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

作　　者：Mengmeng Wu Linghong Xiong Jianfeng Wang 

机构地区：[1]Department of Architecture and Civil Engineering,City University of Hong Kong,Hong Kong,China [2]Shenzhen Research Institute of City University of Hong Kong,Shenzhen,China

出　　处：《Underground Space》2021年第6期678-694,共17页地下空间（英文）

基　　金：supported by General Research Fund Grant(Nos.CityU 11201020 and CityU 11213517)from the Research Grants Council of the Hong Kong SAR;Research Grant(No.51779213)from the National Science Foundation of China.

摘　　要：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.

关 键 词：Grain shape ROUNDNESS Flexible membrane Spherical harmonic analysis Discrete element method 

分 类 号：TU41[建筑科学—岩土工程]