Lateral stability analysis method for mountain tunnel-type air storage caverns

The stability of surrounding rock is the basis for ensuring the safe operation of compressed air energy storage air storage caverns. Due to the inclined surface of mountain tunnel-type caverns, the surrounding rock is prone to lateral instability under high internal pressure. However, the applicability of existing stability evaluation methods to such working conditions is limited. Based on the limit analysis theory, a lateral stability evaluation method is proposed, and the formula for calculating the safety factor is derived. The rationality of the method is verified by comparing the calculation results with those obtained using the strength reduction method through a case study. On this basis, the effects of cavern burial depth, diameter, and surface slope on surrounding rock stability are studied. The results show that under different internal pressure conditions, the failure surface obtained by this method is basically consistent with the shear strain concentration area from the strength reduction method, with an average relative error of safety factor less than 5%. Increasing the cavern burial depth can significantly improve the stability of surrounding rock; increasing the cavern diameter will significantly reduce the stability of surrounding rock, but the influence effect shows a gradually weakening trend; a relatively gentle surface slope is more conducive to cavern stability. The research results can provide a technical method for the safety evaluation of mountain tunnel-type caverns.