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为提高电磁辐射监测方法的准确性,采用单轴压缩实验方法,分析煤体受载破坏过程电磁辐射时域、频域及波形变化特征,并对其变化机理进行探究.研究结果表明:煤体单轴压缩过程中电磁辐射脉冲数、能量值、波形主频及幅值均与所受应力近似呈正相关关系,煤体受载破裂过程中,电磁辐射的主频与幅值不断增大,并在煤体失稳时达到最大,电磁辐射脉冲数、能量值、主频或幅值的急剧增加可以作为煤体失稳的前兆特征;煤体电磁辐射的频带为1 Hz~500 k Hz,煤体失稳破裂时主频达到最大值202 k Hz,随着加载的进行,频带内各频率幅值分布逐渐集中于主频附近;煤体破裂过程电磁辐射特征变化与外部载荷输入的机械能有关.
In order to improve the accuracy of electromagnetic radiation monitoring method, the uniaxial compression experiment method was used to analyze the characteristics of time-frequency, frequency-domain and waveform changes of electromagnetic radiation during the process of coal mass loading failure, and to explore its changing mechanism.The results show that: During uniaxial compression, the number of pulses, the energy value, the dominant frequency and the amplitude of the electromagnetic radiation have a positive correlation with the stress. The frequency and amplitude of the electromagnetic radiation increase continuously during the process of loading and rupturing, and When the coal body becomes unstable, the maximum number of pulses, energy value, frequency or amplitude of electromagnetic radiation can be taken as a precursor to the instability of coal mass. The band of electromagnetic radiation of coal is 1 Hz ~ 500 k Hz, coal The main frequency of instability rupture reached 202 k Hz. With the loading, the amplitude distribution of each frequency in the frequency band gradually concentrated near the main frequency. The change of electromagnetic radiation characteristics during the rupture of coal mass was related to the mechanical energy input by external load.