Load-sharing behavior and influencing factors of lined rock caverns for abandoned-mine compressed air energy storage considering the excavation damaged zone

The structural complexity of abandoned mines, together with the Excavation Damaged Zone (EDZ) induced by excavation and long-term mining deterioration, poses a critical challenge to the stability of compressed air energy storage caverns. This study investigated the load-sharing behavior of lined rock caverns in abandoned mines under high storage pressure by developing an analytical mechanical model that explicitly accounted for the EDZ and provided analytical expressions for stress, displacement, and layer-specific load-sharing ratios. To move beyond the limitations of conventional one-factor analysis, an XGBoost model combined with SHAP interpretation was employed to quantify global parameter sensitivities and identify nonlinear transition ranges, while the analytical solutions were further examined through numerical simulations incorporating spatial heterogeneity within the EDZ. The results reveal a load-sharing behavior dominated by the surrounding rock. Specifically, the deep surrounding rock and the EDZ respectively bear approximately 45% and 35% of the total load, while the concrete lining and sealing layer respectively contribute about 16% and 4%, and mainly serve as secondary restraint and sealing components.SHAP analysis further identifies the in-situ stress and EDZ thickness as the dominant controlling factors, followed by storage pressure, with clear nonlinear transition behavior within the investigated parameter range. Numerical simulations show that EDZ heterogeneity intensifies local stress concentration and energy accumulation near the cavern wall, while the overall response still exhibits a pattern of near-field localization and far-field homogenization. These findings provide a mechanics-based reference for the rehabilitation design and preliminary operational assessment of CAES caverns developed from abandoned mines.