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Collaborative Research: Bridging the In-situ and Elemental Cyclic Response of Transitional Soils

合作研究：弥合过渡性土壤的原位和元素循环响应

基本信息

批准号：
1663654
负责人：
Armin Stuedlein
金额：
$ 63.44万
依托单位：
Oregon State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2021-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1663654&HistoricalAwards=false
关键词：
Collaborative Research Bridging situ Elemental

项目摘要

The consequences of earthquake-induced liquefaction are not trivial; for example, $15B of damage was attributed to soil liquefaction resulting from the recent Canterbury Earthquake Sequence in New Zealand. Large portions of the United States, from Alaska to California and eastward to the New Madrid Seismic Zone and coastal South Carolina and north to the St. Lawrence Seaway, are prone to the impacts from earthquakes. Earthquakes such as those in New Zealand and others have raised awareness about limitations in our understanding of the cyclic response of natural soil deposits. These limitations have arisen through continued use of the traditional practice of simplifying geotechnical analyses by considering two main soil types: drained sands and undrained clays. Design methodologies for nearly all geotechnical systems have developed along these two distinct lines. However, many natural soil deposits do not fit into these simple categories; transitional silty soils, the subject of this research, are an example. This study aims to answer pertinent questions concerning the cyclic response of transitional silty soils through systematic and coordinated field and laboratory studies that will improve our understanding of the potential for large deformations and loss of life and property during large earthquakes. The findings of this research will have broad application across the nation and globe. Furthermore, this research will have a parallel objective of inspiring the next generation of STEM leaders. Collaboration with the Hatfield Marine Science Center (HMSC) in Newport, Oregon will allow our outreach efforts to reach 150,000 visitors and 40,000 K-12 students and teachers per year, through: (1) public demonstrations of liquefaction and in-situ cyclic tests with a large mobile shaker truck, (2) a compilation of video demonstrations, data, and interviews with the researchers into a permanent interactive exhibit, and (3) development of instructional modules for HMSC staff to help their established outreach effort expand instruction to include coastal hazards such as the Cascadia Subduction Zone and associated tsunami. The demonstrations will be leveraged to form permanent exhibits and instructional modules, which will greatly extend this outreach effort.This research will improve our understanding of the in-situ and laboratory cyclic response of silt soils including nonlinearity, degradation of stiffness, triggering of destabilizing excess pore pressures, and the corresponding post-shaking consequences. Specifically, this study will: (1) narrow the threshold fines content and plasticity separating "sand-like" and "clay-like" responses to cyclic shear stresses/strains and identify critical threshold states; (2) compare the in-situ, uniaxial and biaxial cyclic response of transitional soils to understand how changes in strong ground motion directionality impacts generation of pore pressure and volumetric strain; (3) determine the effect of soil fabric, stress history, and degree of saturation on the cyclic and post-cyclic response of transitional soils; (4) link the regional findings from this work to previous efforts on transitional soils; and (5) inspire future seismologists, geologists, earthquake engineers, and natural hazard and resilience planners through a long-lived, coordinated outreach program. This work concentrates on experiments that target small-to-large shear strains, using techniques that range from in-situ cyclic loading from large mobile shakers and blast liquefaction, to specialized and coordinated laboratory tests, allowing the development of an unprecedented dataset critical for improving the understanding of the in-situ and elemental level cyclic response to be bridged.

