不同扰动频率下砂岩冲击岩爆声发射特征研究

Study on Acoustic Emission Characteristics of Sandstone Impact Rockburst under Different Disturbance Frequencies

利用自主研发的冲击岩爆设备,设计并开展了真三轴条件下含圆形孔洞砂岩在不同周期荷载扰动下的岩爆实验。实验采用图像采集装置、声发射装置,模拟了类似实际巷道结构模型的动态荷载诱发的岩爆现象。主要结论:声发射幅值随着周期扰动荷载呈现先增加然后减小,最后再增加的趋势,扰动频率越大,较低幅值(40~60 dB)占比越小,而较高幅值(60~100 dB)越大;声发射累积计数可以划分为快速小幅增长、低速稳定增长及快速大幅增长3个阶段,扰动频率会影响3个阶段的增长速率,频率越大,增速越快;声发射b值随着扰动荷载处在动态变化过程中,不同扰动频率的试样在岩爆破坏时b值均下降到最小值,扰动频率越大,岩爆破坏时声发射b值降低的越多。

Using the self-developed rockburst equipment,true-triaxial rockburst experiments of cubic sandstone sample with a circular hole under different periodic load disturbances were designed and carried out.In the experiment,image acquisition device and acoustic emission device were used to simulate the rockburst phenomenon induced by dynamic load similar to the actual roadway structure model.The main conclusions are as follows,with the periodic disturbance load,the amplitude of acoustic emission first increases,then decreases,and finally increases.The larger the disturbance frequency is,the smaller the proportion of lower amplitude(40-60 dB)is,and the larger the higher amplitude(60-100d B)is.Acoustic emission cumulative counts can be divided into three stages:rapid and small growth,low-speed stable growth and rapid and large growth.The disturbance frequency will affect the growth rate of the three stages.The higher the frequency,the faster the growth rate.The b value of acoustic emission is in the dynamic change process with the disturbance load,and the b value of the samples with different disturbance frequencies drops to the minimum value during rockburst.The higher the disturbance frequency,the more the b value of acoustic emission decreases during rockburst.