Abstract：Damage evolution characteristics of rock mass containing defects during loading were analyzed by using RFPA2 Dnumerical analysis software. Three circular defects with small strength and elastic modulus were preset in the model. The results show that the damages of defective rock mass during loading can be divided into four stages: zero damage at initial stage of loading, stable growth of the damage, rapid growth after the first crack appearance, and a large crack stage throughout the entire rock mass appearance. The stress concentrates around the defects during loading, which results in the proliferation and expansion of cracks. Preset defects eventually are communicate through big cracks and rock mass are destroyed. Meanwhile, the number of cracks is increased by segment after the first crack appearance and up to the peak near the peak point. During the process of crack proliferation and expansion, the acoustic emission characteristics are obvious. The results of the study have important values in guiding and analyzing the damage process of defective rock mass process.

Keyword：defective rock mass;loads;damage;crack;