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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。
The analysis of many “creep type” impact accidents shows that this kind of impact belongs to a typical hidden disaster, which has the characteristics of spontaneous and time-lag. The unknown mechanism of its occurrence makes it extremely challenging to control and give deep and thick coal seam The safe mining caused a serious threat. “Creep type ” impact is closely related to unstable creep. By establishing creep model and three-dimensional creep equation, it is found that high ground stress and extra-thick coal seam provide favorable conditions for the formation of unstable creep. The process of unstable creep destruction of the surrounding rock of the roadway considers unstable creep to initiate impact and reduce the impedance through the strength corrosion and stress relieving so as to form the weak zone in the roadway affected by the superposition of the external static stress. Creep type "impact, and put forward the evaluation formula to determine the possibility of its occurrence. Aiming at the mechanism of this kind of impact, some countermeasures for prevention and control are put forward, such as reasonable layout of roadway, active support, optimization of pressure relief parameters and long-term monitoring.