Use of Properly Designed Flexible Barriers to Mitigate Debris Flow Natural Hazards

Author(s):  
Andrea Roth ◽  
Corinna Wendeler ◽  
Frank Amend
Author(s):  
Hervé Vicari ◽  
C.W.W. Ng ◽  
Steinar Nordal ◽  
Vikas Thakur ◽  
W.A. Roanga K. De Silva ◽  
...  

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 m<sup>3</sup> and 6 m<sup>3</sup> 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.


2015 ◽  
Vol 15 ◽  
pp. 165-172 ◽  
Author(s):  
Federico Vagnon ◽  
Andrea Segalini ◽  
Anna Maria Ferrero

2012 ◽  
Vol 12 (5) ◽  
pp. 1693-1699 ◽  
Author(s):  
L. Canelli ◽  
A. M. Ferrero ◽  
M. Migliazza ◽  
A. Segalini

Abstract. The impact of a debris flow on a structure can have disastrous effects because of the enormous destructive potential of this type of phenomenon. Although the introduction of risk mitigation structures such as the Sabo Dam, the filter dam and more recently flexible barriers is usual, there are very few methods that are universally recognized for the safe design of such structures. This study presents the results of experimental tests, conducted with the use of a specifically created flume, in order to obtain detailed knowledge of the mechanical aspects, and to analyze the dynamics of the impact of a debris flow on different types of structures. The analyses of the tests, together with the calculation of the thrust caused by the flow, have made it possible to analyze the dynamics of the impact, which has shown differing effects, on the basis of the type of barrier that has been installed.


2015 ◽  
Vol 31 (5) ◽  
pp. 323-333 ◽  
Author(s):  
Alessandro Leonardi ◽  
Falk K. Wittel ◽  
Miller Mendoza ◽  
Roman Vetter ◽  
Hans J. Herrmann

2016 ◽  
Vol 53 (10) ◽  
pp. 1700-1717 ◽  
Author(s):  
Wesley Ashwood ◽  
Oldrich Hungr

Flexible barriers are a promising tool for protection against extremely rapid landslides such as debris flow and debris avalanches. With landslide impacts of any size, the total force induced within the barrier and transferred to the anchorage is a fundamental question to design. Current practice limits the investigation to flow parameters, neglecting the behavior of the structure, which can vary significantly. This paper describes steps taken to quantify the total force induced within a flexible barrier. It describes laboratory experiments of dry granular flow against rigid and flexible barriers with observations of resisting force and other filling processes that provide an understanding of the behavior and possible flow–structure interaction for larger scale rapid landslides. Results from the experiments suggest that for granular flows with high discharge the current practice sufficiently quantifies the total force, and for those with lower discharge, the total force is better characterized by active lateral earth pressure calculations. Test results were also used to validate an adaptation to an existing depth-integrated numerical model for landslide mobility to quantify the total force. This model was then used to estimate the resisting forces induced within a full-scale flexible barrier impacted by a controlled debris flow.


Fact Sheet ◽  
2002 ◽  
Author(s):  
M.C. Larsen ◽  
G.F. Wieczorek ◽  
L.S. Eaton ◽  
B.A. Morgan ◽  
Heriberto Torres-Sierra

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