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The phase-field method was used to simulate the propagation of concrete cracks and failure caused by corrosion and expansion of steel bars, which provides ideas for accurate simulation of the corrosion failure process of reinforced concrete (RC) and evaluation of structural durability. In this study, the entire process of corrosion and expansion of steel bars, resulting in cracks and finally falling off of the concrete protective layer, was successfully simulated. The simulation results were in good agreement with the actual observations. By setting different thicknesses of the protective layer, it was found that the thickness of the concrete protective layer had no obvious effect on limiting concrete cracks caused by the corrosion of steel bars. However, increasing the thickness of the protective layer can delay the speed of crack propagation. Simultaneously, considering the corrosion and expansion of multiple steel bars, according to the thickness of the protective layer and the spacing between the reinforcing bars, two forms of wedge-shaped cracking and laminar spalling of the protective layer are simulated. The simulation result is consistent with the actual observation phenomenon. This fully illustrates the possibility of using the phase-field method to simulate the corrosion fracture of RC and provides a reference for the engineering design and durability research of concrete structures.

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Clarifying the origins of fractures and adopting acceptable repair plans are crucial for the design, maintenance, and safe operation of concrete gravity dams. In this research, numerical simulation is largely utilized to investigate the reasons for fractures in the anti-arc portion of the concrete gravity dam and the top of a substation tunnel in Guangdong Province, China. The calculation parameters are chosen based on the design information and engineering expertise to model the temperature field and stress field distribution of the dam during both normal operation and severe weather. The study demonstrates that under the effect of severe structural restraints and high temperatures, the tensile stress at the top of the substation tunnel would be 2.64 MPa in the summer, which is more than the tensile strength by 1.5 MPa and causes deep cracks. The tensile stress reaches 3.0 MPa in the summer under the effect of severe weather near the top of the substation tunnel. When a cold wave strikes in the winter, the concrete’s tensile stress on the overflow dam surface rises from 1.6 MPa to 4.0 MPa, exceeding the tensile strength by 1.9 MPa, resulting in the formation of a connection fracture in the reverse arc section. Both the actual observed crack location and the monitoring findings of the crack opening, as determined by the crack gauge, agree with the modeling results. The technique to lessen the structural restrictions of a comparable powerhouse hydropower station is pointed out based on engineering expertise, and various and practical repair strategies are proposed to guarantee the structure’s safe operation.