Mechanism and experimental investigation of sudden water inrush hazards in surrounding rock due to shear fracture in deep mining operations

In the context of deep high stress, intense osmotic pressure, and mining disturbances, the surrounding rock of faults is highly susceptible to catastrophic instability, resulting in the formation of water inrush channels in the working face and subsequent disasters. This study, rooted in triaxial compression tests on sandstone, delves into the mechanisms driving the formation of shear fractures in deep mining fault zones. Through simulated tests simulating water inrush from the high-pressure bottom plate during deep mining, we illuminate the instability and evolutionary patterns of water inrush channels in fault surrounding rock. Utilizing UDEC numerical software, we analyze the stress field distribution and shear fracture evolution in deep fault surrounding rock. Findings highlight shear failure as the primary rock damage feature under high stress. Mining-induced water inrush disasters occur as fractures in fault surrounding rock initiate, expand, and penetrate, connecting with shear fracture groups on the floor. Shear fractures are the predominant type causing water inrush channels in deep faults, with their initiation and propagation actively promoting channel formation. This study, focusing on the shear instability disaster of fault surrounding rock, significantly contributes to understanding the mechanisms behind fault-related water inrush, distinct from previous studies primarily centered on fault activation.