Plastic zone and surrounding strain analysis in a lined cavern for compressed air energy storage subjected to cyclic high internal gas pressure and temperature

Abstract

In the context of compressed air energy storage (CAES) technology, the strategic excavation of hard rock caverns is pivotal for overcoming geological challenges and advancing CAES deployment. This study adopts a circular profile for the cavern and investigates the impact of variables such as cavern diameter and depth. Considering the influence of cyclic internal gas pressure, temperature fluctuations, and potential leakage on the cavern, a thermo-hydro-mechanical coupled numerical model is developed using Comsol software. This model, grounded in classic elastoplastic constitutive relations, aligns with the conditions of a proposed project. It facilitates the computation of the plastic zone and surrounding strain for both the cavern lining and adjacent rock, post-excavation and throughout a typical ‘charging-storage-discharging-storage’ operational cycle. Through detailed analysis, the study delineates the variations and characteristics of the plastic zone and surrounding strain, thereby providing a solid foundation for a comprehensive examination of cavern stability, and the design of linings and sealing mechanisms.