Microseismic low-frequency precursor effect of bursting failure of coal and rock

As a tough problem in coal mines, there is not an effective solution to rockburst evaluation and prediction as yet. In this paper, an attempt to investigate a rockburst forecasting method was undertaken by applying small scale, laboratory modeling of the coal mine roof, coal and its floor. According to rockburst danger evaluation and forecasting in deep coal mines on the basis of microseismic (MS) monitoring, the frequency-spectrum evolution was analyzed in detail by the band-stop filter and Fourier transform of MS signals monitored in time. Research results show that a strong mainshock induced by coal and rock sample bursting failure would commonly be introduced when the predominant frequency-spectrum of MS signals begins to move to lower band and the vibration velocity gradually increases, and the signals closed to mainshock, precursor signals, which indicate the tendency of increasing low-amplitude and the decreasing high-frequency. Moreover, it is also found that the rockburst disaster intensity increases with the increase of vibration velocity of precursor signal, and it is opposite with the predominant frequency of precursor signal.

► Microseismic (MS) effect of compound coal and rock samples bursting failure.
► Negative relationship between MS predominant frequency and rockburst intensity.
► With load on samples increasing, MS predominant frequency will decrease gradually.
► Negative correlation between the total energy, event count and predominant frequency.