娄全, 何学秋, 宋大钊, 李振雷, 王安虎, 孙冉. 基于全波形的煤样单轴压缩破坏声电时频特征[J]. 工程科学学报, 2019, 41(7): 874-881. DOI: 10.13374/j.issn2095-9389.2019.07.005
引用本文: 娄全, 何学秋, 宋大钊, 李振雷, 王安虎, 孙冉. 基于全波形的煤样单轴压缩破坏声电时频特征[J]. 工程科学学报, 2019, 41(7): 874-881. DOI: 10.13374/j.issn2095-9389.2019.07.005
LOU Quan, HE Xue-qiu, SONG Da-zhao, LI Zhen-lei, WANG An-hu, SUN Ran. Time-frequency characteristics of acoustic-electric signals induced by coal fracture under uniaxial compression based on full-waveform[J]. Chinese Journal of Engineering, 2019, 41(7): 874-881. DOI: 10.13374/j.issn2095-9389.2019.07.005
Citation: LOU Quan, HE Xue-qiu, SONG Da-zhao, LI Zhen-lei, WANG An-hu, SUN Ran. Time-frequency characteristics of acoustic-electric signals induced by coal fracture under uniaxial compression based on full-waveform[J]. Chinese Journal of Engineering, 2019, 41(7): 874-881. DOI: 10.13374/j.issn2095-9389.2019.07.005

基于全波形的煤样单轴压缩破坏声电时频特征

Time-frequency characteristics of acoustic-electric signals induced by coal fracture under uniaxial compression based on full-waveform

  • 摘要: 建立了煤岩受载破坏声电全波形同步采集系统, 对煤样单轴压缩破坏过程中的声电信号进行了全波形采集, 研究了声电信号能量与载荷降之间的相关关系, 并分析了声电信号的频谱特征. 结果表明: (1)煤体受载破坏过程中产生显著的声电信号; 电磁辐射信号是阵发性的, 仅伴随载荷降和较高强度声发射信号出现; (2)相对于声发射, 电磁辐射与载荷降有更好的相关性; 与煤体受载破坏的能量释放累积量相关联的声电信号能量和载荷降累计值三者之间均呈高度正相关; (3)电磁辐射优势频带窄于声发射, 前者主要集中在1~25 kHz, 后者主要集中在1~280 kHz; 受同一裂纹萌生和扩展的影响, 两者在频谱和主频分布上都有近似的低频成分.

     

    Abstract: The geological conditions of coal mines in China are complicated. In recent years, with the continuous increase of intensity and depth of coal mining, coal and rock dynamic disasters are becoming more and more serious, and an important factor threatening the safety of coal mining. The accurate monitoring and early warning of coal and rock dynamic disasters are of great significance for disaster prevention. A large number of experiments conducted on both laboratory and field scales have demonstrated that the energy accumulated in rock material under loading can be released in the forms of acoustic emission (AE), electromagnetic radiation (EMR), etc. Therefore, AE and EMR, as the real-time, dynamic and continuous geophysical monitoring methods, have been widely used and played important roles in the field of monitoring and early-warning of coal and rock dynamic disasters in mines. To further study the time-frequency characteristics of AE and EMR and the relationships between these characteristics and load, and to provide the experimental basis for the monitoring and early warning of coal and rock dynamic disasters, an acoustic-electric full-waveform synchronous acquisition system of coal and rock fracture under loading was constructed in this paper. Using this system, the full-waveforms of AE and EMR of failure processes of coal samples under uniaxial compression were collected. The correlations among AE energy, EMR energy and load drop were studied, and the spectral characteristics of AE and EMR were analyzed. The results show that, (1) obvious acoustic-electric signals are emitted during the process of coal failure under loading. EMR is the paroxysmal signal, only accompanied by load drop and higher intensity AE. (2) Compared with AE, EMR has a higher correlation with load drop. There are high positive correlations among the cumulative values, relating to the cumulative released energy of coal fracture under loading, of AE energy, EMR energy and load drop. (3) The superiority frequency band of EMR is narrower than that of AE, with the former mainly concentrated in 1-25 kHz and the latter mainly in 1-280 kHz. Influenced by the initiation and propagation of the same crack, AE and EMR have similar low frequency components in the spectrum and main-frequency distribution.

     

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