Abstract: To study the acoustic emission (AE) and damage evolution characteristics of sandy mudstone rock samples, MTS-C64.106 and PCI-2 AE System were utilized for uniaxial compression and acoustic emission monitoring tests during the compression. The loading rate was applied between 1.0×10-5s-1 and 1.7×10-3s-1. The results show that the peak strength of rock sample increases with the increase of loading rate. The releasing form of AE energy changes from solitary earthquake type to swarm type along with the increasing of loading rate, and the peak AE energy increases greatly under higher loading rate. In contrast, the number of accumulated ringing counts decreases significantly. In addition, the damage variable conducted by accumulated ringing counts was derived to describe the rock damage evolution, then the rock constitutive equation was deduced. Compared with the observed stress-strain curves and the conducted curves based on Weibull distribution, the damage evolution process under uniaxial compression can be well reflected by the conducted constitutive equations, especially under the higher loading rate. The conclusions can provide some reference to rock deformation, damage evolution, precursor information identification, etc., under different loading rates.

Key words: uniaxial loading, loading rate, constitutive equation, acoustic emission, damage evolution, stress-strain