Experimental Investigation on Uniaxial Compression Mechanical Behavior and Damage Evolution of Pre-Damaged Granite after Cyclic Loading

Failure behavior of pillars in deep mines is affected by various cyclic loads that cause initial pre-damage. Pillars will be further damaged and developed the long-term compressive stress until they are destroyed. To reveal strength characteristics crack damage fracture laws after rock pre-damage, uniaxial compression tests were carried out on granite specimens loading using digital speckle correlation method. The experimental results indicate mechanical properties pre-damaged show large differences for different cycles. variable increases with increase cycle number confining pressure. primarily due to weakening effect caused numbers, pressure restriction not obvious. evolution propagation obvious localization phenomenon. Pre-damaged experienced three failure modes test, namely tensile shear (Mode I), quasi-coplanar II), stepped path III), under pre-damage environments high pressures, dominated Mode II III, respectively.