具有分形级配的多分散颗粒体堆积特性研究  

Study on packing properties of polydisperse particles with fractal gradation

作　　者：李瑞欣[1] 鲁杰[1] 关鹏[2] LI Ruixin;LU Jie;GUAN Peng(The Fourth Geological Exploration Institute of Henan Geology and Mineral Exploration Bureau,Zhengzhou 450000,China;Faculty of Engineering,China University of Geoscience,Wuhan 430074,China)

机构地区：[1]河南省地质矿产勘查开发局第四地质勘查院,河南郑州450000 [2]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《混凝土》2024年第2期88-92,共5页Concrete

基　　金：国家自然科学基金青年基金(41902280);岩土钻掘与防护教育部工程研究中心开放研究基金(202311)。

摘　　要：混凝土骨料或公路工程基层碎石常采用Fuller或Thompson分布作为设计级配,具有分形特性的多分散颗粒堆积体容易形成相对较大的堆积密度,作为理想的设计级配,其作用机理尚没有详细地解释。采用颗粒离散元仿真技术获取了多种具有分形级配的颗粒体在各向同性压缩条件下的堆积密度,颗粒体由光滑(无摩擦)的球形颗粒构成,分形级配曲线的形状由粒径区间和分形维数指标控制。在此基础上,研究了分形级配指标与堆积密度和配位数等宏细观指标的相关性,得出分形维数及粒径区间对堆积密度有重要影响。当级配粒径区间较大时,最大的堆积密度对应的分形维数为2.5左右,与工程中常采用的Fuller和Thompson级配十分一致。通过对堆积体细观颗粒层面的配位数及局部堆积密度的研究得出,分形维数为2.5左右时,试样局部排序和接触分布得到优化。研究结果可为进一步优化混凝土、土石坝或路基等碎石填料的级配设计提供理论指导。The Fuller or Thompson distribution is often used as the design gradation for concrete aggregate or highway engineering base gravel.The polydisperse particle accumulation with fractal properties is easy to form a relatively large bulk density.As an ideal design gradation,its mechanism of action is not yet available explained in detail.The bulk density of a variety of particles with fractal gradation under isotropic compression is obtained by using particle discrete element simulation technology.The particles are composed of smooth(frictionless)spherical particles,and the shape of the fractal gradation curve is determined by the interval and fractal dimension indicator controls.On this basis,the correlation between the fractal gradation index and macro and mesoscopic indexes such as bulk density and coordination number is studied.It is concluded that the fractal dimension and the particle size interval have an important influence on the bulk density.When the gradation particle size interval is large,the fractal dimension corresponding to the maximum bulk density is about 2.5,which is similar to the Fuller and Thompson gradation often used in engineering.By studying the coordination number and local packing density at the meso-grain level of the stack,it is concluded that when the fractal dimension is about 2.5,the local ordering and contact distribution of the sample are optimized.The results can provide theoretical guidance for further optimizing the gradation design of crushed stone fillers such as concrete,earth-rock dams or roadbeds.

关 键 词：分形维数 颗粒级配 离散元 颗粒材料 

分 类 号：TU528.041[建筑科学—建筑技术科学]