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Indexed by:期刊论文

Date of Publication:2017-04-01

Journal:GEOMECHANICS AND ENGINEERING

Included Journals:SCIE、EI

Volume:12

Issue:4

Page Number:639-655

ISSN No.:2005-307X

Key Words:thresholds; granular mixtures; partial coordination number; porosity; direct shear test; DEM

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 (alpha). Researchers determine that two thresholds (P-S and P-L) exist for the peak shear strength of binary mixtures, i.e., at P <= PS, the peak shear strength is controlled by the small granules; at P <= PL, the peak shear strength is controlled by the large granules; at PS <= P <= PL, the peak shear strength is governed by both the large and small granules. However, the thresholds of binary mixtures with different alpha 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 coordination numbers Z(L) for all values of alpha, where Z(L) 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.