不规则颗粒及其集合体三维离散元建模方法的改进

发布时间：2018-04-14 02:17

本文选题：不规则颗粒 + 颗粒集合体　；参考：《岩土工程学报》2017年07期

【摘要】：以土石混合体中的不规则块石和含石量为40%的土石混合体室内大三轴试样为例,研究了如何针对当前岩土材料建模方法的不足进行改进以建立尽可能真实的不规则颗粒及其集合体的三维离散元模型。为了模拟块石的真实形态特征,明确了块石几何模型建模方法的控制参数及其确定方法,建立了与真实块石球度相同、棱角度相似的三维半真实离散元模型。为了计算模型的体积以用于模型密度优化及颗粒集合体孔隙率的计算,提出了一种三维离散元模型虚拟切片技术,结合数字图像处理技术可快速准确计算块石三维半真实离散元模型的体积。为了使得土石混合体大三轴试样三维离散元模型的密实度与室内试样保持一致并兼顾建模效率,提出了基于拟振动压实法和分层复制法的土石混合体大三轴试样三维离散元建模方法。研究结果表明:所提出的不规则块石几何模型建模方法控制参数较少且可分别对球度和棱角度进行单独控制;当块石离散元模型填充球体数较少时,其体积与对应几何模型体积相差较大,不能直接采用对应几何模型的体积;所建立的土石混合体数值试样与室内试样的细观结构特征基本相同,即块石随机散布于土体基质中。
[Abstract]:For example, the irregular block rock in the soil-rock mixture and the large triaxial specimen in the chamber of the earth-rock mixture containing 40% of the rock content are taken as an example.This paper studies how to improve the current modeling methods of geotechnical materials in order to establish the 3D discrete element model of irregular particles and their aggregates as real as possible.In order to simulate the real morphological characteristics of block rock, the control parameters and the determination method of the modeling method of block stone geometric model are defined, and a three-dimensional semi-real discrete element model with the same sphericity and similar angle as the real block stone is established.In order to calculate the volume of the model for the optimization of model density and the calculation of porosity of particle aggregates, a 3D discrete element model virtual slice technique is proposed.Combined with digital image processing technology, the volume of block stone 3D semi-real discrete element model can be calculated quickly and accurately.In order to make the compactness of the three-dimensional discrete element model of the large triaxial specimen of soil-rock mixture consistent with that of the indoor specimen, the modeling efficiency is considered.Based on pseudo-vibration compaction method and stratified replication method, a three-dimensional discrete element modeling method for large triaxial specimens of soil-rock mixture is proposed.The results show that the proposed geometric modeling method has less control parameters and can separately control the sphericity and the angle of edges, and when the discrete element model of block stone is less filled with the number of spheres,The volume of the model is different from that of the corresponding geometric model, and the volume of the corresponding geometric model can not be used directly, and the characteristics of the meso-structure of the soil-rock mixture numerical sample are basically the same as those of the indoor sample, that is, the block stone is scattered randomly in the soil matrix.
【作者单位】：武汉大学土木建筑工程学院;武汉轻工大学土木工程与建筑学院;中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金项目(41272342)
【分类号】：TU411

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