Critical State of Sands Revisited: Fabric Effects

重新审视沙子的临界状态：织物效应

• 批准号: 1162096
• 负责人: Yannis Dafalias
• 金额: $ 34.42万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1162096&HistoricalAwards=false
• 关键词: Critical; State; Sands; Revisited; Fabric

Critical State Soil Mechanics (CSSM) is the paradigm of a framework for soil constitutive modeling. This paradigm will be constructively challenged from the perspective of one important missing factor: the effect of soil fabric, in particular sands, on the premises and conditions characterizing critical state. The hypothesis that the fabric, characterized by an appropriately defined fabric tensor representing the orientational distribution of particles, contact normals or void vectors, evolves towards a critical state value will be investigated by means of discrete granular mechanics (DEM) and continuum mechanics methods. The main objective will be the enhancement of the critical state conditions for stress and void ratios by one additional condition for critical state fabric, the incorporation of the results into a new fabric-enhanced CSSM constitutive framework, and the illustration by examples of fabric effects on constitutive and numerical modeling of Geomechanics boundary value problems. Understanding the sandy soil response when deformed and stressed, is of fundamental importance for the safe design and analysis of geotechnical structures. The existing famework of the most predominant theory, Critical State Soil Mechanics, is in need of an enhancement to account for particular aspects related to the way the soil particles are oriented during their natural deposition process. The project will adress these issues by means of discrete particles modeling simulations and ensuing continuum mechanics methodologies. The successful outcome will drastically change the way CSSM theory is taught at Universities and applied in geotechnical practice, a field of increasing social impact in regards to hazard mitigations related to earthquakes and landslides. It will also offer an engineering perspective to the neighboring fields of granular physics and material sciences, where a continuum engineering approach to fabric effects can be very useful. Such findings will be integrated into an educational program leading to seminar presentations of the simplest aspects to young students and the development of graduate courses. The results of the proposed study will be disseminated through workshops, publications in archival journals and presentations at conferences.

临界状态土力学（CSSM）是土体本构模型的基本框架。 这一范式将建设性地挑战的角度来看，一个重要的缺失因素：土壤结构，特别是沙子，的前提和条件特征的临界状态的影响。 的假设，织物，其特征在于由一个适当定义的织物张量表示的颗粒，接触法线或空隙矢量的取向分布，朝着一个临界状态值的演变将通过离散颗粒力学（DEM）和连续介质力学方法进行研究。 主要目标将是增强的临界状态条件的应力和孔隙比的一个额外的条件临界状态织物，纳入一个新的织物增强CSSM本构框架的结果，并通过示例说明织物的影响本构和数值模拟的地质力学边界值问题。 了解桑迪在变形和应力作用下的响应，对于岩土工程结构的安全设计和分析具有重要意义。 最主要的理论，临界状态土力学，现有的famework，是在需要一个增强，以占有关的方式土壤颗粒在其自然沉积过程中的定向的特定方面。 该项目将通过离散粒子建模模拟和随后的连续介质力学方法来解决这些问题。成功的结果将彻底改变CSSM理论在大学教授和应用于岩土工程实践的方式，这是一个在减轻地震和滑坡灾害方面具有越来越大社会影响的领域。 它还将为颗粒物理和材料科学的邻近领域提供工程视角，其中连续体工程方法对织物效果非常有用。 这些研究结果将被纳入一个教育方案，导致研讨会介绍最简单的方面，以年轻的学生和研究生课程的发展。 拟议研究的结果将通过研讨会、档案期刊出版物和会议演讲来传播。