Abstract This paper presents a model for rainfall-induced shallow landslides, revealing the failure mechanism from initiation of instability to final flow failure. The onset of slope failure occurs with a completely formed plastic shear band that is triggered by a rainfall-induced increase in pore pressure. The subsequent flow-like deformation is caused by the strain-softening effect associated with large strains. Due to the complex non-linearity in stress-seepage coupling and large deformation, modelling the entire progressive failure induced by rainfall is always a challenge. Therefore, the model in this paper uses a two-step strategy, i.e., coupled hydro-mechanical finite element (FE) analysis for step 1 and large deformation FE analysis for step 2, to realize the simulation of the entire failure process. An equivalent strength method is used to ensure the physical continuity between step 1 and step 2. A more reasonable evaluation of large deformation during post-failure can be achieved without a predefined slip surface. The model is applied to the analysis of two real rainfall-induced landslide cases. Numerical analysis demonstrates the ability of this model to evaluate the progressive variations in pore pressure, displacement, plastic strain, and factor of safety (FOS) with rainfall infiltration and simulate the final flow-like deformation.

中文翻译：

---

模拟降雨诱发的滑坡从不稳定开始到故障后

摘要 本文提出了降雨诱发浅层滑坡的模型，揭示了从不稳定开始到最终流动破坏的破坏机制。斜坡破坏的开始发生在完全形成的塑性剪切带时，该剪切带由降雨引起的孔隙压力增加触发。随后的流动状变形是由与大应变相关的应变软化效应引起的。由于应力渗流耦合和大变形的复杂非线性，对降雨引起的整个渐进式破坏进行建模始终是一个挑战。因此，本文模型采用两步策略，即第一步采用流体力学耦合有限元（FE）分析，第二步采用大变形有限元分析，实现对整个失效过程的模拟。使用等效强度方法来确保步骤 1 和步骤 2 之间的物理连续性。可以在没有预定义滑移面的情况下实现对失效后大变形的更合理评估。该模型用于分析两个真实的降雨引发的滑坡案例。数值分析表明该模型能够评估孔隙压力、位移、塑性应变和安全系数 (FOS) 随降雨入渗的渐进变化，并模拟最终的类似流动的变形。