Development of a GIS-based Open Source Simulation Tool for Modelling General Avalanche and Debris Flows over Natural Topography

世界各地的山区都发生着灾害性的颗粒流和泥石流。雪崩、岩石或岩石冰雪崩、泥石流、火山泥流和火山碎屑流只是其中的一些例子。要充分管理与这些现象有关的风险，就需要对这些过程所涉及的机制进行详细和可靠的分析。尽管在这方面已经做了大量的工作，并且确实存在许多具有不同程度的复杂性的基于物理的模型，但是仍然存在一些问题未解决：（1）任意地形上的流动，粘性孔隙流体或流动的两相性质的作用，以及颗粒和/或流体夹带尚未以适当的方式被考虑。(2)到目前为止，还没有成功的尝试，以建立易于处理的开放源码应用程序，这些复杂的模型，这将是必不可少的，使他们能够在大学和公共服务的更广泛的用户群。因此，它关注的是快速的地球物理物质流，包括雪崩和真实的两相泥石流，从一个已知的起始区通过流动路径沿着自然山区地形进入沉积区。对于给定的质量及其在起始区的分布，我们感兴趣的是沿轨迹沿着任意地形的运动和几何变形，包括质量沿着轨迹的侵蚀和沉积过程以及沉积质量的最终分布。这还将包括动态演变的孔隙流体压力和/或固体和流体组分的演变的影响。同样重要的是，应重点开发所开发模型的用户友好且可免费访问的应用程序。该应用程序将建立在地理信息系统软件GRASS的基础上，该软件是根据GNU通用公共许可证提供的开放源码产品。将使用物理模型测试和记录良好的质量流事件对新软件进行评估。这些测试将涵盖广泛的过程和过程链，包括泥石流、碎片雪崩和雪或岩石的雪崩。

Catastrophic granular and debris flows occur in many mountain areas all over the world. Snow avalanches, rock or rock-ice avalanches, debris flows, lahars and pyroclastic flows are only some examples. An adequate management of the risk related to these phenomena requires a detailed and reliable analysis of the mechanisms involved in such processes. Even though much work has been done on this subject, and a number of physically-based models with a varying degree of complexity do exist, some problems still remain unsolved: (1) Flow over arbitrary topography, the role of viscous pore fluid or two-phase nature of flow, and particle and/or fluid entrainment have not yet been accounted for in an appropriate way. (2) Until now, no successful attempts have been made to build easy-to-handle Open Source applications of these complex models, which would be essential to make them available to a broader group of users in universities and public services.This proposal offers an effective, innovative and unified solution to these two problems. It is therefore concerned with rapid geophysical mass flows, including avalanches and real two-phase debris flows, from a known initiation zone through the flow path along natural mountain topography into the deposition zone. For a given amount of mass and its distribution in the initiation zone, we are interested in the motion and geometric deformation along the track down the arbitrary topography, including the processes of erosion and deposition of mass along the track and the ultimate distribution of the deposited mass. This will also include the effect of dynamically evolving pore fluid pressure and/or evolution of the solid and the fluid components. An equally important focus shall be put onto the development of a user-friendly and freely accessible application of the developed model. This application will build upon the GIS software GRASS, which is available as an Open Source product under the GNU General Public License. The new software will be evaluated using physical model tests and well-documented mass flow events. These tests will cover a broad range of processes and process chains including debris flows, debris avalanches and avalanches of snow or rocks.