Coupled thermal-gas-mechanical phase-field modeling for fracture initiation and propagation in the underground caverns for compressed air energy storage

Abstract

With the aim of addressing the large-scale engineering fracture problems in an underground cavern for compressed air energy storage (CAES), in this study, a coupled thermal-gas-mechanical (TGM) phase-field modeling for simulating fracture initiation and propagation in the CAES caverns is proposed. This study also focuses on COMSOL Multiphysics strategy of the TGM phase-field fracture modeling. The temperature field, air seepage field, displacement field, initial geostress field, and phase field are fully coupled and solved in COMSOL. A circular preexisting fracture zone is generated and used to initialize the fracture propagation according to the newly specified history strain field. The results indicate that the proposed TGM phase-field modeling and the corresponding COMSOL implementation strategy can simulate the thermodynamic responses and fracture initiation and propagation well. The lateral pressure coefficient and gravitational stress field have a strong impact on the fracture patterns and critical pressure, inducing fractures.