Search

Anti-sliding stability safety is a critical issue that must be given sufficient and widespread attention during the entire lifecycle of gravity dams. The calculated anti-sliding stability safety factor (ASS-SF) is usually compared with the allowable value required by the standards in the traditional method, which ignores the influence of material parameter uncertainties and leads to unreasonable safety evaluation results. Therefore, the nonlinear functional relationship between the stability safety factor (SF) and the random variable parameters is constructed based on the response surface equations, and the distribution types of SF sequences calculated by the Monte Carlo sampling are determined, then a probabilistic stability evaluation method for concrete gravity dams is proposed. Engineering application shows that the calculated SF obeys the normal distribution; the minimum guaranteed rate of different sliding paths in a gravity dam is 86.66%, and the guaranteed rate for the overload safety factor (OSF) is 36.00%. The results imply that a guaranteed rate for the allowable value of the ASS-SF should be provided when making the stability safety evaluation of the dams, especially the OSF. The outcome of this research will advance the understanding of stability evaluation of concrete dams, and reduce the potential risk of sliding instability of concrete dams. [ABSTRACT FROM AUTHOR]

The performance of corrosion-induced cracking of reinforced concrete members under transverse constraints was studied. Based on the theory of elastic-plastic mechanics and the hypothesis of uniform corrosion of a steel bar, a three-layer hollow cylinder model was established to predict the critical corrosion of the steel bar at the time of the cracking of the concrete cover. Taking the constraint of stirrups on surrounding concrete into consideration, it can be used to predict the corrosion rate of members with stirrups at the time of the cracking of the concrete cover, which further expands the application range of the corrosion-induced cracking models of concrete. On this basis, the critical corrosion rate of concrete under different stirrup ratios at the time of cracking was measured. The calculated results of the model are in accordance with experimental data. For corner steel bars, when the stirrup spacing is less than 100 mm, the existence of stirrups can effectively delay the occurrence of rust expansion cracks and enhance the durability of the structure. On the basis of this study, the problem of corrosion expansion and cracking of the concrete cover caused by non-uniform corrosion of steel bars along longitudinal and radial directions needs to be further studied in the future. [ABSTRACT FROM AUTHOR]

The wetting deformation of the upstream dam shell material during the impoundment of the core wall rockfill dam seriously affects the safety of the dam. Based on the proposed E w - ν w wetting model, this paper proposes its corresponding two methods to simulate the collapse settlement of the rockfill dam: the initial strain method and the initial stress method. By simulating the collapse settlement of the Guanyinyan core wall rockfill dam, it is found that the simulated result using the initial stress method is in good agreement with the field monitoring data, while the displacement simulated using the initial strain method is larger. The distribution of displacement contours simulated using the initial strain method is obviously inconsistent in the area where the wetting deformation occurs, and the simulation results of the initial stress method are more reasonable. With the rise in the water level, the wetting deformation of the upstream dam shell material causes the tensile stress zone at the top of the dam. Therefore, the wetting deformation is the direct cause of the crack at the top of the dam, and the initial stress method should be preferred in the simulation of the wetting deformation of rockfill materials., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Litan Pan et al.)