Research on a closed-form solution for safe burial depth range (SDB-RS) of hard rock compressed air energy storage chambers based on no plastic zone criterion

Abstract Determining the safe burial depth is crucial for ensuring the long-term stability of compressed air energy storage chambers throughout their operational cycle. This study proposes a safe burial depth solution based on elastic and elastoplastic theories, with the safety criterion being the prevention of plastic zone formation in the surrounding rock. An approximate method is used to calculate the boundary of the plastic zone, and a closed-form safe burial depth range solution is determined by ensuring that the plastic zone remains contained within the chamber boundary. The study demonstrates that both overly shallow and overly deep burial depths can result in the formation of plastic zones, whereas no plastic zone occurs in the surrounding rock when the burial depth is within the range solution. The validation through comparison with previous physical model experiments and numerical simulation methods proves the effectiveness of the solution. The study further reveals that the range of safe burial depths is wider and more suitable for air storage when the lateral pressure coefficient is closer to 1 and the shear strength of the surrounding rock is higher. The solution is applicable to surrounding rocks of Class II and above, and can be quickly solved using the maximum air pressure determined by engineering requirements and the geomechanical parameters of the rock mass obtained from geotechnical investigations. The solution provides high computational efficiency and accuracy and offers significant engineering value for site selection and the design of burial depth in CAES chambers.