Investigation on interaction of microscopic parameters of cohesioness granular material via DEM
Received:December 08, 2016  Revised:February 28, 2017
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KeyWord:discrete element method  rolling resistance  microscopic parameters  interaction  factorial experiment design
王智超 湘潭大学 岩土力学与工程安全湖南省重点实验室培育, 湘潭 ;湘潭大学 土木工程与力学学院, 湘潭
旷杜敏 湘潭大学 岩土力学与工程安全湖南省重点实验室培育, 湘潭 ;湘潭大学 土木工程与力学学院, 湘潭
赵涛 四川大学 水利水电学院, 成都 ;成都理工大学 地质灾害防治与地质环境保护国家重点实验室, 成都
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      In order to investigate the interaction of microscopic parameters of cohesioness granular materials,rolling resistance contact model was employed in triaxial compression test with different microscopic parameters via the Discrete Element Method.In this simulation,five microscopic parameters were adopted,namely,contact stiffness ratio α=ks/kn(0.3~0.9),coefficient of rolling stiffness β(0.1~3),normal stiffness kn(1×107~7×107),internal friction angle θ(10~40)and coefficient of plastic moment η (0.1~3),respectively.Meanwhile,parametric studies on five macroscopic parameters,namely,peak stress σp,residual strength σr,Young's modulus E,Poisson's ratio ν and friction angle φ were made.Firstly,comprehensive and factorial experiment design were carried out to conduct a qualitative analysis on the interaction between microscopic parameters and macroscopic parameters,and then multiple nonlinear regression was adopted to analyze the interaction quantitatively.A theoretical formula between macroscopic and microscopic parameters was proposed also,taking the interaction into consideration.The result shows that:(1) Particle internal friction angle and rolling resistance parameters have a significant influence on macroscopic strength parameters,and its deformation parameters are mainly determined by particle contact stiffness and contact stiffness ratio;(2) There are interactions between microscopic parameters and macroscopic parameters at different degrees,which have certain effects on the samples macroscopic properties;(3) As to peak stress,residual stress and internal friction angle,the interactions between two rolling resistance parameters,as well as rolling resistance parameters and particle friction angle are relatively strong.Furthermore,there is a significant interaction between normal contact stiffness and other parameters,which has an influence on Young's modulus and Poisson's ratio.The study contributes to quickly and reasonably determine the microscopic parameters of DEM model.