Long-term stability analysis and evaluation of salt cavern compressed air energy storage power plant under creep-fatigue interaction

To investigate the influence of the fatigue effect of salt rock on the long-term stability of the compressed air energy storage power plant, the numerical simulation method was used to analyze the long-term stability of the energy storage under the conditions of the fatigue effect is considered (the creep-fatigue interaction of salt rock stratum is considered) and not considered (only the creep behavior of salt rock stratum is considered). The numerical calculation results show that when the fatigue effect is considered, the deformation of the surrounding rock and the cavern volume shrinkage are far greater than the corresponding values when the fatigue effect is not considered, indicating that the fatigue effect has an important impact on the stability of the storage. Then based on the numerical simulation results, the minimum pressure, maximum pressure and pillar width of the salt cavern compressed air energy storage power plant were determined by contrasting the displacement of the surrounding rock, the cavern volume shrinkage and the extended range of the plastic zone. Finally, a long-term stability evaluation system for the salt cavern compressed air energy storage power plant was established based on the analytic hierarchy process method, and the long-term stability was quantitatively evaluated using the fuzzy evaluation method. The results show that the stability level of the double salt caverns compressed air energy storage power plant is Level II, indicating that they are in stable state.