scholarly journals Studies of Flexible Barriers Under Debris Flow Impact: An Application to an Alpine Basin

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

The Effects of Upstream Flexible Barrier on the Debris Flow Entrainment and Impact Dynamics on a Terminal Barrier

2021 ◽  
Author(s):  
Hervé Vicari ◽  
C.W.W. Ng ◽  
Steinar Nordal ◽  
Vikas Thakur ◽  
W.A. Roanga K. De Silva ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Impact Force ◽  
Dynamic Pressure ◽  
Pressure Coefficient ◽  
Flexible Barrier ◽  
Impact Forces ◽  
Flexible Barriers ◽  
The Impact ◽  
Bed Entrainment

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.

scholarly journals Debris flow risk mitigation by the means of rigid and flexible barriers – experimental tests and impact analysis

2012 ◽  
Vol 12 (5) ◽  
pp. 1693-1699 ◽  
Author(s):  
L. Canelli ◽  
A. M. Ferrero ◽  
M. Migliazza ◽  
A. Segalini
Keyword(s):  
Debris Flow ◽  
Impact Analysis ◽  
Risk Mitigation ◽  
Experimental Tests ◽  
Detailed Knowledge ◽  
Different Types ◽  
Flexible Barriers ◽  
The Impact ◽  
Destructive Potential

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.

scholarly journals Particle-Fluid-Structure Interaction for Debris Flow Impact on Flexible Barriers

2015 ◽  
Vol 31 (5) ◽  
pp. 323-333 ◽  
Author(s):  
Alessandro Leonardi ◽  
Falk K. Wittel ◽  
Miller Mendoza ◽  
Roman Vetter ◽  
Hans J. Herrmann
Keyword(s):  
Debris Flow ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Flexible Barriers

Estimating total resisting force in flexible barrier impacted by a granular avalanche using physical and numerical modeling

2016 ◽  
Vol 53 (10) ◽  
pp. 1700-1717 ◽  
Author(s):  
Wesley Ashwood ◽  
Oldrich Hungr
Keyword(s):  
Debris Flow ◽  
Current Practice ◽  
Earth Pressure ◽  
Total Force ◽  
Test Results ◽  
Promising Tool ◽  
Flexible Barrier ◽  
Flow Parameters ◽  
Dry Granular Flow ◽  
Flexible Barriers

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.

scholarly journals Laboratory tests for the optimization of mesh size for flexible debris-flow barriers

2015 ◽  
Vol 15 (12) ◽  
pp. 2597-2604 ◽  
Author(s):  
C. Wendeler ◽  
A. Volkwein
Keyword(s):  
Grain Size ◽  
Debris Flow ◽  
Laboratory Tests ◽  
Mesh Size ◽  
Field Measurements ◽  
Maximum Diameter ◽  
Small Scale ◽  
Dimensionless Numbers ◽  
Flexible Barrier ◽  
Flexible Barriers

Abstract. Flexible barriers can be used within channelized riverbeds as an effective and efficient alternative to protect from debris flows. Their retention capability strongly depends on the size of the mesh openings and the gap between the lower barrier edge and the channel's floor. The question is now whether there is a relation between the grain size distribution of the debris material and the openings of a flexible barrier. Small-scale laboratory tests were performed to study these loading aspects of flexible debris-flow barriers for the Milibach river (Canton Berne, Switzerland). In situ debris material has been used to quantify the influence of different mesh sizes and the gap between the lower barrier edge and the riverbed compared to the d90 grain size and the flow height, where d90 is the maximum diameter of 90 % of the grains. It was possible to study the filling process and the retaining behaviour of the barriers as a function of the mesh size. A reasonable retention was reached with the net having a mesh size and a basal gap smaller than or equal to d90. These relations could be transferred to the field. A dimensional analysis reveals possible dimensionless numbers that can be used to scale the laboratory results. The findings are supported by the results of similar laboratory tests using debris material from different locations and by the available field measurements.

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