Abstract

Railway ballast usually experiences continuous abrasion or breakage as subjected to repeated train loads. A novel 2D abrasion model is established based on the Discrete Element Method to capture the abrasion behavior of ballast with irregular shapes. A force-based failure criterion allowing for the Weibull distribution and size scaling law of strength is developed for abrasion recognition. In current model, ballast can abrade in either crushing or shearing mode, with each of them corresponds to a different fragment generation method after corner abrasion. A series of Los Angeles Abrasion (LAA) test simulations are conducted and the LAA loss is calibrated against the existing experimental data. The abrasion model and the calibrated strength parameters are further validated by the biaxial compression simulations. The evolutions of particle size and morphology during LAA test are also analyzed in terms of sphericity variation and ballast breakage index (BBI). The average sphericity and the BBI of ballast aggregates increase at a decreasing rate as abrasion aggravates. Using the calibrated model, the influence of particle morphology on the abrasion behavior of ballast is also investigated. It is found that particles with lower sphericities exhibit greater LAA loss and BBI value during LAA test. The proposed model provides an efficient and robust method to study the abrasion behavior of ballast aggregate involving with irregular shaped particles.

Graphic Abstract

中文翻译：

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一种模拟不规则形状粗粒集料磨损行为的新 DEM 模型

摘要

铁路道碴在承受反复列车载荷时通常会经历持续磨损或破损。基于离散元法建立了一种新颖的二维磨损模型，以捕捉具有不规则形状的道砟的磨损行为。为磨损识别开发了一种基于力的失效准则，允许威布尔分布和强度的尺寸缩放定律。在目前的模型中，道碴可以采用破碎或剪切两种方式进行磨损，每种方式都对应于不同的角部磨损后的碎片生成方法。进行了一系列洛杉矶磨损 (LAA) 测试模拟，并根据现有实验数据校准 LAA 损耗。双轴压缩模拟进一步验证了磨损模型和校准的强度参数。还分析了 LAA 测试过程中粒度和形态的演变，包括球度变化和道碴破损指数 (BBI)。随着磨损加剧，道碴骨料的平均球形度和 BBI 以下降的速度增加。使用校准模型，还研究了颗粒形态对道砟磨损行为的影响。发现具有较低球形度的颗粒在 LAA 测试期间表现出更大的 LAA 损失和 BBI 值。所提出的模型提供了一种有效且稳健的方法来研究包含不规则形状颗粒的道碴骨料的磨损行为。随着磨损加剧，道碴骨料的平均球形度和 BBI 以下降的速度增加。使用校准模型，还研究了颗粒形态对道砟磨损行为的影响。发现具有较低球形度的颗粒在 LAA 测试期间表现出更大的 LAA 损失和 BBI 值。所提出的模型提供了一种有效且稳健的方法来研究包含不规则形状颗粒的道碴骨料的磨损行为。随着磨损加剧，道碴骨料的平均球形度和 BBI 以下降的速度增加。使用校准模型，还研究了颗粒形态对道砟磨损行为的影响。发现具有较低球形度的颗粒在 LAA 测试期间表现出更大的 LAA 损失和 BBI 值。所提出的模型提供了一种有效且稳健的方法来研究包含不规则形状颗粒的道碴骨料的磨损行为。

图形摘要