Routing Debris Flows with Particle Segregation

Takahashi, Tamotsu; Nakagawa, Hajime; Harada, Tatsuo; Yamashiki, Yousuke

doi:10.1061/(asce)0733-9429(1992)118:11(1490)

Cited by 163 publications

(128 citation statements)

References 2 publications

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“…The deposition velocity models of Takahashi et al 3) and others available are proportional to the flow velocity, and deposition upstream of a check dam can not be calculated, when the flow velocity becomes zero, also the calculated deposition upstream of check dam is too small. Therefore, new deposition velocity equation for upstream of a check dam is derived.…”

Section: (2) Deposition Model Upstream Of a Check Dammentioning

confidence: 99%

“…is flow flux in x direction, u is the mean velocity, h is flow depth, b i is erosion ) 0 (> or deposition ) 0 (≤ velocity, C is the sediment concentration in the flow, * C is maximum sediment concentration in the bed, β is momentum correction factor equal to 1.25 for stony debris flow 3) , g is the acceleration due to gravity, θ is bed slope, b τ is bottom shear stress, T ρ is mixture density…”

Section: Numerical Model (1) Basic Governing Equationsmentioning

confidence: 99%

“…The erosion and deposition velocity that have been given by Takahashi et al 3) are used as follows. Erosion velocity, if C is the equilibrium sediment concentration described as follows.…”

Section: Numerical Model (1) Basic Governing Equationsmentioning

confidence: 99%

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Numerical and Experimental Study on Debris-Flow Deposition and Erosion Upstream of a Check Dam

Shrestha

Nakagawa

Kawaike

et al. 2008

PROCEEDINGS OF HYDRAULIC ENGINEERING

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Debris flow is a phenomenon that high-density water with mud and big gravel flows down along a stream at high speed. Because of its high density and speed, it has huge destruction power. Thus damages by debris flows are very severe and sometimes tragic. A check dam is commonly used for preventing the sediment disaster due to debris flow by storing the harmful sediment discharge and has various types. Numerical simulations and experiments have been carried out to investigate the mechanism of debris-flow deposition process upstream of a check dam, and flushing out of deposited sediment due to erosion process by a normal scale flood flow. The simulations and experiments have been performed using closed type and grid type check dams. The simulated results agree well with the experimental results. From the results, it is shown that the grid type check dam can keep their sediment trapping capacity more effectively than the closed type check dam.

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Section: (2) Deposition Model Upstream Of a Check Dammentioning

confidence: 99%

Section: Numerical Model (1) Basic Governing Equationsmentioning

confidence: 99%

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Numerical and Experimental Study on Debris-Flow Deposition and Erosion Upstream of a Check Dam

Shrestha

Nakagawa

Kawaike

et al. 2008

PROCEEDINGS OF HYDRAULIC ENGINEERING

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“…If a debris flow velocity profile is reasonably blunt, α 1 =α 2 =1. For parabolic velocity profile and debris flows with no basal sliding, α 1 =α 2 =6/5, and for a stone-type debris flow on a rough inclined plane, α 1 = α 2 =1.25 (Takahashi et al, 1992). We may write for (13) using α=α 1 =α 2 , …”

Section: Governing Equationsmentioning

confidence: 99%

“…Correspondence to: C. Wang (chunxiangwang@hotmail.com) (Takahashi et al, 1991(Takahashi et al, , 1992; and the collapse of a natural dam (Han and Wang, 1996;Valiani and Caleffi, 2003). All the debris flows have at least four characters: rainfall or dam-break is the triggering factor; a debris flow is a gravitydriven flow with free upper surface that move across threedimensional terrain; the nature of the flow itself, which is rapid, transient, and includes a steep front mainly constituted of boulders (Laigle and Coussot, 1997); and debris flows have very strong destructive power and bring about extensive property damage and loss of life to the communities in their path (Takahashi, 1991;Hunt, 1994;Huang and Garcia, 1997;Lien and Tsai, 2003).…”

Section: Introductionmentioning

confidence: 99%

GIS-based two-dimensional numerical simulation of rainfall-induced debris flow

Wang

Esaki

2008

Nat. Hazards Earth Syst. Sci.

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Abstract. This paper aims to present a useful numerical method to simulate the propagation and deposition of debris flow across the three dimensional complex terrain. A depth-averaged two-dimensional numerical model is developed, in which the debris and water mixture is assumed to be continuous, incompressible, unsteady flow. The model is based on the continuity equations and Navier-Stokes equations. Raster grid networks of digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the continuity and momentum equations are solved numerically using the finite difference method. The numerical model is applied to simulate the rainfall-induced debris flow occurred in 20 July 2003, in Minamata City of southern Kyushu, Japan. The simulation reproduces the propagation and deposition and the results are in good agreement with the field investigation. The synthesis of numerical method and GIS makes possible the solution of debris flow over a realistic terrain, and can be used to estimate the flow range, and to define potentially hazardous areas for homes and road section.

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Granular avalanches on the Moon: Mass‐wasting conditions, processes, and features

et al. 2017

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Seven lunar crater sites of granular avalanches are studied utilizing high‐resolution images (0.42–1.3 m/pixel) from the Lunar Reconnaissance Orbiter Camera; one, in Kepler crater, is examined in detail. All the sites are slopes of debris extensively aggraded by frictional freezing at their dynamic angle of repose, four in craters formed in basaltic mare and three in the anorthositic highlands. Diverse styles of mass wasting occur, and three types of dry‐debris flow deposit are recognized: (1) multiple channel‐and‐lobe type, with coarse‐grained levees and lobate terminations that impound finer debris, (2) single‐surge polylobate type, with subparallel arrays of lobes and fingers with segregated coarse‐grained margins, and (3) multiple‐ribbon type, with tracks reflecting reworked substrate, minor levees, and no coarse terminations. The latter type results from propagation of granular erosion‐deposition waves down slopes dominantly of fine regolith, and it is the first recognized natural example. Dimensions, architectures, and granular segregation styles of the two coarse‐grained deposit types are like those formed in natural and experimental avalanches on Earth, although the timescale of motion differs due to the reduced gravity. Influences of reduced gravity and fine‐grained regolith on dynamics of granular flow and deposition appear slight, but we distinguish, for the first time, extensive remobilization of coarse talus by inundation with finer debris. The (few) sites show no clear difference attributable to the contrasting mare basalt and highland megaregolith host rocks and their fragmentation. This lunar study offers a benchmarking of deposit types that can be attributed to formation without influence of liquid or gas.

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Routing Debris Flows with Particle Segregation

Cited by 163 publications

References 2 publications

Numerical and Experimental Study on Debris-Flow Deposition and Erosion Upstream of a Check Dam

Numerical and Experimental Study on Debris-Flow Deposition and Erosion Upstream of a Check Dam

GIS-based two-dimensional numerical simulation of rainfall-induced debris flow

Granular avalanches on the Moon: Mass‐wasting conditions, processes, and features

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