Debris avalanches and dry granular flows exhibit similar characteristics. In order to comprehend the fundamental mechanisms and improve the accuracy in predicting disasters such as landslides, debris flows, and rock avalanches, the collapse characteristics of a binary granular column are investigated through a three‐dimensional discrete element model. A novel approach is proposed by incorporating the concept of local granular velocity fluctuation and applying a cluster analysis method. Then, the flow mechanism of the binary granular column is analyzed, by considering the inhomogeneous particle size distribution. The research results show that: (1) The normalized final packing height of the granular column gradually increases when the content of coarse particles exceeds 20% and when the coarse‐fine particle size ratio increases. Conversely, the normalized run‐out distance of the granular column decreases gradually with the increase in coarse particle content and the coarse‐fine particle size ratio. (2) The particles with higher granular velocity fluctuations tend to move together and form clusters, demonstrating dynamical heterogeneity. As the coarse particle content and coarse‐fine particle size ratio increase, there is a greater tendency for particles to assemble into larger‐scale active clusters. This means that a larger number of particles exhibit collective behavior during the collapse process, resulting in increased resistance to shear deformation. Ultimately, this leads to a greater packing height and a reduced run‐out distance when observed from a macroscopic perspective.

中文翻译：

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考虑非均匀粒径分布的二元颗粒柱的塌陷特性


泥石流和干燥颗粒流表现出相似的特征。为了理解滑坡、泥石流、岩崩等灾害的基本机理，提高预测精度，通过三维离散元模型研究二元颗粒柱的崩塌特征。通过结合局部颗粒速度波动的概念并应用聚类分析方法，提出了一种新方法。然后，考虑不均匀粒径分布，分析二元颗粒柱的流动机理。研究结果表明：（1）当粗颗粒含量超过20%且粗细粒度比增大时，颗粒柱归一化最终堆积高度逐渐增大。相反，随着粗颗粒含量和粗细颗粒尺寸比的增加，颗粒柱的归一化跳动距离逐渐减小。 (2)具有较高粒速度波动的颗粒倾向于一起移动并形成团簇，表现出动力学不均匀性。随着粗颗粒含量和粗细颗粒尺寸比的增加，颗粒更有可能聚集成更大规模的活性团簇。这意味着在塌陷过程中更多的颗粒表现出集体行为，从而导致抗剪切变形的能力增加。最终，从宏观角度观察，这会导致更大的堆积高度和更短的跳动距离。