A laboratory investigation of bed-load transport of gravel sediments under dam break flow

Khosravi, Khabat, Chegini, Amir, Cooper, James , Mao, Luca, Habibnejad, Mahmood, Shahedi, Kaka and Binns, Andrew (2021) A laboratory investigation of bed-load transport of gravel sediments under dam break flow. International Journal of Sediment Research, 36 (2). pp. 229-234. ISSN 1001-6279

Full content URL: https://doi.org/10.1016/j.ijsrc.2020.08.005

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A laboratory investigation of bed-load transport of gravel sediments under dam break flow
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Abstract

Dam break flows and resulting river bed erosion can have disastrous impacts on human safety, infrastructure, and environmental quality. However, there is a lack of research on the mobility of non-uniform sediment mixtures resulting from dam break flows and how these differ from uniform sized sediment. In this paper, laboratory flume experiments revealed that coarse and fine fractions in non-uniform sediment had a higher and a lower bed-load parameter, respectively, than uniform sediments of the same size. Thus, the finer fractions were more stable and the coarser fractions were more erodible in a non-uniform bed compared to a uniform-grained bed. These differences can be explained by the hiding and protrusion of these fractions, respectively. By investigating changes in mobility of the mixed-size fractions with reservoir water levels, the results revealed that at low water levels, when the coarser fractions were only just mobile, the bed-load parameter of the finer fractions was higher than the coarser fractions. The opposite was observed at a higher water level, when a significant proportion of the coarsest fractions was mobilized. The higher protrusion of these grains had an important effect on their mobility relative to the finer grains. The transported sediment on these mixed-sized beds was coarser than the initial bed sediment, and became coarser with an increase in reservoir water level.

Keywords:Dam break, Bed-load transport, Gravel, Laboratory flume
Subjects:F Physical Sciences > F820 Geomorphology
Divisions:College of Science > School of Geography
ID Code:45351
Deposited On:25 Jun 2021 09:35

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