Dynamic prediction model for surface settlement of horizontal salt rock energy storage

Abstract

In order to theoretically calculate the surface settlement of horizontal salt rock energy storage, the conformal mapping method in the complex variable function was adopted, and the superposition principle and viscoelastic correspondence principle were considered to derive a theoretical displacement formula. This formula can be used to calculate the radial displacement of the surrounding rock on the cross section of horizontal elliptical cylindrical salt rock storage at any time, and then the volume shrinkage of the storage can be obtained. Based on the assumption that the volume shrinkage during the long-term operation of the horizontal salt rock storage is proportional to the volume of the surface settlement trough, a compound power function was proposed to describe the surface settlement curve, and then a dynamic prediction model for the surface settlement of the horizontal salt rock storage was established. The numerical simulation results of surface settlement during the long-term operation of horizontal elliptical cylindrical salt rock storage were used to verify the rationality of the surface settlement model. The comparison shows that when the operation time is 0, the error between the settlement of the center point calculated from theoretical model and that from numerical simulation is 241.61%, and then the error gradually decreases with increasing time. When the operation time exceeded 3 years, the settlement at the center point and the surface settlement curves calculated from the theoretical model are all in good agreement with numerical simulation results, and the maximum error, occurs at the center point of surface, is only 8.11% when the operation time is 15 years.