, in the prevention and control of bursts, it is necessary to strengthen the identification and prevention of these hidden coal pillar burst risks.

     

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