Evaluating Liquefaction Potential of Challenging Soil Sites: Linking Geomorphological Controls and Novel Approaches for Site Characterization

评估具有挑战性的土壤场地的液化潜力：将地貌控制与场地表征新方法联系起来

• 批准号: 1825189
• 负责人: Russell Green
• 金额: $ 120万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1825189&HistoricalAwards=false
• 关键词: Evaluating; Liquefaction; Potential; Challenging; Soil

This project focuses on improving engineering models for predicting the severity of earthquake-induced liquefaction at "challenging soil sites." Liquefaction is a phenomenon wherein loose, saturated, sandy soils lose their strength during earthquake shaking, leading to significant damage to nearby infrastructure. Field investigations performed following recent earthquakes in Christchurch, New Zealand highlighted the limitations of the current engineering liquefaction severity models for profiles having clay layers interbedded within the liquefiable sandy layers (i.e., "challenging soil sites"); similar geologic profiles are common in the US and worldwide. However, the root cause of the model shortcomings is unknown. The ramifications of not being able to accurately predict the liquefaction response of these deposits are high. For example, a recent liquefaction hazard study for the Hawke's Bay region of New Zealand (Napier and Hastings) predicts severe liquefaction for the design event. Similarly, a study performed for a stretch of levees in the northern portion of the Netherlands also predicts a high liquefaction hazard. In both cases, the deposits that are predicted to severely liquefy have similar characteristics to those in Christchurch, New Zealand that highlight the limitations in currently used evaluation procedures. As a result, government regulators are faced with the question of whether limited resources should be expended, potentially/likely unnecessarily, to mitigate the perceived risk of liquefaction based on these studies (e.g., the remediation cost for only one stretch of levees in the Netherlands is estimated to be ~$100mil, with costs potentially exceeding $1bil to remediate all the levees in the region). On the contrary, the consequences could be even higher if the results of the liquefaction hazard studies are offhandedly dismissed, and the deposits are truly susceptible to severe liquefaction when subjected shaking from future earthquakes. Challenging soil sites similar to those in Hawke's Bay, Christchurch, and the Netherlands are prevalent in regions across the US and worldwide. Towards understanding the root cause of the shortcoming in current engineering models, large vertical slices of soils will be extracted from challenging soil sites in Christchurch, New Zealand where the engineering models accurately and inaccurately predicted the severity of liquefaction. The existence of evidence of the occurrence of liquefaction at depth in these profiles will be determined by examining these "geo-slices," allowing us to determine whether the issue with current models is related to predicting the occurrence of liquefaction or whether the issue is related to predicting the severity of the manifestations of liquefaction at the ground surface. Additionally, the characteristics of these soil profiles will be documented in detail. New, advanced tools for identifying the types of profiles will be developed and used in conjunction with revised engineering models to accurately predicted the occurrence and severity of liquefaction in future earthquakes. Two doctoral students from Virginia Tech and the University of Michigan will work on this project, in collaboration with New Zealand-funded students from the University of Auckland and the University of Canterbury, New Zealand. The Principle Investigator for this project has established an outreach program for military veterans and will use the project to further his efforts of working with veterans. Comparison of predicted versus observed severity of surficial liquefaction manifestations at "challenging" soil sites (e.g., sandy soil deposits with interbedded silt and clay layers) during the 2010-2011 Canterbury, New Zealand earthquake sequence (CES) highlights significant limitations in currently used procedures for evaluating the liquefaction response of these deposits. The potential issues with current procedures include limitations in commonly used site characterization techniques and distinguishing between evaluating liquefaction triggering at depth versus severity of surficial liquefaction manifestations, where the latter has been shown to correlate with damage potential. The ramifications of not being able to accurately predict the liquefaction response of these deposits are high. Accordingly, this research will development a procedure to evaluate the liquefaction response of challenging soil sites based on the linkage of geomorphological controls of challenging soil sites and novel approaches for site characterization. This study will exploit to the extent possible the wealth of field performance data from recent earthquakes in New Zealand, as well as data from other well-documented historic liquefaction case histories, and will employ ?geo-slicing? and Vision Cone Penetration Tests, VisCPT, as well as more conventional field and laboratory testing. The project will be performed collaboratively by researchers from Virginia Tech, University of Michigan, and QuakeCoRE: New Zealand Centre for Earthquake Resilience (i.e., Univ. of Canterbury, Univ. of Auckland, and Tonkin + Taylor Ltd).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目着重于改善工程模型，以预测“挑战性土壤地点”地震引起的液化的严重性。 液化是一种现象，在地震摇动期间，松散，饱和的沙质土壤失去了强度，从而导致附近的基础设施造成重大破坏。 在新西兰基督城最近的地震发生后，进行了现场调查，强调了当前工程液化严重性模型的局限性，用于在可液化的沙质层中相互作用的粘土层（即“具有挑战性的土壤位点”）；类似的地质概况在美国和全球很常见。 但是，模型缺点的根本原因尚不清楚。 无法准确预测这些沉积物的液化反应的后果很高。 例如，最近针对新西兰霍克湾地区（Napier and Hastings）的液化危害研究预测了设计事件的严重液化。 同样，一项研究在荷兰北部进行了一系列堤防的研究也预计会有很高的液化危险。 在这两种情况下，预计将严重液化的沉积物具有与新西兰基督城基督城相似的特征，这些特征强调了当前使用的评估程序的局限性。 结果，政府监管机构面临着一个问题，即是否应该在这些研究基于这些研究的基础上消耗有限的资源，以减轻液化风险（例如，荷兰仅一段义务的补救成本估计为〜100万美元，估计为〜1亿美元，超过了1亿美元的价格，该领域的成本超过了1亿美元的价格。 相反，如果液化危险研究的结果被偶然地驳回，后果可能会更高，并且当受到未来地震震动时，沉积物确实容易受到严重液化的影响。 与霍克湾，克赖斯特彻奇和荷兰类似的挑战性土壤站点在美国和全球各地普遍存在。为了理解当前工程模型中缺点的根本原因，将从新西兰基督城的具有挑战性的土壤站点中提取大量土壤的垂直切片，在那里工程模型准确，不准确地预测了液化的严重性。 这些概况中深度液化发生的证据的存在将通过检查这些“地理单位”来确定，从而使我们能够确定当前模型的问题是否与预测液化的发生有关，或者该问题是否与预测地面液化表现的表现严重程度有关。 此外，将详细记录这些土壤剖面的特征。新的高级工具，用于识别配置文件类型，并与修订的工程模型一起开发和使用，以准确预测未来地震中液化的发生和严重性。 来自弗吉尼亚理工大学和密歇根大学的两名博士生将与来自奥克兰大学和新西兰坎特伯雷大学的新西兰资助的学生合作。 该项目的主要调查员已为退伍军人建立了一项宣传计划，并将利用该项目来进一步与退伍军人合作。 在2010 - 2011年新西兰地震序列（CES）期间，比较“具有挑战性的”土壤地点（例如，具有磨砂粉与粘土层的沙质土壤沉积物）在“具有挑战性”土壤地点（例如沙质土壤沉积物）的比较与观察到的比较。 当前程序的潜在问题包括常用位点表征技术的局限性，并区分评估液化在深度与表面液化表现的严重程度的液化触发，后者已证明与损伤潜力相关。 无法准确预测这些沉积物的液化反应的后果很高。 因此，这项研究将根据具有挑战性的土壤站点的地貌控制和现场表征的新方法来开发一种评估具有挑战性土壤位点的液化反应的程序。 这项研究将在新西兰最近地震以及其他有据可查的历史液化案例历史的数据中利用大量现场绩效数据，并且会采用？和视觉锥渗透测试，viscpt，以及更常规的现场和实验室测试。 该项目将由弗吉尼亚理工大学，密歇根大学和Quakecore的研究人员合作进行：新西兰地震弹性中心（即，奥克兰大学坎特伯雷大学和Tonkin + Taylor Ltd的坎特伯雷大学）。 标准。

