This paper presents a new viscohypoplastic model for soft clays accounting for their typical features—strength anisotropy and rate dependency. The model is based on the hypoplastic model for clays enhanced by the anisotropic shape of the asymptotic state boundary surface. It has been shown that if the surface is skewed, the model predicts different ultimate strength in compression and in extension. Additional enhancement makes the tensor L bilinear in the strain rate, which more realistically predicts the stress paths of K₀ consolidated samples. The new model has been evaluated by simulating laboratory experiments on soft marine clays (Singapore and Bangkok clays). The model can be easily calibrated using only undrained triaxial and odometer tests. The model is subsequently enhanced by the rate effects. The resulting viscohypoplastic model has been evaluated using experiments of remolded kaolin clay and St. Herblain clay. It is shown that the enhanced model can predict important features of soil viscous behavior, such as rate dependency of strength and preconsolidation pressure, relaxation, and creep.

中文翻译：

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具有强度各向异性的软黏土的塑性模型和黏塑性模型

本文提出了一种新的软黏土增塑模型，解释了它们的典型特征-强度各向异性和速率依赖性。该模型基于通过渐近状态边界面的各向异性形状增强的粘土的次塑性模型。已经表明，如果表面倾斜，则该模型会预测压缩和延伸的最终强度不同。额外的增强使张量L在应变率上呈双线性，从而更实际地预测K ₀的应力路径合并样本。通过模拟在软质海洋粘土（新加坡和曼谷粘土）上的实验室实验对新模型进行了评估。仅使用不排水的三轴和里程表测试即可轻松校准模型。模型随后通过速率效应得到增强。使用重塑的高岭土和圣赫伯伦粘土的实验评估了所得的粘塑性增塑模型。结果表明，改进后的模型可以预测土壤黏性行为的重要特征，例如强度与预固结压力，松弛和蠕变的速率相关性。