Analytical model and evolution law of the surrounding rock failure zone in lined rock caverns for compressed air energy storage power stations

Compressed air energy storage lined rock caverns are subject to various complex failure modes during operation, particularly under high-pressure conditions, where tensile and shear failures are prone to occur, posing serious threats to structural stability and operational safety. Focusing on the coupling characteristics of failure mechanisms, an analytical model of the surrounding rock failure zone was developed based on the full stress path from excavation to operation. The influences of rock mass quality, burial depth, tensile strength, and in-situ stress anisotropy on the evolution of failure zones were systematically analyzed. The results indicate that the failure mode during operation is significantly affected by the initial state of the surrounding rock after excavation: for high-quality rock masses that remain elastic after excavation, both high-pressure tensile and shear failures may occur during operation; whereas for lower-quality rock masses where shear failure zones have already developed after excavation, only further shear zone expansion is observed during operation. When the excavation-induced failure zone is smaller than the high-pressure failure zone, increasing burial depth effectively suppresses the expansion of both tensile and shear failure zones. The occurrence of tensile failure under high pressure significantly increases the overall degree of surrounding rock failure. However, relatively low tensile strength can inhibit its initiation. The critical tensile strength required for suppression decreases with increasing burial depth. In-situ stress anisotropy generates direction-dependent. As anisotropy increases, the critical internal pressure for high-pressure failure decreases, whereas the tensile strength required to suppress tensile failure increases.