【摘要】 利用大型煤与瓦斯突出模拟试验系统,研制密封效果好、流变性能强的突出口材料及其制作工艺,模拟垂直和水平应力综合作用下自动触发煤与瓦斯突出的试验过程,利用高灵敏性的微震监测系统全程响应煤与瓦斯突出4个阶段,监测不同阶段突出腔体内的瓦斯压力,素描出突出孔洞大小和形状。微震响应信号分析频率0~2 000 Hz,优选小波基函数,确定小波包最大分解层数,采用小波包分解分析模拟突出孕育、激发、发生和残余4个阶段微震信号时频特征;孕育阶段为高频信号,激发阶段信号频带范围逐渐加宽直至出现低频信号,突出阶段全频带响应,残余阶段信号由相对较低频带逐渐向高频过渡。研究成果为微震预警煤与瓦斯突出提供基础试验依据。更多还原

【Abstract】 In this paper, by using the large-scaled coal & gas outburst simulation experiment system, as well as the developed materials in cavity opening with the property of high sealing performance and powerful rheological behavior, the automatic outburst process was simulated under the comprehensive action of vetical and horizontal stresses. Meanwhile, the whole experiment processes were monitored by microseismic system with high sensitivity installed on the cavity surface. The gas pressure within the outburst assembly cavity in each stage was monitored, and the dimension and shape of the outburst cavity were outlined. The analyzed frequency ranges from 0 to 2 000 Hz. By the optimization of wavelet primary function, the maximum decomposition of wavelet packet was determined. Then, the frequency characteristics in the four stages was acquired by the decomposition and reconstitution of signals based on Wavelet Packet Transform. The results show that the signal frequencies in the inoculation stage are in the high frequency range, while the signals in the excitation stage start to broaden and the low frequency signals appear. In addition, the frequency in the outburst stage is distributed in the full-band, while the signals transmit from the low frequency band to high frequency in the residual stage. The research results can provide reference to the early-warning of outburst by microseismic monitoring.更多还原