A nonlinear damage constitutive model applicable to the surrounding rock of compressed air energy storage caverns

Considering both construction and operational costs, shallow cavern excavation in hard rock formations is a promising solution for large-scale compressed air energy storage (CAES). In such strata, the surrounding rock is subjected to cyclic tensile stress during air injection and extraction, potentially compromising long-term cavern stability. This study investigates the cyclic tensile behavior of rock under varying maximum stress conditions. The results indicate that cyclic tensile loading induces irreversible plastic strain, which escalates with increasing maximum tensile stress. When the tensile stress exceeds a critical threshold, fatigue-induced tensile failure occurs. To address this, a nonlinear constitutive model incorporating fractional derivatives was developed to characterize rock deformation under cyclic tensile stress. The proposed model effectively captures the temporal evolution of tensile strain by accounting for changes in tensile stress and rock viscosity. Parameter fitting and model validation reveal that the model accurately predicts rock deformation under cyclic tensile conditions, providing a valuable tool for assessing the long-term stability of CAES caverns. © 2024 Elsevier Ltd