权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Collaborative Research: Integrated Field and Laboratory Based Assessment of Liquefaction Triggering and Residual Strength of Gravelly Soil

合作研究：基于现场和实验室的碎石土液化触发和剩余强度综合评估

基本信息

批准号：
1663546
负责人：
Kyle Rollins
金额：
$ 18.81万
依托单位：
Brigham Young 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：
2017-09-15 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1663546&HistoricalAwards=false
关键词：
Collaborative Research Integrated Field Laboratory

项目摘要

One of the leading causes of damage during earthquakes is soil liquefaction. Liquefaction causes loose soil to behave more like a heavy liquid than a solid which can result in settlement of buildings as well as landslides and dam failures. Recently, extensive gravel liquefaction and damage was observed in the 2008 Wenchuan, China, earthquake and the 2014 Cephalonia, Greece, earthquake sequences, and the evidence indicates that gravelly soils that were considered non-liquefiable using existing liquefaction susceptibility methods, did liquefy. This study will provide a fundamental understanding, as well as practical guidance on assessing whether a gravel deposit will liquefy. Such deposits are encountered widely and their potential liquefaction is commonly a critical consideration in the stability of our nation's ports, dams, levees and in general, civil infrastructure. The improved procedures that will be developed will enhance the resiliency of these facilities, and will help in avoiding unnecessary expenses when gravel liquefaction is not really an issue, or more importantly, highlight the need for stabilization when gravel liquefaction is indeed expected. The research team will establish a web-site with a gravel liquefaction database, and document all available case histories of gravel liquefaction. Videos on the mechanism of liquefaction that can be used for outreach purposes will be developed, as well as a recorded webinar and other educational resources on the outcomes of this study with emphasis on the recommended procedures for liquefaction assessment of gravelly soils. Characterization of gravelly soils in a reliable, cost-effective manner for routine engineering projects remains a challenge and methods such as the Cone Penetration Test and Standard Penetration Test are not considered appropriate. Even for large projects, such as dams and energy projects, characterization is expensive (if Becker testing is used) and problematic. Nevertheless, because liquefaction is known to have occurred in gravelly soils in a significant number of earthquakes, dam engineers are frequently called upon to assess the potential for liquefaction in gravels and liquefaction mitigation costs often run into millions of dollars. With the majority of research in soil liquefaction engineering focused on the assessment of the likelihood of "triggering" of liquefaction in sands and silty soils, new approaches, and transformative methods for characterizing gravels are needed. In this collaborative project, there is a coordinated plan that combines unique large scale laboratory testing and innovative field testing at key gravel liquefaction sites to develop liquefaction triggering charts and post-liquefaction shear strength recommendations for gravelly soils. A prototype 300-mm diameter cyclic simple shear (CSS) device has been developed at the University of Michigan and will be used to evaluate the cyclic (and monotonic) undrained shear response of gravelly soils in the laboratory. A next-generation dynamic cone penetration test (DPT) that was originally developed in China will be modernized with key instrumentation and will be used for field testing along with in-situ shear wave velocity (Vs) measurements. Field testing will be conducted in the USA, China, and Greece, leveraging resources from international partners, in-situ testing firms and organizations. The PIs will leverage well-documented case studies of gravel liquefaction in the recent Cephalonia earthquake to validate the new methods and augment the field performance record of gravel liquefaction.

地震期间造成破坏的主要原因之一是土壤液化。液化使松散的土壤表现得更像重液体，而不是固体，这可能导致建筑物的沉降以及山体滑坡和大坝坍塌。最近，在2008年中国汶川地震和2014年希腊塞帕洛尼亚地震序列中观察到了广泛的砾石液化和破坏，证据表明，用现有的液化敏感性方法认为不能液化的砾石土确实发生了液化。这项研究将为评价砾石矿床是否会液化提供基本的认识和实践指导。这类沉积物普遍存在，它们的潜在液化通常是我国港口、大坝、堤坝和一般民用基础设施稳定性的关键考虑因素。将开发的改进程序将增强这些设施的弹性，并将有助于避免在碎石液化不是真正问题时的不必要费用，或更重要的是，在确实预期碎石液化时突出稳定的必要性。研究小组将建立一个带有砂砾液化数据库的网站，并将所有可用的砂砾液化案例记录在案。将制作关于可用于推广目的的液化机制的视频，以及关于这项研究结果的录音网络研讨会和其他教育资源，重点是砂砾土液化评估的建议程序。对于常规工程项目来说，以可靠、经济有效的方式表征砾石土仍然是一个挑战，圆锥贯入试验和标准贯入试验等方法被认为是不合适的。即使对于大型项目，如大坝和能源项目，定性也是昂贵的(如果使用Becker测试)，而且存在问题。然而，由于众所周知，在相当多的地震中，砾石土中发生了液化，大坝工程师经常被要求评估砾石中液化的可能性，缓解液化的成本往往高达数百万美元。由于土壤液化工程的大部分研究都集中在对砂土和粉质土壤中“触发”液化的可能性的评估上，因此需要新的途径和变革性的方法来表征砾石。在这个合作项目中，有一个协调的计划，将独特的大规模实验室测试和关键砾石液化场地的创新现场测试相结合，以开发砾石土的液化触发图和液化后剪切强度建议。密歇根大学研制了一台直径300 mm的循环简单剪切装置，并将在实验室中用于评价砾石土的循环(和单调)不排水剪切响应。最初由中国开发的新一代动态触探测试(DPT)将通过关键仪器进行现代化改造，并将用于现场测试和现场剪切波速(VS)测量。现场测试将在美国、中国和希腊进行，利用国际合作伙伴、现场测试公司和组织的资源。PIS将利用最近Cephalonia地震中记录在案的砾石液化案例来验证新方法，并扩大砾石液化的现场表现记录。

项目成果

期刊论文数量（17）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Gravel liquefaction assessment using dynamic cone penetration and shear wave velocity tests based on field performance from the 1964 Alaska earthquake

DOI：
10.1016/j.soildyn.2022.107357
发表时间：
2022
期刊：
Soil Dynamics and Earthquake Engineering
影响因子：
4
作者：
Jashod Roy;K. Rollins;A. Athanasopoulos-Zekkos;McKay Harper;Nicolas Linton;Michelle Basham;W. Greenwood;D. Zekkos
通讯作者：
Jashod Roy;K. Rollins;A. Athanasopoulos-Zekkos;McKay Harper;Nicolas Linton;Michelle Basham;W. Greenwood;D. Zekkos

Evaluation and Optimization of Dynamic Cone Penetration test (DPT) for Assessment of Liquefaction in Gravelly Soils, Association of State Dam Safety Officials Annual Meeting

用于评估碎石土液化的动态锥入度试验 (DPT) 的评估和优化，州大坝安全官员协会年会