采矿应力路径下岩石破坏声发射特征研究

Acoustic emission characteristics of rock failure under mining stress paths

  • 摘要: 为了研究采矿路径下的岩石声发射参数的演变以及岩石破裂破坏过程的差异,检测了大理石在单轴压缩试验、直接拉伸试验和间接拉伸试验中的声发射信号。然后,分析了不同加载模式下声发射参数的时空演化和岩石损伤发展。结果表明,不同加载模式下声发射事件总数和声发射计数的顺序为单轴压缩试验>直接拉伸试验>间接拉伸试验。在直接拉伸试验和间接拉伸试验中,声发射信号的能量释放集中在峰值应力处,随后迅速减弱,而在单轴压缩试验中,在峰后阶段仍然存在大量的声发射信号,并伴有剧烈的声发射能量释放。不同加载模式下岩石中声发射源的产生机制及相应的破坏模式各不相同。此外,不同加载模式下声发射事件的声发射b值随着应力水平的增加而减小,b值急剧下降的应力水平顺序为单轴压缩试验<直接拉伸试验<间接拉伸试验。上述研究结果对今后围岩失稳监测及破坏预测研究具有一定指导意义。

     

    Abstract: In order to study the evolution of rock acoustic emission parameters under mining paths and the differences in rock fracture damage process, the acoustic emission signals of marble in uniaxial compression test, direct tensile test and indirect tensile test were detected.The spatiotemporal evolution of the acoustic emission parameters and the rock damage development in different loading modes were analyzed.The results showed that the order of the total number of acoustic emission events and acoustic emission counts in different loading modes was uniaxial compression test>direct tensile test>indirect tensile test.In the direct and indirect tensile tests, the energy release of the acoustic emission signals was concentrated at the peak stress and then rapidly weakened, whereas in the uniaxial compression test, a large number of acoustic emission signals still existed at the post-peak stage, accompanied by a violent acoustic emission energy release.The generation mechanisms of acoustic emission sources and the corresponding damage modes in rocks under different loading modes are different.In addition, the acoustic emission b values of the acoustic emission events under different loading modes decreased with the increase of stress levels, and the order of the stress levels at which the b values decreased sharply was uniaxial compression test<direct tensile test<indirect tensile test.

     

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