Dispersive Pressure, Boundary Jerk and Configurational Changes in Debris Flows

Bartelt, Perry; McArdell, Brian W.; Graf, Christoph; Christen, Marc; Buser, Othmar

doi:10.13101/ijece.9.1

Cited by 7 publications

(3 citation statements)

References 11 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where µ, which represents the Coulomb friction coefficient, dominates the deceleration behavior when the flow is slow and ξ, which represents the turbulent friction coefficient, prevails when the flow is rapid [29,36]. Numerical models based on shallow-water-type governing equations frequently suffer from the imbalance that occurs between the slope of the water depth and the slope on irregular terrain.…”

Section: Governing Equation and Numerical Modelmentioning

confidence: 99%

A Simple Deposition Model for Debris Flow Simulation Considering the Erosion–Entrainment–Deposition Process

Lee

Kim

et al. 2022

Remote Sensing

View full text Add to dashboard Cite

This study aimed to determine the depositional effect and improve the identification of debris flow risk zones. To accomplish this goal, we developed a two-dimensional debris flow model (Deb2D) based on a hyperbolic conservation form of the mass and the momentum balance equation with consideration of the erosion–entrainment effect as well as the depositional effect. In this model, we implemented a widely-used rheological equation—the Voellmy equation—and a quadtree adaptive grid-based shallow-water equation. This model was applied to two study sites to assess the depositional effect. The impact area, volume of soil loss, maximum velocity, inundated depth, and erosion depth resulting from the debris-flow modeling were compared with the field data. The simulation results with/without deposition were evaluated using the receiver operating characteristic method. The implementation results of the erosion–entrainment model with deposition showed superior accuracy when estimating the damage range and flow time.

show abstract

Section: Governing Equation and Numerical Modelmentioning

confidence: 99%

A Simple Deposition Model for Debris Flow Simulation Considering the Erosion–Entrainment–Deposition Process

Lee

Kim

et al. 2022

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…3. Because the configuration of the particles in the dilated volume defines the potential energy D, we sometimes refer to the energy D as the configurational energy of the debris flow [28][29][30]. Importantly, we are making the following physical assumption: the potential energy is associated with the buoyant weight of the solid particles immersed in the inter-granular fluid.…”

Section: Review Papermentioning

confidence: 99%

A dilatant, two-layer debris flow model validated by flow density measurements at the Swiss illgraben test site

Meyrat¹,

McArdell

Ivanova³

et al. 2021

Landslides

View full text Add to dashboard Cite

We propose a dilatant, two-layer debris flow model validated by full-scale density/saturation measurements obtained from the Swiss Illgraben test site. Like many existing models, we suppose the debris flow consists of a matrix of solid particles (rocks and boulders) that is surrounded by muddy fluid. However, we split the muddy fluid into two fractions. One part, the inter-granular fluid, is bonded to the solid matrix and fills the void space between the solid particles. The combination of solid material and inter-granular fluid forms the first layer of the debris flow. The second part of the muddy fluid is not bonded to the solid matrix and can move independently from the first layer. This free fluid forms the second layer of the debris flow. During flow the rocky particulate material is sheared which induces dilatant motions that change the location of the center-of-mass of the solid. The degree of solid shearing, as well as the amount of muddy fluid and of solid particles, leads to different flow compositions including debris flow fronts consisting of predominantly solid material, or watery debris flow tails. De-watering and the formation of muddy fluid washes can occur when the solid material deposits in the runout zone. After validating the model on two theoretical case studies, we show that the proposed model is able to capture the streamwise evolution of debris flow density in time and space for real debris flow events.

show abstract

“…[117] but only some of the codes available for the debris-flow simulation have the option to incorporate this aspect (e.g. FlatModel (Medina et al, 2008) or RAMMS (Bartelt et al, 2012)). There are mainly two approaches to physically describe the entrainment mechanism:…”

Section: Approaches To Estimate Debris-flow Entrainment and Total Eve...mentioning

confidence: 99%

Monitoring and geomorphologic characterization of debris flows at catchment scale : contributions to debris-flow hazard assessment

Abancó¹

View full text Add to dashboard Cite

Debris flows are very fast mass movements and are considered as one of the most hazardous phenomenain mountainous regions. Research on this field has strongly improved during the last decades. However,many open questions remain concerning the details of the triggering mechanisms of this type of phenomena and their dynamic behaviour; both of them key points in the hazard assessment. The global purpose of this work is to improve some aspects of the debris-flow hazard assessment atcatchment scale; particularly the estimation of the events¿ magnitude, the determination of their intensity and the characterization of the triggering factors. Most of the objectives have been carried out by means of the auscultation of a catchment in wich the debris flows are frequent. Furthermore, data of geomorphological characterization of other catchments have been analysed. This work aims at increasing the knowledge on debris flows in the Pyrenees. In the context of this thesis, a debris-flow monitoring system has been set up in the Pyrenees, in the Rebaixader torrent (Alta Ribagorça, Central Pyrenees). Since July 2009, six debris flows involving volumes ranging from 1000 to 21000 m3, eleven debris floods (volumes from 350 to 2800 m3) and four rockfalls have been registered. The distinction between processes and the identification of the different phases of the flow events have mainly been based on ground vibration data. The detailed analysis of the ground vibration generated by torrential processes has revealed that there are several on-site factors strongly influencing the signal registered by the geophones. In particular, a significant decrease of the signal has been recognized at the geophones that were not placed close to the active channel. The ground vibration signal generated by some debris-flow events has not only been registered using the conventional digital sampling of the ground velocity signal, but also by means of transforming the ground velocity into impulses. Both techniques are suitable for the detection and characterization of the debris-flow events. However, the transformation into impulses shows interesting advantages, such as the low power consumption and the simplicity of the analysis of this type of signal in comparison to the conventional one. Both aspects are crucial in early warning and alarm systems (EWAS). Besides, the characterization of the rainfalls in the catchment has revealed that the most common debris-flow triggering rainfalls in the Rebaixader torrent last around 2 hours and the critical hourly intensity value is around 15 mm/h. However, it has been detected that also spring episodes of moderate intensity, accompanied by the potential infiltration from snowmelt can trigger torrential flows and rockfalls. In particular, a detailed analysis of three rockfalls that occurred in spring is presented. Moreover, a methodology to estimate the entrainment of bed material in a debris-flow event is presented within this study. The methodology was based on the creation of a decision tree (applying data mining techniques) over a database of geomorphologic parameters, collected in the field and from a digital elevation model, which incorporates 110 reaches from 17 torrents. Finally, a general decision tree was proposed that should be calibrated and adapted, in order to widen its application to other catchments and climatic regions.

show abstract

Dispersive Pressure, Boundary Jerk and Configurational Changes in Debris Flows

Cited by 7 publications

References 11 publications

A Simple Deposition Model for Debris Flow Simulation Considering the Erosion–Entrainment–Deposition Process

A Simple Deposition Model for Debris Flow Simulation Considering the Erosion–Entrainment–Deposition Process

A dilatant, two-layer debris flow model validated by flow density measurements at the Swiss illgraben test site

Monitoring and geomorphologic characterization of debris flows at catchment scale : contributions to debris-flow hazard assessment

Contact Info

Product

Resources

About