IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Water engineering : Study of breach characteristics and scour pattern for overtopping induced river dyke breach
Study of breach characteristics and scour pattern for overtopping induced river dyke breach
Author : PAWAN KUMAR BHATTARAI(1), HAJIME NAKAGAWA(2), KENJI KAWAIKE(3) & HAO ZHANG(4)
ABSTRACT
Every year flood discharge induced overtopping flow through river dykes causes large damage to society, the environment and infrastructure. Although several researches have been conducted to understand embankment dam failure, there has been little focus on river dyke breaches. The dynamic lateral widening of the breach process, resulting flow and sediment hydrographs and the scour beneath or downstream of dyke are poorly understood. Therefore, elaborate laboratory tests were conducted to investigate the dynamic lateral widening process, breach characteristics and scour process. The experimental model is constructed in Ujigawa open laboratory, DPRI, Kyoto University, Japan. The 1m long and 15cm high homogenous non-cohesive dyke is prepared along the 4m long river flume placed parallel to the river flow and a small pilot channel is made at the center of the dyke to initiate the widening process. The entire process was recorded optically using video and three-dimensional cameras for detailed analysis of the breaching phenomena and the discharge of flow and sediments are measured downstream of dyke by collecting box method. For the determination of scour process, the foundation and the downstream bed are also made movable and equilibrium scour patterns are observed for two scenarios by laser measurement.
The result indicates the important effect of particle size on the dynamic lateral widening process, breach discharge and the scour pattern. The result shows the impact of particle size on the widening process, resulting hydrograph and scour pattern. Finer Sediment sizes show resistance to erosion and failure as well as higher scour at the foundation whereas coarser particles show opposite characteristics. The maximum scour depth is seen to follow approximately linear relation with the sediment size and the location of such scour is observed within the center of dyke towards the toe.
File Size : 1,493,416 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Water engineering
Date Published : 18/08/2015
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