Effect of Fracture Coincidence on Mechanical Properties and Damage Evolution of Sandstone

To study the effect of fracture coincidence on mechanical properties and damage evolution of fractured sandstone, five kinds of sandstone specimens with different crack distributions were simulated by RFPA^2D software under uniaxial compression test. The mechanical properties, acoustic emission characteristics and damage evolution process under different crack distributions were analyzed. The results show that the closer the coincidence degree of prefabricated cracks is to 100%, the greater the peak strength and initiation strength of sandstone samples with parallel cracks, the more the number of acoustic emission counts will increase. Crack propagation starts from the initiation of wing cracks. Under different crack distribution, the trend of wing crack development is obviously different. When the coincidence degree of cracks is less than 100%, the acoustic emission counts will increase. When the crack coincidence is more than 100%, the crack will not penetrate at the rock bridge, but the wing crack at both ends will propagate independently until it forms a penetrating crack.