Index test for the degradation potential of carbonate sands during hydraulic transportation

Ngan-Tillard, D.J.M.; Haan, J. F. de; Laughton, David G.; Mulder, A.; Kolff, Art Nooy van der

doi:10.1016/j.enggeo.2009.06.005

Cited by 12 publications

(6 citation statements)

References 5 publications

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“…Based on the Bed Behavior Diagram proposed by Mellmann (2001), the type of particle movement of all RUNs is similar. In addition, Ngan-Tillard et al (2009) found that the degradation of sand particles during Micro-Deval test is mainly influenced by the mass ratio between sand and steel balls. Therefore, the major factor affecting the damage of gravel during rotation should be the mass ratio between the gravel and the steel balls.…”

Section: Micro-deval Testingmentioning

confidence: 99%

Multi-scale particle morphology evolution in rotating drum tests: Role of particle shape and pore fluid

Yao

Yang

Lourenço

et al. 2022

Engineering Geology

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Section: Micro-deval Testingmentioning

confidence: 99%

Multi-scale particle morphology evolution in rotating drum tests: Role of particle shape and pore fluid

Yao

Yang

Lourenço

et al. 2022

Engineering Geology

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“…Their kurtosis values should be similar whether grain sizes are derived from bulk or carbonate‐free sediment (in these cases, all bioclastic particles have been fragmented). In contrast, poorly‐sorted sediments have different kurtosis values between bulk and carbonate‐free samples and sorting coefficients >1.0, indicating that carbonate particles are less fragmented (Folk, 1966; Force, 1969; Heathershaw & Codd, 1986; Ngan‐Tillard et al ., 2009).…”

Section: Methodsmentioning

confidence: 99%

Wave‐influenced deposition of carbonate‐rich sediment on the insular shelf of Santa Maria Island, Azores

et al. 2022

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Formulae for sediment thresholds of motion are commonly based on flume experiments on rounded quartz particles and it is unclear how well they predict thresholds in natural settings. Here, sediment threshold shear stresses were calculated from one such formula using surface grain‐size data from 112 sites around Santa Maria Island, Azores. To compare with those stresses, a Simulating Waves Nearshore model was run for three typical winter months to predict shelf stress maxima due to waves. As wind‐driven and other circulations also increase stresses, the model predictions are under‐estimates. Comparison of the two stress estimates suggests that the whole shelf of the island was mobile during extreme conditions. However, three forms of evidence contradict this. First, 129 rollovers of sandy clinoforms lying in 30 to 200 m water depths around the island were identified from boomer seismic data. It has been suggested that such rollovers mark depths at which hydrodynamic stresses fall beneath the sediment threshold of motion. Second, differences in grain‐size diversity between carbonate‐free and whole sediment indicate where carbonate particle fragmentation occurs. Third, seabed images reveal variations in ripple character and presence. The combined data suggest that deposition has occurred in the middle and outer shelf, overlapping where the model predicts sediment mobilization. However, by decreasing the model bottom shear stress or increasing the shear stress at threshold of motion by a factor of two to three, deposition is predicted to have occurred immediately deeper than the shallow active rollovers. Therefore, in practice, the ratio of wave‐imposed shear stress to stress at threshold of motion is two to three times smaller than predicted. This is speculated to be due to the presence of widespread hard substrates and other features shielding particles between them from wave stresses. Alternatively, the threshold of motion is higher than expected from the formulae for these sediments dominated by bioclastic particles.

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“…Note that the fraction of fines may be a composite of the fines available in the soil and those created or removed by the work method. Additional fines can be created due to degradation during dredging (Ngan-Tillard et al, 2009). Hydraulic transport, pump impeller impact, but also crushing by cutter head, drag head or bucket can cause a significant creation of fines.…”

Section: Assess the Total Amount Of Available Finesmentioning

confidence: 98%

Estimating source terms for far field dredge plume modelling

Becker¹,

Eekelen²,

Wiechen³

et al. 2015

Journal of Environmental Management

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Index test for the degradation potential of carbonate sands during hydraulic transportation

Cited by 12 publications

References 5 publications

Multi-scale particle morphology evolution in rotating drum tests: Role of particle shape and pore fluid

Multi-scale particle morphology evolution in rotating drum tests: Role of particle shape and pore fluid

Wave‐influenced deposition of carbonate‐rich sediment on the insular shelf of Santa Maria Island, Azores

Estimating source terms for far field dredge plume modelling

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