Simulating the entire rainfall-induced landslide process using the material point method for unsaturated soil with implicit and explicit formulations
Simulating the entire rainfall-induced landslide process using the material point method for unsaturated soil with implicit and explicit formulations
复制标题
采用隐式和显式公式的非饱和土物质点法模拟整个降雨诱发滑坡过程
DOI：
10.1007/s10346-023-02052-4
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发表时间：
2023-05
期刊：
影响因子：
6.7
通讯作者：
Y. Yamaguchi;Fumiyasu Makinoshima;Y. Oishi
中科院分区：
文献类型：
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作者：
Y. Yamaguchi;Fumiyasu Makinoshima;Y. Oishi
降雨引发的山体滑坡造成各种类型的破坏，包括对基础设施的破坏，导致毁灭性的经济损失和人员伤亡。虽然已经开发了各种数值方法来预测滑坡的发生和泥沙流动的程度，但由于计算效率以及变形和流动的表示的限制，以统一的方式对整个滑坡过程进行三维分析仍然具有挑战性。在这项研究中，我们提出了一个数值方法的非饱和多孔介质的耦合流体力学材料点法（MPM）的基础上隐式和显式的配方，使所有的非饱和诱发滑坡过程的有效分析，包括准静态和动态过程的滑坡诱发滑坡。所开发的方法包括一个隐式MPM的基础上简化的配方，这是第一次应用到准静态分析的预失效阶段，雨水渗入地面。显式MPM，然后应用到动力分析的后故障阶段，地面塌陷和流动。本文在散体粘塑性模型中引入粘聚力的影响，改进了适用于滑坡起动和泥沙运动模拟的土体本构关系。将该方法应用于日本熊本芦北镇的三维地形模型，该城镇于2020年7月3日至4日因强降雨而发生实际山体滑坡。与单相MPM相比，从拟议的流体力学耦合的数值结果表明，孔隙水起着重要的作用，在了解所有的滑坡引起的滑坡过程中，从滑坡开始的泥沙排放。
Rainfall-induced landslides cause various types of damage, including damage to infrastructure, leading to devastating economic losses and human casualties. Although various numerical methods have been developed to predict landslide occurrence and the extent of sediment flow, three-dimensional analysis of the entire landslide process in a unified manner is still challenging owing to limitations in computational efficiency and the representation of deformation and flow. In this study, we present a numerical method of rainfall-induced landslides using the coupled hydromechanical material point method (MPM) for unsaturated porous media based on implicit and explicit formulations, which enables the efficient analysis of all rainfall-induced landslide processes, including both quasi-static and dynamic processes. The developed method includes an implicit MPM based on a simplified formulation, which is first applied to the quasi-static analysis in the pre-failure stages in which rainwater infiltrates the ground. The explicit MPM is then applied to the dynamic analysis for post-failure stages in which the ground collapses and flows. A constitutive law for soils is improved in the simulation of landslide initiation and sediment flow by incorporating the effect of cohesion in a visco-plastic model for granular materials. The proposed method was applied to a three-dimensional terrain model of Ashikita town, Kumamoto, Japan, where an actual landslide occurred owing to intense rainfall on July 3–4, 2020. Numerical results from the proposed hydromechanical coupling compared with single-phase MPM indicated that pore water plays an important role in understanding all rainfall-induced landslide processes, from landslide initiation to sediment discharge.