Rheometry ever since made part of soil physical characterization, but only since the availability of highly sensitive rheometers, amplitude sweep tests (AST) and thixotropy tests are conducted on structured and homogenized soil, mostly one the base of few or one rheological parameter. Comprehensive and simultaneous analysis of different parameters has not been done yet, though it offers valuable clues to the highly complex soil processes and their multidimensional (spatial, temporal, and stress-rate-dependent) interferences, especially with regard to the role of the most important soil aggregation factors, i.e., soil organic matter (SOM) and water content. Consequently, we conducted a strain-controlled AST under varying normal stresses σ n on different soil aggregate fractions of either high or low SOM content and at different water contents. We determined shear stress τ , loss and storage modulus G ″ and G ′, respectively, and their ratio, tan δ, at the end of the linear viscoelastic range (LVR) and the yield point (YP) as well as the strain at which they occurred. In addition, we analyzed tan δ curves for dilatancy, and classified shear failure behavior (plastic or brittle). Viscoelasticity parameters were mostly affected by SOM (i.e., electrostatical attractive forces) and strain (spatial impact), while shear stress parameters altered with SOM, σ n , and water content (friction and particle coordination). Based on integrated interpretation of the AST and its resulting parameters, we developed a conceptual framework to be used in future soil (micro)mechanical characterization, where rheological parameters serve as input data to model, e.g., erosion, landslides, or soil deformation under shear.

中文翻译：

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全面表征土壤微观力学的振幅扫描测试：脆性和弹性颗粒间键及其对主要土壤聚集因子有机质和含水量的干扰

自那以后，流变学成为土壤物理表征的一部分，但只是因为高灵敏度流变仪的可用性，振幅扫描测试 (AST) 和触变性测试是在结构化和均质土壤上进行的，主要是少数或一个流变参数的基础。尚未对不同参数进行全面和同步分析，尽管它为高度复杂的土壤过程及其多维（空间、时间和应力速率相关）干扰提供了宝贵的线索，尤其是在最重要的作用方面。重要的土壤聚集因子，即土壤有机质 (SOM) 和含水量。因此，我们在不同的法向应力 σ n 下对高或低 SOM 含量和不同含水量的不同土壤团聚体部分进行了应变控制 AST。我们分别确定了线性粘弹性范围 (LVR) 和屈服点 (YP) 末端的剪切应力 τ 、损耗和储能模量 G '' 和 G ' 以及它们的比值 tan δ 以及他们发生了。此外，我们分析了剪胀性的 tan δ 曲线，并对剪切破坏行为（塑性或脆性）进行了分类。粘弹性参数主要受 SOM（即静电吸引力）和应变（空间冲击）的影响，而剪切应力参数随 SOM、σ n 和含水量（摩擦和粒子配位）而改变。基于对 AST 及其结果参数的综合解释，我们开发了一个概念框架，用于未来土壤（微）力学表征，其中流变参数用作模型的输入数据，例如侵蚀、滑坡、