Cyclic Loading Behavior of Fine-Grained Soils

9502530布朗格这项研究项目的目标是建立一个基本框架，用于理解和描述“可液化”细粒土壤在循环和单调不排水荷载作用下的行为--这是发展可靠的设计方法以评估土壤液化潜力的必要步骤。“可液化”一词是指细粒土壤，在地震荷载作用下容易发生严重的强度损失。实现这一目标的主要任务是对选定的低塑性粉土和粘土进行全面的实验室研究，研究建立基本框架所需的各种条件。该项目包括单调加载、循环加载、后循环单调加载以及在大范围围压和孔隙比范围内的固结试验，以研究不排水加载行为与初始状态、准稳定状态和稳定状态条件之间的相互关系。它还包括研究样品制备方法、应力历史和加载路径(即三轴剪切和扭转剪切)对各种孔隙比和围压的影响。这项研究的结果将填补了解细粒土在地震荷载作用下行为的一个重要空白，从而有助于制定与细粒土地震荷载响应相关的潜在地震危险的工程程序。教育计划教育计划的目标是使土木工程专业的学生具备健全的工程哲学，在工程基础和基础方面有严格的基础，并认识到理论和判断的互补作用。教育计划包括几个细节，这些细节将增强现有课程的基本实力，从而有助于在土木工程和环境工程方面进行鼓舞人心的全面教育。它包括以下项目：在设计课程中，有一名实践专业人员协助建立设计项目，然后在课程结束时讨论替代设计；选择这些和其他新的课程项目，以说明基本理论和工程判断在土木工程和环境工程实践中的互补作用；制作关于现场表征的钻探和采样程序的教学视频；将基于计算机的数据采集系统引入本科实验室课程；通过暑期就业和独立研究选修课让本科生参与研究项目；在适当的课程中介绍最近的研究成果*

9502530 Boulanger The objective of this research project is to develop a fundamental framework for understanding and describing the behavior of "liquefiable" fine-grained soils subjected to cyclic and monotonic undrained loading -- a necessary step in the development of reliable design methodologies for assessing liquefaction potential of soils. The term "liquefiable" is used to denote fine-grained soils that would be considered susceptible to severe strength loss during earthquake loading. The primary task towards achieving this objective is a comprehensive laboratory study of select low-plasticity silts and clays over the wide range of conditions necessary to establish a fundamental framework. The project includes monotonic loading, cyclic loading, post-cyclic monotonic loading, and consolidation tests over a wide range of confining stresses and void ratios to investigate the interrelationships between the undrained loading behavior and the conditions of initial state, quasi-steady state, and steady state. It also includes an investigation of the influence of sample preparation method, stress history, and loading path (i.e., triaxial versus torsional shear) over a wide range of void ratios and confining stresses The results of this study will fill a vital gap in the understanding of the behavior of fine-grained soils during earthquake loading, and thereby assist in the development of engineering procedures for assessing potential earthquake hazards related to the earthquake loading response of fine-grained soils. EDUCATION PLAN The objective of the education plan is to equip civil engineering students with a sound philosophy of engineering, a rigorous grounding in engineering basics and fundamentals, and an appreciation of the complementary roles of theory and judgment. The education plan covers several details which will enhance the basic strength of the existing curriculum, and thereby contribute to an inspiring, well-rounded education in civil and environmental engineering. It includes the following items: In design courses, have a practicing professional assist in setting up the design project, and then discuss alternative designs at the end of the course; select these and other new course projects to illustrate the complementary roles of fundamental theory and engineering judgment in the practice of civil and environmental engineering; develop an instructional video on drilling and sampling procedures for site characterization; introduce computer- based data-acquisition systems into the undergraduate laboratory curriculum; involve undergraduates in research projects via summer employment and independent research electives; and introduce results from recent research in appropriate courses ***