高地应力特厚煤层“蠕变型”冲击机理研究

多起“蠕变型”冲击事故分析表明：该类冲击属于典型的隐蔽性灾害，具有自发性和时滞性的特点，发生机理的不明导致其防治极具挑战，给深部特厚煤层的安全开采造成了严重威胁。“蠕变型”冲击与不稳定蠕变密切相关，通过建立蠕变模型和三维蠕变方程，得到高地应力与特厚煤层为不稳定蠕变的形成提供了有利的孕育条件;分析了巷道围岩不稳定蠕变破坏的过程，认为不稳定蠕变通过强度“腐蚀”和应力解除2方面实现启动冲击和减小阻抗，从而在受外部静态应力叠加影响的巷道薄弱区域形成“蠕变型”冲击，并提出了判别其发生可能性的评估公式。针对这类冲击的发生机理，提出了针对性的防治措施建议：合理布置巷道、加强主动支护、优化卸压参数和长期监测。

Mechanism of creep-induced rock burst in extra-thick coal seam under high ground stress

A number of creep-induced rock bursts suggest that this type of rock burst belongs to hidden disasters featuring spontaneity and time delay. Lacking knowledge of its mechanism leads to challenging rock burst prevention and control, posing a severe threat to deep mining safety of extra-thick coal seam. Creep-induced rock burst is closely related to unstable creep. By establishing a creep model and a three-dimensional creep equation, it is found that high ground stress and extra-thick coal seam provide favorable conditions for its formation. The breaking process of roadway surrounding rock due to unstable creep is studied, and it is found that unstable creep activates rock burst and reduces resistance through strength corrosion and stress relief, thus inducing rock burst in weak areas of roadway by the impact of external static stress. An estimation formula for assessing possibility of creep-induced rock bursts is proposed. Based on the mechanism of creep-induced rock bursts, some specific measures of prevention and control are put forward: optimization of roadway layout, strengthening of active support, optimization of pressure relief parameters and long-term stress monitoring.