Research on the Safe Burial Depth Range of Hard Rock Compressed Air Energy Storage Chambers Based on No Plastic Zone Condition

Abstract

The high internal pressure and high surrounding pressure in the surrounding rocks of the compressed air energy storage (CAES) chamber can cause plastic zones, resulting in cracks and affecting the stability of the chamber. This paper proposes a safe burial depth solution method based on elastic and elastic-plastic theories, with the condition that no plastic zone occurs. An approximate method is used to solve the boundary of the plastic zone, and by requiring the plastic zone to be contained within the boundary of the chamber, the range of safe burial depth is determined. The verification, sensitivity and limitation of the solution are finally discussed. The comparison with numerical simulation and previous experimental results proved that the error of this solution is extremely small, and it possess the following advantages: (1) The surrounding rocks remain elastic, ensuring the stability of chambers; (2) Being closed-form solutions, infinite resolution is preserved throughout; (3) Can be directly solved through the air pressure and accessible geomechanical parameters. Further studies found that the range of selectable burial depths is wider, and more suitable as a gas storage cavern site when the lateral pressure coefficient is closer to 1 and the shear strength of the surrounding rocks is higher. The research results have sizable engineering application value for site selection and design of buried depth of CAES chambers.