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利用煤岩低频电磁辐射实验系统,采集型煤试样单轴压缩加载过程中的低频电磁辐射信号。基于希尔伯特-黄变换(HHT)的降噪原理去除高频噪声,得到有效低频电磁信号成分,并将有效低频电磁辐射信号幅值和压力进行关联分析,得出低频电磁辐射信号的能量变化规律和频率分布范围。结果表明:在型煤压密阶段,低频电磁信号幅值和能量较大;在煤体线弹性阶段,会阵发性的产生低频电磁信号,但是其能量较弱;在型煤破裂阶段,低频电磁信号幅值和能量急剧增强。低频电磁辐射信号的频段范围为0~18 Hz,型煤破裂过程电磁信号具有较明显的低频特性,且幅值和能量的变化能很好地反映型煤的破裂状况。
Low-frequency electromagnetic radiation experiment system of coal and rock was used to collect low-frequency electromagnetic radiation signals during uniaxial compression loading of briquette samples. Based on the Hilbert-Huang transform (HHT) noise reduction principle, the high frequency noise is removed to obtain the effective low frequency electromagnetic signal components. The correlation between the effective low frequency electromagnetic radiation signal amplitude and pressure is analyzed to obtain the energy of the low frequency electromagnetic radiation signal Variation and frequency distribution. The results show that the amplitude and energy of low-frequency electromagnetic signal are large during briquette compaction stage. Low-frequency electromagnetic signals are generated intermittently in the elastic phase of coal body, but their energies are weak. In briquette rupture stage, Electromagnetic signal amplitude and energy increased dramatically. The frequency range of low frequency electromagnetic radiation signal is 0 ~ 18 Hz. The electromagnetic signal in briquette rupture has obvious low frequency characteristics. And the change of amplitude and energy can well reflect the rupture of briquette.