Abstract: Using rock cavern for compressed air energy storage is a promising method for large-scale energy storage. Ensuring the sealing performance and structural safety of the storage cavern are the core tasks in such construction. To verify the feasibility of shallow rock cavern, a lined cavern within granite stratum was constructed in an exploratory tunnel in Pingjiang pumped storage power station, Hunan, as the first compressed air energy storage in China. The cavern was subjected to 10 cycles of charge and discharge during the test. The test results show that the temperature of the compressed air exhibits a significantly uneven distribution, and the evolution of the temperature can be effectively controlled by the heat exchange system. The leakage rate of the chamber is about 3.2% under the long-term high-pressure condition, implying that good sealing performance is achieved. The maximum deformation of surrounding rock is about 0.35 mm under an internal pressure of 8.7 MPa, and the deformation affected zone caused by high internal pressure is within 10 m, indicating that the surrounding rock is safe. The results can help understand the working performance of underground high-pressure gas storage and can provide a reference for the design of compressed air energy storage in shallow rock caverns.

Key words: compressed air energy storage, shallow rock cavern, air tightness, mechanical responses of surrounding rock