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开展了单轴压缩自然和饱水煤样受载破坏实验,测试了煤样在整个加载过程中声发射信号脉冲、能量及主频等各参数的变化规律,对比分析了这2种煤样破坏声发射各参数随加载应力变化的差异性,总结了煤样失稳过程中声发射信号的前兆特征。结果表明:在压密阶段,2种煤样脉冲数和能量值较小,频带范围较宽,主频不突出;在线弹性阶段,自然煤样声发射脉冲数、能量值及主频波动上升,而饱水煤样在该阶段中后期声发射现象才开始明显出现;随着加载的进行,2种煤样声发射都出现了平静期,饱水煤样平静期出现较晚,持续时间也较短;煤样主频逐渐向低频移动,主频振幅却呈现出快速增高后下降趋势。
Uniaxial compression tests of natural and saturated water samples under load were carried out to test the variation law of parameters such as pulse, energy and frequency of acoustic emission signals during the whole loading process. The damage of these two kinds of coal samples The parameters of acoustic emission vary with the variation of loading stress, and the precursory characteristics of acoustic emission signals during coal instability are summarized. The results show that the pulse numbers and energy values of two kinds of coal samples are small, the frequency range is wide and the dominant frequency is not prominent at the compaction stage. The pulse number, energy value and frequency of natural acoustic emission increase during the linear elastic phase, However, the phenomenon of acoustic emission began to appear obviously in the middle and late stage of the stage of full-water coal samples. With the loading process, the acoustic emission of two kinds of coal samples all appeared calm period, and the duration of quiescent period of saturated coal samples appeared later Short; coal-based frequency gradually moving to low frequency, the main frequency amplitude showed a rapid increase after the downward trend.