摘要
针对纯圆形颗粒在模拟土工直剪试验中的缺陷,以砂土直剪试验为研究对象,基于PFC^(3D)颗粒流程序,以纯圆颗粒为基本形状进行二次开发,利用FISH语言编程,引入了由pebble构成的块体(clump)单元,建立了哑铃形和椭圆形两种不同颗粒形状的簇颗粒,对纯圆颗粒及簇颗粒进行直剪试验模拟对比,并分析了颗粒初始配位数与内摩擦角的关系以及不同颗粒试样的体积变化规律,从细观上描述了不同形状颗粒的空间活跃程度。结果表明:颗粒形状直接影响着数值模拟的精度,椭圆形颗粒的吻合度最高,哑铃形颗粒次之,圆形颗粒较差,椭圆形颗粒较纯圆颗粒的精度提高了7.05%;簇颗粒的初始配位数相比纯圆颗粒较大,其试样表现出较高的强度和稳定性;颗粒形状对试样体积变化有着显著影响;纯圆颗粒的空间活跃程度较为明显,簇颗粒则相对稳定。该研究可为土工试验模拟在颗粒选择及模拟方法上提供一定的参考。
In order to solve the defects of pure round particles in the simulated direct shear test of soil, the direct shear test of sand is taken as the research object, based on PFC^3D particle flow program, pure round particles are developed for the second time, and a clump unit composed of Pebble is introduced by fish language programming, and two clusters of particles with different particle shapes, dumbbell-shaped and oval, are set up to simulate and compare the direct shear test of pure round particles and cluster particles, and the relationship between the initial coordination number of particles and internal friction angle and the volume change law of different particle samples are analyzed, and particles with different shapes are described from the microscopic point of view. The results show that the shape of particles directly affects the accuracy of numerical simulation, and the oval particles have the highest degree of coincidence, followed by dumbbell-shaped particles, and the round particles are poor, and the accuracy of oval particles is 7.05% higher than that of pure round particles;the initial coordination number of cluster particles is larger than that of pure round particles, and their samples show higher strength and stability;the particle shape has a significant influence on the volume change of the sample;the spatial activity of pure round particles is obvious, while cluster particles are relatively stable. This study can provide some reference for geotechnical test simulation in particle selection and simulation methods.
作者
杨升
李晓庆
YANG Sheng;LI Xiaoqing(College of Water Conservancy and Civil Engineering,Xinjiang Agricultural University,Urumqi 830052,China)
出处
《水利水电技术》
北大核心
2019年第3期139-144,共6页
Water Resources and Hydropower Engineering
基金
新疆维吾尔自治区自然科学基金面上项目(2013211A027)
国家自然科学基金项目(41262012)
关键词
颗粒流
直剪试验
数值模拟
离散元法
簇颗粒
particle flow code
direct shear test
numerical simulation
discrete element method
particle cluster
