Cross-scale refined analysis and reinforcement design for the rigid-flexible mixed region in hybrid dams

Abstract

To energizing implementation of “Carbon Peaking and Carbon Neutrality” strategy, a batch of pumped storage power stations represented by asphalt concrete panel dams have been planned in China. The safety assessment of the anti-seepage system is crucial to engineering construction. In this paper, a cross-scale approach and SBFEM are employed to investigate the deformation characteristics of a typical dam under various conditions, combining the generalized plastic model. The location of the weak area in the anti-seepage system is identified. Subsequently, a fresh step-type design is proposed based on simulations, aiming to enhance the stability performance of anti-seepage joint. The mechanism and influence of the step-type scheme are discussed from different perspectives through simulations. The research indicates that the asphalt panel slides along the underlying lapped concrete platform due to the uneven settlement between rockfill and concrete. Resulting in significant horizontal tensile strain at the top of the asphalt panel. The step-type design provides a positive reinforcement effect, significantly reducing slipping displacements along the interface and the tensile strain of the asphalt panel by hindering the slip path of the rockfill. An optimal range for the step-type design is recommended to be between 0.375 m and 0.45 m below the junction point. Additionally, a height of 0.45 m is suggested for the single-step form, while a height of 0.075 m is recommended for each step in the multiple-step form. For multiple steps, performance improves as the spacing between the steps increases. The adaptability of the panel to deformation is enhanced through the presented method, enhancing the safety margin of the anti-seepage system and offering guidance for similar projects.