Abstract: In order to study the influence of time on rock stress memory , an experimental study has been performed to investigate the Kaiser effect of acoustic emission on schist at time interval of 2 days, 7 days, 15 days, 30 days and 45 days between the first and second loading under the condition of uniaxial compression, by making use of rock testing machine, as well as a testing apparatus of AE, SDAES. The test results show that with the increase of time interval between two loading cycles, Kaiser effect in rock gradually disappears and the effect is well-pronounced at time interval of 7 days and remains detectable within 30 days, while it is hard to be detected after more than 45 days. The stress level of the first loading affects the fade of Kaiser effect in rock, and rock’s memory ability of precious stress is the best when the stress level of the first loading is of between 30% to 80% of rock strength.

Key words: acoustic emission, Kaiser effect, uniaxial compression, stress memory, retention time