Fracture initiation and propagation in the lined underground caverns for compressed air energy storage: Coupled thermo-mechanical phase-field modeling

In this study, to investigate the mechanism of fracture initiation and propagation in the CAES caverns, a coupled thermo-mechanical phase-field model (PFM) considering cavern excavation is proposed. The proposed PFM is coupled with the thermodynamic process of CAES and solved in COMSOL Multiphysics. To verify the capability and accuracy of the numerical model for predicating the tensile cracks of the CAES caverns, the numerical results obtained by using the proposed model are compared with the existing analytical and numerical results. The influence of the lateral pressure coefficient, critical energy release rate, elastic modulus of rock mass and buried depth on the fracture patterns and critical internal pressure is investigated. The results indicate that the fracture patterns are mainly related to the lateral pressure coefficient. As the lateral pressure coefficient of rock mass increases, the tensile fractures gradually deflect to the horizontal direction. With the increase in the lateral pressure coefficient, critical energy release rate, elastic modulus and buried depth, the critical internal pressure inducing the tensile fractures of the CAES caverns increases.