Sensitive clays, when subjected to large strains, exhibit a unique strain-softening behavior, transforming into a remolded liquid with remarkably low shear strength. When a slope fails, this behavior leads to the remolded clay moving away from its original position, triggering subsequent failures and catastrophic outcomes. To accurately predict such scenarios, it is crucial to incorporate realistic strain-softening characteristics into the constitutive soil model. This paper presents a novel yet practical strain-softening law developed by the authors that effectively captures the post-peak behavior of sensitive clays down to their remolded strength. The softening law is implemented in an elastoplastic Mohr-Coulomb model and incorporated into Anura3D, an open-source software that uses the Material Point Method to simulate large deformations. The constitutive model is calibrated by simulating the stress-strain behavior through direct shear tests conducted at three sensitive clay landslide locations. The accuracy of the overall numerical framework is assessed by predicting the post-failure movements of these landslides. Notably, two of the landslides, Sainte-Monique (1994) and Saint-Jude (2010), have previously been analyzed using other numerical tools, allowing for a comparative analysis with the method presented here. The third landslide, the Saint-Luc-de-Vincennes landslide, representing a composite flow slide and spread, has been numerically simulated for the first time. The post-failure behavior observed in the landslide events is compared with field observations and other numerical analyses. The results show that the MPM models with the proposed strain-softening law can reasonably predict post-failure retrogression and runout distance, which are crucial parameters for determining the risk of landslides in sensitive clays.

中文翻译：

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通过将新型应变软化定律纳入质点法来预测敏感粘土中的后退滑坡


敏感粘土在受到大应变时，会表现出独特的应变软化行为，转变为剪切强度极低的重塑液体。当斜坡失效时，这种行为会导致重塑的粘土远离其原始位置，引发后续的失效和灾难性后果。为了准确预测此类情况，将真实的应变软化特征纳入本构土模型至关重要。本文提出了作者开发的一种新颖而实用的应变软化定律，该定律有效地捕获了敏感粘土的峰后行为，直至其重塑强度。软化定律在弹塑性 Mohr-Coulomb 模型中实现，并合并到 Anura3D（一款使用质点法模拟大变形的开源软件）中。本构模型是通过在三个敏感粘土滑坡位置进行的直接剪切试验来模拟应力应变行为来校准的。通过预测这些滑坡发生后的运动来评估总体数值框架的准确性。值得注意的是，其中两处滑坡，Sainte-Monique (1994) 和 Saint-Jude (2010)，之前曾使用其他数值工具进行过分析，因此可以与此处介绍的方法进行比较分析。第三次滑坡，即圣吕克德文森滑坡，代表了复合流滑坡和扩散，首次进行了数值模拟。将滑坡事件中观察到的破坏后行为与现场观察和其他数值分析进行比较。 结果表明，采用所提出的应变软化定律的MPM模型可以合理地预测破坏后的回归和跳动距离，这是确定敏感粘土滑坡风险的关键参数。