Study on Acoustic Emission Evolution Characteristic of Plastic and Brittle Coal Failure Process

Abstract

Under uniaxial compression loading, the failure experiments of plastic and brittle coal are carried out to study the acoustic emission evolution characteristic. The results show that the evolution of acoustic emission during the coal failure process corresponds with the process of coal crack initiation, propagation and coalescence. The acoustic emission event rate of the typical plastic coal displayed the variation of up-peak-down during the failure process. The event rate of acoustic emission increase sharply and then drop steadily is the precursor that the main crack plane of the plastic coal would coalescence and the coal will lose its stability. During the failure process of typical brittle coal, the event rate increased steadily with the increase of stress, showing the variation of up-peak; the down stage of acoustic emission is not obvious because the brittle coal suddenly fail after stress peak. The study results can provide a theoretical basis for explanations of the variation of acoustic emission and the establishment of instability criteria in coal and rock stability monitoring engineering by AE technology.