Creep Properties and Constitutive Model of Salt Rocks Under Slow Cyclic Loadings

Abstract

The construction of compressed air energy storage (CAES) plants using the huge space created by salt rock mining is a key technology that can optimize China's energy structure. The creep properties of salt rock are an important parameter for the long-term stable operation of CAES plants. Based on the operation mode of the CAES plant, creep tests on salt rock under the influence of slow loading and unloading were conducted. The test results indicate that the history of slow loading and unloading locally changes the process of creep development, but does not affect the overall process of creep, and the steady state creep rate of salt rock depends mainly on the magnitude of external stress. Moreover, the creep test was monitored simultaneously using acoustic emission (AE) technology, and the distribution of the AE absolute energy during the initial loading phase and the steady state creep phase satisfied the power law. In order to more accurately describe the creep characteristics of salt rock under the influence of slow loading and unloading, a full process creep constitutive model of salt rock was constructed using state variable, fracture expansion factor and unloading factor.

Keywords: Energy storage, Salt rock, Creep properties, Constitutive model, Cyclic Loading