Non-uniform sediment incipient velocity

Xu, Haitao; Lu, Jinyou; Liu, Xiaobin

doi:10.1016/s1001-6279(08)60006-2

Cited by 26 publications

(18 citation statements)

References 3 publications

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“…The incipient velocity for non-uniform sediment varies more in comparison with that of uniform sediment. Advances in the non-uniform sediment movement play a key role in theoretical analysis and engineering practice pertaining to channel and reservoir design, physical sediment model analysis and numerical simulation (Xu et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Armour Layer Analysis of Local Scour around Bridge Abutments Under Ice Cover

Hirshfield

Sui

2014

River Research & Apps

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A set of experiments was conducted for the local scour around bridge abutments under ice cover in non‐uniform sediments. By taking into account of the grain size of the armour layer and ice cover roughness, the dimensionless maximum scour depth is analysed. With an increase in grain size of the armour layer, the dimensionless maximum scour depth decreases. With the increase in ice cover roughness, the dimensionless maximum scour depth increases correspondingly. By using dimensional analysis, a regression relationship supports this conclusion. The conclusions drawn from this study provide crucial evidence for the protection of bridge foundations in winter time. Copyright © 2014 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Armour Layer Analysis of Local Scour around Bridge Abutments Under Ice Cover

Hirshfield

Sui

2014

River Research & Apps

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“…In his proposed bed-load function, he used a comprehensive hiding factor to represent the interaction effects between the coarse particles and the fine particles. Ever since, several researchers have developed formulae to determine the incipient motion of nonuniform sediment mixtures [46,47]. For instance, Xu et al [47] studied the incipient velocity of nonuniform sediment.…”

Section: The Incipient Motion Of Sediment Particles Under Ice-coveredmentioning

confidence: 99%

“…Ever since, several researchers have developed formulae to determine the incipient motion of nonuniform sediment mixtures [46,47]. For instance, Xu et al [47] studied the incipient velocity of nonuniform sediment. As pointed out by Xu et al [47], the incipient velocity for the coarse particles of the nonuniform sediment is less than that for same particle size of uniform sediment, and the incipient velocity for the finer particles of the nonuniform sediment is greater than that for the same particle size of uniform sediment (Figure 2).…”

Section: The Incipient Motion Of Sediment Particles Under Ice-coveredmentioning

confidence: 99%

Experimental Study of Local Scour around Side-by-Side Bridge Piers under Ice-Covered Flow Conditions

Namaee¹,

Sui²,

Wu³

2020

Current Practice in Fluvial Geomorphology - Dynamics and Diversity

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A precise prediction of maximum scour depth (MSD) around piers under icecovered conditions is crucial for the safe design of the bridge foundation. Due to the lack of information for local scour under ice-covered flow condition, it is extremely hard to give proper estimation of MSD. In the current study, a set of flume experiments were completed to investigate local scour around four pairs of circular bridge piers with nonuniform bed materials under open channel, smooth and rough ice cover conditions. Three different bed materials with median particle size of 0.47, 0.50, and 0.58 mm were used to simulate natural river conditions. Regardless of pier size, the maximum scour depths were observed in front of the piers under all flow conditions. Additionally, a smaller pier size and a larger space between piers yield a smaller scour depth. Results showed that the maximum scour depth decreases with increase in the grain size of armor layer. The distribution of vertical velocity shows that the strength of downfall velocity is the greatest under rough ice cover. Empirical equations were developed to estimate the maximum scour depth around side-by-side bridge piers under both open-channel and ice-covered flow conditions.

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“…Chen and Xie (1988) found that the equivalent roughness of nonuniform sediment depends not only on large diameter grains but also on the coarse sand distribution as influenced by the current velocity near the bottom of a river. Applying the nonuniform sediment exposure height and grain size, Sun (1996) deduced the nonuniform sediment incipient velocity formula, which was also studied by Han and He (2000), Liu et al (2000), Wu et al(2000), and Xu (2008). Yang et al (2008) developed a flormula to describe the incipient velocity based on the relation of force vectors upon and the exposure degree of the particles, but that formula was only suitable for sand and fine gravel.…”

Section: Threshold For Incipient Motion Based On Repose Angle Of Nonumentioning

confidence: 99%

Bed load transport rates during scouring and armoring processes

et al. 2010

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Dambreak-induced bed scouring may undermine the foundation of bridge piers and other structures, and that destruction can pose a serious threat. Consequently, this paper aims at exploring the mechanisms of scouring and armoring. Firstly, the incipient velocity for nonuniform sediment particles was studied, and a formula was derived based on the angle of repose of nonuniform sediment. The results showed that the mechanism of incipient motion for sand and fine gravel differed from that for coarse gravel and cobbles. Also, comparison between experimental and field data shows that the results from the proposed formula agree well with those observed for all conditions. Secondly, a birth-death, immigration-emigration Markov process was developed to describe the bed load transport rate associated with scouring and armoring. The comparison between experimental data and computed results shows that our model can predict the bed load transport rate, although there may be some limitations, the chief of which is that there are many variables in the model to be determined through experiment. This makes its application in river engineering inconvenient.

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Non-uniform sediment incipient velocity

Cited by 26 publications

References 3 publications

Armour Layer Analysis of Local Scour around Bridge Abutments Under Ice Cover

Armour Layer Analysis of Local Scour around Bridge Abutments Under Ice Cover

Experimental Study of Local Scour around Side-by-Side Bridge Piers under Ice-Covered Flow Conditions

Bed load transport rates during scouring and armoring processes

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