[最新文献]滑坡径流的估计: 经验与数值方法比较 [10/26/2020]

1 论文

Published Online: October 26, 2020

Operational Estimation of Landslide Runout: Comparison of Empirical and Numerical Methods. Geosciences 2020, 10(11), 424

滑坡径流的估计: 经验与数值方法比较

Abstract: A key point of landslide hazard assessment is the estimation of their runout. Empirical relations linking angle of reach to volume can be used relatively easily, but they are generally associated with large uncertainties as they do not consider the topographic specificity of a given study site. On the contrary, numerical simulations provide more detailed results on the deposits morphology, but their rheological parameters can be difficult to constrain. Simulating all possible values can be time consuming and incompatible with operational requirements of rapid estimations. We propose and compare three operational methods to derive scaling power laws relating the landslide travel distance to the destabilized volume. The first one relies only on empirical relations, the second one on numerical simulations with back-analysis, and the third one combines both approaches. Their efficiency is tested on three case studies: the Samperre cliff collapses in Martinique, Lesser Antilles (0.5 to 4×106 m^3), the Frank Slide rock avalanche (36×106 m3) and the Samperre cliff collapses in Martinique, Lesser Antilles (0.5 to 4×106 m^3) the Fei Tsui debris slide in Hong Kong (0.014×106 m^3). Purely numerical estimations yield the smallest uncertainty, but the uncertainty on rheological parameters is difficult to quantify. Combining numerical and empirical approaches allows to reduce the uncertainty of estimation by up to 50%, in comparison to purely empirical estimations. However, it may also induces a bias in the estimation, though observations always lie in the 95% prediction intervals. We also show that empirical estimations fail to model properly the dependence between volume and travel distance, particularly for small landslides (<20,000 <0.02×106 m^3). 

Keywords: landslide; runout; numerical modeling; statistical analysis; uncertainty

摘要：滑坡灾害评估的一个关键点是对其径流的估计。经验性的角度与体积关系可以比较容易地使用，但它们通常具有很大的不确定性，因为它们没有考虑到特定研究地点的地形特征。相反，数值模拟提供了沉积物矿床形态的更详细的结果，但其流变参数可能难以限制。模拟所有可能的值可能会很耗时，而且不符合快速估算的操作要求。我们提出并比较了三种操作方法来推导与滑坡行程距离和失稳体积相关的比例幂律。第一种方法仅依靠经验关系，第二种方法依靠数值模拟与反分析，第三种方法结合两种方法。它们的效率在三个案例研究上得到了检验：单纯的数值估算得出的不确定性最小，但流变参数的不确定性难以量化。将数值和经验方法结合起来，与单纯的经验估计相比，估计的不确定度可降低50%。然而,尽管观测结果总是在95%的预测区间内,  但这也可能会引起估计的偏差。同时还表明，经验估计不能正确模拟体积和移动距离之间的依赖关系，特别是对于小型滑坡(<20,000 <0.02×106 m^3)。

关键词：滑坡；径流；数值模拟；统计分析；不确定性

2 相关文献

[1] Landslide Runout Analysis - Current Practice and Challenges

[2] Rock avalanche runout prediction using stochastic analysis of a regional dataset

[3] Runout of open pit slope failures: an update

[4] Contaminated landslide runout deposits in rivers – Method for estimating long-term ecological risks

[5] Stability and Run-out Analysis of Earthquake-induced Landslides

[6] Numerical modelling of large landslides stability and runout

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