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Geomechanics and Engineering
  Volume 12, Number 4, April 2017, pages 639-655
DOI: http://dx.doi.org/10.12989/gae.2017.12.4.639
 


Analysis of the thresholds of granular mixtures using the discrete element method
Gong Jian and Liu Jun

 
Abstract
    The binary mixture consists of two types of granular media with different physical attributes and sizes, which can be characterized by the percentage of large granules by weight (P) and the particle size ratio (α). Researchers determine that two thresholds (PS and PL) exist for the peak shear strength of binary mixtures, i.e., at PPS, the peak shear strength is controlled by the small granules; at PPL, the peak shear strength is controlled by the large granules; at PSPPL, the peak shear strength is governed by both the large and small granules. However, the thresholds of binary mixtures with different α values, and the explanation related to the inner details of binary mixtures to account for why these thresholds exist, require further confirmation. This paper considers the mechanical behavior of binary mixtures with DEM analysis. The thresholds of binary mixtures are found to be strongly related to their ZL coordination numbers for all values of α, where ZL denotes the partial coordination number only between the large particles. The arrangement structure of the large particles is examined when P approaches the thresholds, and a similar arrangement structure of large particles is formed in both 2D and 3D particle systems.
 
Key Words
    thresholds; granular mixtures; partial coordination number; porosity; direct shear test; DEM
 
Address
State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China.
 

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