Effect of a second layer on the time to failure of compressed riprap as mountain riverbank protection

Jafarnejad Chaghooshi, Mona (Laboratory of Hydraulic Constructions (LCH), École Polytechnique Fédérale de Lausanne (EPFL)) ; Franca, Mario (Laboratory of Hydraulic Constructions (LCH), École Polytechnique Fédérale de Lausanne (EPFL) ; Water Science and Engineering Department, IHE Delft Institute for Water Education, Delft, the Netherlands) ; Pfister, Michael (Laboratory of Hydraulic Constructions (LCH), École Polytechnique Fédérale de Lausanne (EPFL) ; School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland) ; Schleiss, Anton (Laboratory of Hydraulic Constructions (LCH), École Polytechnique Fédérale de Lausanne (EPFL))

Recently, Jafarnejad, Franca, Pfister, and Schleiss [2017. Time-based failure analysis of compressed riverbank riprap. Journal of Hydraulic Research, 55(2), 224–235. doi:10.1080/00221686.2016.1212940] presented an experimental study on the stability of compressed riprap, which means that it is composed of individually placed blocks with a single layer as riverbank protection. The relationship between the time to failure and dimensionless bed shear stress was presented. Here, the authors complement the previous investigation with results regarding the effect of a second riprap layer. In total, 49 tests (28 tests with one and 21 tests with two riprap layers) were performed using a single block size, three longitudinal channel slopes and three different riprap bank inclinations. Under similar conditions, the second layer can significantly delay the time to failure, whereas the block erosion rate was found to increase. The second layer has a more stabilizing role when the bank angle of the riprap is approaching the angle of repose of the blocks.


Keywords:
Article Type:
scientifique
Faculty:
Ingénierie et Architecture
School:
HEIA-FR
Institute:
iTEC - Institut des technologies de l'environnement construit
Subject(s):
Ingénierie
Date:
2018-09
Pagination:
6 p.
Published in:
Journal of Hydraulic Research
Numeration (vol. no.):
2018
DOI:
ISSN:
0022-1686
Appears in Collection:

Note: The status of this file is: restricted


 Record created 2018-10-17, last modified 2018-12-20

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