有效围压对煤体破裂声发射信号影响研究

Study on influence of effective confining pressure on acoustic emission signal in coal fracture

含瓦斯煤体受载破裂声发射信号监测对煤与瓦斯突出等动力灾害预测研究具有重要意义。为了提高井下动力灾害预测准确性和及时性,在不同围压、不同孔隙压力条件,进行了煤体受载破裂声发射信号监测试验。结果表明:围压作用使声发射信号滞后且峰值增大,瓦斯压力使声发射信号首次高振铃计数提前;用围压和孔隙压力差值表示有效围压,通过引用有效围压,可以综合讨论围压和孔隙压力对声发射信号的影响,并且通过最小二乘法拟合发现有效围压与煤体破裂声发射信号峰值具有线性关系。利用有效围压与声发射信号的线性关系可以推导信号峰值,将信号峰值的30%设置为信号阀值,为煤与瓦斯突出等动力灾害预测提供一种新的方法。

Study on monitoring AE signals in loaded fracture of coal containing gas has important significance to forecast dynamic disaster, such as coal and gas outburst, etc.In order to improve the accuracy and timeliness of dynamic disaster forecast, in this paper, the monitoring tests on AE signals in coal loaded fracture under different confining pressure and pore pressure were conducted.The results showed that：the AE signal delays and the peak value increases under the effect of confining pressure, and the first high ringing counts of AE signal occurs earlier under the effect of pore pressure.The influence of confining pressure and pore pressure on AE signals was compre-hensively discussed by quoting effective confining pressure that indicated by the difference value of confining pres-sure and pore pressure.By fitting with least squares principle, a linear relationship between effective confining pressure and peak value of AE signal in coal fracture was found, and the peak value of signal could be deduced by the above linear relationship.The 30%of peak value was set to be the threshold of signal, which provides a new method to forecast coal and gas outburst and other dynamic disaster.