Influence of spatial variability in surrounding rock on fracture propagation in compressed air energy storage caverns

Abstract

Abstract The expansion of fractures around underground caverns for compressed air energy storage (CAES) has a significant impact on engineering stability. We established a thermo-mechanical coupled random phase field model to investigate the trajectory of fractures in the heterogeneous surrounding rock of underground gas storage caverns. By simulating the different mechanical parameters under different coefficients of variation and autocorrelation distances, we explored the impact of spatial variability of rock mass on the fracture mode of surrounding rock in underground gas storage caverns. The results indicate that when only the spatial variability of elastic modulus is considered, the coefficient of variation primarily affects the inclination and curvature degree of fractures while the autocorrelation distance has a slight impact on the bending shape of fractures. When only the spatial variability of fracture energy release rate is considered, both the coefficient of variation and the autocorrelation distance have a negligible effect on fracture propagation. Compared with the elastic modulus of the rock mass, the fracture energy release rate has a more significant impact on the path of the cavern fractures.