Study on dynamic mechanism of granular flow erosion and entrainment based on DEM theory

IF 3.8 Q2 ENVIRONMENTAL SCIENCES Geoenvironmental Disasters Pub Date : 2024-07-02 DOI:10.1186/s40677-024-00278-5

Xurong He, Xiewen Hu, Zihao Huo, Jianfeng Tang, Shilin Zhang

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Abstract

Granular flows are common on the Qinghai–Tibet Plateau and the Hengduan Mountains in China, and their dynamic process processes have obvious erosional and entrainment effects. On the one hand, the volume of the granular flow increases by a factor of several or ten, which significantly increases its ability to cause a catastrophe; on the other hand, the eroded loose material affects the granular flow dynamics process and changes its state of motion. In this paper, the dynamic mechanism of granular flow erosion and entrainment is investigated by DEM simulation. The effects of different substrate materials and substrate boundary conditions on granular flow erosion and entrainment are analyzed, and the effects of material mixing caused by erosion and entrainment on the state of motion of granular flow are discussed. It was verified that the kinetic mechanisms of granular flow erosion and entrainment includes impact erosion, ploughing, and shear abrasion. And discovered that small matrix particle size, small matrix boundary friction, and small matrix thickness lead to stronger ploughing and shear abrasion; Large matrix fractal dimensions result in stronger ploughing and weaker shear abrasion, and the granular flow does not entrain large amounts of material to the accumulation zone. Meanwhile, the dynamics of erosion and entrainment of granular flow were investigated, and the results showed that: 1. The greater the erosion rate, the greater the velocity and kinetic energy of the granular flow, the greater the distance traveled, and the smaller the apparent friction angle (i.e., the greater the mobility). 2. The amount of small granules in a granular flow changes its fluidity, the more small granules there are, the more fluid it is. 3. The fit reveals that the substrate fractal dimension has the strongest effect on the velocity and kinetic energy of granular flow, followed by substrate thickness and substrate boundary friction.

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基于 DEM 理论的颗粒流侵蚀和夹带动态机理研究

颗粒流在我国青藏高原和横断山脉十分常见，其动力过程过程具有明显的侵蚀和夹带效应。一方面，颗粒流的体积以几倍或十几倍的速度增大，致灾能力显著增强；另一方面，被侵蚀的松散物质会影响颗粒流的动力过程，改变其运动状态。本文通过 DEM 仿真研究了颗粒流侵蚀和夹带的动力学机理。分析了不同基质材料和基质边界条件对颗粒流侵蚀和夹带的影响，讨论了侵蚀和夹带引起的物质混合对颗粒流运动状态的影响。验证了颗粒流侵蚀和夹带的动力学机制包括冲击侵蚀、犁蚀和剪切磨蚀。并发现基质粒径小、基质边界摩擦力小、基质厚度小会导致较强的犁蚀和剪切磨损；基质分形尺寸大会导致较强的犁蚀和较弱的剪切磨损，颗粒流不会夹带大量物质到堆积区。同时，研究了颗粒流的侵蚀和夹带动力学，结果表明： 1：1.侵蚀速率越大，颗粒流的速度和动能越大，移动距离越远，表观摩擦角越小（即流动性越大）。2.颗粒流中小颗粒的数量会改变其流动性，小颗粒越多，流动性越强。3.拟合结果表明，基底分形维度对颗粒流动的速度和动能影响最大，其次是基底厚度和基底边界摩擦。

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来源期刊

Geoenvironmental Disasters Social Sciences-Geography, Planning and Development

CiteScore

8.90

自引率

6.20%

发文量

期刊介绍： Geoenvironmental Disasters is an international journal with a focus on multi-disciplinary applied and fundamental research and the effects and impacts on infrastructure, society and the environment of geoenvironmental disasters triggered by various types of geo-hazards (e.g. earthquakes, volcanic activity, landslides, tsunamis, intensive erosion and hydro-meteorological events). The integrated study of Geoenvironmental Disasters is an emerging and composite field of research interfacing with areas traditionally within civil engineering, earth sciences, atmospheric sciences and the life sciences. It centers on the interactions within and between the Earth''s ground, air and water environments, all of which are affected by climate, geological, morphological and anthropological processes; and biological and ecological cycles. Disasters are dynamic forces which can change the Earth pervasively, rapidly, or abruptly, and which can generate lasting effects on the natural and built environments. The journal publishes research papers, case studies and quick reports of recent geoenvironmental disasters, review papers and technical reports of various geoenvironmental disaster-related case studies. The focus on case studies and quick reports of recent geoenvironmental disasters helps to advance the practical understanding of geoenvironmental disasters and to inform future research priorities; they are a major component of the journal. The journal aims for the rapid publication of research papers at a high scientific level. The journal welcomes proposals for special issues reflecting the trends in geoenvironmental disaster reduction and monothematic issues. Researchers and practitioners are encouraged to submit original, unpublished contributions.