Stability analysis of Jintan underground rock salt gas storage cavern

Purpose - The purpose of this paper is to analyze stability of Jintan underground rock salt gas storage caverns during operation period. Some factors such as complex geological and operation conditions and high variability of physico-mechanical parameters which will influence the safety of underground storage caverns are also considered. Design/methodology/approach - In this paper, taking account of stability and sealability, numerical models of single cavern and two caverns for Jintan rock salt are established and calculated based on Mohr-Coulomb criterion and damage-dilatancy criterion. Response surface method combining with Monte Carlo method are adopted to calculate the failure probabilities of elements near the caverns. Various working conditions including different operation pressures and distances between caverns are also considered. Findings - Shear failure is the main failure mode of Jintan underground rock salt gas storage caverns. The major failure area is located in the middle of the cavern. Reliability of the middle part of the cavern improves as storage pressure increases. Research limitations/implications - According to the simulation results on stability and sealability of caverns, the smallest internal operation pressure should be controlled strictly during the gas release process. Plastic area and failure probabilities of elements near the caverns increase obviously as the distance between caverns decreases. Damaged and dilatancy areas have the same trend. Twice the diameter of the cavern is recommended as the minimum distance between caverns. Originality/value - The conclusions can be used as a guide during operation and design period of underground caverns.