Collaborative Research: Improving the Sampling and Characterization of Intermediate Soils

合作研究：改进中层土壤的采样和表征

• 批准号: 1436793
• 负责人: Don DeGroot
• 金额: $ 33万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1436793&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; Sampling; Characterization

Intermediate soils, which consist of varying mixtures of silts, clays, and sands, are common, naturally occurring deposits that can create design challenges for infrastructure projects involving dams, levees, highways, and building and bridge foundations. Geotechnical engineering practice is able to characterize clays and sands well, but it is the mixture of these two materials in combination with silt that can be particularly problematic. In some cases intermediate soils behave like clays and in others the behavior is like sands, and this uncertain transitional behavior violates the well-established knowledge base and standard of engineering practice used for clays and sands. The uncertainty in the characterization of intermediate soils forces engineers to be overly conservative (i.e., uneconomical) in the design of infrastructure projects to ensure the safety of society. This award supports research that will develop new methodologies for collecting intermediate soil samples by drilling and sampling, evaluating the quality of soil samples obtained, and accurately measuring their engineering properties in the laboratory for design of infrastructure. Outcomes from the research will provide practical guidance to the engineering profession leading to more reliable and economical design of infrastructure built upon intermediate soils. The project will also result in workforce development through the education and training of students and practicing engineers by incorporation of project findings into the classroom and professional short courses. The primary objective of this collaborative research project is to improve the understanding of how sampling influences the measured behavior of intermediate soils. The scope involves advanced triaxial testing that will simulate the sampling process, numerical modeling of the influence of various sampler geometries on sample state, creation of a conceptual sample disturbance framework, and implementation and validation of research findings at two field sites. The intellectual merit originates from three aspects: (1) research data and findings that will expand our knowledge of the effects of sampling on intermediate soils and their measured behavior; (2) formulation of a new conceptual framework that tracks the effect of sample disturbance on intermediate soils and creation of a corresponding new sample quality "index" parameter; and (3) development and validation via field testing of practice guidelines. The project will provide new scientific understanding and practical guidance that is urgently needed by the geotechnical engineering community. It is also anticipated that the research findings will be applicable to a broader range of materials, most notably fly ash, dredge materials, and mine tailings.

中间土由粉土、粘土和砂土的不同混合物组成，是常见的自然形成的沉积物，可能会给涉及大坝、堤坝、高速公路以及建筑和桥梁基础的基础设施项目带来设计挑战。岩土工程实践能够很好地描述粘土和砂土的特性，但这两种材料与粉土的混合物可能特别成问题。在某些情况下，中间土的行为类似粘土，而在另一些情况下，这种不确定的过渡行为违反了用于粘土和砂的成熟的知识库和工程实践标准。中间土特性的不确定性迫使工程师在设计基础设施项目时过于保守(即不经济)，以确保社会安全。该奖项支持的研究将开发新的方法，通过钻探和取样收集中间土壤样本，评估获得的土壤样本的质量，并在实验室中准确测量其工程性质，用于基础设施设计。研究结果将为工程专业提供实用指导，从而更可靠、更经济地设计建立在中间土壤上的基础设施。该项目还将通过教育和培训学生以及将项目成果纳入课堂和专业短期课程来培养实习工程师，从而促进劳动力发展。这个合作研究项目的主要目标是提高对采样如何影响中间土壤测量行为的理解。该范围包括模拟采样过程的高级三轴试验、对不同采样器几何形状对样品状态的影响的数值模拟、创建概念性样品扰动框架以及在两个实地实施和验证研究结果。学术价值来自三个方面：(1)研究数据和结果，将扩大我们对采样对中间土壤的影响及其测量行为的知识；(2)制定一个新的概念框架，跟踪样品干扰对中间土壤的影响，并创建相应的新样品质量“指数”参数；(3)通过实践指南的现场测试开发和验证。该项目将提供岩土工程界迫切需要的新的科学理解和实践指导。预计研究结果将适用于更广泛的材料，最明显的是飞灰、疏浚材料和尾矿。