Landslide mobility with erosion: Proof-of-concept and application - Part I: Modelling, Simulation & Validation

侵蚀可以通过大规模地放大山体滑坡的体积、流动性和冲击力来显著增加其破坏力。侵蚀性滑坡所造成的威胁与其流动性直接相关。然而，到目前为止，还没有明确的力学条件来说明滑坡何时、如何以及因侵蚀而获得或失去多少能量。最近，我们开创了一个侵蚀性滑坡能量收支的力学模型，该模型可以控制增强或减少的流动性（Pudasaini & Krautblatter, 2021）。有了一个全新的认识，我们证明了惯性的增加与夹带速度有关。确定了侵蚀性滑坡的真实惯性，在正确确定滑坡移动性方面取得了突破。值得注意的是，我们发现侵蚀速度调节着能量收支，并决定着滑坡的流动性是增强还是减弱。这取决于新开发的能量发生器，它提供了有史以来第一个侵蚀能量的机械量化和流动性的精确描述。这解决了一个长期存在的问题，即为什么许多侵蚀性滑坡产生更高的流动性，而另一些则降低了流动性。我们证明了侵蚀和夹带是根本不同的过程。当侵蚀速度大于夹带速度时，滑坡获得能量并增强流动性。能量速度描述了三种过剩能量状态：正、负和零。我们严格地证明了现有的非常有影响力的带侵蚀的质量流模型在物理上和数学上都是错误的（Pudasaini & Krautblatter, 2021）。我们提出了一组动力学方程，正确地包括侵蚀引起的净动量产生。然而，这些开创性的理论原理必须通过实验室实验来验证，以获得进一步的信心，并通过现场事件进行验证，并可能用于预测目的。在这里，我们的目标是实现概念验证，以实现在Pudasaini & Krautblatter（2021）中提出的关于滑坡流动性与侵蚀机制的新物理原理。为了探索、验证和展示模拟侵蚀性滑坡事件的新概念的实际用途，我们开创了创新的实验设施和研究新方法。本文首次对复杂的夹带现象及其对多阶段侵蚀性滑坡的流动性的影响进行了完整而科学的描述，为滑坡从业者预测和减轻自然灾害提供了非常有用和独特的工具。

Erosion can act to significantly increase the destructive power of landslides by massively amplifying their volume, mobility, and impactforce. The threat posed by an erosive-landslide is directly linked to its mobility. However, no clear-cut mechanical condition has been presented so-far for when, how, and how much energy landslides gain or lose by erosion. Recently, we pioneered a mechanical model for the energy-budget of erosive-landslides that controls the enhanced or reduced mobility (Pudasaini & Krautblatter, 2021). With a fundamentally new understanding, we proved that the increased inertia is related to an entrainment-velocity. This ascertains the true inertia of erosive landslides, making a breakthrough in correctly determining landslide mobility. Outstandingly, we showed that the erosion-velocity regulates the energy-budget and decides whether the landslide mobility will be enhanced or reduced. This depends on the newly developed energy-generator, which provides the first-ever mechanical quantification of erosional energy and a precise description of mobility. This addresses the long-standing question of why many erosive landslides generate higher mobility, while others reduce mobility. We demonstrated that erosion and entrainment are fundamentally different processes. Landslides gain energy and enhance mobility if the erosion-velocity is greater than the entrainment-velocity. The energy-velocity delineates three excessenergy-regimes: positive, negative, and zero. We rigorously proved that the existing, very influential mass flow models with erosion are physically and mathematically wrong (Pudasaini & Krautblatter, 2021). We presented a set of dynamical equations that correctly includes erosion-induced net momentum production. However, these seminal theoretical principles must be verified with laboratory experiments to gain further confidence, and be validated with field events, and potentially be used for predictive purposes. Here, we aim to achieve the proof-of-concept to realize the new physical principles presented in Pudasaini & Krautblatter (2021) on the mechanics of landslide mobility with erosion. We pioneer inventive experimental facilities and examine novel approaches in order to explore, verify, and demonstrate the practical usefulness of novel concepts to simulate erosive landslide events. This offers a first-ever complete and scientifically sound description of the complex entrainment phenomena and their impact on mobility of multi-phase erosive landslides, serving a very useful and unique tool for landslide practitioners in predicting and mitigating natural hazards.