Experimental and numerical study of the tidal bore impact on a newly-developed sheet-pile groin in Qiantang river

Abstract An experimental study of the tidal bore impact on an innovatively-developed Sheet-Pile Groin (SPG) was conducted in a circulating flume. The water levels, tidal bore propagation velocity, temporal and spatial pressure distributions on a SPG were measured and analyzed. Then the pressure difference between the front and rear of the SPG piles was predicted and analyzed by FLOW 3D under various SPG perviousness ratio. The tidal bore height was a good index of the tidal bore strength and a good linear relationship was observed between the initial Froude number and the relative tidal bore height. The maximum rise of the water level at the SPG could reach 2.5 times the tidal bore height. The tidal bore pressure on the SPG can be reduced significantly by increasing the SPG perviousness ratio, especially when the tidal bore is high. The pressure difference between the front and rear of the pile distribute as an inverted trapezoid along the pile depth and can be significantly reduced with the increase of SPG perviousness ratio. These findings can provide guidelines for the design of the newly-developed SPG in tidal bore zone.