Investigation on the damage and failure characteristics of bedded salt rock under cyclic loading

• A novel experimental device was proposed to observe the damage and failure laws of bedded salt rocks and stress transfer mechanisms under cyclic loading. • The effective monitoring of the fracture transfer characteristics between different components. • The damage and failure mechanisms of the bedded salt rock are thoroughly investigated by integrating numerical simulations. The damage and failure characteristics of layered salt rock under cyclic loading presents critical implications for the stability of underground salt cavern gas storages. This investigation employed an innovative micro-scale loading-observation system to characterize fracture propagation and damage evolution in cyclically loaded salt rock specimens. Through a multidisciplinary methodology combining laboratory mechanical tests, SEM microstructural analysis, and numerical simulation analysis, three progressive failure modes were identified under incremental cyclic stress conditions. The failure mechanism initiates with transverse shear fracture formation, accompanied by a characteristic stress redistribution pattern evolving from circumferential to fan-shaped and ultimately band-like concentration zones. These findings provide significant insights for optimizing the design and operational safety of salt cavern gas storage systems.