Study On The Stress Wave Propagation Attenuation Laws In The Elastoplastic Coal And Rock

Acoustic emission technique of predicting coal and rock dynamic catastrophes is one of the developing tendencies of non-contact prediction technique. Based on the actual experiment of AE predicting rock burst in the 83001# second-stage of Laohutai coal mine, theory analysis,numerical calculation and lab experiments are aggregately applied in the paper, and AE stress wave propagation attenuation laws in the coal and rock and wave guide are chiefly studied:(1) Based on actual AE proceeding mechanism and the consumption that coal and rock is infinity elastic body, the spherical propagation model is used to describe the stress wave propagation process, and AE stress wave equation is inferred, and AE stress wave propagation attenuation characters are analyzed; on the basis of quality factor (Q), AE stress wave propagation attenuation equation are deduced, and the amplitude of stress wave reduces in the form of negative exponent.(2) The stress wave propagation process in the elastic and elastoplastic medium models is simulated, and the attenuation laws of stress wave are obtained, by using the international universal finite element dynamics software ANSYS/LS-DYNA. AE stress wave in the elasoplastic model reduces faster than it in the elastic model, but the total attenuation tendency in the two models is accordant, that is, with the propagation distance increasing, the acceleration amplitudes both reduce in the form of negative exponent.(3) The stress wave propagating around the loose circle of roadway is simulated, by using the software ANSYS/LS-DYNA. Combing with the quality factor (Q) theory and the simulation result, we know that the fixed end of wave guide must be installed in the original elastic region.(4) AE stress wave propagation attenuation laws in wave guide are studied from numerical simulation and lab experiment. When the diameter of wave guide varies in the range 5mm～40mm, it effects not obviously on the AE stress wave propgation; when the length of wave guide is bigger than 1m, the maximal absolute amplitude of acceleration reduces totally in the form of negative exponent.