Failure analysis of arch dam under fault action based on inter-generational coordination

Complex geological faults play a crucial role in the site selection and construction of dams. In this paper, considering the intergenerational coordination theory and addressing the complex geological fault conditions of the LCGX hydropower project, the entire life cycle of the arch dam is divided into four stages: initial state, dam foundation excavation, arch dam casting, and reservoir operation. Improved multiple linear regression with modified boundary conditions is employed for the inversion of initial stress, considering the unloading effects caused by dam foundation excavation and the temperature differentials arising from concrete hydration during arch dam casting, and considering the effective stress principle during the water storage operation stage. Based on the above considerations, the whole life cycle of LCGX arch dam from initial state to excavation and casting operation and maintenance is analyzed, including the impact of faults in the LCGX dam site area on the arch dam. The water pressure overload method is employed to evaluate the safety of the arch dam. And the concrete grid backfill replacement is carried out by the combination of open excavation and hole excavation. The results indicate that faults have varying degrees of influence across different stages of intergenerational coordination, with f119 and F115 showing more pronounced effects. In the overload calculation, the f119 fault, along with the hazardous rock mass formed by cutting the foundation surface, and the f124 fault, cause the arch dam to undergo displacement, thus the arch dam occurs shear failure, the reinforcement greatly improves the safety of arch dam. This study systematically investigates the arch dam and slope displacement caused by complex geological faults in the LCGX hydroelectric project dam site area. It explores the specific impact of faults on the arch dam, providing essential references for structural safety during dam maintenance.