A transient backward erosion piping model based on laminar flow transport equations

2021 ◽  
Author(s):  
Manuel Wewer ◽  
Juan Pablo Aguilar-López ◽  
Matthijs Kok ◽  
Thom Bogaard
Keyword(s):  
Sediment Transport ◽  
Laminar Flow ◽  
Particle Motion ◽  
Model Performance ◽  
Conservation Equation ◽  
Transport Equations ◽  
Bedload Transport ◽  
Internal Erosion ◽  
Backward Erosion Piping ◽  
Sandy Aquifers

<p>Backward erosion piping (BEP) has been proven to be one of the main failure mechanisms of water-retaining structures worldwide. Dikes, which are often built on sandy aquifers, are particularly vulnerable to this special type of internal erosion. In this research, we propose a numerical solution that combines a 2D Darcy groundwater solution with Exner’s 1D sediment transport mass conservation equation. The inclusion of criteria for incipient particle motion, as well as the linkage of the bedload transport rate to the pipe progression, enables us to build a stable time-dependent piping model. As an estimate of sediment transport, we tested four different empirical transport equations for laminar flow. The model performance was evaluated based on the results of a real-scale dike failure experiment. Through this, we were able to demonstrate the applicability of existing sediment transport equations to the description of particle motion during piping erosion. The proposed transient piping model not only predicts the pipe progression in time, it also allows for an identification of pore pressure transitions due to the erosion process. The main finding of the study is that from the four different modeling approaches for laminar flow, it is recommended to follow the approach of Yalin et al. (1963, 1979) to simulate backward erosion piping in dikes.</p>

scholarly journals A transient backward erosion piping model based on laminar flow transport equations

2021 ◽  
Vol 132 ◽  
pp. 103992
Author(s):  
Manuel Wewer ◽  
Juan Pablo Aguilar-López ◽  
Matthijs Kok ◽  
Thom Bogaard
Keyword(s):  
Laminar Flow ◽  
Transport Equations ◽  
Model Based ◽  
Flow Transport ◽  
Backward Erosion Piping

scholarly journals MODELING OF BERM FORMATION AND EROSION AT THE SOUTHERN COAST OF THE CASPIAN SEA

2020 ◽  
pp. 19
Author(s):  
Mohammad Tabasi ◽  
Mohsen Soltanpour ◽  
Takayuki Suzuki ◽  
Ravindra Jayaratne
Keyword(s):  
Sediment Transport ◽  
Caspian Sea ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Transport Equations ◽  
Southern Coast ◽  
Beach Profile ◽  
The Caspian Sea ◽  
Erosion Model ◽  
Wave Conditions

Cross-shore beach profile data from field measurements performed at six locations on the southern coast of the Caspian Sea are used to investigate bathymetry change due to various wave conditions. Beach profile measurements are analyzed and subsequently compared with the results of a berm formation and erosion model. The model comprises distinct empirical sediment transport equations for predicting the cross-shore sediment transport rate under various wave conditions. To yield a berm formation and erosion model, empirical cross-shore sediment transport equations are combined with the mass conservation equation. Simulations results obtained from the model compared well with the measurements, proving the capability of the model in simulating berm formation and erosion evolution.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/FTgAr73h5rA

Sediment transport over fixed deposited beds in sewers - An appraisal of existing models

1997 ◽  
Vol 36 (8-9) ◽  
pp. 123-128 ◽  
Author(s):  
C. Nalluri ◽  
A. K. El-Zaemey ◽  
H. L. Chan
Keyword(s):  
Sediment Transport ◽  
Fixed Bed ◽  
Transport Equations ◽  
Design Criterion ◽  
Pipe Diameter ◽  
Transport Velocity

An appraisal of the existing sediment transport equations was made using May et al (1989) and Ackers (1991) sediment transport equations for the limit of deposition design criterion and with a deposit depth of 1% of the pipe diameter allowed in the sewers. The applicability of those equations for sewers with larger fixed bed deposit depth was assessed, the equations generally over-estimated the transport velocity. Modifications were made to enable the equations to apply to sewers with large fixed bed deposits present.

scholarly journals One-dimensional sediment transport modelling with Engelund–Hansen and Ackers–White transport equations for the Lower Danube River

2021 ◽  
pp. 103-117
Author(s):  
Davor Kvočka
Keyword(s):  
Sediment Transport ◽  
Negative Impact ◽  
Statistical Tests ◽  
Field Measurements ◽  
River Basin Management ◽  
Transport Equations ◽  
Danube River ◽  
Transport Modelling ◽  
1D Modelling ◽  
Sediment Transport Modelling

