Post-Blast Analysis of Microseismic Dynamics in Building Early Warning Systems for Coal and Gas Outburst
【摘要】：A novel analysis mainly using Wavelet Packet Analysis(WPA) of post-blast dynamic microseismic signals is conducted in this study. The methodology is based on recognizing different characteristics of microseismic signals from the coal and gas outbursts induced by blasting excavation, and tend to outline a microseismic monitoring based early warning system. Wavelet base functions are produced from analyzing recorded seismic events, which are further categorized into 4 scales. Recorded events are classified into four types according to their temporal-spatial and magnitude properties: blasts, coal burst, coal fracturing, and rock fracturing. Initial roof stress evidently exhibits stronger shifting in time than others: there are 5 coal bursts emerged in first 15 seconds, reaches its maximum in 3.5 seconds, and get stabilized in 26 minutes. It indicates clearly the coal and rock fracturing is activated by coal excavation processes, and is a dynamic stress adjustment process. More importantly, such a dynamic process can be depicted to constitute an early warning.