Numerical simulation of rock avalanches: Influence of a local dissipative contact model on the collective behavior of granular flows
Numerical simulation of rock avalanches: Influence of a local dissipative contact model on the collective behavior of granular flows
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DOI：
10.1029/2011jf002202
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发表时间：
2012-06
影响因子：
--
通讯作者：
G. Mollon;V. Richefeu;P. Villard;D. Daudon
中科院分区：
文献类型：
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作者：
G. Mollon;V. Richefeu;P. Villard;D. Daudon
[1]岩石雪崩是山区发展中的一个重大问题。因此，需要可靠地预测雪崩的沉积区域。为了提高这种事件的数值模拟，并提供有关这种类型的颗粒流的物理现象的信息，一个离散元模型，它考虑到摩擦和碰撞耗散在颗粒尺度与角形元素，被用来调查集体行为的颗粒物质传播的斜坡。离散元模型（DEM）的参数是从跌落试验中定义的，跌落试验涉及单个颗粒与平坦表面的碰撞。数值模型的有效性估计与实验室实验的结果进行比较，涉及干颗粒流在斜面上。数值模型提供了有价值的信息，无论是在基地或传播的粒状质量和有关的运动学的流动和形状的存款的能量耗散的方式，提高了对岩石雪崩的理解。接触法参数的影响进行了研究，使用的灵敏度研究。它示出的流动是强烈的影响，由基础摩擦，而颗粒间摩擦和碰撞耗散现象主要是在流动扰动的区域（如两个斜坡之间的过渡区）的干预。斜坡表面的宏观粗糙度引起颗粒运动中的无序增加，这增加了颗粒质量内的摩擦耗散和碰撞耗散。使用一个平面的斜坡和增加摩擦参数可以重现这种粗糙度的明显影响。
[1] Rock avalanches are a significant concern in developing mountain areas. Thus a reliable prediction of depositional areas from avalanches is needed. In order to improve the numerical modeling of such events and to provide information concerning the physical phenomena underlying this type of granular flow, a discrete element model, which takes into account frictional and collisional dissipation at grain scale together with angular-shaped elements, is used to investigate the collective behavior of granular masses propagating down a slope. The discrete element model (DEM) parameters are defined from drop tests involving the collision of an individual particle with a flat surface. The validity of the numerical model is estimated by comparison with the results of a laboratory experiment involving a dry granular flow on an inclined plane. The numerical model improves the understanding of rock avalanches by providing both valuable information about the way energy is dissipated either at the base or within the propagating granular mass and relevant information about the kinematics of the flow and the shape of the deposit. The influence of contact-law parameters is investigated using a sensitivity study. It is shown that the flow is strongly influenced by basal friction, while inter-particle friction and collisional dissipation phenomena intervene mostly in areas of flow perturbation (such as transition zones between two slopes). A macroscopic roughness of the slope surface induces an increased disorder in the particle motion which increases both frictional and collisional dissipation within the granular mass. Using a planar slope and increasing the frictional parameter can reproduce the apparent influence of this roughness.