DEM study on effect of particle roundness on biaxial shearing of sand

Mengmeng Wu, Linghong Xiong, Jianfeng Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)


In this study, discrete element method (DEM) simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales. First, a stack of microcomputed tomography images were binarized, segmented, and labeled using advanced image processing and analysis techniques. Second, a spherical harmonic (SH) analysis, which involves a complete set of orthogonal functions, was implemented to rebuild the natural particle shape. Then, five templates of virtual particles were built in a DEM simulation, four of which were obtained from SH degrees of 3, 8, 12, and 15, and one template was an elementary sphere. A flexible membrane was numerically generated to allow the material to deform freely under a prescribed confining stress. Finally, the effect of particle roundness on the mechanical properties of granular materials was investigated and discussed. Two shear bands were found to intersect, forming an X shape in both the rotation and displacement fields. Moreover, a lower particle roundness results in higher deviatoric stress and stronger dilation in the volumetric change. A decrease in particle roundness leads to less rotation of particles despite a higher displacement value. In addition, a larger SH degree leads to smaller normalized contact forces of the particles. This implies that decreasing the roundness results in higher anisotropy of the contact forces.

Original languageEnglish
Pages (from-to)678-694
Number of pages17
JournalUnderground Space (China)
Issue number6
Publication statusPublished - Dec 2021
Externally publishedYes


  • Discrete element method
  • Flexible membrane
  • Grain shape
  • Roundness
  • Spherical harmonic analysis

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Geotechnical Engineering and Engineering Geology


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