Damage evolution law based on acoustic emission and Weibull distribution of granite under uniaxial stress

Abstract

The research on rock damage mechanisms during loading has a significant reference value for the deformation damage issues in the rock engineering industry. In this paper, Electrohydraulic Servo Material Test System MTS815 and PCI-2 based AE System were utilized for uniaxial compression tests of granite specimens and acoustic emission monitoring tests during the compression respectively. According to the test data, there is a well defined correspondence between the curves of acoustic emission count rate with time and stress-strain curves of rock. Moreover, from the stress-strain curves, the characteristics of brittle fracture have been showed. Four stages were identified, namely compression stage, linear elastic stage, weakening stage and failure stage. There are also four stages in acoustic emission count rate with time curves: quiet period, slow growth period, intense growth period and attenuation period. Based on the acoustic emission data and the Weibull distribution, two different damage variables were derived describing the damage evolution of rock during loading. In addition, the corresponding constitutive equations have been deduced. The conclusions of this paper can provide references for the issues of the rock deformation and the damage during loading.