煤与瓦斯突出的级联破裂发展机制

Cascade rupture development mechanism of coal and gas outburst

  • 摘要: 煤与瓦斯突出是地下煤矿开采过程中最具破坏性的动力灾害之一,表现为煤层潜能的突然失稳释放与煤岩系统的快速破裂。现有研究虽已广泛探讨突出机制,但对突出灾害从局部失稳向系统性演化的内在机理认识仍显不足。基于煤岩破裂与能量转化的耦合演化规律,提出基于能量反馈驱动的“煤体破裂—能量释放—级联触发—能量放大”正反馈机制,揭示了突出级联破裂的动力学特征。基于真三轴突出模拟系统开展物理相似模拟试验,运用高灵敏度次声探测技术捕捉突出演化的动态特征。通过构建幅值积分序列解析方法,发现突出过程呈现明显的双相演化特征,即初始高幅值脉冲期(振幅为180~350 Pa,持续期小于0.2 s)和后续低幅值持续期(振幅小于100 Pa,持续期为0.2~1.8 s)。次声解析序列呈现的阶梯式增长为煤体级联破裂提供了直接观测证据。在此基础上,构建级联破裂演化定量模型,提出重叠触发、邻近触发及累积面积阈值等关键级联准则。通过工程实例验证,该模型可有效预测突出传播路径和发展规模,揭示了突出演化的3个关键阶段,即初始积累期(级联半径增长率小于0.2 m/次)、快速级联期(级联半径增长率为1.0~1.6 m/次,较初始期提高5~8倍)和衰减终止期(级联半径增长率趋于0)。结果表明:破裂路径在多尺度观测下呈现显著的分形特征,证实了局部与整体破裂模式的自相似性。突出发展表现出指数型增长规律,其最终规模主要由级联阶段的持续时间决定,能量赋存条件在这一过程中起着决定性作用。

     

    Abstract: Coal and gas outbursts constitute one of the most destructive dynamic disasters in underground coal mining operations, manifesting as sudden destabilization of coal seam potential energy and rapid fracturing within the coal-rock system. Although extensive research has investigated outburst mechanisms, the understanding of how localized instability evolves into systemic failure remains inadequate. An energy-driven cascading mechanism is introduced which couples coal fracturing, energy dissipation, sequential triggering, and energy amplification processes to characterize the dynamic evolution of outburst phenomena. Physical similarity experiments were conducted using a true triaxial outburst simulation system incorporating high-sensitivity infrasound detection technology to capture outburst evolution dynamics. The newly developed amplitude integral sequence analysis method revealed distinct biphasic evolution characteristics: An initial high-amplitude pulse phase (180~350 Pa, duration < 0.2 s) followed by a sustained low-amplitude phase ( < 100 Pa, duration 0.2~1.8 s). The step-wise growth pattern observed in the infrasound analysis sequence provided direct evidence of coal body cascade fracturing. A quantitative model for cascade fracture evolution was developed incorporating overlap triggering, proximity triggering, and cumulative area thresholds as key cascade criteria. Engineering case validation demonstrated the model’s capability in predicting outburst propagation paths and development scales, revealing three critical evolution stages: Initial accumulation (growth rate < 0.2 m/event), rapid cascade (growth rate 1.0~1.6 m/event, 5~8 times higher than initial phase), and decay termination (growth rate approaching 0). The fracture paths exhibited significant fractal characteristics under multi-scale observation, demonstrating self-similarity between local and global fracture patterns. Outburst development followed exponential growth laws, with the final scale determined by cascade phase duration, while energy storage conditions served as the dominant controlling factor throughout the process.

     

/

返回文章
返回