Reconstruction of a destructive debris‐flow event via numerical modeling: the role of valley geometry on flow dynamics
Reconstruction of a destructive debris‐flow event via numerical modeling: the role of valley geometry on flow dynamics
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通过数值模拟重建破坏性泥石流事件：山谷几何形状对流动动力学的作用
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
G. Scarascia Mugnozza
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文献类型：
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作者：
L. Schilirò;F. D. De Blasio;C. Esposito;G. Scarascia Mugnozza
泥石流是一种广泛存在的自然现象，其特点是流动性大(速度快、落差大)和冲击力大，经常造成人员伤亡和对基础设施的重大破坏。为了更好地了解这类事件的动力学，特别是分析山谷几何形状对水流速度、径向和动员量的影响，本文通过数值模拟重建了一个真实的泥石流事件。具体地说，我们使用了Bing模型的修改版本，这是一种流体动力深度集成的泥石流数值模型，已经进行了适当的修改，以考虑山谷沿线的宽度变化。所研究的事件于2009年10月1日在意大利西西里岛东北部的Scaletta Zanclea(梅西纳)发生，受到现场和地形信息的极好限制。在这方面，根据现场证据从两个特定位置估计的流速、基于地震前后数字高程模型(DEM)的比较而得到的瑞奇纳佐河谷沿线侵蚀和沉积区的分布以及跳动距离被用作校准模型的约束条件。此外，我们根据水文记录和目击者报告，详细描述了主要事件的特征。数值模拟结果与目击者的报告和Scaletta Marina村的严重破坏情况相一致，突出了山谷几何形状对泥石流速度和侵蚀/沉积过程的影响。改变山谷宽度的影响也被量化，导致与山谷变窄和高原停滞相对应的碎屑加速。版权所有©2015 John Wiley&Sons，Ltd.
Debris‐flows are widespread natural phenomena characterized by high mobility (high velocity and long runout distance) and impact forces, which frequently cause human casualties and significant damage to infrastructure. To better understand the dynamics of such events, analyzing in particular the effect induced by the valley geometry on flow velocity, runout and mobilized volumes, in this work we reconstruct a real debris‐flow event through numerical modeling. Specifically, we used a modified version of the BING model, a fluid‐dynamic depth‐integrated numerical model for debris flows, which has been properly modified to account for width changes along the valley. The studied event, which occurred in Scaletta Zanclea (Messina, north‐eastern Sicily, Italy) on October 1, 2009, is exceptionally well constrained by field and topographic information. In this respect the flow velocity, estimated from two specific locations on the basis of field evidence, the distribution of erosional and depositional areas along the Racinazzo valley, based on the comparison of pre‐ and post‐event digital elevation models (DEMs), and the runout distance were used as constraints to calibrate the model. Furthermore, we report a detailed description of the main event characteristics based on hydrological records and witness reports. The numerical modeling results are consistent with witness reports and the severe damage recorded in the Scaletta Marina village, and highlight the effect of the valley geometry on both the debris flow velocity and the erosion/deposition processes. The effect of changing valley width has been also quantified, resulting in accelerations of the debris in correspondence of the valley narrowing and stagnations at the plateaus. Copyright © 2015 John Wiley & Sons, Ltd.