含瓦斯煤破裂过程声发射时空演化规律

Temporospatial Evolution Rules of Acoustic Emission Caused by the Failure Process of Gas-saturated Coal

利用MTS815岩石力学试验系统和气体渗透试验系统,开展不同瓦斯压力下含瓦斯原煤煤样的3轴压缩声发射试验,研究含瓦斯煤破裂过程中声发射时空演化规律。试验结果表明,煤样内的声发射定位点随载荷增加逐渐密集且主要分布在主裂纹面附近;随着载荷的增加,单位载荷区间的声发射振铃数经历了初期的沉寂期、中期的低水平稳定期、峰值前的快速发展期和峰后的高水平稳定期,与煤样累计声发射振铃数变化特征类似;瓦斯压力增加增强了损伤前煤样的声发射活动,减小了煤样的初始损伤应力,促进了煤样的损伤发展。

To study the temporospatial evolution rules of Acoustic Emission （AE） caused by the failure process of gas-saturated coal, a series of triaxial compression AE tests were carried out by using MTS815 rock mechanics test system and gas seepage test system on raw coal samples with the different gas pressures. The experimental results indicate that the cumulative number of AE locating points gradually increases with load increasing, and the AE locating points mainly distribute in the vicinal area of main crack surface. With load increasing, the AE counts in unit load interval experience initial quiet period, low-level stabilization period in the medium-term, rapid development period before the peak, and high-level stabilization period in the post peak; it is similar to the variation of the cumulative AE counts of coal samples. The increase of gas pressure enhances the AE activity of coal samples before the initial damage, reduces the initial damage stress, and promotes the damage development of coal samples.