关键词: 压气储能地下洞室, 钢筋混凝土衬砌, 裂缝演化规律, 内聚力模型

Abstract: To reveal the full-process evolution of cracks at critical locations in reinforced concrete linings of underground caverns for compressed air energy storage (CAES) under high internal pressure, from crack initiation and propagation to penetration, a lining fracture analysis model based on zero-thickness cohesive elements is established. The cohesive parameters and crack-width calculation method are validated through lining model tests. The quadratic nominal stress criterion is adopted to determine crack initiation, and the Benzeggagh-Kenane criterion is used to describe the evolution of mixed-mode fracture energy. Based on this model, a case study of an underground CAES cavern is conducted to analyze the crack initiation pressure, penetration pressure, and crack-width evolution at typical lining orientations. The effects of the lateral pressure coefficient and reinforcement ratio on the fracture behavior of the lining are further investigated. The results show the following: (1) The lining cracks propagated radially in the model test. The crack initiation pressure predicted by the numerical model was approximately 0.19 MPa, deviating by approximately 9.5% from the experimental value of 0.21 MPa. The variation in crack width with increasing internal pressure was basically consistent with the test results. (2) Under the characteristic engineering conditions considered in this study, cracks first initiated at the midpoint of the lower lining wall, with an initiation pressure of approximately 5.33 MPa and a penetration pressure of approximately 5.87 MPa. For cracks at other typical orientations, the initiation pressure ranged from 5.58 to 6.97 MPa. Throughcracks formed when the internal pressure increased by 0.25－0.60 MPa after crack initiation. At an internal pressure of 13.00 MPa, the maximum crack width reached 0.44 mm, indicating rapid crack penetration and nonlinear crack opening after initiation under high internal pressure. (3) The lateral pressure coefficient affected crack development at different lining orientations. When the lateral pressure coefficient was close to 1.0, the lining experienced a relatively uniform stress distribution, and crack widths at critical locations were small. Under the engineering conditions considered in this study, the maximum crack width could be significantly reduced by increasing the reinforcement ratio to approximately 2.5%. Additional reinforcement measures are still required in zones where cracks are excessively wide.

Key words: compressed air energy storage underground caverns, reinforced concrete lining, crack evolution behavior, cohesive model