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| Titel |
An expression for the water-sediment moving layer in unsteady flows valid for open channels and embankments |
| VerfasserIn |
A. M. Berta, G. Bianco |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 10, no. 5 ; Nr. 10, no. 5 (2010-05-28), S.1051-1059 |
| Datensatznummer |
250008155
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| Publikation (Nr.) |
 copernicus.org/nhess-10-1051-2010.pdf |
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| Zusammenfassung |
| During the floods, the effects of sediment transport in river beds
are particulary significant and can be studied through the evolution
of the water-sediment layer which moves in the lower part of a flow,
named "moving layer". Moving layer variations along rivers lead to
depositions and erosions and are typically unsteady, but are often
tackled with expressions developed for steady (equilibrium)
conditions. In this paper, we develop an expression for the moving
layer in unsteady conditions and calibrate it with experimental
data. During laboratory tests, we have in fact reproduced a rapidly
changing unsteady flow by the erosion of a granular steep slope.
Results have shown a clear tendency of the moving layer, for fixed
discharges, toward equilibrium conditions. Knowing the equilibrium
achievement has presented many difficulties, being influenced by
the choice of the equilibrium expression and moreover by the
estimation of the parameters involved (for example friction angle).
Since we used only data relevant to hyper-concentrated
mono-dimensional flows for the calibration – occurring for slope
gradients in the range 0.03–0.20 – our model can be applied both
on open channels and on embankments/dams, providing that the flows
can be modelled as mono-dimensional, and that slopes and applied
shear stress levels fall within the considered ranges. |
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