地震引起的液化的后果并非微不足道。例如，新西兰最近发生的坎特伯雷地震序列造成的土壤液化造成了 $15B 的损失。美国的大部分地区，从阿拉斯加到加利福尼亚，向东到新马德里地震带和南卡罗来纳州沿海，以及向北到圣劳伦斯海道，都容易受到地震的影响。新西兰和其他国家发生的地震提高了人们对自然土壤沉积物循环响应理解的局限性的认识。这些限制是由于继续使用传统做法，通过考虑两种主要土壤类型（排水沙子和不排水粘土）来简化岩土分析。几乎所有岩土系统的设计方法都是沿着这两条不同的路线发展的。然而，许多天然土壤沉积物并不属于这些简单的类别；本研究的主题——过渡性粉质土就是一个例子。本研究旨在通过系统和协调的现场和实验室研究来回答有关过渡性粉质土循环响应的相关问题，这将提高我们对大地震期间发生大变形和生命财产损失的可能性的理解。这项研究的结果将在全国和全球范围内得到广泛应用。此外，这项研究的并行目标是激励下一代 STEM 领导者。与俄勒冈州纽波特的哈特菲尔德海洋科学中心 (HMSC) 合作，我们的外展工作将通过以下方式每年覆盖 150,000 名参观者和 40,000 名 K-12 学生和教师：(1) 使用大型移动摇床进行液化和原位循环测试的公开演示，(2) 将视频演示、数据和研究人员访谈汇编成永久互动展览，以及 (3) 开发教学材料为 HMSC 工作人员提供模块，帮助他们既定的外展工作扩大指导范围，以涵盖沿海灾害，例如卡斯卡迪亚俯冲带和相关海啸。这些演示将被用来形成永久性展览和教学模块，这将极大地扩展这一推广工作。这项研究将提高我们对粉土的现场和实验室循环响应的理解，包括非线性、刚度退化、触发不稳定的超孔隙压力以及相应的震后后果。具体来说，本研究将：（1）缩小细粉含量和塑性阈值，区分对循环剪切应力/应变的“沙状”和“粘土状”响应，并确定临界阈值状态；（2）比较过渡土的原位、单轴和双轴循环响应，了解强地震动方向性的变化如何影响孔隙压力和体积应变的产生； (3) 确定土结构、应力历史和饱和度对过渡土循环和循环后响应的影响； (4) 将这项工作的区域发现与之前关于过渡性土壤的努力联系起来； (5) 通过长期、协调的外展计划激励未来的地震学家、地质学家、地震工程师以及自然灾害和复原力规划人员。这项工作集中于针对从小到大剪切应变的实验，使用从大型移动振动筛和爆炸液化的原位循环加载到专门和协调的实验室测试等技术，从而开发出前所未有的数据集，这对于提高对原位和元素级循环响应的理解至关重要。

项目成果

期刊论文数量（14）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Dynamic, In-situ, Nonlinear-Inelastic Response and Post-Cyclic Strength of a Plastic Silt Deposit

塑性淤泥沉积物的动态、原位、非线性非弹性响应和循环后强度

DOI：
10.1139/cgj-2020-0652
发表时间：
2021
期刊：
Canadian Geotechnical Journal
影响因子：
3.6
作者：
Jana, Amalesh;Stuedlein, Armin W.
通讯作者：
Stuedlein, Armin W.

Influence of Natural Soil Fabric on the Cyclic Resistance of Low and High Plasticity Silts

天然土结构对低塑性粉土和高塑性粉土循环阻力的影响

DOI：
发表时间：
2022
期刊：
12th National Conference on Earthquake Engineering
影响因子：
0
作者：
Dadashiserej, A.;Jana, A.;Evans, T.M.;Stuedlein, A.W.
通讯作者：
Stuedlein, A.W.

Monotonic, Cyclic, and Post-Cyclic Response of Willamette River Silt at the Van Buren Bridge

范布伦桥威拉米特河淤泥的单调、循环和后循环响应

DOI：
10.1061/9780784484043.042
发表时间：
2022
期刊：
Geo-Congress 2022
影响因子：
0
作者：
Dadashiserej, Ali;Jana, Amalesh;Ortiz, Susan C.;Walters, James J.;Stuedlein, Armin W.;Evans, T. Matthew
通讯作者：
Evans, T. Matthew

Monotonic, Cyclic, and Postcyclic Responses of an Alluvial Plastic Silt Deposit

冲积塑性粉砂沉积物的单调、循环和后循环响应