土石混合料振动压实特性的三维离散元分析

Three-dimensional discrete element analysis of vibratory compaction characteristics of soil-rock mixture

为探究试验条件和颗粒细观参数对土石混合料三维离散元模型压实效果的影响,基于三维离散元方法,建立土石混合料表面振动压实试验模型。假定粗、细颗粒密度相同,不考虑含水率的影响,提出以孔隙率作为模拟试验压实质量的量化评价指标。首先通过模拟试验分析含石量和颗粒最大粒径对压实效果的影响,并与室内试验结果对比,验证模拟试验的可靠性。在此基础上,分析试验条件和颗粒细观参数对压实效果的影响。模拟结果表明:(1)试验条件方面,孔隙率随着试筒直径与颗粒最大直径的比值增大而降低;孔隙率随着荷载振动频率的增加而增加;试筒刚度增大时,孔隙率先增加后减小;(2)细观参数方面,颗粒摩擦系数对孔隙率影响微弱,随着颗粒刚度、阻尼系数的增加,孔隙率逐渐增加。

In order to explore the influence of experimental conditions and particle mesoscopic parameters on the compaction effect of three-dimensional discrete element model of soil-rock mixture,a vibratory compaction test model for soil-rock mixture surface was established based on three-dimensional discrete element method.Assuming that the density of coarse and fine particles is the same and the influence of moisture content is not considered,the porosity is taken as the quantitative evaluation index of the compaction quality of the simula-tion test. Firstly,the influence of the content of stone and the maximum particle size on the compaction effect was analyzed by simulation test,and compared with the results of indoor test,the reliability of the simulation test was verified. On this basis,the influence of experimental conditions and the mesoscopic parameters on the compaction effect was analyzed. The simulation results show that：（ 1） In terms of test conditions,the porosity decreases with the ratio of the diameter of the test cylinder to the maximum diameter of the particles; the porosity increases with the increase of the vibration frequency of the load; when the rigidity of the test cylinder increases,the porosity first Increased and then decreased;（ 2） In terms of meso-parameters,the particle friction coefficient has a weak influence on the porosity,and with the increase of particle stiffness and damping coefficient,the porosity increases gradually.