Study on b-value characteristics of acoustic emission of red sandstone during short-time creep process

The creep property is one of the most important factors that affect rock failure. Therefore, it is necessary to forecast rock creep failure. The creep tests on red sandstone were carried out using step loading and unloading method, and the characteristics of b-value acoustic emission were analyzed during the primary creep stage, the steady state creep stage, and the tertiary stage. The results show that the b-value increases in primary creep stage and steady state creep stage as the specimens are in volumetric deformation state, and keeps stable in steady state stage as the specimens are in both constant volume and dilatancy state. When the specimens step into tertiary creep stage, the b-value firstly takes on a declining trend, and then increases with time increasing, and finally declines again before the specimen failure. Therefore, the red sandstone creep failure can be forecasted by the variation characteristics of b-value to some extent. ©, 2015, China Coal Society. All right reserved.