Large deformation slope failure — A perspective from multiscale modelling
Large deformation slope failure — A perspective from multiscale modelling
复制标题
大变形边坡破坏——多尺度建模视角
DOI：
10.1016/j.compgeo.2022.104886
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发表时间：
2022-10
影响因子：
5.3
通讯作者：
Di Wang;Bin Wang;Quanguo Jiang;N. Guo;Wei Zhang;Kaiyuan He
中科院分区：
文献类型：
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作者：
Di Wang;Bin Wang;Quanguo Jiang;N. Guo;Wei Zhang;Kaiyuan He
边坡失稳分析是岩土工程中的一个传统课题。目前用唯象本构模型建立的连续介质模型不能很好地反映粒子尺度上的物理机制。离散数值方法可以很好地描述颗粒尺度特征，但在处理实际工程问题时受到计算成本的限制。本文建立并实现了一个多尺度的MPM/DEM多尺度耦合模型，用于边坡破坏分析，旨在全面了解边坡的破坏和破坏后的行为。为了提高数值稳定性，通过引入仿射质点单元(APIC)速度更新格式和B样条基函数对标准MPM版本进行了修改。针对边坡破坏模拟中存在的变形过大问题，提出了一种表示体积单元(RVE)置换方法。研究了粘性土边坡和无粘性土坡的动力破坏过程。研究发现，对于无粘性土坡，其稳定性主要受微观摩擦特性和级配的控制，而破坏后阶段主要受颗粒水平摩擦的控制。对于粘性土坡，采用Johnson-Kendall-Robert(JKR)粘性模型来描述颗粒间的粘结效应。结果表明，随着地表能量密度的增加，边坡的破坏模式由崩塌向剪切破坏过渡。通过对颗粒间引力的统计分析，发现剪切带的强度受控于顶部的内聚力和中下部的摩擦特性。
Slope failure analysis is a traditional topic in geotechnical engineering. Current continuum modelling with phenomenological constitutive models fails to capture the physical mechanism at the particle scale. Discrete numerical methods may well describe particle scale features but are limited by the computational cost to handle practical engineering problems. In this paper, a coupled MPM/DEM hierarchical multiscale model is developed and implemented for slope failure analysis, aiming to obtain a comprehensive understanding of the slope failure and post-failure behaviours. For improving the numerical stability, the standard MPM version is modified by incorporating the Affine-particle-in-cell (APIC) velocity update format and B-spline basic function. A represent volume element (RVE) replacement approach is proposed in solving the excessive deformation problem during the slope failure simulation. Both the dynamic failure processes of cohesive and non-cohesive soil slopes are investigated. It is found that for non-cohesive soil slopes, the stability is mainly controlled by the microscopic frictional property and gradation, while the post-failure stage is dominated by particle level friction. For cohesive soil slopes, Johnson–Kendall–Robert (JKR) cohesive model is adopted in representing adhesive effect between particles. The results show that the slope failure pattern transmits from collapse to shear failure with increasing surface energy density. By statistical analysis on the attractive force between particles, the strength of the shear band is found to be controlled by cohesive effect for the top part and frictional property for medium and bottom parts.