Abstract: This paper presents the experimental study results of the state variables, physical parameters and acoustic emission properties of sandstone samples under various cyclic loading levels. The results indicate that, 1) under loadingunloading conditions, the amount of plastic strain increases with the increase of loading level; 2) distinct acoustic emissions are observed during the fissure closing period in the loading stage and no acoustic emissions are observed during the unloading stage; 3) Distinct Felicity Effect is encountered in both loading and unloading conditions. Different Felicity Effects are found in different stress levels. A lower stress level usually contributes a higher Felicity Effect. With the increase of the stress level, the state variables and the physical parameters demonstrate a trend of increase.

Key words: Sandstone, Cyclic Loading, Acoustic Emission, Felicity Effect