eprintid: 10190541 rev_number: 13 eprint_status: archive userid: 699 dir: disk0/10/19/05/41 datestamp: 2024-04-11 09:23:05 lastmod: 2024-04-25 20:04:24 status_changed: 2024-04-11 09:23:05 type: article metadata_visibility: show sword_depositor: 699 creators_name: Coop, Matthew R creators_name: Altuhafi, Fatin N creators_name: Wong, Cacin PY title: The discrete and continuum behaviour of railway ballast ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F44 note: Copyright © 2024 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). abstract: The mechanics of coarse-grained geomaterials have traditionally been examined from a continuum mechanics standpoint, but this has led to ever more complex constitutive models as an increasing number of novel aspects of behaviour are investigated. For this reason, there is a tendency to move towards discrete approaches. Such approaches require accurate definition and modelling of the particle shapes, for which considerable progress has been made, and also the contact mechanics between particles, about which little is known. For very coarse materials such as railway ballast, our understanding at the continuum scale has been hampered further by the technical difficulties in the laboratory testing so that the very small strain behaviour has been difficult to define with accuracy. New apparatus and techniques will be described to test ballast at both the continuum and particulate scales. These allow the small strain stiffness to be defined with accuracy in triaxial tests and to carry out precise particle-to-particle contact tests. At the particle contact scale, the behaviour is dominated by the roughness of the particles and their relatively sharp contacts, so that plasticity and particle wear predominate, which both change the contact properties significantly. It is the contact plasticity that then controls the decay in continuum stiffness with strain. The work emphasises the inadequacy of using simple linear and/or elastic DEM models calibrated from macro-scale tests rather than deriving the correct contact behaviour directly. date: 2024-05 date_type: published publisher: Elsevier official_url: https://doi.org/10.1016/j.trgeo.2024.101251 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2266850 doi: 10.1016/j.trgeo.2024.101251 lyricists_name: Coop, Matthew Richard lyricists_id: MRCOO77 actors_name: Coop, Matthew Richard actors_id: MRCOO77 actors_role: owner funding_acknowledgements: EP/S026460/1 [Engineering and Physical Sciences Research Council]; EP/W000563/1 [Engineering and Physical Sciences Research Council]; ARCDP 220102862 [Australian Research Council] full_text_status: public publication: Transportation Geotechnics volume: 46 article_number: 101251 issn: 2214-3912 citation: Coop, Matthew R; Altuhafi, Fatin N; Wong, Cacin PY; (2024) The discrete and continuum behaviour of railway ballast. Transportation Geotechnics , 46 , Article 101251. 10.1016/j.trgeo.2024.101251 <https://doi.org/10.1016/j.trgeo.2024.101251>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10190541/1/1-s2.0-S2214391224000722-main.pdf