Influence of construction gap on the force of steel lining in compressed air storage cavern

Due to the inevitable dry shrinkage of concrete, there will be construction gaps between the steel lining and concrete lining of the compressed gas energy storage artificial chamber, which brings great risks to the stability and tightness of the artificial chamber. In order to study the influence of construction gaps on the force of the steel lining of the compressed gas energy storage artificial chamber, a theoretical analysis method was proposed to simplify the concrete lining-surrounding rock double-layer cylinder model into a single-cylinder model with equivalent characterization parameters. An analytical model is developed to characterize the stress distribution in steel linings before and after gap closure. Its effectiveness is verified by numerical simulation. Based on the equivalent theoretical model, the sensitivity analysis of different parameters such as air pressure, elastic modulus of surrounding rock, cohesion of surrounding rock, friction angle of surrounding rock and burial depth is carried out. Analytical solutions for the stress in the steel lining under varying parameter conditions were obtained for both before and after the closure of the construction gap. The hoop prestress ratio in the steel lining under various parameter settings was determined prior to the closure of the construction gap. The results indicate that the width of the construction gap is the key factor influencing the steel lining’s prestress. A larger gap leads to a greater proportion of hoop prestress and a higher hoop stress after the gap closes during gas injection. Furthermore, the internal air pressure, the elastic modulus of the surrounding rock, its cohesion, and the burial depth of the cavern significantly influence the mechanical response of the steel lining. By contrast, the friction angle of the surrounding rock exerts only a minor effect. During construction, the gap width must be strictly controlled. Furthermore, priority should be given to sites exhibiting a high elastic modulus of the surrounding rock, high rock cohesion, and greater burial depth during the site selection phase. The maximum gas storage pressure must be maintained within the permissible limit. Together, these measures underpin the gas storage facility’s long-term operational safety.