Sediment deposit thickness and its effect on critical velocity for incipient motion

Bong, Charles Hin Joo; Lau, Tze Liang; Ghani, Aminuddin Ab.; Chan, Ngai Weng

doi:10.2166/wst.2016.376

Cited by 26 publications

(11 citation statements)

References 14 publications

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“…In slurry transportation, the minimum hydrodynamic velocity at which particles leave a crack beneath the flow is called the incipient [32][33][34][35][36][37][38] or accumulation velocity. At the incipient velocity, particles start to move by rolling and migration.…”

Section: Model Of Optimal Plugging Flow Ratementioning

confidence: 99%

Cement Slurry Plugging Law and Optimal Plugging Flow Rate at a High Hydraulic Gradient

Jia

Liu

et al. 2021

Advances in Civil Engineering

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With the continuous development of coal and rock mass engineering, water inrush grouting has become an urgent problem in engineering disaster management. Herein, a theoretical model of the optimal plugging flow rate was established, and a comparative theoretical analysis was performed based on the results of indoor model tests. The particle incipient velocity was defined as the optimal plugging flow rate. The effects of hydrodynamic velocity, water-cement ratio, grouting pressure, and fracture aperture on the cement slurry grouting plugging were studied, and the optimal threshold of the plugging flow rate was obtained for theoretical model verification. Results showed that, at a high hydraulic gradient, the plugging effect of the grout was mainly affected by the hydrodynamic velocity, water-cement ratio, and grouting pressure (listed in the order of importance). When the hydrodynamic velocity was low, the difference in the slurry deposition thickness was large under different water–cement ratios and pipe diameters. When the hydrodynamic velocity was increased, the influence of various factors on the slurry deposition thickness decreased. Through a comparative analysis of the experimental and theoretical values, the optimal plugging velocity of pure cement slurry was 0.5–0.55 m·s−1 under different conditions, and the error between the experimental and theoretical values was less than 0.1 m·s−1, which confirmed the rationality of the proposed model.

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Section: Model Of Optimal Plugging Flow Ratementioning

confidence: 99%

Cement Slurry Plugging Law and Optimal Plugging Flow Rate at a High Hydraulic Gradient

Jia

Liu

et al. 2021

Advances in Civil Engineering

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“…Detailed studies reported that various criteria for incipient motion of sediment are mainly based on dimensionless shear stress (Beheshti and Ataie-Ashtiani 2008, Cao et al 2006, Cheng 2004 and critical shear velocity (Bong et al 2016, Mao et al 2011, Zhao et al 2013. Various values of dimensionless shear stress were proposed in different literatures, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, shear velocity is another criterion frequently employed to predict incipient motion of sediment. Bong et al (2016) conducted lots of experiments, and analyzed the effect of deposition thickness on incipient motion of sediment according to the criterion for velocity. May (2003) and Zounemat-Kermani et al (2018) reported different kinds of formulas on basis of shear velocity, describing the incipient motion of sediment under different conditions.…”

Section: Introductionmentioning

confidence: 99%

Critical runoff depth estimation for incipient motion of non-cohesive sediment on loose soil slope under heavy rainfall

Yuan

Neng

et al. 2019

Geomatics, Natural Hazards and Risk

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Incipient motion of non-cohesive sediment, as a branch of water erosion, has been studied for decades, and criteria proposed in predicting incipient motion mainly focus on dimensionless shear stress and shear velocity. The two parameters could provide runoff erosive power, however, are invisible and not easy-measured in experiment. In this paper, critical runoff depth was recognized as another parameter, which is visible, measurable, and closely connected with shear velocity. To get it, a mathematical model coupling surface flow and subsurface flow was established, and they are governed by Navier-Stokes equation and Brinkman-extended Darcy equation, respectively. Velocity derived from the model could be indirectly applied in particle force analysis and finally a new criterion about critical runoff depth was obtained. Accuracy of the criterion was verified by comparison of experimental and theoretical values, e.g. theoretical critical runoff depth ranges from 2.71 $ 1.14 mm with a slope angle range of 20 $ 28 and mean particle diameter of 2.5 mm while the corresponding experiment values ranges from 3 $ 1 mm and the absolute errors are less than 0.3 mm. Compared with Yang's formula, this criterion could also be applied in predicting incipient motion of non-cohesive sediment for its significant advantages of high accuracy and concise formulation.

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“…Selfcleansing is defined by May, Ackers, Butler, and John (1996), Butler, May, and Ackers (2003), and Safari, Aksoy, Unal, and Mohammadi (2017a), as a flow condition in which Research Article accumulated sediment at the channel bottom should be removed (bed sediment motion criteria) or sediment particles which are transported through the flow should be retained in motion (nondeposition criteria). The former covers the "incipient motion" and "scouring" criteria (Bong, Lau, & Ab Ghani, 2013;Bong, Lau, Ab Ghani, & Chan, 2016;Novak & Nalluri, 1984;Safari, Aksoy, Unal, & Mohammadi, 2017b) while the latter includes "nondeposition with and deposited bed, " "nondeposition without deposited bed, " and "incipient deposition" conditions (Aksoy, Safari, Unal, & Mohammadi, 2017;Ota & Nalluri, 2003;Ota & Perrusquía, 2013;Safari, Aksoy, & Mohammadi, 2015Safari & Danandeh Mehr, 2018;Safari, Shirzad, & Mohammadi, 2017;Vongvisessomjai, Tingsanchali, & Babel, 2010). Detailed comparison of the different self-cleansing criteria is reported in Safari, Mohammadi, and Ab Ghani (2018).…”

Section: Introductionmentioning

confidence: 99%

Self‐cleansing design of sewers: Definition of the optimum deposited bed thickness

Safari

Shirzad

2019

Water Environment Research

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Sediment deposits may influence the performance of the sewer systems. Sediments are the main store of pollutants which causes sewer systems overflows. In order to prevent the deposition of sediment in sewer systems, self‐cleansing design criteria are used. Among various criteria, “self‐cleansing with deposited bed” criterion is found appropriate for designing of large sewers. Allowing small thickness of deposited bed in large sewers decreases the required channel bed slope and construction costs. This study presents a bed load self‐cleansing model established on wide ranges of experimental data. Comparison of developed model with the existing models in the literature shows its higher performance on variety of data sources. Examples for the application of the model are presented, and design graphs and charts for different pipe sizes are proposed. As a result, the optimum deposited bed thickness is found 1%–5% of the pipe diameter; however, 1% is recommended for sewer pipes design. Practitioner points Nondeposition sediment transport condition with a bed deposit criterion is found appropriate for large sewer pipe design. The precision of a model is linked to the ranges of experimental data and parameters used for the models development. The optimum range of deposited bed thickness can be adopted in the range of 1% to 5% of the pipe diameter.

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Sediment deposit thickness and its effect on critical velocity for incipient motion

Cited by 26 publications

References 14 publications

Cement Slurry Plugging Law and Optimal Plugging Flow Rate at a High Hydraulic Gradient

Cement Slurry Plugging Law and Optimal Plugging Flow Rate at a High Hydraulic Gradient

Critical runoff depth estimation for incipient motion of non-cohesive sediment on loose soil slope under heavy rainfall

Self‐cleansing design of sewers: Definition of the optimum deposited bed thickness

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