To study the effect of loading rate on the characteristic stresses of brittle rocks

uniaxial compression tests were carried out using MTS815 test machine and acoustic emission (AE) test system. The volume strain method

AE method

and bonded particle model (BPM) method based on the development of micro-cracks were adopted to determine the characteristic stresses of samples and investigate the loading rate effect of characteristic stresses for marble. Results show that values of the normalized characteristic stress determined by the three methods are relatively close

and the BPM method based on the numbers of micro-crack is a reliable and effective method. Moreover

the normalized characteristic stresses decrease as loading rates increase in the range of medium and low. Numerical simulation results show that when the loading rates increased in a wide range

the normalized crack initial stress and crack damage stress both decrease. When the loading rates are in medium and low range

the normalized characteristic stresses decrease significantly. However

it tend to be stable when the loading rates are high

especially for the normalized crack damage stress. In comparison

the loading rate effect of normalized crack damage stress is more obvious than that of the normalized crack initial stress.