Abstract:The impact and destructive capacity of debris flow on bridge piers are influenced by factors such as debris flow velocity, solid matter content, and solid particle composition. On this basis, a novel protective grille designed to shield bridge piers from debris flow erosion is proposed. The protective grille works by continuously regulating the solid particles in the debris flow, reducing the bulk density, the solid particle size, and impact force, thereby effectively protecting the bridge piers. A series of laboratory model tests were carried out to investigate the impact of structural parameters on the protection effect. Results indicate that: (1) As the drainage angle increases, the reduction rates of bulk density and coarse particle content in the debris flow within the grille initially increase and then decrease, following a quadratic function relationship; (2) As the grille span increases, the reduction rates of bulk density and coarse particle content consistently increase, displaying a linear relationship; (3) The scour height of the debris flow at the grille decreases as the relative opening spacing of the grille increases, showing an exponential function relationship. By contrast, the scour height gradually increases with the drainage angle, exhibiting a linear relationship. Meanwhile, through theoretical analysis, a method was developed to determine the structural parameters of the novel grille, including the drainage angle, span, height, and spacing. This approach provides a foundation for engineering design.
