Critical slowing characteristics of sandstone under uniaxial compres-sion failure

In order to study the characteristics of acoustic emission of rock burst failure in the perspective of critical slowing,the experiment of sandstone uniaxial compression was carried out. Based on the theory of critical slowing,the acoustic emission signals generated by uniaxial compression failure of sandstone were analyzed. The results show that the acoustic emission signals produced by sandstone destruction can reflect the obvious characteristics of the stage dur- ing the whole loading process. Different window lengths and lagging steps have effects on the volatility stability of the autocorrelation coefficient and the variance of the critical slowing point of sandstone failure. The sudden increases of the autocorrelation coefficient and the variance can be used as the precursor of sandstone damage. Compared with the autocorrelation coefficient,the variance is more obvious in the early warning,and the precursor point reaches more than 80% on the total time and the peak stress,with a good timeliness.