Collaborative Research: A New Framework for Fine-grained Soil Characterization (Moving Beyond Atterberg Limits)

该项目的目标是通过探索一种基于自动和快速测量水蒸气吸收行为的细粒土壤表征的新方法，使岩土指标测试现代化。与历史方法不同，历史方法依赖于繁琐的人工确定的指数，这些指数只与粘土成分间接相关，如阿特贝格？新框架将基于粘土的基本表面特性，包括比表面积（SSA）和阳离子交换容量（CEC）。尽管人们认识到SSA和CEC与粘土的宏观行为有关，但它们在岩土工程实践中的应用有限，因为这些联系仍然不确定，测量方法仍然复杂。新方法将被开发出来，使用比现有技术更系统、更经济、更容易自动化的基于吸附的程序来获得这些粘土的基本性质。通过探索所有粘土特有的固有水蒸气吸收等温线的概念，以及通过提高对粘土表面性质和宏观行为之间联系的基本理解，将作出智力贡献。开发一种新的细粒度土壤表征框架将改变岩土工程现场调查的方式，并提高岩土工程项目的执行效率。一个基本可靠的膨胀土表征方法将减轻这些材料造成的严重经济和社会负担。该框架将允许设计工程师在较短的时间内以较低的成本测试更大、更多样化的样本套件，从而更有效地量化现场的可变性。提高对细颗粒土壤行为的基本理解将影响这些材料的广泛应用，包括环境应用，如废物容器，过滤和膜，以及工业吸附剂。教育和推广活动将与研究相结合，以充分利用该项目的合作性质，包括研究生交换计划、多样性倡议和教育倡议，其特点是将基于吸附的土壤分类模块整合到本科岩土工程实验室课程中。

The goal of this project is to modernize geotechnical index testing by exploring a new approach for fine-grained soil characterization based on automated and rapid measurements of water vapor sorption behavior. Unlike historical methods that have relied on cumbersome manually-determined indices only indirectly related to clay composition such as Atterberg?s limits, the new framework will be based on fundamental clay surface properties including specific surface area (SSA) and cation exchange capacity (CEC). Despite recognition that SSA and CEC are linked to macroscopic clay behavior, their usage has seen limited application in geotechnical practice because these links remain uncertain and measurement methods remain complex. New methods will be developed to derive these basic clay properties using sorption-based procedures that are more systematic, economical, and readily automated than existing techniques. Intellectual contributions will be made by exploring the concept of an intrinsic water vapor sorption isotherm unique to all clays and by improving basic understanding of linkages between clay surface properties and macroscopic behavior. Development of a new fine-grained soil characterization framework will transform the way geotechnical site investigations are performed and improve the efficiency with which geotechnical engineering projects are executed. A fundamentally sound approach for expansive soil characterization will alleviate the severe economic and social burden of damages resulting from these materials. The framework will allow design engineers to more effectively quantify site variability by allowing a larger and more diverse suite of samples to be tested in a short amount of time and at lower cost than existing methods. Improved basic understanding of fine-grained soil behavior will impact the broad range of applications where these materials have found use, including environmental applications such as waste containment, filtration and membranes, and as industrial adsorbents. Education and outreach initiatives will be integrated with the research to capitalize on the collaborative nature of the project, including a graduate student exchange program, a diversity initiative, and an educational initiative featuring integration of sorption-based soil classification modules into undergraduate geotechnical engineering laboratory courses.