Study of response regularity of acoustic emission in gas jet orifice

Abstract

In order to prevent danger of coal and gas outburst in process of rock cross-cut coal uncovering, tests and analysis on acoustic emission in rock cross-cut coal uncovering process in a coal mine were conducted based on acoustic emission monitoring system. The analysis and research results indicates that acoustic emission intensity increases rapidly in 2-3 hours before jet orifice occurred, peak strength can reach 2-3 times higher than that no outburst danger, then dropped to lower level before jet orifice occurred. The more serious the jet orifice was, the higher the intensity of acoustic emission was. The variation range of the acoustic emission intensity could reflect severity of the jet orifice, the more obvious the jet orifice was, the more severe the changes of gas concentration was, the greater the growth rate of coal and rock acoustic emission intensity was and the higher the peak intensity was. The analysis and research results have important reference significance for monitoring and forecasting of coal outburst risk in rock cross-cut coal uncovering.

Keywords

• rock cross-cut coal uncovering
• jet orifice
• acoustic emission
• precursor law
• stress concentratio