ASSESS VIABILITY OF MICRO-CT FOR SOIL MICROSTRUCTURE STUDIES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 砂土的微观结构可以提供对宏观材料响应的重要洞察。此前已有研究使用CT来量化砂岩的微观结构。用常规CT研究土体微结构需要在分辨率、穿透深度和试件大小之间进行权衡。为了绕过这些问题，PI使用了一种破坏性的法医技术，包括对沙子样本进行树脂浸渍，然后对优惠券进行切片和抛光，以便随后进行图像捕获和分析。这种方法在极高的分辨率下产生高质量的结果，但劳动强度大、速度慢，并且仅提供关于土壤微观结构的统计信息(即，每个单独颗粒的位置和方向未知)。能够测量组件中每个颗粒的位置、形状和方向将允许对数值模型进行校准和验证，并将提供一种快速模拟广泛的实验室测试的手段。PI希望对杜克大学活体显微镜中心的单个沙子样本进行成像，以评估Micro-CT在土壤微结构研究中的可行性。如果这被证明是一种在微尺度上量化沙子的可行方法，将提交提案，以资助对颗粒材料的微尺度研究感兴趣的机构，如国家科学基金会和空军科学研究办公室。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The microstructure of sands can provide significant insight into macroscale material response. There have been previous studies that use CT to quantify the microstructure of sands. The study of soil microstructure using conventional CT suffers from tradeoffs between resolution, penetration depth, and specimen size. To circumvent these issues, the PI has used a destructive forensic technique that involves resin impregnation of sand specimens followed by sectioning and polishing of coupons for subsequent image capture and analysis. This method produces high quality results at extremely high resolutions, but is labor-intensive, slow, and provides only statistical information regarding soil microstructure (i.e., the location and orientation of each individual particle is not known). Being able to measure the location, shape, and orientation of every particle in an assembly would allow for calibration and verification of numerical models and would provide a means for rapid simulation of a wide array of laboratory tests. The PI would like to image a single sand specimen at the Duke Center for In Vivo Microscopy to assess the viability of micro-CT for soil microstructure studies. If this proves to be a viable method for quanifying sands on the microscale, proposals will be submitted to grant agencies interested in funding microscale research on granular materials, such as the National Science Foundation and the Air Force Office of Scientific Research.