AE Characteristic and Mechanical Behaviors of Red Sandstone with Two Prefabricated Close-Collinear-Equal Length Cracks under Compression.

Preexisting cracks are of great significance for the stability of rocks, they can influence the growth and propagation pattern of cracks. For revealing the failure characteristics of rocks with prefabricated cracks, the mechanical behaviors of red sandstone with two close-collinear-equal length cracks were studied by acoustic emission (AE) monitoring experiment. The results indicated that the stress of red sandstone specimens showed an obvious stepwise growth phenomenon, and AE ring counts can better characterize the growth of microcracks of rocks. Moreover, AE events were mainly distributed near the prefabricated cracks of rocks. Then, a novel modified Kachanov method for analyzing collinear-close cracks was proposed. The influences of crack length and crack spacing on the interaction force of cracks were discussed. Then, it can be found that this modified method had a good applicability for two close-collinear-equal length cracks of rocks under compression.