Effect of loading frequency on fatigue characteristics of granite under tri-axial compression

The dynamic fatigue compression test under the tri-axial condition is carried out by using the MTS815 rock mechanics test system to Beishan granite with good lithology uniformity to investigate the influence of loading frequency on rock deformation characteristics and damage evolution.Through the experimental analysis, it is concluded that the fatigue deformation process of granite can be divided into three stages “sparse-density-sparse”, which has nothing to do with lithology and test conditions; and its damage process is also mainly dominated by lateral expansion.In addition, the change of frequency does not change the ultimate deformation of rock sample failure.The fatigue damage process of rock sample can be reasoned by plastic volumetric strain method and elastic modulus method.The influence of the frequency for fatigue life of rock sample is also revealed.