scholarly journals Protection against debris flows with 13 flexible barriers in the Milibach River (Canton Berne, Switzerland) and first event analysis

2012 ◽  
Author(s):  
C. Wendeler ◽  
B. Vjekoslav
Keyword(s):  
Debris Flows ◽  
Event Analysis ◽  
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.

Anticipating cascading risks at the imminent Hochvogel peak failure

2021 ◽  
Author(s):  
Johannes Leinauer ◽  
Manfred Meindl ◽  
Benjamin Jacobs ◽  
Verena Stammberger ◽  
Michael Krautblatter
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Point Clouds ◽  
Volume Estimation ◽  
Rock Fall ◽  
Recent Case ◽  
Hazard Evaluation ◽  
Event Analysis ◽  
Worst Case ◽  
Cascading Effects

&lt;p&gt;Climatic changes are exacerbating the risk of alpine mass movements for example through more frequent and extreme heavy precipitation events. To cope with this situation, the monitoring, anticipation, and early warning of rock slope failures based on process dynamics is a key strategy for alpine communities. However, only investigating the release area of an imminent event is insufficient, as the primary hazard can trigger or increase secondary hazards like debris flows or the damming of a river. Nevertheless, recent case studies dealing with successive hazards are rarely existent for the Calcareous Alps. In this study, we precisely investigate the cascading effects resulting from an imminent rock fall and perform a pre-event analysis instead of back-modelling of a past event.&lt;/p&gt;&lt;p&gt;The Hochvogel summit (2592 m&amp;#160;a.s.l., Allg&amp;#228;u Alps, Germany/Austria) is divided by several pronounced clefts that separate multiple instable blocks. 3D-UAV point clouds reveal a potentially instable mass of 260,000&amp;#160;m&amp;#179; in six main subunits. From our near real time monitoring system (Leinauer et al. 2020), we know that some cracks are opening at faster pace and react differently to heavy rainfall, making a successive failure of subunits likely. However, pre-deformations are not yet pronounced enough to decide on the exact expected volume whereas secondary effects are likely as the preparing rock fall mass will be deposited into highly debris-loaded channels. Therefore, we developed different rock fall scenarios from the gathered monitoring information, which we implemented into a RAMMS modelling of secondary debris flows. To obtain best- and worst-case results, each scenario is calculated with different erosion parameters in the runout channel. The models are calibrated with a well-documented debris flow event at Ro&amp;#223;bichelgraben (10&amp;#160;km NW and similar lithology) and are supported by field investigations in the runout channel including electrical resistivity tomography profiles (ERT) for determination of the depth of erodible material as well as a drone survey for mapping the area and the generation of an elevation model.&lt;/p&gt;&lt;p&gt;Here we show a comprehensive scenario-based assessment for anticipating cascading risks at the Hochvogel from initial rock failure volume estimation to debris flow evolution and potential river damming. This recent case study from an alpine calcareous peak is an excellent and rare chance to gain insights into cascading risks modelling and an improved hazard evaluation.&lt;/p&gt;

scholarly journals Experimental testing of flexible barriers for containment of debris flows

1999 ◽  
Author(s):  
Jay S. DeNatale ◽  
Richard M. Iverson ◽  
Jon J. Major ◽  
Richard G. LaHusen ◽  
Gregg L. Fliegel ◽  
...  
Keyword(s):  
Debris Flows ◽  
Experimental Testing ◽  
Flexible Barriers

scholarly journals Large Scale Physical Modelling Study of a Flexible Barrier under the Impact of Granular Flows

2018 ◽  
Author(s):  
Dao-Yuan Tan ◽  
Jian-Hua Yin ◽  
Wei-Qiang Feng ◽  
Jie-Qiong Qin ◽  
Zhuo-Hui Zhu
Keyword(s):  
Debris Flows ◽  
Large Scale ◽  
Impact Force ◽  
Granular Flows ◽  
Physical Modelling ◽  
Flexible Barrier ◽  
Impact Forces ◽  
Flexible Barriers ◽  
Open Question ◽  
The Impact

Abstract. Flexible barriers are being increasingly applied to mitigate the danger of debris flows. However, how barriers can be better designed to withstand the impact loads of debris flows is still an open question in natural hazard engineering. Here we report an improved large-scale physical modelling device and the results of two consecutive large-scale granular flow tests using this device to study how flexible barriers react under impact from granular flows. In the study, the impact force directly on the flexible barrier and the impact force transferred to the supporting structures are measured, calculated and compared. Based on the comparison, the impact loading attenuated by the flexible barrier is quantified. The hydro-dynamic and hydro-static approaches are also validated using the calculated impact forces.

scholarly journals Large-scale physical modelling study of a flexible barrier under the impact of granular flows

