Experimental Study on Mechanical Characteristics of Excavated Unloaded Rock Mass under Dry and Wet Cycle Conditions

Investigating rock mass mechanical characteristics in dry-wet cycle conditions is crucial for uncovering deformation and failure mechanisms in reservoir slope subsidence zones resulting from manual excavation. Wet-dry cycling and triaxial reloading tests were performed on unloaded rock masses exposed to various excavation disturbances. The findings indicate that the order of unloading directly influences deformation patterns and rock sample failure strength during wet-dry cycles. Additionally, increasing dry-wet cycles leads to a reduction in peak strength during rock sample reloading, corresponding to increased deformation, and the elastic modulus, cohesion, and friction angle also decrease. Moreover, as unloading magnitude and the number of dry-wet cycles increase, the occurrence of cracks during rock sample failure rises significantly, demonstrating notable distinctions between the two unloading magnitudes.