It has been well recognized that unsaturated natural loess shows significant volume contraction upon wetting due to its metastable internal structure. But the structural effect on stress-strain relationship of saturated natural (undisturbed) loess is much less explored. Few attempts have been made in proposing a constitutive model for saturated natural loess. This study presents both laboratory tests and constitutive modelling of a saturated natural loess, with special focus on the structural effect and evolution of structure damage during loading. Oedometer and drained triaxial compression tests have been carried out on undisturbed and remolded saturated loess samples. It is found that the natural soil structure has dramatic influence on mechanical behavior of loess, including the compressibility, dilatancy and shear strength. Destructuration, which is the damage of soil structure with deformation, is observed in both oedometer and triaxial tests. A constitutive model is proposed for saturated loess based on the experimental observations. The model is established within the theoretical framework of subloading and superloading surface concepts. Destructuration of loess is assumed to be affected by both plastic volumetric and shear strain. A new method for determining the initial degree of structure is proposed. The model can reasonably predict the compression and shear behavior of both undisturbed and remolded saturated loess.

中文翻译：

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饱和天然黄土的破坏：从实验到本构建模

众所周知，不饱和的天然黄土由于其亚稳态内部结构，在润湿时表现出显着的体积收缩。但是对饱和天然（未受干扰）黄土的应力-应变关系的结构影响却很少被探索。很少有人尝试提出饱和天然黄土的本构模型。本研究介绍了饱和天然黄土的实验室测试和本构模型，特别关注加载过程中的结构效应和结构损坏的演变。对原状和重塑的饱和黄土样品进行了固结仪和排水三轴压缩试验。研究发现，自然土壤结构对黄土的力学行为有显着影响，包括压缩性、剪胀性和抗剪强度。破坏，这是土壤结构变形的破坏，在固结仪和三轴试验中都观察到。基于实验观察，提出了饱和黄土的本构模型。该模型是在分载和超载表面概念的理论框架内建立的。假定黄土的破坏受到塑性体积应变和剪切应变的影响。提出了一种确定初始结构度的新方法。该模型可以合理地预测原状和重塑饱和黄土的压缩和剪切行为。该模型是在分载和超载表面概念的理论框架内建立的。假定黄土的破坏受到塑性体积应变和剪切应变的影响。提出了一种确定初始结构度的新方法。该模型可以合理地预测原状和重塑饱和黄土的压缩和剪切行为。该模型是在分载和超载表面概念的理论框架内建立的。假定黄土的破坏受到塑性体积应变和剪切应变的影响。提出了一种确定初始结构度的新方法。该模型可以合理地预测原状和重塑饱和黄土的压缩和剪切行为。