On the interface friction in direct shear test

Liu, S.H.; Li, Jingpei; Matsuoka, Hiroaki

doi:10.1016/j.compgeo.2005.05.002

Cited by 62 publications

(24 citation statements)

References 6 publications

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“…The lower part of A2 the shear box was then moved horizontally at a velocity of 0.1x10 -4 mm/time step to a maximum horizontal displacement of 40 mm, while the upper section was fixed (Liu et al 2005). During shearing, the displacement of the top plate was monitored to determine the associated change in volume, and the shear stress was captured using the subroutines developed by the Authors.…”

Section: Modelling Of Fresh and Fouled Ballast In Demmentioning

confidence: 99%

DEM simulation of the behaviour of geogrid stabilised ballast fouled with coal

Ngo

Indraratna

Rujikiatkamjorn

2014

Computers and Geotechnics

159

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Geogrids are commonly used in railway construction for reinforcement and stabilisation. When railway ballast becomes fouled due to ballast breakage, infiltration of coal fines, dust and subgrade soil pumping, the reinforcement effect of geogrids decreases significantly. This paper presents results obtained from Discrete Element Method (DEM) to study the interface behaviour of coal-fouled ballast reinforced by geogrid subjected to direct shear testing. In this study, irregularly-shaped aggregates (ballast) were modelled by clumping together 10-20 spheres in appropriate sizes and positions. The geogrid was modelled by bonding a large number of small spheres together to form the desired grid geometry and apertures. Fouled ballast with 40% Void Contaminant Index (VCI) was modelled by injecting a predetermined number of miniature spheres into the voids of fresh ballast. A series of direct shear tests for fresh and fouled ballast reinforced by the geogrid subjected to normal shear stresses varying from 15 kPa to 75 kPa were then simulated in the DEM. The numerical results showed a good agreement the laboratory data, indicating that the DEM model is able to capture the behaviour of both fresh and coal-fouled ballast reinforced by the geogrid. The advantages of the proposed DEM model in terms of capturing the correct stress-displacement and volumetric behaviour of ballast, as well as the contact forces and strains developed in the geogrids are discussed. ABSTRACTGeogrids are commonly used in railway construction for reinforcement and stabilisation.When railway ballast becomes fouled due to ballast breakage, infiltration of coal fines, dust and subgrade soil pumping, the reinforcement effect of geogrids decreases significantly. This paper presents results obtained from Discrete Element Method (DEM) to study the interface bahaviour of coal-fouled ballast reinforced by geogrid subjected to direct shear testing. In this study, irregularly-shaped aggregates (ballast) were modelled by clumping together ten to twenty spheres in appropriate sizes and positions. The geogrid was modelled by bonding a large number of small spheres together to form the desired grid geometry and apertures.Fouled ballast with 40% Void Contaminant Index (VCI) was modelled by injecting a predetermined number of miniature spheres into the voids of fresh ballast. A series of direct shear tests for fresh and fouled ballast reinforced by the geogrid subjected to normal shear stresses varying from 15kPa to 75kPa were then simulated in the DEM. The numerical results showed a good agreement the laboratory data, indicating that the DEM model is able to capture the behaviour of both fresh and coal-fouled ballast reinforced by the geogrid. The advantages of the proposed DEM model in terms of capturing the correct stress-displacement and volumetric behaviour of ballast, as well as the contact forces and strains developed in the geogrids are discussed.3

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Section: Modelling Of Fresh and Fouled Ballast In Demmentioning

confidence: 99%

DEM simulation of the behaviour of geogrid stabilised ballast fouled with coal

Ngo

Indraratna

Rujikiatkamjorn

2014

Computers and Geotechnics

159

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“…The experimental value for the granular platform is n = 0.18, which corresponds to a dense state. It should be pointed out that the porosity of an assembly constituted by rods is incomparable to the porosity of real soils [23]. Simulations with porosities equal to 0.21 and 0.23 were also performed (0.23 was the maximum value to achieve a stable geometrical state, which then corresponds to a loose state).…”

Section: Influence Of the Platform Porositymentioning

confidence: 99%

Discrete element modelling of a granular platform supported by piles in soft soil – Validation on a small scale model test and comparison to a numerical analysis in a continuum

Jenck

Dias

Kastner

2009

Computers and Geotechnics

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“…Shear testers are classical apparatus, which are widely used to measure the flow properties of particulate materials such as the angle of friction and the relationship between shear and normal stresses [2]. One of the typical shear testers is Jenike's shear cell, which has been extensively investigated experimentally [3,4] and numerically [5][6][7][8][9][10]. Another important shear tester is the annular shear cell, which is also of great interest in scientific and industrial fields.…”

Section: Introductionmentioning

confidence: 99%

Microdynamic analysis of solid flow in a shear cell

Wang

Zhu

2012

Granular Matter

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Granular flow in a model shear cell under conditions relevant to those in an annular cell is investigated based on the results obtained by means of the discrete element method. The spatial and statistical distributions of microdynamic variables such as velocity, porosity, coordination number and contact force are established, and the dependence of these variables on some key physical and operational parameters of particles and the cell is studied. It is shown that the normal pressure, shear velocity of the cell, particle friction coefficient and rolling friction coefficient have noticeable influences on these microdynamic variables. However, the effects of wall friction coefficient and damping coefficient are negligible. There is a linear relationship between overall coordination number and packing density, when the coordination number ranges between 5 and 6.5. The deviation from the relation derives from the cases where the normal pressure is varied as a result of the significant change in the normal contact forces between particles.

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On the interface friction in direct shear test

Cited by 62 publications

References 6 publications

DEM simulation of the behaviour of geogrid stabilised ballast fouled with coal

DEM simulation of the behaviour of geogrid stabilised ballast fouled with coal

Discrete element modelling of a granular platform supported by piles in soft soil – Validation on a small scale model test and comparison to a numerical analysis in a continuum

Microdynamic analysis of solid flow in a shear cell

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