项目成果

Development of region-specific soil behavior type index correlations for evaluating liquefaction hazard in Christchurch, New Zealand

开发特定区域土壤行为类型指数相关性，用于评估新西兰基督城的液化危险

• DOI: 10.1016/j.soildyn.2018.04.059
• 发表时间: 2019
• 期刊: Soil Dynamics and Earthquake Engineering
• 影响因子: 4
• 作者: Maurer, B.W.;Green, R.A.;van Ballegooy, S.;Wotherspoon, L.
• 通讯作者: Wotherspoon, L.

The Sed360 Test for Rapid Sand Particle Size Distribution Determination

用于快速测定砂粒尺寸分布的 Sed360 测试

• DOI: 10.1520/gtj20220032
• 发表时间: 2023
• 期刊: Geotechnical Testing Journal
• 影响因子: 1.6
• 作者: Ventola, Andrea;Hryciw, Roman D.
• 通讯作者: Hryciw, Roman D.

Evaluating Liquefaction Triggering Potential Using Seismic Input Parameters that Are Consistent with ASCE 7-16

使用符合 ASCE 7-16 的地震输入参数评估液化触发潜力

• DOI: 10.1061/9780784482810.010
• 发表时间: 2020
• 期刊: Geo-Congress 2020: Geotechnical Earthquake Engineering and Special Topics
• 作者: Green, R.A. and

What is the Smallest Earthquake Magnitude that Needs to be Considered in Assessing Liquefaction Hazard?

• DOI: 10.1193/032218eqs064m
• 发表时间: 2019-08
• 期刊: Earthquake Spectra
• 影响因子: 5
• 作者: R. Green;J. Bommer

Liquefaction Hazard in the Groningen Region of the Netherlands due to Induced Seismicity

• DOI: 10.1061/(asce)gt.1943-5606.0002286
• 发表时间: 2020-08
• 期刊: Journal of Geotechnical and Geoenvironmental Engineering
• 影响因子: 3.9
• 作者: R. A. Green;J. Bommer;P. Stafford;B. Maurer;P. Kruiver;B. Edwards;A. Rodriguez-Marek;G. D. De Lange;S. Oates;T. Storck;P. Omidi;S. Bourne;J. van Elk