The effects of upstream flexible barrier on the debris flow entrainment and impact dynamics on a terminal barrier

The destructive nature of debris flows is mainly caused by flow bulking from entrainment of an erodible channel bed. To arrest these flows, multiple flexible barriers are commonly installed along the predicted flow path. Despite the importance of an erodible bed, its effects are generally ignored wh...

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Bibliographic Details
Published in:Canadian geotechnical journal 2022-06, Vol.59 (6), p.1007-1019
Main Authors: Vicari, Hervé, Ng, Charles W.W., Nordal, Steinar, Thakur, Vikas, De Silva, W.A. Roanga K., Liu, Haiming, Choi, Clarence E.
Format: Article
Language:English
Subjects:
barrière flexible
canal d’écoulement
Canals
Centrifugal force
Centrifuges
Control
coulée de débris
Debris flow
Detritus
Dynamic pressure
Entrainment
entraînement
Environmental aspects
flexible barrier
flume
Flumes
glissement de terrain
Hydrodynamics
Hydrofoil boats
Impact loads
landslide
Landslides
Norway
Overflow
River beds
Soil erosion
Surges
Upstream
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Summary:The destructive nature of debris flows is mainly caused by flow bulking from entrainment of an erodible channel bed. To arrest these flows, multiple flexible barriers are commonly installed along the predicted flow path. Despite the importance of an erodible bed, its effects are generally ignored when designing barriers. In this study, three unique experiments were carried out in a 28 m long flume to investigate the impact of a debris flow on both single and dual flexible barriers installed in a channel with a 6 m long erodible soil bed. Initial debris volumes of 2.5 and 6 m 3 were modelled. For the test setting adopted, a small upstream flexible barrier before the erodible bed separates the flow into several surges via overflow. The smaller surges reduce bed entrainment by 70% and impact force on the terminal barrier by 94% compared to the case without an upstream flexible barrier. However, debris overflowing the deformed flexible upstream barrier induces a centrifugal force that results in a dynamic pressure coefficient that is up to 2.2 times higher than those recommended in guidelines. This suggests that although compact upstream flexible barriers can be effective for controlling bed entrainment, they should be carefully designed to withstand higher impact forces.
ISSN:0008-3674
1208-6010
DOI:10.1139/cgj-2021-0119