Sediment transport can have a negative impact on riparian environments, as it can lead to the deterioration of ecological diversity and increase flood risks. Sediment transport modelling is thus a key tool in river basin management and the development of river training structures. In this study, we examined the appropriateness of 1D modelling for total sediment transport loads using the Engelund–Hansen and Ackers–White transport equations for the Lower Danube River. The study evaluated the effect of sediment grading on the accuracy of 1D model results, the appropriateness of 1D sediment transport modelling within technical or engineering projects, and the appropriateness of the Engelund–Hansen and Ackers–White equations for estimating sediment yield in the area of the Lower Danube River. The model results have been compared to field measurements, with the accuracy of the modelling results being evaluated with statistical tests. The obtained results show: (i) the sediment grading does not have a significant impact on the 1D modelling results, (ii) 1D sediment transport modelling gives sufficiently accurate results for practical engineering use (e.g. the estimation of dredging activities), and (iii) the Engelund–Hansen equation is generally better for sediment transport modelling in the Lower Danube River.

scholarly journals Analisa Angkutan Sedimen Pada Hulu Bendung Aepodu Kabupaten Konawe Selatan

2021 ◽  
Vol 2 (1) ◽  
pp. 1-7
Author(s):  
Ramadhan Hidayat Putra ◽  
Amad Syarif Syukri ◽  
Catrin Sudarjat ◽  
Vickky Anggara Ilham
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Suspended Load ◽  
Bedload Transport ◽  
Bed Load ◽  
Average Flow ◽  
Load Transport ◽  
Bed Load Transport ◽  
Transport Analysis

Research on Aepodu Weir Sediment Transport Analysis in South Konawe District, based on observations in the field, Aepodu Weir hasa sediment buildup that has now exceeded the height of the weirlight house. The purpose of the study was to analyze the magnitudeof Aepodu river flow and to analyze the amount of sedimenttransport that occurred in the Aepodu dam. The method used todetermine the amount of bed load transport uses stchoklitscht, whilefor transporting suspended load using forcheimer.The results of the analysis of the average flow of the Aepodu riverwere 3,604 m3/ second. Sediment transport that occurs in Aepoduweir is Bedload transport (Qb) of 291625.771 tons / year, andsuspended load transport (Qs) of 16972,423 tons / year, so that thetotal sediment transport (QT) is 308598,194 tons / year.

scholarly journals Backward erosion progression rates from small-scale flume tests

2021 ◽  
Author(s):  
Axel Montalvo-Bartolomei ◽  
Bryant Robbins ◽  
Jamie López-Soto
Keyword(s):  
Failure Probability ◽  
Internal Erosion ◽  
Small Scale ◽  
Army Corps ◽  
Progression Rate ◽  
Army Corps Of Engineers ◽  
Current State ◽  
Flume Tests ◽  
Temporal Aspects ◽  
Backward Erosion Piping

Backward erosion piping (BEP) is an internal erosion mechanism by which erosion channels progress upstream, typically through cohesionless or highly erodible foundation materials of dams and levees. As one of the primary causes of embankment failures, usually during high pool events, the probability of BEP-induced failure is commonly evaluated by the U.S. Army Corps of Engineers for existing dams and levees. In current practice, BEP failure probability is quantitatively assessed assuming steady state conditions with qualitative adjustments for temporal aspects of the process. In cases with short-term hydraulic loads, the progression rate of the erosion pipe may control the failure probability such that more quantitative treatment of the temporal development of erosion is necessary to arrive at meaningful probabilities of failure. This report builds upon the current state of the practice by investigating BEP progression rates through a series of laboratory experiments. BEP progression rates were measured for nine uniform sands in a series of 55 small-scale flume tests. Results indicate that the pipe progression rates are proportional to the seepage velocity and can be predicted using equations recently proposed in the literature.

