Investigation of the Acoustic Emission Behavior and Crack Evolution Characteristics of Limestone Broken by Static Crushing Agent

: In order to investigate the effect of crack and acoustic emission evolution behaviour during the deformation and damage of rock specimens under the action of SCA, static crushing tests were systematically carried out on tuff specimens in the laboratory. Based on AE real-time monitoring techniques and macroscopic crack observations, the crack evolution mechanism of the cracked specimens during deformation and damage was investigated. The results show that there are three stages of microcrack incubation, macroscopic crack extension and cracking damage during SCA crushing. The tensile stress is 0.06-0.1 times of the compressive stress when brittle materials such as rocks are subjected to SCA leading to cracking damage. A large number of AE events with small amplitudes and a small number of AE events with large amplitudes represent that macroscopic cracks are generated by the rapid aggregation of a large number of microcracks before they are slowly formed. The cracking is usually done by first connecting adjacent holes into lines and then extending to the free surface. The direction of static crushing and the cracking effect can be controlled by designing the borehole location and free surface distribution.