Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach
Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach
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DOI：
10.5194/gmdd-6-1367-2013
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
S. Raía;M. Alvioli;M. Rossi;R. Baum;J. Godt;F. Guzzetti
中科院分区：
文献类型：
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作者：
S. Raía;M. Alvioli;M. Rossi;R. Baum;J. Godt;F. Guzzetti
滑坡时空分布预测模型是建立在确定性规律基础上的。这些模型在空间上扩展了岩土工程中采用的静态稳定性模型，并采用了一个无限坡的几何形状来平衡作用在滑动体上的阻力和驱动力。渗透模型用于确定降雨如何改变孔隙水条件，调节当地的稳定性/不稳定性条件。现有模型的一个问题在于难以获得描述边坡材料特性的几个变量的准确值。当模型应用于大面积时，问题尤其严重，因为通常无法获得有关斜坡岩土和水文条件的足够信息。为了帮助解决这个问题，我们提出了一个概率蒙特卡罗方法的分布式模拟的地震诱发浅层滑坡。为此，我们修改了瞬态降雨入渗和基于网格的区域边坡稳定性分析（TRIGRS）代码。新的代码（TRIGRS-P）采用概率的方法来计算，在一个细胞的基础上，瞬态孔隙压力的变化和相关的变化，由于降雨入渗的安全系数。渗透建模使用偏微分方程的解析解描述一维垂直流在各向同性，均质材料。可以考虑饱和和非饱和土壤条件。TRIGRS-P通过允许TRIGRS模型输入参数的值从给定的概率分布中随机抽样，来处理边坡材料的机械和水文特性所固有的自然变异性。[..]
Distributed models to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides are based on deterministic laws. These models extend spatially the static stability models adopted in geotechnical engineering, and adopt an infinite-slope geometry to balance the resisting and the driving forces acting on the sliding mass. An infiltration model is used to determine how rainfall changes pore-water conditions, modulating the local stability/instability conditions. A problem with the operation of the existing models lays in the difficulty in obtaining accurate values for the several variables that describe the material properties of the slopes. The problem is particularly severe when the models are applied over large areas, for which sufficient information on the geotechnical and hydrological conditions of the slopes is not generally available. To help solve the problem, we propose a probabilistic Monte Carlo approach to the distributed modeling of rainfall-induced shallow landslides. For the purpose, we have modified the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis (TRIGRS) code. The new code (TRIGRS-P) adopts a probabilistic approach to compute, on a cell-by-cell basis, transient pore-pressure changes and related changes in the factor of safety due to rainfall infiltration. Infiltration is modeled using analytical solutions of partial differential equations describing one-dimensional vertical flow in isotropic, homogeneous materials. Both saturated and unsaturated soil conditions can be considered. TRIGRS-P copes with the natural variability inherent to the mechanical and hydrological properties of the slope materials by allowing values of the TRIGRS model input parameters to be sampled randomly from a given probability distribution. [..]