The present study investigates the quality of four three-dimensional (3D) printing technologies to accurately reproduce the complex pore structure of a real undisturbed soil sample for laboratory experiments of transport in porous media at a 1:1 scale. Four state-of-the-art 3D printing technologies were evaluated (digital light synthesis, PolyJet with gel support material, low-force stereolithography, and PolyJet with water-soluble support material) using a combination of 3D image analysis from microtomopraphy and flow simulations of the pore structure produced with each 3D printing technique. Accuracy, as determined by matching solid and void volumes, permeability, connected porosity, specific surface area, and pore size distribution of the print against the original digital soil structure, was found to be substantially better for digital light synthesis, as compared to the other tested technologies. Repeatability, as determined by the same metrics but compared between identical prints, was found to be comparable across all printing technologies and did not significantly improve for prints at greater magnification (1.5×). Wettability of the samples was improved by plasma treatment of the prints. The thorough analysis herein presented demonstrates that advanced, yet relatively inexpensive 3D printing approaches can be used to generate real-scale high quality analogs of soils/rocks that are much needed for experimental laboratory work. Such a method can open countless opportunities for studying the coupling of pore-structure and hydrodynamics on reactive mass transport in environmental science and engineering, soil science, and other subsurface related fields.

中文翻译：

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通过 3D 打印以原始比例复制土壤类似物：定量评估孔隙结构异质性的准确性和可重复性


本研究调查了四种三维 （3D） 打印技术的质量，以准确再现真实未受干扰土壤样品的复杂孔隙结构，用于 1：1 比例在多孔介质中运输的实验室实验。通过将来自显微断层物理学的 3D 图像分析和每种 3D 打印技术产生的孔结构的流动模拟相结合，评估了四种最先进的 3D 打印技术（数字光合成、带凝胶支撑材料的 PolyJet、低力立体光固化成型和带水溶性支撑材料的 PolyJet）。与其他测试技术相比，通过匹配打印件的固体和空隙体积、渗透率、连接孔隙率、比表面积和孔径分布来确定的准确性，对于数字光合成来说要好得多。由相同指标确定但相同打印件之间进行比较的可重复性发现，在所有打印技术中都具有可比性，并且在更大放大倍率 （1.5×） 下打印的打印件没有显着改善。通过对打印件进行等离子处理，样品的润湿性得到改善。本文提供的深入分析表明，先进但相对便宜的 3D 打印方法可用于生成实验实验室工作急需的真实规模的高质量土壤/岩石类似物。这种方法可以为环境科学与工程、土壤科学和其他地下相关领域研究孔隙结构和流体动力学对反应质量传递的耦合提供无数机会。