基于离散单元法的溜砂坡堆积形态数值研究

发布时间：2018-01-28 14:24

本文关键词： 离散元溜砂坡堆积形态细观机制颗粒形状分形　出处：《中南大学学报(自然科学版)》2017年07期 　论文类型：期刊论文

【摘要】：采用离散单元法模拟了溜砂坡的堆积过程,研究粒间摩擦因数和颗粒形状对溜砂坡堆积形态的影响,建立粒间摩擦因数、颗粒形状与堆积形态的相关关系。研究结果表明:颗粒堆积体上、下部的粒径分布均具有分形特性,摩擦因数越大,堆积体上部分形维数和堆积角度越大。对比不同的颗粒形状,颗粒浑圆度越差,堆积体上部分形维数和堆积角度越大。随着粒间摩擦因数的增大,强力链数目减少,弱力链数目增多,力链结构的各向异性增强,颗粒间法向接触力的水平分量变小,接触法向的主方向向竖直方向偏转。圆形颗粒堆积体中力链分布呈树根状,考虑颗粒形状后的堆积体内强力链方向基本与斜坡平行。溜砂坡下部分形维数与其内部孔隙率呈较好的线性关系,下部分形维数越大,堆积体孔隙率越小。
[Abstract]:The accumulation process of sliding slope is simulated by discrete element method. The effects of intergranular friction coefficient and particle shape on the accumulation morphology of sliding slope are studied, and the friction coefficient between grains is established. The results show that the particle size distribution in the lower part of the grain accumulator has fractal characteristics, and the friction coefficient is higher. The bigger the shape dimension and the bigger the stacking angle is, the bigger the shape dimension and the angle of accumulation are, compared with the different particle shape, the bigger the shape dimension and the angle of accumulation are, with the increase of friction coefficient between grains. The number of strong chains decreases, the number of weak chains increases, the anisotropy of the chain structure increases, and the horizontal component of normal contact force between particles becomes smaller. The main direction of contact is vertical deflection. The distribution of the force chain in the circular granular accumulation is tree root. After considering the shape of grain, the direction of the strong chain is basically parallel to the slope. There is a good linear relationship between the shape dimension and the internal porosity of the sand slide slope. The larger the shape dimension of the lower part is, the smaller the porosity of the accumulated body is.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;武汉大学水工岩石力学教育部重点实验室;
【基金】：国家优秀青年科学基金资助项目(51322905) 中国博士后科学基金面上资助项目(2015M572195)~~
【分类号】：P642.2
【正文快照】： 边坡表面的岩体经物理风化而形成的碎石、砂砾等松散砂石,常常在重力作用下沿坡面溜动,最终以自然休止角堆积成锥状斜坡,即溜砂坡。此类堆积体结构松散,颗粒间的黏聚力几乎为零,完全依靠颗粒间的摩擦和咬合作用自稳。因此,溜砂坡的稳定性较差,极易因外界扰动而发生大面积的二

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