Rock Salt Under Cyclic Loading with High-Stress Intervals

During the operation of a CAES (compressed air energy storage) system, the rock surrounding a salt cavern suffers cyclic loading with high-stress intervals (HSIs). To investigate the effect of HSIs on the fatigue of rock salt, fatigue tests with constant stress intervals at different stress levels and interval durations were conducted. Results show that the axial stress-strain curves with HSIs present three stages of sparse-dense-sparse. The hysteresis loops in a single cycle consist of seven phases (crack compaction, elastic deformation, plastic deformation, creep deformation, cease, elastic recovery and pore restore). The irreversible deformation per cycle and fatigue life with HSIs present an upward and downward trend, respectively, compared to cases without intervals. The surface of fractured specimens shows a mix of shear and tensile cracks, and the salt crystals present the interaction of intra-grain and inter-grain cracks.

Automated summary

This study investigates the effect of high-stress intervals (HSIs) on the fatigue of rock salt in a compressed air energy storage system. The results show that HSIs contribute to changes in stress-strain curves and fatigue performance.