Analytical solution for load sharing in the structure of an underground lined rock cavern for compressed air energy storage and analysis of influencing factors

Unlike traditional underground engineering without inner pressure, the lined rock cavern of compressed air energy storage(CAES) serves as the basis for its design and construction, bearing alternating thermal and pressure cyclic expansion loads. The interaction mechanism, deformation characteristics, and load sharing mechanism of the surrounding rock mass-support-sealing structure have not yet been established, and related research is urgently needed. Firstly, a theoretical model for the CAES under high inner pressure was established based on the multi-layer thick-walled cylinder theory, and the analytical solutions for its stress and deformation were provided. Then, under the set calculation scheme, the influences of sensitive parameters such as the radius of the CAES, maximum inner pressure, and steel lining thickness on the mechanical response and load sharing ratio of the CAES were analyzed, revealing phenomena where the radial compression of the structures, small displacement, and mainly hoop tension occur. It was clarified that the deformation modulus of the surrounding rock mass is the most significant factor influencing the mechanical response of the CAES, followed by the radius of the CAES, maximum inner pressure, and thickness of the concrete lining, while the strength of the concrete lining has a minor impact but an increase in strength may exacerbate cracking. The thickness of the steel lining has almost no effect. It was demonstrated that the surrounding rock mass bears the main load, followed by the concrete lining, while the steel lining hardly bears any load. Secondly, the mechanical response during the charging and discharging process of the CAES were discussed, revealing the phenomenon of hoop tension and compression transition, with the potential cracking zone expanding with the increase of inner pressure. Finally, the concepts of critical inner pressure of the steel lining yielding and critical inner pressure of the concrete lining cracking were proposed, and it was revealed that the deformation modulus of the surrounding rock mass and the crustal stress are the key factors controlling the deterioration and even cracking of the steel lining and concrete lining. The related achievements provide theoretical support for the design and construction of lined rock cavern for compressed air energy storage. © 2024 Academia Sinica. All rights reserved.