Hydro-morphological Behaviour Around Erosion Protective Structure With Downward Seepage

Abstract

River bank protection is crucial in hydraulic river engineering to safeguard natural rivers, lands, and critical structures like bridges. Spur dikes, aimed at diverting flow from the bank and decreasing velocity, are effective in preventing erosion. Achieving stable river banks and sustainable foundations necessitates an in-depth understanding of scour processes, precise scour depth assessment, and meticulous planning for spur dike installation. This study aimed to optimize spur dike shapes (T-shape, L-shape, and rectangular) for managing flow turbulence and reducing local scour, considering the effect of downward seepage. Results showed that T-shaped dikes had the lowest scour depths, both with and without seepage. Without seepage, L-shaped dikes had the greatest scour depth, but with seepage, rectangular dikes had the deepest scour. Maximum velocity was observed near the water surface around rectangular dikes, and this increased with seepage. T-shaped dikes, in contrast, exhibited weaker velocities. The negative impact on velocity and RSS magnitude was observed at the near channels bed at maximum scour depth and was linked to flow reversal, horseshoe vortices, and particle detachment, which was accelerated by downward seepage, deepening scour depressions.