Author(s): Kazumasa Matsumoto; Xujian Wu; Michio Sanjou; Taka-Aki Okamoto; Takahiro Koshiba; Tetsuya Sumi

Linked Author(s): Kazumasa Matsumoto

Keywords: Self-lining; Abrasion countermeasure; Strip roughness; Sediment deposition; PIV

Abstract: Abrasion countermeasures for sediment bypass tunnels (SBTs) are necessary to improve utility and sustainability of dams. This study focuses on a countermeasure by self-lining in which strip roughness elements are attached to a tunnel invert to enhance sediment deposition and thereby to relieve damage by collision with large gravel. The purpose of this study is to reveal the flow structure and the sediment deposition mechanisms over triangular strip roughness elements to investigate the feasibility of the self-lining method. First, flow velocity measurements by particle image velocimetry (PIV) were performed to reveal the flow structure between the roughness elements. Second, sediment deposition experiments were conducted to observe the deposition processes between the roughness elements and to evaluate the coverage rate of a channel bottom. To clarify optimal setups and hydraulic conditions for self-lining, nine cases with different roughness intervals and Froude numbers were considered. Results of the experiments suggest that downward flows between roughness elements cause bed scouring and prevent the sediment deposition on the channel bottom.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1682-cd

Year: 2025