Influence of Particle Size Distribution on Density State of Soil

土壤一般由不同大小的颗粒组成，颗粒大小分布是影响土壤力学性质的主要因素。然而，在土力学中，粒径分布对力学性能的影响仅以经验方式考虑。没有一种分析方法可以明确地解释粒度分布的影响。因此，分析粒度分布的影响的能力是理解由于土壤的非均质性而导致的力学行为的重要一步。该奖项支持基础研究，以发展必要的知识，模拟颗粒大小分布的影响。该研究结果将有助于分析粉砂液化、风化土滑坡、细颗粒侵蚀导致的堤坝破坏、颗粒破碎导致的大坝失稳等岩土工程问题。本研究中开发的方法可以帮助减少未来的故障风险，开发更稳健的设计方法，并更好地进行有针对性的缓解工作。因此，这项研究的结果对美国经济和社会具有潜在的好处。本研究的成果和活动被纳入土力学课程，促进工程教育与研究的整合。本研究的主要目的是建立一种基于土壤粒径分布的土壤堆积结构的补充描述符理论。利用这一补充描述符，提出了一种预测任意粒径分布土壤密度状态的方法。为了帮助理论发展，采用离散元法对不同粒径分布类型的土壤进行了一系列数值模拟试验和一系列室内试验。本研究的智力价值是双重的：(1)本研究基于一种新颖的方法，该方法可以根据土壤的粒径分布对土壤的填料结构进行数学分类。(2)本研究为分析非均质材料的行为提供了一种有用的方法，拓展了连续介质力学的知识边界。

Soil generally consists of particles of different sizes, and particle size distribution is the main factor that affects the mechanical properties of soil. However, in soil mechanics, the influence of particle size distribution on mechanical properties is only considered in an emperical manner. There is no analytical method that can explicitly account for the effect of particle size distribution. Thus, the ability to analyze the effect of particle size distribution is an important step in the understanding of mechanical behavior due to the heterogeneity of soil. This award supports fundamental research to develop the necessary knowledge for modeling the effect of particle size distribution. Results from this research will be useful for analyzing geotechnical engineering problems, such as liquefaction of silty sand, land slides of weathered soil, levee failure due to erosion of fine particles, and dam instability due to grain crushing. The method developed in this research can help reducing the future risks of failures, developing more robust design methodologies, and better targeted mitigation works. Therefore, results from this research has potential benefits to the U.S. economy and society. The resuts and activities of this research are incorporated into courses on soil mechanics contributing to the integration of engineering education and research. The main goal of this research is to develop a theory of a supplementary descriptor for the packing structure of soil based on its particle size distribution. Using this supplementary descriptor, a method is developed for predicting the density state of soil with arbitrary particle size distributions. To aid in the theoretical development, a series of numerical simulation tests using discrete element method and a series of laboratory tests are performed on soils with various types of particle size distribution. The intellectual merit of this research is twofold: (1) This investigation is based on a novel approach, which can mathematically categorize the packing structures of a soil based on its particle size distribution. This offers a rational way to predict the density state and other mechanical properties, (2) This investigation provides a useful methodology to analyze the behavior of heterogeneous material, which pushes forward the knowledge boundary of continuum mechanics.