Journal ArticleDOI
The Avalanching of Granular Solids on Dune and Similar Slopes
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In this article, the authors show that the frequency, size, and behavior of the avalanches thus released depend on the particle deposition-rate gradient, the particle concentration at the time of deposition, particle size and density, and the avalanching medium.Abstract:
Avalanching occurs on slopes underlain by loose granular solids, for example, the slip faces of dunes and deltas and mountain screes, in response to a particle deposition-rate gradient which steepens these slopes to states of instability. The frequency, size, and behavior of the avalanches thus released are shown theoretically to depend on the particle deposition-rate gradient, the particle concentration at the time of deposition, the particle size and density, and the avalanching medium. Experiments made under simplified conditions using natural sands, glass beads, and natural grains provide satisfactory confirmation of major features of the theory, though some unexplored problems remain. The results are significant for the interpretation of certain kinds of sedimentary structure and landscape form and, insofar as data are available, prove consistent with the properties of avalanches observed from experimental sand dunes and mountain screes.read more
Citations
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Journal ArticleDOI
Water escape structures in coarse-grained sediments
TL;DR: Water escape structures as discussed by the authors represent both the direct rearrangement of sediment grains by escaping fluids and the deformation of hydroplastic, liquefied, or fluidized sediment in response to external stresses.
Journal ArticleDOI
Basic types of stratification in small eolian dunes
TL;DR: The thinnest recognizable strata in modern eolian dune sands can be grouped into six classes as discussed by the authors : planebed laminae, rippleform laminaes, ripple-foreset crosslaminae, climbing translatent strata, grainfall lamina, and sandflow cross-strata.
Journal ArticleDOI
Gravity flow of cohesionless granular materials in chutes and channels
TL;DR: In this article, a constitutive equation appropriate for flow of cohesionless granular materials at high deformation rates and low stress levels is proposed, which consists of an extension and a reinterpretation of the theory of Goodman & Cowin (1972).
Book ChapterDOI
The Mechanics of Rapid Granular Flows
TL;DR: In this article, the authors present a review of the classical papers of Bagnold and a discussion of the various modes and regimes of granular flow, such as vertical channels and inclined chutes.
Journal ArticleDOI
Rock glaciers : II models and mechanisms
TL;DR: In this paper, a review of the mechanisms of rock glacier formation and flow is presented, where the presence of a copious debris supply is important in all models, although the source of ice necessary for glacier formation is not considered.
References
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Journal ArticleDOI
Experiments on a Gravity-Free Dispersion of Large Solid Spheres in a Newtonian Fluid under Shear
TL;DR: In this article, a large number of spherical grains of diameter D = 0.13 cm were sheared in Newtonian fluids of varying viscosity (water and a glycerine-water-alcohol mixture) in the annular space between two concentric drums.
Journal ArticleDOI
Packing of Spheres
TL;DR: In this article, Scott et al. described experiments with equi-sized steel balls of 0.3175 cm. diameter in loose and in dense random stable packings, having volume packing densities of 1.15(6) ± 0.02.
Journal ArticleDOI
Angle of repose and angle of sliding friction: an experimental study
TL;DR: In this article, a controlled experimental study was conducted to obtain dependable information for use in geomorphic investigations and the results showed that the angle of repose varies inversely with size of fragments in perfectly sorted materials, but directly in those imperfectly sorted materials.
Journal ArticleDOI
The Production of Preferred Orientation in a Concentrated Dispersion of Elongated and Flattened Grains
TL;DR: In this paper, a mechanism is discussed in which a statistical alignment of long and short axes might be produced as a result of the encounters occurring between elastic particles during the shearing of a concentrated dispersion of them in a fluid of negligible viscosity and inertia.
Stability of Natural Slopes
TL;DR: The significance of progressive failure in slides of natural or cut slopes is reviewed and qualitative methods for taking it into account are discussed in this paper, where it is concluded that present procedures do not permit reliable assessment of the factor of safety under most conditions encountered in practice.