Importance of particle shape on stress-strain behaviour of crushed stone-sand mixtures

Janaka J. Kumara, Kimitoshi Hayano

Abstract

In ballasted railway tracks, ballast fouling due to finer material intrusion has been identified as a challenging issue in track maintenance works. In this research, deformation characteristics of crushed stone-sand mixtures, simulating fresh and fouled ballasts were studied from laboratory and a 3-D discrete element method (DEM) triaxial compression tests. The DEM simulation was performed using a recently developed DEM approach, named, Yet Another Dynamic Engine (YADE). First, void ratio characteristics of crushed stone-sand mixtures were studied. Then, triaxial compression tests were conducted on specimens with 80 and 50% of relative densities simulating dense and loose states respectively. Initial DEM simulations were conducted using sphere particles. As stress-strain behaviour of crushed stone-sand mixtures evaluated by sphere particles were different from laboratory specimens, in next DEM simulations, the particles were modeled by a clump particle. The clump shape was selected using shape indexes of the actual particles evaluated by an image analysis. It was observed that the packing behaviour of laboratory crushed stone-sand mixtures were matched well with the DEM simulation with clump particles. The results also showed that the strength properties of crushed stone deteriorate when they are mixed by 30% or more of sand, specially under dense state. The results also showed that clump particles give closer stress-strain behaviour to laboratory specimens than sphere particles.

Original languageEnglish
Pages (from-to)455-470
Number of pages16
JournalGeomechanics and Engineering
Volume10
Issue number4
DOIs
StatePublished - 2016 Apr 1

Fingerprint

Finite difference method
Sand
Fouling
Image analysis
Compaction
Engines

Keywords

  • Discrete element method
  • Fouled ballast
  • Railway track
  • Stress-strain behaviour
  • Triaxial test

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Civil and Structural Engineering

Cite this

Importance of particle shape on stress-strain behaviour of crushed stone-sand mixtures. / Kumara, Janaka J.; Hayano, Kimitoshi.

In: Geomechanics and Engineering, Vol. 10, No. 4, 01.04.2016, p. 455-470.

Research output: Contribution to journalArticle

Kumara, Janaka J.; Hayano, Kimitoshi / Importance of particle shape on stress-strain behaviour of crushed stone-sand mixtures.

In: Geomechanics and Engineering, Vol. 10, No. 4, 01.04.2016, p. 455-470.

Research output: Contribution to journalArticle

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