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| Titel |
Acoustic measurements of a liquefied cohesive sediment bed under waves |
| VerfasserIn |
R. Mosquera, V. Groposo, F. Pedocchi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Proceedings of river, coastal and estuarine morphodynamics ; Nr. 39 (2014-04-01), S.1-7 |
| Datensatznummer |
250121297
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| Publikation (Nr.) |
 copernicus.org/adgeo-39-1-2014.pdf |
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| Zusammenfassung |
| In this article the response of a cohesive sediment deposit
under the action of water waves is studied with the help of
laboratory experiments and an analytical model. Under the same regular wave condition
three different bed responses were observed depending on the degree of
consolidation of the deposit: no bed motion, bed motion of the upper layer
after the action of the first waves, and massive bed motion after several
waves. The kinematic of the upper 3 cm of the deposit were measured
with an ultrasound acoustic profiler, while the pore-water pressure inside
the bed was simultaneously measured using several pore pressure sensors. A
poro-elastic model was developed to interpret the experimental observations.
The model showed that the amplitude of the shear stress increased down into
the bed. Then it is possible that the lower layers of the deposit experience
plastic deformations, while the upper layers present just elastic
deformations. Since plastic deformations in the lower layers are necessary
for pore pressure build-up, the analytical model was used to interpret the
experimental results and to state that liquefaction of a self consolidated
cohesive sediment bed would only occur if the bed yield stress falls within
the range defined by the amplitude of the shear stress inside the bed. |
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