煤岩单轴压缩声发射试验分形特征分析

Fractal Characteristics of Coal Uniaxial Compression Acoustic Emission Test

  • 摘要: 针对有效预测煤岩破裂引起的动力灾害的难题,运用分形理论建立了声发射参数分形维数计算模型,对冲击倾向性煤岩单轴压缩声发射试验信号分形特征进行了研究. 结果表明:随试件的加载进程,声发射能量计盒维数逐步上升,破坏前上升到最高;关联维数降低,试件破坏前下降到最低;Gauss Amp方程能较好地描述煤岩在单轴压缩荷载作用下声发射能量关联维数随荷载的变化规律;可将声发射能量关联维数的持续降低作为煤岩失稳破坏的前兆.

     

    Abstract: To effectively forecast the dynamic disaster induced by coal rupture, fractal dimension calculation model of acoustic emission (AE) parameters were established using fractal theory. Study on the fractal characteristics of AE test signals generated by uniaxial compressing burst tendency coal were conducted. The results show that the AE energy box dimension gradually raises as the specimen loading process going on, and it reaches to the highest one before destruction, but the relevant dimension cuts down to a minimum before the destruction of the specimen. Gauss Amp equation could be used to describe the variation of AE energy relevant dimension with loading for coal under uniaxial compression loads. The continuous reduction of the AE energy relevant dimension could provide a precursor of instability or failure for coal mine. Results also give useful theoretical guidance for effectively forecasting dynamic disaster caused by coal rupture.

     

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