Evolution of stony debris flows in laboratory experiments

Baselt, Ivo; Oliveira, Gustavo Queiroz de; Fischer, Jan-Thomas; Pudasaini, Shiva P.

doi:10.1016/j.geomorph.2020.107431

Cited by 27 publications

(28 citation statements)

References 63 publications

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“…The main purpose here is to construct several new analytical solutions to (2), and combine these with the existing solutions (Pudasaini and Krautblatter, 2022) for (1). This facilitates the description of the landslide motion down a slope consisting of multiple segments with accelerating and decelerating movements, with positive and negative net driving forces, as well as the landslide run-out.…”

Section: The Modelmentioning

confidence: 99%

The Entire Landslide Velocity

Pudasaini

2022

Preprint

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Abstract. The enormous destructive energy carried by a landslide is principally determined by its velocity. Pudasaini and Krautblatter (2022) presented a simple, physics-based analytical landslide velocity model that simultaneously incorporates the internal deformation and externally applied forces. They also constructed various general exact solutions for the landslide velocity. However, previous solutions are incomplete as they only apply to accelerating motions. Here, I advance further by constructing several new general analytical solutions for decelerating motions and unify these with the existing solutions for the landslide velocity. This provides the complete and honest picture of the landslide in multiple segments with accelerating and decelerating movements covering its release, motion through the track, the run-out as well as deposition. My analytical procedure connects several accelerating and decelerating segments by a junction with a kink to construct a multi-sectoral unified velocity solution down the entire path. Analytical solutions reveal essentially different novel mechanisms and processes of acceleration, deceleration and the mass halting. I show that there are fundamental differences between the landslide release, acceleration, deceleration and deposition in space and time as the dramatic transition takes place while the motion changes from the driving force dominated to resisting force dominated sector. I uniquely determine the landslide position and time as it switches from accelerating to decelerating state. Considering all the accelerating and decelerating motions, I analytically obtain the exact total travel time and the travel distance for the whole motion. Different initial landslide velocities with ascending or descending fronts result in strikingly contrasting travel distances, and elongated or contracted deposition lengths. Time and space evolution of the marching landslide with initial velocity distribution consisting of multiple peaks and troughs of variable strengths and extents lead to a spectacular propagation pattern with different stretchings and contractings resulting in multiple waves, foldings, crests and settlements. The analytical method manifests that, computationally costly numerical solutions may now be replaced by a highly cost-effective, unified and complete analytical solution down the entire track. This offers a great technical advantage for the geomorphologists, landslide practitioners and engineers as it provides immediate and very simple solution to the complex landslide motion.

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Section: The Modelmentioning

confidence: 99%

The Entire Landslide Velocity

Pudasaini

2022

Preprint

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“…Equivalently, β is the ratio between the one half of the "system-force", 1 2 mα (the driving force), and the (maximum) kinetic energy, 1 2 mu 2 max , of the landslide. With the knowledge of the relevant maximum kinetic energy of the landslide (Körner, 1980), the model (17) for the drag can be closed.…”

Section: A Model For Viscous Dragmentioning

confidence: 99%

The Landslide Velocity

Pudasaini,

Krautblatter

2021

Preprint

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Proper knowledge of velocity is required in accurately determining the enormous destructive energy carried by a landslide. We present the first, simple and physics-based general analytical landslide velocity model that simultaneously incorporates the internal deformation (non-linear advection) and externally applied forces, consisting of the net driving force and the viscous resistant. From the physical point of view, the model stands as a novel class of non-linear advective − dissipative system where classical Voellmy and inviscid Burgers' equation are specifications of this general model. We show that the non-linear advection and external forcing fundamentally regulate the state of motion and deformation, which substantially enhances our understanding of the velocity of a coherently deforming landslide. Since analytical solutions provide the fastest, the most costeffective and the best rigorous answer to the problem, we construct several new and general exact analytical solutions. These solutions cover the wider spectrum of landslide velocity and directly reduce to the mass point motion. New solutions bridge the existing gap between the negligibly deforming and geometrically massively deforming landslides through their internal deformations. This provides a novel, rapid and consistent method for efficient coupling of different types of mass transports. The mechanism of landslide advection, stretching and approaching to the steady-state has been explained. We reveal the fact that shifting, up-lifting and stretching of the velocity field stem from the forcing and non-linear advection. The intrinsic mechanism of our solution describes the fascinating breaking wave and emergence of landslide folding. This happens collectively as the solution system simultaneously introduces downslope propagation of the domain, velocity up-lift and non-linear advection. We disclose the fact that the domain translation and stretching solely depends on the net driving force, and along with advection, the viscous drag fully controls the shock wave generation, wave breaking, folding, and also the velocity magnitude. This demonstrates that landslide dynamics are architectured by advection and reigned by the system forcing. The analytically obtained velocities are close to observed values in natural events. These solutions constitute a new foundation of landslide velocity in solving technical problems. This provides the practitioners with the key information in instantly and accurately estimating the impact force that is very important in delineating hazard zones and for the mitigation of landslide hazards.

