Starting to Move through a Granular Medium

Costantino, D. J.; Scheidemantel, Thomas J.; Stone, M. B.; Conger, C.; Klein, K.; Lohr, Matthew; Modig, Z.; Schiffer, P.

doi:10.1103/physrevlett.101.108001

Cited by 24 publications

(21 citation statements)

References 30 publications

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“…Interestingly, with small ratios of B/d, studies of bearing capacities of foundation footing have detected some noticeable grain-size effects (Tatsuoka et al, 1997;Cerato & Lutenegger, 2007). Similarly, some results suggest that uplift capacities of plate anchors would increase with the grain size for relatively small B/d Hsu & Chang, 2007;Costantino et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Grain-size effect on uplift capacity of plate anchors in coarse granular soils

Athani

Kharel

Airey

et al. 2017

Géotechnique Letters

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This letter investigates the uplift capacity of plate anchors in granular soils. Simulations based on a discrete-element method are used to measure the uplift capacity of anchors of differing widths to embedment B/H and width to grain-size B/d ratios. Results confirm that the uplift capacity of anchors with a large B/d ratio is well described by existing models developed from continuum mechanics, with no grain-size effect. In contrast, results reveal a strong deviation from these models for anchors with relatively small B/d ratios. A semi-empirical model is introduced that captures this strong grain-size effect. This model is further supported by a micro-mechanical analysis, indicating that anchor uplift capacities are not only governed by a frustum mechanism predicted by continuum mechanics but also involve the mobilisation of grains surrounding this frustum. These results and model are particularly important to rationalise uplift capacities measured in small-scale experiments, typically involving small B/d ratios, and to safely upscale them to larger anchor size relevant to field applications.

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Section: Introductionmentioning

confidence: 99%

Grain-size effect on uplift capacity of plate anchors in coarse granular soils

Athani

Kharel

Airey

et al. 2017

Géotechnique Letters

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“…One promising experimental approach to the granular rheology near the jamming point is to study the drag force acting on an obstacle immersed in granular media. At high velocities (≳100 mm=s) and high densities, several groups have independently confirmed a force component scaling with velocity squared through impact experiments [14][15][16], while many studies on the drag force have been performed and different velocity dependences have been reported in particular at much slower velocities [17][18][19][20][21][22][23][24][25].…”

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confidence: 97%

High-Velocity Drag Friction in Granular Media near the Jamming Point

Takehara

Okumura

2014

Phys. Rev. Lett.

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Drag friction that acts on a disk in a two-dimensional granular medium is studied at high packing fractions. We concentrate on a high-velocity region, in which the dynamic component of the force, obtained as an average of a strongly fluctuating force, clearly scales with velocity squared. We find that the total force composed of dynamic and static components, as well as its fluctuation, diverges with practically the same exponent as the packing fraction approaches the jamming point. To explain the critical behavior, we propose a simple theory equipped with a diverging length scale, which agrees well with the data and elucidates physical pictures for the divergence.

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“…Among the most intriguing granular phenomena are those that result when the grains "jam" locally to resist an externally applied pressure or force, creating a skeleton of connected grains that provide structural strength against a distortion of the grain pack [2]. One result of such jamming on a local scale is the drag force resisting the low-velocity motion of an object through a granular sample [3,4,5,6,7,8,9,10,11,12]. This granular drag is unrelated to the surface friction between the object and the grains [8], but rather arises from the necessary dilation and local rearrangement of the jammed grains, typically allowed by a free top surface.…”

mentioning

confidence: 99%

“…The granular drag force is thus nearly velocity-independent in the low velocity regime, since it is not associated with the transfer of momentum. Previous studies of the drag on intruders moving through a granular sample have both directly measured the resulting drag force [3][4][5][6][7][8][9][10][11][12] and also used simulations [13] as well as imaging of the grains [7,11,14]. Furthermore, in two dimensional systems, imaging of the grains can even access the inter-grain forces resulting from the drag process [7].…”

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confidence: 99%

Low-velocity granular drag in reduced gravity

et al. 2011

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We probe the dependence of the low-velocity drag force in granular materials on the effective gravitational acceleration (g(eff)) through studies of spherical granular materials saturated within fluids of varying density. We vary g(eff) by a factor of 20, and we find that the granular drag is proportional to g(eff), i.e. that the granular drag, F(probe), on a vertical cylinder follows the expected relation F(probe)=ηρ(grain)g(eff)d(probe)h(probe)(2) where the drag is related to the probe's depth of insertion, h(probe); the probe's diameter, d(probe); the grain material's density, ρ(grain); and a dimensionless constant, η. The dimensionless constant shows no systematic variation over four orders of magnitude in effective grain weight, demonstrating that the relation holds over that entire range to within the precision of our data.

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Starting to Move through a Granular Medium

Cited by 24 publications

References 30 publications

Grain-size effect on uplift capacity of plate anchors in coarse granular soils

Grain-size effect on uplift capacity of plate anchors in coarse granular soils

High-Velocity Drag Friction in Granular Media near the Jamming Point

Low-velocity granular drag in reduced gravity

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