Stability Analysis on the Long-Term Operation of the Horizontal Salt Rock Underground Storage

The construction of the vertical cavern in the salt dome deposit can meet the requirements of both storage capacity and tightness. However, if the vertical cavern is still used as the design shape of the salt rock underground storage in the layered salt rock deposit, the high design capacity cannot be guaranteed while the tightness is satisfied. In this case, the use of a large-span horizontal cavern as the design shape of the salt rock storage can not only effectively increase the design capacity of the storage, but also solve the problems such as the stability and tightness of the storage during the operation period by improving the structural form and working mode. Based on this, the ellipsoid-shaped horizontal salt rock underground storage is taken as an example, and a single-cavern horizontal salt rock underground storage model with different diameter-to-height ratios is established by using FLAC3D software. The change law of vertical and horizontal displacements, volume loss rate, and plastic zone distribution of salt rock storage changing with the diameter-to-height ratio are studied, and the optimal diameter-to-height ratio is determined. And then the long-term operation process of the double-cavern horizontal salt rock underground storage under the optimal diameter-to-height ratio is simulated, and the optimal pillar width is obtained.