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“…Dynamic data are rare (de Haas et al, 2020). So, many of the low-resolution measurements are locally or discretely based on points in time and space (Berger et al, 2011;Schürch et al, 2011;McCoy et al, 2012;Theule et al, 2015;Dietrich and Krautblatter, 2019). Therefore, laboratory or field experiments (Iverson et al, 2011; de Haas and van Woerkom, 2016;Lu et al, 2016;Lanzoni et al, 2017;Li et al, 2017;Pilvar et al, 2019;Baselt et al, 2021) and theoretical modeling (Le and Pitman, 2009;Pudasaini, 2012;Pudasaini and Mergili, 2019) remain the major source of knowledge in landslide and debris flow dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…So, many of the low-resolution measurements are locally or discretely based on points in time and space (Berger et al, 2011;Schürch et al, 2011;McCoy et al, 2012;Theule et al, 2015;Dietrich and Krautblatter, 2019). Therefore, laboratory or field experiments (Iverson et al, 2011; de Haas and van Woerkom, 2016;Lu et al, 2016;Lanzoni et al, 2017;Li et al, 2017;Pilvar et al, 2019;Baselt et al, 2021) and theoretical modeling (Le and Pitman, 2009;Pudasaini, 2012;Pudasaini and Mergili, 2019) remain the major source of knowledge in landslide and debris flow dynamics. Recently, there has been a rapid increase in comprehensive numerical modeling for mass transports (McDougall and Hungr, 2005;Medina et al, 2008;Cascini et al, 2014;Frank et al, 2015;Iverson and Ouyang, 2015;Cuomo et al, 2016;Mergili et al, 2020a, b;Qiao et al, 2019;Liu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

The landslide velocity

Pudasaini

Krautblatter

2022

Earth Surf. Dynam.

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Abstract. Proper knowledge of velocity is required in accurately determining the enormous destructive energy carried by a landslide. We present the first, simple and physics-based general analytical landslide velocity model that simultaneously incorporates the internal deformation (nonlinear advection) and externally applied forces, consisting of the net driving force and the viscous resistant. From the physical point of view, the model represents a novel class of nonlinear advective–dissipative system, where classical Voellmy and inviscid Burgers' equations are of this general model. We show that the nonlinear advection and external forcing fundamentally regulate the state of motion and deformation, which substantially enhances our understanding of the velocity of a coherently deforming landslide. Since analytical solutions provide the fastest, most cost-effective, and best rigorous answer to the problem, we construct several new and general exact analytical solutions. These solutions cover the wider spectrum of landslide velocity and directly reduce to the mass point motion. New solutions bridge the existing gap between negligibly deforming and geometrically massively deforming landslides through their internal deformations. This provides a novel, rapid, and consistent method for efficient coupling of different types of mass transports. The mechanism of landslide advection, stretching, and approaching the steady state has been explained. We reveal the fact that shifting, uplifting, and stretching of the velocity field stem from the forcing and nonlinear advection. The intrinsic mechanism of our solution describes the fascinating breaking wave and emergence of landslide folding. This happens collectively as the solution system simultaneously introduces downslope propagation of the domain, velocity uplift, and nonlinear advection. We disclose the fact that the domain translation and stretching solely depend on the net driving force, and along with advection, the viscous drag fully controls the shock wave generation, wave breaking, folding, and also the velocity magnitude. This demonstrates that landslide dynamics are architectured by advection and reigned by the system forcing. The analytically obtained velocities are close to observed values in natural events. These solutions constitute a new foundation of landslide velocity in solving technical problems. This provides practitioners with key information for instantly and accurately estimating the impact force that is very important in delineating hazard zones and for the mitigation of landslide hazards.

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Evolution of stony debris flows in laboratory experiments

Cited by 27 publications

References 63 publications

The Entire Landslide Velocity

The Entire Landslide Velocity

The Landslide Velocity

The landslide velocity

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