摘要
离散单元法(discrete element method,DEM)数值仿真中,孔隙率场已用于观测剪切带宽度,观测剪切带宽度有助于理解剪切带宽度与颗粒特性的关系。孔隙率场可由测量圆测得,但测量圆半径通常按经验确定。针对测量圆半径定义缺乏理论和数值研究等问题,开展了孔隙率测量精度与测量圆半径关系的研究。提出基于孔隙率场的“1/2宽度估算法”和“1/2曲率极值法”,将其应用于直剪和双轴压缩试验的剪切带宽度测量,并将测量结果与转角法和网格法测量结果进行了对比。DEM数值研究结果表明:提出的方法能够用于量测直剪试验和双轴压缩试验中的剪切带宽度;直剪试验中剪切带宽度随粒径增大而逐渐增大;因为试样的非对称和不均匀性,双轴压缩试验的X形剪切带中的两条剪切带宽度不相等,且剪切带随轴向加载过程逐渐变宽。
In the numerical simulation of the discrete element method(DEM),the porosity field has been employed to observe the width of shear bands,which aids in understanding the relationship between shear band width and particle characteristics.The porosity field is obtained by measurement circles.However,the measurement circle radius is usually determined empirically,lacking theoretical and numerical simulation research.Therefore,a study was conducted to investigate the relationship between the accuracy of porosity measurement and the measurement circle radius.Furthermore,the“1/2 width estimation method”and“1/2 curvature extremum method”based on the porosity field were proposed and applied to measure the shear band width in direct shear and biaxial compression tests.The measurement results were compared with those obtained using the particle rotation method and grid method.The DEM numerical results show that the proposed methods are effective for measuring the shear band width in direct shear and biaxial compression tests.In the direct shear test,the shear band width gradually increases with the increase of particle size.Due to the asymmetry and non-uniformity of the specimen,the two shear band widths in the X-shaped shear band of the biaxial compression test are not equal,and the shear band widens gradually during the axial loading process.
作者
刘宗祺
陈曦
崔柳生
唐建彬
LIU Zong-qi;CHEN Xi;CUI Liu-sheng;TANG Jian-bin(Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第S01期742-750,共9页
Rock and Soil Mechanics
基金
国家自然科学基金面上项目(No.52178309)
关键词
离散元方法
剪切带
测量圆
孔隙率
测量技术
discrete element method
shear band
measurement circle
porosity
measuring technique
作者简介
第一作者:刘宗祺,男,1995年生,博士研究生,主要从事计算岩土力学、岩土工程信息化与智能化方面的研究。E-mail:21115032@bjtu.edu.cn;通讯作者:陈曦,男,1977年生,博士,教授,博士生导师,主要从事计算岩土力学、岩土工程信息化与智能化方面的研究。E-mail:xichen.geo@gmail.com