Test of selected bed-material load transport models: Nottawasaga River, Ontario

1994 ◽  
Vol 21 (5) ◽  
pp. 770-777 ◽  
Author(s):  
T. J. Chandler ◽  
R. A. Kostaschuk
Keyword(s):  
Sediment Transport ◽  
Engineering Application ◽  
Model Performance ◽  
Material Transport ◽  
Flow Strength ◽  
Transport Models ◽  
Data Scatter ◽  
Load Transport ◽  
Material Load ◽  
Bed Material

Predictions from 13 bed-material load sediment transport models are compared with 19 measurements of bed-material transport in Nottawasaga River, Ontario, using summary plots and geometric statistics. Model selection is based on recent engineering application and suitability for the flow and sediment conditions of the river. The models of Laursen (1958) and Yang (1979) perform best, followed by those of Ackers and White (1973). The models of Van Rijn (1984), Maddock (1976), Karim and Kennedy (1983), Brownlie (1981), and Yang (1973) have considerable data scatter. The models of Engelund and Hansen (1967) and Shen and Hung (1972) are the poorest predictors. Poor model performance is primarily due to overestimation of flow strength needed for particle entrainment and an excessively steep slope in the relations between flow strength and sediment transport. Key words: bed-material load transport models, test, Nottawasaga River.

scholarly journals Passive acoustic measurement of bedload grain size distribution using self-generated noise

2018 ◽  
Vol 22 (1) ◽  
pp. 767-787 ◽  
Author(s):  
Teodor Petrut ◽  
Thomas Geay ◽  
Cédric Gervaise ◽  
Philippe Belleudy ◽  
Sebastien Zanker
Keyword(s):  
Grain Size ◽  
Sediment Transport ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Measurement Techniques ◽  
Bedload Transport ◽  
Transport Processes ◽  
Signal Spectrum ◽  
Inversion Method ◽  
Passive Acoustic

Abstract. Monitoring sediment transport processes in rivers is of particular interest to engineers and scientists to assess the stability of rivers and hydraulic structures. Various methods for sediment transport process description were proposed using conventional or surrogate measurement techniques. This paper addresses the topic of the passive acoustic monitoring of bedload transport in rivers and especially the estimation of the bedload grain size distribution from self-generated noise. It discusses the feasibility of linking the acoustic signal spectrum shape to bedload grain sizes involved in elastic impacts with the river bed treated as a massive slab. Bedload grain size distribution is estimated by a regularized algebraic inversion scheme fed with the power spectrum density of river noise estimated from one hydrophone. The inversion methodology relies upon a physical model that predicts the acoustic field generated by the collision between rigid bodies. Here we proposed an analytic model of the acoustic energy spectrum generated by the impacts between a sphere and a slab. The proposed model computes the power spectral density of bedload noise using a linear system of analytic energy spectra weighted by the grain size distribution. The algebraic system of equations is then solved by least square optimization and solution regularization methods. The result of inversion leads directly to the estimation of the bedload grain size distribution. The inversion method was applied to real acoustic data from passive acoustics experiments realized on the Isère River, in France. The inversion of in situ measured spectra reveals good estimations of grain size distribution, fairly close to what was estimated by physical sampling instruments. These results illustrate the potential of the hydrophone technique to be used as a standalone method that could ensure high spatial and temporal resolution measurements for sediment transport in rivers.

scholarly journals Origin of the scaling laws of sediment transport

2017 ◽  
Vol 473 (2197) ◽  
pp. 20160785 ◽  
Author(s):  
Sk Zeeshan Ali ◽  
Subhasish Dey
Keyword(s):  
Sediment Transport ◽  
Froude Number ◽  
Scaling Laws ◽  
Scaling Law ◽  
Bedload Transport ◽  
Inertial Range ◽  
Channel Width ◽  
Densimetric Froude Number ◽  
Relative Roughness ◽  
Contraction Ratio

In this paper, we discover the origin of the scaling laws of sediment transport under turbulent flow over a sediment bed, for the first time, from the perspective of the phenomenological theory of turbulence. The results reveal that for the incipient motion of sediment particles, the densimetric Froude number obeys the ‘(1 +  σ )/4’ scaling law with the relative roughness (ratio of particle diameter to approach flow depth), where σ is the spectral exponent of turbulent energy spectrum. However, for the bedforms, the densimetric Froude number obeys a ‘(1 +  σ )/6’ scaling law with the relative roughness in the enstrophy inertial range and the energy inertial range. For the bedload flux, the bedload transport intensity obeys the ‘3/2’ and ‘(1 +  σ )/4’ scaling laws with the transport stage parameter and the relative roughness, respectively. For the suspended load flux, the non-dimensional suspended sediment concentration obeys the ‘ − Z ’ scaling law with the non-dimensional vertical distance within the wall shear layer, where Z is the Rouse number. For the scour in contracted streams, the non-dimensional scour depth obeys the ‘4/(3 −  σ )’, ‘−4/(3 −  σ )’ and ‘−(1 +  σ )/(3 −  σ )’ scaling laws with the densimetric Froude number, the channel contraction ratio (ratio of contracted channel width to approach channel width) and the relative roughness, respectively.

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