Debris-flow dynamics: Understanding phase separation and wave formation

泥石流是威胁山区人民和基础设施的自然灾害。由于高降雨强度事件的数量不断增加，山体滑坡变得更加频繁(Petely等人，2012年，《全球山体滑坡造成的生命损失模式》)。地质学40,927-930)。泥石流的破坏性潜力因涌浪的发展而大大增强(图3+视频)，它将泥石流集中成通常携带大岩石和巨石的大振幅波。尽管经过了近40年的研究，但对于这些波的形成原因仍然缺乏了解，也缺乏可以用于测试模型的良好的现场数据集(活动流厚度和速度的现场测量)。这严重限制了泥石流风险分析的准确性，因为当前的泥石流模型无法定量地捕捉到这些波或将最大颗粒聚集在泥石流最深和最快部分的颗粒尺寸分离。这项提议旨在通过将(A)瑞士伊尔格拉本泥石流观测站在环境传感方面的新创新(激光雷达/高清混合视频)与(B)曼彻斯特(Gray&Edwards，2014，Gray 2018，Rocha等人)在模拟非线性波浪形成和颗粒尺寸分离方面的最新理论进展相结合，在我们预测泥石流涌浪形成的能力方面取得重大突破。2019年)。组建的研究小组非常适合解决这一问题，因为它汇集了具有强大理论背景以及实验室和现场数据收集专业知识的各种专家。这将使该小组能够将目前在伊尔格拉本收集的最先进的现场数据(并作为本提议的一部分加以改进)纳入尖端的理论和数字模型，以便使我们对涌浪的理解发生阶段性变化，并为泥石流社区用于危险风险评估提供新的计算工具。

Debris flows are natural hazards that threaten people and infrastructure in mountainous terrain. They are becoming more frequent due to the increasing number of high rainfall intensity events (Petely et al., 2012, Global patterns of loss of life from landslides. Geology 40, 927-930). The destructive potential of debris flows is strongly enhanced by the development of surge waves (Fig 3 + video), which concentrate the flow into large amplitude waves that often carry large rocks and boulders. Despite nearly forty years of research there is still a lack of understanding about why these waves form, as well as a dearth of good field data sets (in-situ measurements of active flow thickness and velocity) that can be used to test models. This severely limits the accuracy of debris-flow risk analysis, because current debris-flow models are not able to capture quantitatively these waves or the particle-size segregation that concentrates the largest particles in the deepest and fastest-flowing part of the flow. This proposal aims to make a major breakthrough in our ability to predict debris-flow surge wave formation by coupling (a) new innovations (hybrid LiDAR/HD video) in environmental sensing at the Illgraben debris-flow observation station in Switzerland with (b) recent theoretical advances in modelling nonlinear wave formation and particle-size segregation made in Manchester (Gray & Edwards 2014, Gray 2018, Rocha et al. 2019). The assembled research team is uniquely suited to address this question, as it combines a diverse range of experts who have a strong theoretical background as well as expertise in laboratory and field data collection. This will enable the team to integrate state-of-the-art in-situ data currently being collected at Illgraben (and improved on as part of this proposal) into cutting-edge theoretical and numerical models in order to generate a step change in our understanding of surge waves as well as new computational tools for use by the debris-flow community in hazard risk assessment.