【摘要】 通过单轴加载煤岩破坏全过程声发射试验,运用多重分形消除趋势波动分析法(MF-DFA),分析了声发射强度序列的长程相关性及多重分形特征,在此基础上研究了不同应力水平下声发射强度序列长程相关指数H的变化趋势。结果表明:声发射强度时间序列内部波动不是完全随机的现象,而是由内在自相似机制决定的长程相关过程,其波动是一个有序的多重分形分布;H的变化与煤岩体的变形破坏过程能够较好的对应,声发射强度H值的"最大—减小"模式可以作为煤岩体失稳事件的前兆,这为利用声发射进行煤岩体稳定性现场监测预报提供了新的理论依据及方法。更多还原

【Abstract】 Acoustic emission tests of coal-rock specimens under uniaxial compression were carried out;then the long-range correlation and multifractal characteristics of acoustic emission strength sequence were analyzed by multifractal detrended fluctuation analysis method(MF-DFA).On this basis,the trend of long-range correlation exponent H of AE strength sequence with different stress levels was studied.The results show that the inner fluctuation of AE sequence is a well-regulated multifractals,which is rather a long-range correlated process determined by intrinsic self-similar properties and not complete random on time scale.The trend of AE parameter H corresponds well with the process of coal-rock fracture development;the ’maximum-decrescence’ model of which can be used as a precursory factor of coal-rock failure.The results provide a theoretical basis and method for monitoring and forecasting coal-rock stable condition based on acoustic emission in site.更多还原