Study on compound signal characteristics of acoustic emission and charge induction in coal rock failure under different loading paths

With the experimental study on the mechanical properties of coal-rock and the characteristics of acoustic emission-charge induction signals during the coal-rock failure process under different loading paths, in terms of energy, the variation of mechanical behavior and carrying capacity of the coal-rock with the influence of loading path had been analyzed.The production and attenuation of the coal-rock micro-potential caused by polarization was theoretically deduced.The theoretical analysis results can interpret the characteristics of acoustic emission-charge induction signals and variation during the coal-rock failure process.The result shows that the acoustic emission-charge induction signals fluctuation had a good consistency with the bearing structure damage caused by the stress drop during the coal-rock failure process.At the preliminary stage of loading, the two signals in lower amplitude belong to discrete signals, with the stress increase, the intensive degree of signals significantly improves, the signals distribution transits from discrete to continuous, and at failure stage, high value singles appear continuously.The more coal-rock is subjected to a change of load, the higher change-rate of ring-count and energy, the higher strength and pre-peak strain energy, and the grater change-rate of charge induction.Thus the prediction method of destruction and instability disaster of coal rock was put forward, which is based on the acoustic emission-charge induction compound signal amplitude and signal change rate.