Study on main Frequency precursor characteristics of Acoustic Emission from Deep buried Dali Rock explosion

Abstract

Rock burst disaster events have become one of the most common disasters in the field of underground engineering, and it is of great practical significance to study the prediction and early warning signs of rock burst. Acoustic emission waveforms generated during a rock burst event, which are often characterized by parameter analysis, that analysis of the waveform spectrum can reflect the characteristics of rock damage and failure. Based on a single-axis strain-type rock burst test of deep buried marble, characteristics of the frequency spectrum, as well as the time-domain dominant frequency of acoustic emissions during the entire rock burst process, were analyzed. We find that the acoustic emission spectrum characteristics also have their own characteristics at different stages of rock burst. In general, The main frequency amplitude value presents an increasing trend, the peak shape of the acoustic emission spectrum shifts between unimodal and multimodal, and the secondary frequency typically appears in the plastic deformation stage. In the high-frequency domain (more than 200 kHz) of the initial loading of stress redistribution, the elastic phase of the energy build-up shows a relatively quiet period, the main frequency distribution of plastic deformation stage shows increasing tendency. Before and after the rock burst event, the dense area of the main frequency migrates from the high-frequency domain to the low-frequency domain, the main frequency in the high frequency field appears dense distribution on the eve of rock burst. These changes were distinguished as characteristic criteria for impending rock burst and can therefore be used for the prediction and early warning of rock burst events.