Abstract The original stress-fractional plasticity approach was developed for the axisymmetric stress state. However, it cannot accurately capture the stress-strain behaviour, e.g., quasi-steady state flow, temporary stress peak and state-dependent dilatancy of soils under different loading conditions. In this study, a modified fractional-order plasticity model for soils under the general stress state is developed using an alternative yielding surface with a reduced elastic region at the dry side of the critical state line. The proposed model is then validated against the results of a series of drained and undrained tests conducted on different soils, including sand, rockfill, ballast and clay, subjected to different loading paths. It is observed that the proposed model can reasonably simulate the key features, such as the hardening/softening, contraction/dilation, liquefaction, quasi-steady state flow and steady state flow behaviour, of different soils.

中文翻译：

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具有减小弹性区域的应力分形土模型

摘要 原始应力分塑性方法是针对轴对称应力状态开发的。然而，它不能准确地捕捉应力应变行为，例如在不同加载条件下土壤的准稳态流动、临时应力峰值和状态相关的剪胀。在这项研究中，使用临界状态线干燥侧弹性区域减小的替代屈服面开发了一般应力状态下土壤的修正分数阶塑性模型。然后根据在不同土壤（包括沙子、堆石、压载物和粘土）上进行的一系列排水和不排水测试的结果验证所提出的模型，这些测试受到不同的加载路径。观察到，所提出的模型可以合理地模拟关键特征，例如硬化/软化，