Effect of Strain Rate on Mechanical Properties and AE Characteristics of Hard Rock Under the Impact of Uniaxial Compression

To study the effect of strain rate on mechanical response, energy mechanism, damage mode and AE characteristics of granite rock, the uniaxial compression tests under different loading strain rates were carried out. The results showed that the higher the loading strain rate was, the greater the threshold stress and threshold energy were. There exists a good logarithmic relationship between the threshold stress, threshold energy and the loading strain rate. When the strain rate was low, the shear failure occurred in the granite sample with a large number of cuttings were generated; under the condition of high strain rate, the granite specimen occurred tensile failure, and the specimen was completely destroyed. Besides, for the low loading strain rate, the damage of the granite sample was developed, the acoustic emission signal increased continuously, and the cumulated number of AE ringing counts was continuously increased; on the contrary, for the high loading strain rate, the number of AE ringing counts was small and firstly increased stepwise, and sharply increased to the maximum value.