中文摘要：

针对凸多面体颗粒,提出了基于最小投影的粒径评估方法,并与体积评估法和垂直于最小惯性主轴的最小包围正方形评估法进行了对比分析.最后,利用基于最小投影的粒径评估法对道砟颗粒进行粒径评估,并建立了单一粒径级配和指定宽粒径级配的道砟颗粒堆积体,分析了不同颗粒级配对道砟沉降的影响.结果表明：基于最小投影的最小包围矩形粒径评估法比体积评估法和最小包围正方形评估法更精确;道砟初始堆积密度为1.55g·m-3时,宽粒径级配颗粒的轨枕累积沉降值比单一粒径级配的轨枕累积沉降值要小,而且级配单一的大粒径颗粒的轨枕累积沉降值要比级配单一的小粒径的轨枕累积沉降值要大.

英文摘要：

Based on a model of convex polyhedron ballast, a method for evaluation of the particle size is proposed under the condition of minimal shadow area of it. By contrast with the evaluation methods of particle volume and minimum bounding square perpendicular to the principal axis of minimum moment of inertia, a detailed analysis of the abovementioned method is carried out. Then the particle size of ballast particle is evaluated through using it. By establishing the accumulation masse of ballast particles with single and broad particle size distribution, the influence of different particle size distributions on the ballast settlement is analyzed. The results show that the proposed evaluation method in this paper provides a more accurate evaluation for the particle size of ballast particle. When the initial packing density of ballast is 1.55 g · m^-3, the value of accumulated settlement of sleeper with broad particle size distribution is less than the one with single particle size distribution. And the value of accumulated settlement of sleeper with a large particle size is greater than the one with a small particle size.