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Particle-scale simulations of the compression and shearing of kaolin clay (2023)
Journal Article
de Bono, J. P., & McDowell, G. R. (2023). Particle-scale simulations of the compression and shearing of kaolin clay. Géotechnique, https://doi.org/10.1680/jgeot.22.00423

This paper presents a new model for particle-scale simulations of clay. Using the discrete-element method, featuring realistically shaped platelets with separate interactions between the various platelet surfaces, simulations of isotropic normal comp... Read More about Particle-scale simulations of the compression and shearing of kaolin clay.

Simulating multifaceted interactions between kaolinite platelets (2022)
Journal Article
de Bono, J., & McDowell, G. (2023). Simulating multifaceted interactions between kaolinite platelets. Powder Technology, 413, Article 118062. https://doi.org/10.1016/j.powtec.2022.118062

It is well known that kaolinite platelets readily aggregate into ‘stacks’, having face-to-face contact. The traditional view of kaolin has been that the platelet faces are negatively charged and the edges are positively charged in an acidic environme... Read More about Simulating multifaceted interactions between kaolinite platelets.

Discrete element modelling of normal compression of clay (2022)
Journal Article
de Bono, J. P., & McDowell, G. R. (2022). Discrete element modelling of normal compression of clay. Journal of the Mechanics and Physics of Solids, 162, Article 104847. https://doi.org/10.1016/j.jmps.2022.104847

The discrete element method (DEM) has only rarely been used to simulate clay, due to difficulties in modelling clay particle shape and capturing the various particle interactions. This paper presents a new approach to simulate clay in three dimension... Read More about Discrete element modelling of normal compression of clay.

Some important aspects of modelling clay platelet interactions using DEM (2021)
Journal Article
de Bono, J. P., & McDowell, G. R. (2022). Some important aspects of modelling clay platelet interactions using DEM. Powder Technology, 398, Article 117056. https://doi.org/10.1016/j.powtec.2021.117056

The discrete element method (DEM) is a popular tool for simulating soils, however it has rarely been used for modelling clays. This is despite the behaviour of clays being much less well understood compared to sands. This paper aims to increase the u... Read More about Some important aspects of modelling clay platelet interactions using DEM.

A new time-delayed periodic boundary condition for discrete element modelling of railway track under moving wheel loads (2021)
Journal Article
Li, H., McDowell, G., & De Bono, J. (2021). A new time-delayed periodic boundary condition for discrete element modelling of railway track under moving wheel loads. Granular Matter, 23(4), Article 75. https://doi.org/10.1007/s10035-021-01123-4

A new time-delayed periodic boundary condition (PBC) has been proposed for discrete element modelling (DEM) of periodic structures subject to moving loads such as railway track based on a box test which is normally used as an element testing model. T... Read More about A new time-delayed periodic boundary condition for discrete element modelling of railway track under moving wheel loads.

Relating Hydraulic Conductivity to Particle Size Using DEM (2020)
Journal Article
McDowell, G., & de Bono, J. (2021). Relating Hydraulic Conductivity to Particle Size Using DEM. International Journal of Geomechanics, 21(1), Article 0602003. https://doi.org/10.1061/%28asce%29gm.1943-5622.0001670

For over 100 years it has been accepted that the permeability or hydraulic conductivity of a soil is controlled by the size of pores through which the fluid flows, and that this pore size should be a function of particle sizes. All well-known formula... Read More about Relating Hydraulic Conductivity to Particle Size Using DEM.

A new abrasive wear model for railway ballast (2020)
Journal Article
De Bono, J., Li, H., & McDowell, G. (2020). A new abrasive wear model for railway ballast. Soils and Foundations, 60(3), 714-721. https://doi.org/10.1016/j.sandf.2020.05.001

A new method to model the abrasion of granular particles using the discrete element method is demonstrated in this paper. This new, simple method is based on a classical theory of abrasive wear, relating the volume of solid lost to the frictional wor... Read More about A new abrasive wear model for railway ballast.

The effects of particle shape on the yielding behaviour of crushable sand (2020)
Journal Article
De Bono, J., & Mcdowell, G. (2020). The effects of particle shape on the yielding behaviour of crushable sand. Soils and Foundations, 60(2), 520-532. https://doi.org/10.1016/j.sandf.2020.04.001

Discrete element method simulations are used to investigate the effects of particle shape on the plastic behaviour of sand. This is achieved by using four different shapes of crushable particles. The behaviours of the different particles when subject... Read More about The effects of particle shape on the yielding behaviour of crushable sand.

On the packing and crushing of granular materials (2018)
Journal Article
de Bono, J. P., & McDowell, G. R. (2020). On the packing and crushing of granular materials. International Journal of Solids and Structures, 187, 133-140. https://doi.org/10.1016/j.ijsolstr.2018.07.011

This paper is a study of the dependence of the volume of voids in a granular material on the particle size distribution. It has previously been proposed that the volume of voids is proportional to the volume of the smallest particles. In a particle s... Read More about On the packing and crushing of granular materials.

Micro mechanics of the critical state line at high stresses (2018)
Journal Article
de Bono, J. P., & McDowell, G. R. (2018). Micro mechanics of the critical state line at high stresses. Computers and Geotechnics, 98, https://doi.org/10.1016/j.compgeo.2018.02.016

A critical state line is presented for a crushable numerical soil, which is parallel to the isotropic normal compression line. A previous theory for the normal compression line, which correctly predicts the slope as a function of the size-effect on p... Read More about Micro mechanics of the critical state line at high stresses.

