颗粒尺寸对压实多分散颗粒体接触力分布的影响

Effect of particle size on contact force distribution in compacted multi-dispersed granule

为了研究多分散颗粒体的接触力分布规律,预估颗粒体中颗粒破碎的分布范围,采用颗粒流离散元法(discrete element method,DEM)构建不同颗粒级配(分散度)的颗粒体,对土体的三轴压缩试验进行模拟,以研究颗粒粒径对颗粒体接触力分布的影响。通过分析不同颗粒级配试样中法向接触力的概率密度分布和累积分布,对比不同颗粒级配试样中具有相同粒径的子颗粒集的配位数分布和最大接触力,调查了颗粒级配对密实颗粒体接触力分布特性的影响。结果表明:试样中粒径较大的颗粒相比于小粒径颗粒,试样中粒径较大的颗粒会承受更大的接触力;粒径较小的子颗粒集相比于粒径较大的颗粒体具有较小的最大接触力和配位数;细颗粒倾向于分布在大颗粒包围的孔隙中,此时,细颗粒基本上不参与传递接触力;颗粒级配越好,颗粒粒径对接触力分布的影响越小。

In order to study the contact force distribution of multi-dispersed particles,the distribution range of particle breakage in the particles was estimated.The particle flow discrete element method(DEM)was used to construct particles with different particle gradations(dispersity),and the triaxial compression test of the soil was conducted to simulate the influence of particle size on the distribution of particle contact force.By analyzing the probability density distribution and cumulative distribution of the normal contact force in different particle grading samples,and comparing the coordination number distribution and maximum contact force of the sub-particle sets with the same particle size in different particle grading samples,the effect of gradation on the contact force distribution characteristics of dense particles were investigated.The results show that particles with larger diameters in the sample are more likely to bear stronger contact force than particles with small diameters.The sub-particle set with a smaller size has a smaller maximum contact force and coordination number than that with a larger size.The fine particles tend to be distributed in the pores surrounded by the large particles.Hence,the fine particles do not substantially participate in the transmission of contact force.The better the particle gradation,the smaller the influence of particle size on the contact force distribution.