Compressed air energy storage (CAES) is a key technology for the consumption of renewable energy and peak shaving of power grid. Artificial cavern gas storage has promising application prospects because it is less constrained by site selection and offers better controllability of construction quality. However

the lining and surrounding rock are subjected to significant tensile stress during high-pressure operation. When the maximum tensile stress exceeds the material’s critical strength

tensile failure occurs. To address this issue

the reinforcement ratio of the lining must usually be increased

or the chamber size and storage pressure must be reduced. However

these measures increase construction costs and limit storage capacity. In this study

an optimized structure is proposed in which the lining is placed inside the sealing layer. From the inside outward

the structure consists of the lining

sealing layer

leveling layer

initial support

and surrounding rock. Numerical simulations and analyses are conducted based on a thermo-mechanical coupling model. The results show that the sealing layer temperature in the optimized structure is significantly lower than that in the traditional structure because of the protective effect of the lining. When using steel plate as the sealing material

the maximum temperature is reduced by 46.08%. In terms of stress

the entire lining structure is subjected to circumferential tension and radial compression. After structural optimization

the maximum tensile stresses in the sealing layer

concrete lining

and surrounding rock are reduced by 16.00%

28.19%

and 24.73%

respectively. Furthermore

the load-sharing results show that more than 70% of the pressure is borne by the surrounding rock in both structures. In terms of deformation

the maximum displacement occurs at the top of the lining. The overall displacement variation of the optimized structure is relatively small. Further analysis examines the lining structure’s mechanical response under high

medium

and low in situ stress levels. Compared with the traditional structure

the optimized structure reduces the sealing layer’s maximum first principal stress by 40.26%

32.01%

and 22.46% under high

medium

and low in situ stress levels

respectively. This reduction demonstrates the optimized structure’s effectiveness in mitigating circumferential tensile stress in the sealing layer. Surrounding rock grade and deformation modulus significantly influence the structure’s mechanical response. For gas storage sites

surrounding rock of Grade III or higher is selected. Moreover

the mechanical properties of four kinds of sealing layer materials are compared. The steel plate and fiber-reinforced plastic (FRP) are subjected to circumferential tension and radial compression

whereas flexible concrete and rubber are in compression. Steel plate is recommended for traditional structure

whereas flexible concrete is recommended as the sealing material for optimized structure

because it minimizes stress and deformation in the surrounding rock. In summary

for artificial cavern gas storage

the optimized structure proposed in this study is more conducive to structural stability than the traditional structure. The findings provide valuable guidance for the design of artificial cavern lining structures in compressed air energy storage applications.