This paper focuses on the numerical simulation of the deformation processes occurring in the slopes when soils with strain-softening behaviour are involved. In these circumstances, a progressive failure may occur with the consequent motion of the unstable soil mass in the post-failure stage. This problem can be only solved using advanced numerical techniques capable also of accounting for the occurrence of large deformations. However, the solution is generally mesh dependent and may be affected by lack of convergence. In this study, the material point method is employed to simulate the occurrence of large deformations, in conjunction with a strain-softening Mohr–Coulomb constitutive model, in which the shear strength parameters are reduced as a function of the accumulated deviatoric plastic strain, and a model parameter controlling the rate of strength decrease. To evaluate this parameter and to reduce the effects of the mesh dependency on the numerical solution, a novel procedure based on the results of direct shear tests is presented. This methodology is completely analytical and requires few parameters with a clear physical meaning and of simple experimental determination. Some simulations are performed to assess the reliability of the proposed procedure.

中文翻译：

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在涉及脆性土壤的滑坡建模中减少网格依赖性的简单方法

本文重点研究了具有应变软化行为的土体在边坡中发生的变形过程的数值模拟。在这些情况下，在破坏后阶段不稳定的土体随之运动可能会发生渐进破坏。这个问题只能使用先进的数值技术来解决，该技术也能够解释大变形的发生。但是，该解决方案通常取决于网格，并且可能会受到缺乏收敛性的影响。在这项研究中，材料点法用于模拟大变形的发生，并结合应变软化 Mohr-Coulomb 本构模型，其中剪切强度参数作为累积偏塑性应变的函数而降低，以及控制强度下降速率的模型参数。为了评估该参数并减少网格依赖性对数值解的影响，提出了一种基于直接剪切试验结果的新程序。这种方法是完全分析性的，需要很少的参数，具有明确的物理意义和简单的实验确定。进行了一些模拟以评估所提出程序的可靠性。