A DEM investigation on simple shear behavior of dense granular assemblies
来源期刊：中南大学学报(英文版)2015年第12期
论文作者：SHI Dan-da XUE Jian-feng ZHAO Zhen-ying SHI Ji-yu
文章页码：4844 - 4855
Key words：simple shear; non-coaxiality; fabric anisotropy; shear strength; discrete element method
Abstract: A micromechanical investigation on simple shear behavior of dense granular assemblies was carried out by discrete element method. Three series of numerical tests were performed to examine the effects of initial porosity, vertical stress and particle shape on simple shear behavior of the samples, respectively. It was found that during simple shear the directions of principal stress and principal strain increment rotate differently with shear strain level. The non-coaxiality between the two directions decreases with strain level and may greatly affect the shear behavior of the assemblies, especially their peak friction angles. The numerical modelling also reveals that the rotation of the principal direction of fabric anisotropy lags behind that of the major principal stress direction during simple shear, which is described as fabric hyteresis effect. The degrees of fabric and interparticle contact force anisotropies increase as particle angularity increases, whereas the orientations of these anisotropies have not been significantly influenced by particle shape. An extended stress–dilatancy relationship based on ROWE-DAVIS framework was proposed to consider the non-coaxiality effect under principal stress rotation. The model was validated by present numerical results as well as some published physical test and numerical modelled data.
SHI Dan-da(史旦达)1, XUE Jian-feng(薛剑峰)2, ZHAO Zhen-ying(赵振营)1, SHI Ji-yu(史跻宇)3
(1. School of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China;
2. School of Engineering and Information Technology, Federation University Australia, Churchill 3842, VIC, Australia;
3. Jiangsu Zhongshe Engineering Consultancy Group, Wuxi 214072, China)
Abstract:A micromechanical investigation on simple shear behavior of dense granular assemblies was carried out by discrete element method. Three series of numerical tests were performed to examine the effects of initial porosity, vertical stress and particle shape on simple shear behavior of the samples, respectively. It was found that during simple shear the directions of principal stress and principal strain increment rotate differently with shear strain level. The non-coaxiality between the two directions decreases with strain level and may greatly affect the shear behavior of the assemblies, especially their peak friction angles. The numerical modelling also reveals that the rotation of the principal direction of fabric anisotropy lags behind that of the major principal stress direction during simple shear, which is described as fabric hyteresis effect. The degrees of fabric and interparticle contact force anisotropies increase as particle angularity increases, whereas the orientations of these anisotropies have not been significantly influenced by particle shape. An extended stress–dilatancy relationship based on ROWE-DAVIS framework was proposed to consider the non-coaxiality effect under principal stress rotation. The model was validated by present numerical results as well as some published physical test and numerical modelled data.
Key words:simple shear; non-coaxiality; fabric anisotropy; shear strength; discrete element method
