Study on creep characteristics and constitutive model of typical argillaceous salt rock in energy storage caverns in China

Abstract

Salt rocks are internationally recognized as a suitable medium for energy storage because of their excellent properties, so the creep behavior of salt rocks has received a lot of attention from scholars at home and abroad. However, the creep behavior of Chinese salt rocks is different from that of high purity salt rocks because they are mostly interbedded, which poses a significant challenge to the safe operation of energy storage salt caverns in China. Therefore, this paper takes a typical muddy salt rock in China as the research object and conducts uniaxial creep tests, considering the accelerated creep phase as a coupled process of loading and creep. A new nonlinear creep damage constitutive model was derived, which was verified based on the creep test data and compared with the traditional classical element model. The model can describe the accelerated creep stage of the specimen well. The model's applicability is also examined, and it is found that the model has a good description for mudstone, high-purity salt rock and mudstone salt rock combination, which provides theoretical support for the safe operation of salt caverns containing interbedded energy storage.