2018 ◽  
Vol 18 (10) ◽  
pp. 2625-2640 ◽  
Author(s):  
Dao-Yuan Tan ◽  
Jian-Hua Yin ◽  
Wei-Qiang Feng ◽  
Jie-Qiong Qin ◽  
Zhuo-Hui Zhu
Keyword(s):  
Debris Flows ◽  
Large Scale ◽  
Impact Force ◽  
Granular Flows ◽  
Physical Modelling ◽  
Flexible Barrier ◽  
Static Approach ◽  
Flexible Barriers ◽  
Open Question ◽  
The Impact

Abstract. Flexible barriers are being increasingly applied to mitigate the danger of debris flows. However, how barriers can be better designed to withstand the impact loads of debris flows is still an open question in natural hazard engineering. Here we report an improved large-scale physical modelling device and the results of two consecutive large-scale granular flow tests using this device to study how flexible barriers react under the impact of granular flows. In the study, the impact force directly on the flexible barrier and the impact force transferred to the supporting structures are measured, calculated, and compared. Based on the comparison, the impact loading attenuated by the flexible barrier is quantified. The hydro-dynamic approaches with different dynamic coefficients and the hydro-static approach are validated using the measured impact forces.

Coupling Depth-Averaged and 3D models for debris flow: a multi-domain strategy 

2021 ◽  
Author(s):  
Andrea Pasqua ◽  
Alessandro Leonardi ◽  
Marina Pirulli
Keyword(s):  
Debris Flow ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Debris Flows ◽  
Laboratory Tests ◽  
3D Model ◽  
Fluid Structure Interaction ◽  
Structure Interaction ◽  
Flexible Barriers ◽  
Boltzmann Method

&lt;p&gt;Debris flows are landslide phenomena which occur worldwide, posing a major threat to mountain settlements. They consist of flowing fine and coarse sediment saturated with water, which propagate mainly in channelized paths. Because of their high velocity and unpredictability, the evacuation of local populations is often impossible. Losses of human lives and economical damages can be avoided if a correct risk mitigation procedure is adopted. Hence, mitigation structures, such as filter barriers or flexible barriers are often installed in high-risk areas. The primary goal of these structures is to reduce the flow energy and to retain the coarsest boulders. Their design process, which is still frequently based only on empirical or simplified models, would greatly benefit from the support of a reliable numerical model.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;In this framework, continuum-based Depth-Averaged Models (DAMs) have been the dominant numerical tool since the 90s. DAMs can simulate events propagating over a wide area while keeping the computational time low, even on complex topographies (Pirulli, 2010). Nevertheless, the averaging process applied to velocity and pressure causes a loss of information, which is critical when the flow impact against structures is evaluated. A full 3D model would allow for a more accurate resolution of fluid-structure interaction (Leonardi et al., 2016). However, debris flows may propagate up to kilometres, and a complete 3D analysis would therefore require exceedingly long computational times.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;To bypass the shortcomings mentioned above, this work aims to couple DAMs to a 3D model based on the Lattice Boltzmann Method (LBM). Thus, the domain is split into two parts. First, DAMs describes the flow evolution from its initialization to the transport phase. In this portion of the domain, no structures are present. When the flow approaches a structure, DAMs is coupled to a 3D model. To verify the coupling procedure accuracy, the model is benchmarked on the laboratory tests conducted by Moriguchi et al. (2009). These laboratory tests targeted the flow of dry sand on a steep chute, evaluating the flow impact on a barrier. Preliminary results suggest that the coupled model reproduces the laboratory results reasonably well.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords: &lt;/strong&gt;debris flow, coupled numerical modelling, depth-averaged method, 3D Lattice-Boltzmann Method&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;REFERENCES&lt;/p&gt;&lt;p&gt;Leonardi, A., Wittel, F. K., Mendoza, M., Vetter, R., &amp; Herrmann, H. J. (2016). Particle-Fluid-Structure Interaction for Debris Flow Impact on Flexible Barriers. Computer-Aided Civil and Infrastructure Engineering, 31(5), 323&amp;#8211;333.&lt;/p&gt;&lt;p&gt;Moriguchi, S., Borja, R. I., Yashima, A., &amp; Sawada, K. (2009). Estimating the impact force generated by granular flow on a rigid obstruction. Acta Geotechnica, 4(1), 57&amp;#8211;71.&lt;/p&gt;&lt;p&gt;Pirulli, M. (2010). On the use of the calibration-based approach for debris-flow forward-analyses. Natural Hazards and Earth System Science, 10(5), 1009&amp;#8211;1019.&lt;/p&gt;

Initiation and frequency of debris flows in Grand Canyon, Arizona

1996 ◽  
Author(s):  
Peter G. Griffiths ◽  
Robert H. Webb ◽  
Theodore S. Melis
Keyword(s):  
Debris Flows ◽  
Grand Canyon
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