Abstract: Lined rock caverns (LRC) constitute a primary approach for constructing compressed air energy storage (CAES) power plants. Their mechanical capacity to withstand high internal pressures makes the stability of the overlying rock mass a crucial consideration in engineering design. For tunnel-type chambers, we establish a mechanical model of passive rock and soil pressure under the limit stress state of the overlying rock mass, based on the Mohr-Coulomb (M-C) strength criterion and the limit equilibrium concept. Stress boundary integration is applied to derive a system of three-moment equilibrium equations, and a rigorous method for calculating the safety factor of arbitrarily shaped failure surfaces is introduced. Parameter sensitivity analysis reveals that the safety factor is primarily influenced by burial depth, in-situ stress ratio, maximum air storage pressure, and chamber radius. The safety factor exhibits a nonlinear positive correlation with burial depth and a nonlinear negative correlation with both air storage pressure and chamber radius. For grade III rock mass, the permissible ranges of design parameters, such as burial depth, chamber radius, and maximum air storage pressure, that meet stability requirements are provided, offering valuable guidance for engineering design.

Key words: compressed air energy storage (CAES), lined rock caverns (LCR), ultimate equilibrium method, stability, factor of safety