Loess, a Quaternary wind-blown deposit, is a problem soil that gives rise to frequent geohazards such as landslides and water-induced subsidence. The behaviour of loess is controlled by its microstructure, consisting of silt-sized skeleton particles and complex bonding structures formed by clay-sized particles. Achieving a deep understanding and precise modelling of loess behaviour necessitates comprehensive knowledge of the realistic 3D microstructure. In this paper, a correlative investigation of the 3D loess microstructure is performed using X-ray micro-computed tomography (μXCT) and focused ion beam scanning electron microscope (FIB-SEM). Details of clay structures in loess, such as clay coatings, clay bridges and clay buttresses, are visualized and characterized in 3D based on FIB-SEM images with a voxel size of 10 × 10 × 10 nm3. The clay structures exhibit a diverse degree of complexity and their impact on the mechanical properties of loess is highlighted. Statistical analysis of the skeleton particles, including size, shape and orientation, are derived from μXCT images with a voxel size of 0.7 × 0.7 × 0.7 μm3. The findings provide insights into the collapse mechanism and particle-scale modelling of loess. The combination of μXCT and FIB-SEM proves to be a powerful approach for characterizing the intricate micro-structures of loess, as well as other geomaterials.

中文翻译：

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黄土微观结构的高级多尺度表征：集成 μXCT 和 FIB-SEM 以进行详细的结构分析和岩土工程影响


黄土是第四纪风吹沉积物，是一种问题土壤，经常引发山体滑坡和水沉降等地质灾害。黄土的行为是由其微观结构控制的，其由粉砂大小的骨架颗粒和粘土大小的颗粒形成的复杂的粘结结构组成。要深入了解黄土行为并进行精确建模，需要全面了解真实的 3D 微观结构。本文利用X射线显微计算机断层扫描（μXCT）和聚焦离子束扫描电子显微镜（FIB-SEM）对3D黄土微观结构进行了相关研究。基于体素尺寸为 10 × 10 × 10 nm3 的 FIB-SEM 图像，以 3D 方式对黄土中的粘土结构细节（例如粘土涂层、粘土桥和粘土扶壁）进行可视化和表征。粘土结构表现出不同程度的复杂性，其对黄土力学性能的影响尤为突出。骨架颗粒的统计分析，包括尺寸、形状和方向，均来自体素尺寸为 0.7 × 0.7 × 0.7 μm3 的 μXCT 图像。这些发现为黄土的崩塌机制和颗粒尺度建模提供了见解。 μXCT 和 FIB-SEM 的结合被证明是表征黄土以及其他岩土材料复杂微观结构的有效方法。