CAREER: Micromechanical Model of Undrained Cyclic Soil Behavior

9875334托马斯·E·普莱斯密西西比州立大学生涯：不排水循环土壤行为的微观力学模型摘要本研究的目的是扩展现有的离散元模拟(DEM)技术，以显式地解释饱和土壤中的孔隙流体响应。DEM方法通过考虑作用在土体内单个土壤颗粒上的力，特别适合于预计会发生大颗粒变形的问题。近年来，随着计算能力的快速增长，DEM在颗粒土特性计算中的应用日益普及。然而，事实证明，在计算土体的响应时，很难明确地考虑连续介质孔隙流体的响应。在这项研究中，将建立一个流体饱和无粘性土的三维细观数值模型。土壤相离散单元模型将与流体连续体的有限元表示相连接。流体模型是从著名的两相多孔介质运动方程发展而来的。由此产生的模型将能够对土壤样本进行广泛的数值测试，包括没有足够的经验数据来校准连续统模型的土壤。由于DEM的微观机械性质，所获得的数据的分辨率将大大高于通过实验室或野外研究可能获得的分辨率。这样开发的数值模型将提供一个强大的工具，以扩大现有的分析和经验土壤响应数据的数据库。潜在的应用领域包括细粉在路面下的迁移、地震引起的液化和环境运输现象。学生在整个研究过程中的参与将在研究生和高年级本科生层面上实施。没有直接参与这项研究的学生将受益于将DEM课程模块添加到研究生计算力学课程的课程中。与工程兵部队岩土实验室的人行道和机场司建立有意义的伙伴关系将确保研究结果的适用性。最后，将通过发布研究结果来实现将研究结果传播给更远的研究人员，通过两种常规方式

9875334 Thomas E. Price Mississippi State University CAREER: Micromechanical model of undrained cyclic soil behavior Abstract The objective of this study is to extend existing Discrete Element Modeling (DEM) technologies to explicitly account for pore fluid response in saturated soils. DEM methodologies act through consideration of the forces acting on individual soil particles within the soil mass, and are particularly well suited to problems in which large particle deformations are expected to occur. The rapid growth in recent years of computing power has popularized the use of DEM in calculating the behavior of granular soils. However, it has proven difficult to explicitly account for the response of the continuum pore fluid in computing the response of the soil mass. In this study, a three-dimensional numerical, micromechanical model of fluid-saturated cohesionless soil will be developed. The soil-phase discrete element model will interface with a finite element representation of the fluid continuum. The fluid model has been developed from the well-known equations of motion for two-phase porous media. The resulting model will enable extensive numerical testing of soil samples, including soils for which insufficient empirical data is available to calibrate continuum models. Because of the micromechanical nature of DEM, the data obtained will be of significantly higher resolution than is possible through laboratory or field studies. The numerical model thus developed will provide a powerful tool to augment the existing database of analytic and empirical soil response data. Potential application areas include fines migration beneath pavement slabs, earthquake-induced liquefaction, and environmental transport phenomena. Student participation throughout the course of the study will be enacted at both the graduate and senior undergraduate level. Students not directly involved in the study will benefit by means of a course module on DEM to be added to the curriculum of a graduate computational mechanics course. Meaningful partnering with the Pavements and Airfields Division of the Corps of Engineers Geotechnical Laboratory will ensure applicability of the study findings. Finally, dissemination of the study results to more distant researchers will be achieved through publishing of the study results, through both conventional