Guide for Writing a Specification for Flexible Barrier Rollstock Materials

2021 ◽  
Author(s):  
Keyword(s):  
Flexible Barrier

Debris flow impact on a flexible barrier: laboratory flume experiments and force-based mechanical model validation

2021 ◽  
Vol 106 (1) ◽  
pp. 735-756
Author(s):  
R. Brighenti ◽  
L. Spaggiari ◽  
A. Segalini ◽  
R. Savi ◽  
G. Capparelli
Keyword(s):  
Debris Flow ◽  
Model Validation ◽  
Mechanical Model ◽  
Flume Experiments ◽  
Flexible Barrier ◽  
Laboratory Flume

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 Investigations of the Rockfall Impacts on the Flexible Protective Barriers under Seismic Loading

2021 ◽  
Author(s):  
Ziwei Ge ◽  
Hongyan Liu
Keyword(s):  
Field Test ◽  
Seismic Waves ◽  
Maximum Shear Stress ◽  
Seismic Loading ◽  
Maximum Elongation ◽  
Protective Barrier ◽  
Flexible Barrier ◽  
Novel Approach ◽  
Simulation Results ◽  
Deformation Area

Abstract Rockfall triggered by earthquakes can cause severe infrastructure losses and even fatalities. The flexible protective barrier is an efficient rockfall protection system that has been widely used against rockfall. This studyproposed a novel approach to simulate a field test of rockfall impacting the flexible barrier, and the simulation results showed an excellent match with the field test results. Based on this approach, the seismic loading was applied to the numerical model, and four types of seismic loading were adopted, e.g., non-seismic, x-directional seismic, y-directional seismic, and z-directional seismic. This study aims at investigating the dynamic behavior of the flexible protective barrier under different seismic loading during the rockfall impact process. The following findings can be obtained from the simulation results. First of all, the seismic loading can increase the maximum elongation and decrease the final elongation of the flexible protective barrier comparing to non-seismic loading. Second, the largest deformation area of the protective barrier is at the diagonal position when x-directional seismic loading was applied, which is at the vertical bisector position when y-directional and z-directional seismic loading was applied. Third, the maximum elongation of the protective barrier decreased with the increasing seismic wave period. But in general, the amplitude and period of seismic waves have negligible effects on the elongation, maximum normal stress, and maximum shear stress of the flexible protective barrier.

scholarly journals Surface wave scattering by porous and flexible barrier over a permeable bed

2019 ◽  
Author(s):  
Sumanta Shagolshem ◽  
Siluvai Antony Selvan ◽  
Muhammad Sani ◽  
Harekrushna Behera
Keyword(s):  
Surface Wave ◽  
Wave Scattering ◽  
Flexible Barrier

scholarly journals Impact mechanisms of granular and viscous flows on rigid and flexible barriers

2017 ◽  
Vol 54 (2) ◽  
pp. 188-206 ◽  
Author(s):  
C.W.W. Ng ◽  
D. Song ◽  
C.E. Choi ◽  
L.H.D. Liu ◽  
J.S.H. Kwan ◽  
...  
Keyword(s):  
Earth Pressure ◽  
Viscous Flows ◽  
Rigid Barrier ◽  
Geotechnical Centrifuge ◽  
Flow Energy ◽  
Mountainous Regions ◽  
Barrier Energy ◽  
Flexible Barrier ◽  
Barrier Type ◽  
Flexible Barriers

Structural countermeasures such as rigid and flexible barriers are commonly installed in mountainous regions to intercept mass-wasting processes. Without sufficient and reliable comparable physical data, the study of impact mechanisms remains difficult and not well understood. In this study, a newly developed flexible model barrier together with a rigid barrier are used to simulate either dry granular or viscous liquid impacts on these model barriers in a geotechnical centrifuge. The novel flexible barrier is made of four instrumented cables controlled by spring mechanisms to replicate a bilinear prototype loading response. Tests revealed that regardless of barrier type, both dry granular and viscous flows could have similar frontal dynamic impact coefficients around unity. Compared with the kinetic energy of flow mass (∼10 MJ), only 249 kJ of flexible barrier energy capacity was mobilized. This implies that debris-resisting barriers may only be required to intercept the dynamic flow front as the subsequent flow energy may mainly be dissipated through internal shearing. Attributing to the large deformation of the flexible barrier, the granular static load acting on the flexible barrier could be 39% lower than that on the rigid barrier, resulting in an active failure mode and a lower earth pressure.

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