On the micro mechanics of yielding and hardening of crushable granular soils (2018)
Journal Article
de Bono, J. P., & McDowell, G. R. (2018). On the micro mechanics of yielding and hardening of crushable granular soils. Computers and Geotechnics, 97, https://doi.org/10.1016/j.compgeo.2018.01.010

Stress path tests are used to investigate the yield surface of a crushable numerical soil. Triaxial samples with isotropic and anisotropic stress histories are examined to determine the nature of the yield surface and to establish what governs yield.... Read More about On the micro mechanics of yielding and hardening of crushable granular soils.

Micro mechanics of drained and undrained shearing of compacted and overconsolidated crushable sand (2017)
Journal Article
de Bono, J. P., & McDowell, G. R. (2018). Micro mechanics of drained and undrained shearing of compacted and overconsolidated crushable sand. Géotechnique, 68(7), 575-589. https://doi.org/10.1680/jgeot.16.P.318

A numerical crushable soil sample has been created using the previously published McDowell and de Bono (2013) model and subjected to a range of stress paths. Compacted sand simulations are performed using conventional triaxial stress paths, constant... Read More about Micro mechanics of drained and undrained shearing of compacted and overconsolidated crushable sand.

Validation of the log e–log σ normal compression law using particle strength data (2017)
Journal Article
de Bono, J. P., & McDowell, G. R. (in press). Validation of the log e–log σ normal compression law using particle strength data. Géotechnique, https://doi.org/10.1680/jgeot.17.T.007

This note is a study of experimental data on particle strength and normal compression, to establish whether the recently proposed normal compression law by McDowell and de Bono (2013) is supported and confirmed. A number of different sands are examin... Read More about Validation of the log e–log σ normal compression law using particle strength data.

Particle breakage criteria in discrete-element modelling (2016)
Journal Article
De Bono, J., & McDowell, G. (2016). Particle breakage criteria in discrete-element modelling. Géotechnique, 66(12), 1014-1027. https://doi.org/10.1680/jgeot.15.P.280

© 2016, ICE Publishing. All rights reserved. Previous work by the authors using the discrete-element method (DEM) has used the octahedral shear stress within a sphere together with a Weibull distribution of strengths and a size effect on average stre... Read More about Particle breakage criteria in discrete-element modelling.

Investigating the effects of particle shape on normal compression and overconsolidation using DEM (2016)
Journal Article
de Bono, J. P., & McDowell, G. R. (in press). Investigating the effects of particle shape on normal compression and overconsolidation using DEM. Granular Matter, 18(3), https://doi.org/10.1007/s10035-016-0605-5

Discrete element modelling of normal compression has been simulated on a sample of breakable two-ball clumps and compared to that of spheres. In both cases the size effect on strength is assumed to be that of real silica sand. The slopes of the norma... Read More about Investigating the effects of particle shape on normal compression and overconsolidation using DEM.

The fractal micro mechanics of normal compression (2016)
Journal Article
de Bono, J. P., & McDowell, G. R. (2016). The fractal micro mechanics of normal compression. Computers and Geotechnics, 78, 11-24. https://doi.org/10.1016/j.compgeo.2016.04.018

The fundamental fractal micro mechanics of normal compression of granular materials is studied using DEM. This paper examines the emergence of a finite fractal bounded by two particle sizes as stress increases, and the evolution of various definition... Read More about The fractal micro mechanics of normal compression.

On the micro mechanics of one-dimensional normal compression (2015)
Journal Article
McDowell, G. R., & de Bono, J. P. (2015). On the micro mechanics of one-dimensional normal compression. Géotechnique, 63(11), https://doi.org/10.1680/geot.12.P.041

Discrete-element modelling has been used to investigate the micro mechanics of one-dimensional compression. One-dimensional compression is modelled in three dimensions using an oedometer and a large number of particles, and without the use of agglome... Read More about On the micro mechanics of one-dimensional normal compression.

Discrete element modelling and cavity expansion analysis of cone penetration testing (2015)
Journal Article
Falagush, O., McDowell, G. R., Yu, H., & de Bono, J. P. (in press). Discrete element modelling and cavity expansion analysis of cone penetration testing. Granular Matter, 17(4), https://doi.org/10.1007/s10035-015-0570-4

This paper uses the discrete element method (DEM) in three dimensions to simulate cone penetration testing (CPT) of granular materials in a calibration chamber. Several researchers have used different numerical techniques such as strain path methods... Read More about Discrete element modelling and cavity expansion analysis of cone penetration testing.

Micro mechanics of critical states for isotropically overconsolidated sand (2015)
Journal Article
McDowell, G. R., Yue, P., & de Bono, J. P. (2015). Micro mechanics of critical states for isotropically overconsolidated sand. Powder Technology, 283, https://doi.org/10.1016/j.powtec.2015.05.043

The discrete element method has been used to investigate the micro mechanics of shearing to a critical state on the loose and dense sides of critical. Isotropic compression has previously been modelled in 3D using a large number of particles and with... Read More about Micro mechanics of critical states for isotropically overconsolidated sand.

Discrete element modelling of creep of asphalt mixtures (2015)
Journal Article
Cai, W., McDowell, G. R., Airey, G., & de Bono, J. P. (in press). Discrete element modelling of creep of asphalt mixtures. Geomechanics and Geoengineering, 11(1), https://doi.org/10.1080/17486025.2015.1006689

Creep tests on asphalt mixtures have been undertaken under four stress levels in the laboratory while the Discrete Element Model (DEM) has been used to simulate the laboratory tests. A modified Burger’s model has been used to represent the time-depen... Read More about Discrete element modelling of creep of asphalt mixtures.