Giant landslides can cause significant damage to their dynamic runout processes. Understanding the mechanics of the runout process is essential for landslide risk assessment and mitigation design. This paper investigates the runout process of the 1.16 × 109 m3 giant Daguangbao landslide triggered by the 2008 Ms 8.0 Wenchuan earthquake. The Daguangbao landslide is a typical bedding-plane slide and the properties of basal sliding surface play a key role in the runout behaviors of the landslide. The material point method (MPM) is adopted as a numerical tool of the simulations. A thermal-based velocity-weakening friction law is used to simulate the contact between the sliding body and the basal sliding surface. A strain-softening constitutive model is used to evaluate the damages inside the landslide body and their effects on the runout behaviors of the landslide. Numerical results reveal that landslide mass slides along the bedding-plane as a whole body initially and then disintegrates during the runout process. The calculated duration of sliding is 64 s and the maximum velocity reaches 60 m/s. The friction coefficient of the slip surface decreases sharply as the landslide body starts to move, and a steady-state friction coefficient μ ≈ 0.06 is reached when the velocity exceeds approximately 20 m/s. Friction degradation of the slip surface shows a sensible influence on the final runout distance and the depth of the deposit zone. The dynamic fragmentation of the landslide body, the final runout distance, and deposition topography are also significantly affected by material softening.

中文翻译：

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大光堡巨型滑坡动态跳动过程的MPM评价

巨大的滑坡会对它们的动态滑坡过程造成重大破坏。了解滑坡过程的机制对于滑坡风险评估和缓解设计至关重要。本文研究了2008年汶川8.0级地震引发的1.16×109 m3巨型大光堡滑坡的跳动过程。大光堡滑坡是典型的层状滑坡，基底滑面的性质对滑坡的跳动行为起着关键作用。采用材料点法（MPM）作为模拟的数值工具。使用基于热的速度减弱摩擦定律来模拟滑动体与基底滑动面之间的接触。应变软化本构模型用于评估滑坡体内部的损伤及其对滑坡跳动行为的影响。数值结果表明，滑坡体最初作为一个整体沿层理面滑动，然后在滑移过程中解体。计算出的滑动持续时间为 64 s，最大速度达到 60 m/s。随着滑坡体开始运动，滑面摩擦系数急剧下降，当速度超过约20 m/s时，达到稳态摩擦系数μ≈0.06。滑动面的摩擦退化显示出对最终跳动距离和沉积区深度的显着影响。滑坡体的动态破碎，最终的跳动距离，