Characterizing Concrete Lining Damage in Lined Rock Caverns for High-Pressure Energy Storage with Validated Numerical Models

To enable large-scale storage of clean energy carriers such as hydrogen or compressed air, underground lined rock caverns (LRCs) operating at high internal pressure are critical infrastructures. The integrity of their concrete lining is paramount for safety and durability. To investigate the damage development and identify the dominant factors influencing the concrete lining in a LRC for high-pressure gas storage. A three-dimensional refined numerical model of the composite system comprising a steel-concrete lining and surrounding rock was developed based on the Swedish Skallen demonstration project. The model reliability was verified against field hydraulic test data. The Concrete Damaged Plasticity (CDP) model was employed to systematically characterize the damage evolution process and distribution features of the concrete lining under high pressure. Subsequently, a systematic analysis was conducted with respect to five key factors: sealing layer material, concrete strength grade, burial depth, coefficient of lateral pressure, and rock mass quality, focusing on their influence on the development, spatial distribution, and morphology of concrete damage. The relative influence of each factor on cavern stability was quantitatively compared. The results reveal a tension-dominated failure mode in concrete lining, with its extent and spatial distribution primarily governed by the rock mass quality and in-situ stress state. The influence of concrete strength and sealing layer material is relatively limited, and the effectiveness of increased concrete strength in suppressing damage shows diminishing returns. Based on these mechanisms, a damage-control design principle is proposed, which prioritizes competent geological conditions and employs lining optimization as a supplementary measure. This provides a theoretical basis for site selection and performance-based design of LRC under high internal pressure.