Author(s): Asataro Shinohara; Yasuo Nihei; Yuki Kurakami; Kengo Suzuki
Linked Author(s):
Keywords: River levee; Crest reinforcement; Erosion; Large-scale model test; Structural measure
Abstract: Extreme rainfall frequently causes levee breaches and subsequent large-scale flood disasters throughout the world. The objective of our research was to test the effectiveness of structural measures under extreme flood conditions. Reinforcement technology was used for the levee crest to increase the river levees’ resistance against overtopping, and the effects of crest improvement were examined using laboratory experiments with small- and large-scale model levees under overtopping conditions. Two types of crest reinforcement technology are proposed: the first is to increase the rigidity of the levee crest, and the second is to cover the rigid pavement from the crest to the top of the back slope. The height of the model levees was set at 0.2 m and 1.0 m in the small- and large-scale tests, respectively. Hokota sand with d50=0.2 mm was used as a levee material. The results indicated that the two types of crest reinforcements significantly increased the resistance of the river levee against overtopping. The rigid pavement can ensure the position of the crest is maintained, even after the levee material under the crest is eroded. The rigid pavement from the crest to the top of the back slope has higher resistance because the separation point of the overflow water is moved in the downstream direction. These experimental results show similar patterns on small-scale and large-scale model levees, indicating the reliable performance of the present reinforcement technology to prevent overtopping.
Year: 2018