多边形道砟颗粒堆积和压缩特性的 DDA数值模拟研究

摘要

Discontinuous deformation analysis (DDA) is considered to be an efficient way to study deformation behavior of ballast ,in which polygon particles can be easily captured. In this paper ,a new method was proposed to generate polygon particles and was successfully implied in DDA simulation of spontaneous stacking and uniaxial compression process of ballast. T he results demonstrate as follow s :T he spontaneous repose angle of ballast is affected by the angle of friction of particle surfaces ,interlocking effect of particles and the angle of friction between particles and ballast slabs ;the DDA method is a useful method for the investigation of deformation behavior of ballast ;three stages can be identified in compaction of ballast as the elastic ,plastic and elastic hardening stages ,the hardening stress controls the plastic strain and has a function similar to the pre-consolidated stress.%非连续变形分析方法（DDA ）能方便地模拟多边形颗粒的接触和变形。本文提出多边形道砟颗粒的生成方法，并使用DDA方法分析道砟的自然堆积和单轴压缩过程。研究结果表明：道砟自然堆积休止角同时受到道砟颗粒表面摩擦角、颗粒咬合作用、颗粒和底板摩擦角的影响；DDA方法能够成功反演室内单轴压缩试验，是研究道砟压缩特性的有效手段；由于道砟颗粒较硬，松散道砟堆积体的单轴压缩过程即在塑性阶段后还存在一个弹性硬化阶段，在这两个阶段的转折点上“弹性硬化应力”可以看作是道砟的“先期固结压力”。