Acousto-optic characteristics of dry and wet damaged rock under cyclic impact loads

Extensive engineering experience and research findings suggest that rock mass instability is typically attributed to human engineering activities and natural disturbances, resulting in general dynamic mechanical properties. This is attributed to external interference resulting from the extensive use of the mechanical and blasting techniques necessary for mineral extraction. Quantifying the impact of dynamic disturbances on rock deformation behavior is essential for comprehending the long-term response of surrounding rock during excavation. This study placed the rock to sustained pressure and investigated the impact of varying hammer heights and dry and wet (W–D) damage on its shear failure behavior. This study investigated the fatigue disturbance studies on W–D damaged sandstone samples via W–D equipment, a disturbance creep device, digital image correlation (DIC), and acoustic emission (AE) technology. The experimental findings suggest that acoustic emission sensors can be utilized to quantify the internal damage of rock samples during cyclic impact, whereas DIC technology (optical measurement) is capable of capturing the surface crack propagation of samples. Under repeated impact and the combined action of W–D conditions, the bearing capacity of sandstone decreases, whereas the deformation capacity increases. Furthermore, the W–D cycles and impact strength are inversely related to the fatigue life. The intensity of W–D damage and disturbances further accelerates the development and propagation of cracks under cyclic disturbances. The research results are of preventive significance to ensure the safety and sustainable development of engineering construction.