STUDIES ON ACOUSTIC EMISSION CHARACTERISTICS OF CYCLIC LOADING-UNLOADING GRANITE FAILURE

This paper studies on the variation of acoustic emission(AE)characteristics during granite failure under cyclic loading through the MTS815 rock mechanics testing system. Changes of AE parameters of granite were studied under different confining pressure, cycle times and water content. Based on the recorded AE data, the rock failure process is divided into three stages, namely, the initial stage, uniform development stage and the acceleration transition stage. The variation characteristics of RA value, damage parameter D and Kaiser Effect in each stage are studied. The results show that:(1)The RA value of the saturated rock is less than the RA value of the rock in the natural state, and the rocks of both states appear obvious high RA zone before failure. (2)The confining pressure can effectively prolong the time of the accelerating transition phase and improve the compressive strength of the rock.(3)The average value of the damage parameter D in the last cycle is increased by 0.6. (4)The limitation of the rock Kaiser effect is verified, and the rock will not be destroyed by the cumulative damage after the Felicity Effect occurs.