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Quasi-realistic non-spherical models in discrete element modeling of coarse soils

DOI：10.7511/jslxCMGM202203

 作者 单位 E-mail 张昌辉 华南理工大学 土木与交通学院, 广州 5106411 赵仕威 华南理工大学 土木与交通学院, 广州 5106411香港科技大学 土木及环境工程学系, 香港 ceswzhao@ust.hk 赵吉东 香港科技大学 土木及环境工程学系, 香港 李泽贤 华南理工大学 土木与交通学院, 广州 5106411

颗粒形状对粗粒土的物理力学特性有着显著的影响。离散元法广泛应用于粗粒土宏观物理力学特性的细观机理研究。为了考虑颗粒形状的影响,亟待发展计算高效的离散元非球趋真颗粒模型。本文基于X射线CT扫描技术并结合数字图像处理技术,对光滑和棱角性两类典型粗粒土(鹅卵石与碎石)进行三维重构,并提出了两类趋真颗粒模型,分别采用扩展超椭球模型和球多面体模型进行趋真逼近;开展了两类颗粒试样的3D打印和单轴压缩试验,分析了配位数和局部孔隙率分布等细观特性;基于离散元开源程序SudoDEM开展了两类试样的离散元模拟,并将模拟细观分析结果与物理试验进行了对比。结果表明,提出的两类趋真颗粒模型能够较好地对粗粒土颗粒进行离散元建模。

Particle shape has a significant effect on the physical and mechanical properties of coarse-grained soils.The discrete element method (DEM) has been widely used to study the microscopic and mesoscopic mechanisms of macroscopic physical and mechanical properties of coarse-grained soils.In order to consider the effect of particle shape,it is urgent to develop a computationally efficient discrete aspheric element model of true-trending particles.In this paper,based on X-ray CT scanning technology combined with digital image processing technology,two types of typical coarse-grained soils,smooth pebbles and angular gravels,are reconstructed in 3D,and two types of quasi-realistic particle DEM models,the Poly-Superellipsoid model and the Sphero-polyhedron model,are proposed to represent the realistic coarse particles.The 3D printing and uniaxial compression tests of the two types of particle samples are carried out,and the mesoscopic characteristics such as coordination number and local porosity distribution are analyzed.The Discrete element simulations of two types of samples are carried out based on the open source DEM program SudoDEM,and the simulation results are compared with physical experiments.The results show that the proposed two types of true particle models have good performances in discrete element modeling of coarse-grained soil particles.