RAPID/Collaborative Research: Liquefaction Triggering & Consequences for Low-Plasticity Silty Soils, Christchurch, New Zealand

RAPID/协作研究：液化触发

• 批准号: 1407364
• 负责人: Jonathan Bray
• 金额: $ 13万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1407364&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; Liquefaction; Triggering

There is a pressing need to investigate the seismic response of silty soils at sites that were strongly shaken during the 2010-11 Canterbury, New Zealand (NZ) earthquakes but did not exhibit evidence of liquefaction, although state-of-the-art liquefaction procedures indicate that significant ground failure should have occurred. The overestimation of liquefaction-induced ground failure by current procedures could potentially waste millions of dollars during the Christchurch recovery in addition to costs incurred worldwide, because engineers are requiring expensive ground improvement or building foundations where these procedures indicate that liquefaction is likely. The NZ government is keen to fund research on this important topic and desire international participation. A comprehensive NZ proposal has been developed to perform additional testing to advance their understanding of the role of fines in liquefaction triggering and ground failure. They are eager to partner with US researchers in this effort. The over-prediction of liquefaction triggering by established procedures appears to be a result of their inability to capture the response of silty soils. The empirical database used to develop these procedures consists primarily of triggering data from clean sand sites. Conservatism of the empirical liquefaction triggering procedures also contributes to the over-prediction of liquefaction. To evaluate conclusively the liquefaction potential of low plasticity silty soils requires advanced laboratory testing. As the Christchurch recovery continues, engineers are faced with a dilemma - How can the prediction of significant liquefaction in these silty soils using established liquefaction triggering procedures be reconciled with the contradictory observation that little or no liquefaction damage was observed during strong shaking on multiple occasions? The question is of great importance for developing practical engineering solutions that strike a sensible balance between risk and affordability. This research takes advantage of the substantial work already performed in NZ to guide the rebuilding of Christchurch. The NZ government funding agencies are only interested in this effort if it can be performed quickly so it can assist engineers and planners during their rebuild. Thus, the work is urgent, and U.S. researchers must participate during the compressed NZ work schedule. This work leverages prior and current research in Christchurch funded by the NSF and does not duplicate ongoing efforts. The high-quality case studies and associated laboratory testing and analysis developed through this research will advance ongoing research regarding the liquefaction of silty soils and enable widespread benefits worldwide. Documenting and learning from observations after design level earthquakes are invaluable to advancing our understanding in earthquake engineering. Investigating the occurrence or nonoccurrence of liquefaction of silty soils and evaluating the effects of liquefaction on buildings and lifelines provide invaluable information that will serve as benchmarks to our understanding of soil liquefaction. This project will provide high-quality data from post-earthquake observations, geotechnical investigations, and laboratory testing to the worldwide research community. These data can be incorporated into the existing international dataset to help improve empirical correlations regarding soil parameters, liquefaction triggering, and consequential effects. Most of the research data currently available relates to sandy soils, so addition of this information regarding silty soils will assist greatly in broadening the applicability of empirical design methods. Lastly, the proposed research supports an international research partnership that will advance knowledge worldwide in liquefaction engineering while providing critical information to NZ engineers during their urgent rebuild.

需要调查在2010-11新西兰坎特伯雷（NZ）地震期间强烈动摇的地点的粉质土壤的地震反应，但没有表现出液化的迹象表明应该发生重大的地面故障。 除当前程序对液化引起的地面故障的高估可能会在基督城恢复期间浪费数百万美元，除了全球产生的成本外，由于工程师需要昂贵的地面改进或建造这些程序表明可能是液化的基础。 新西兰政府热衷于为这个重要主题的研究提供资金，并渴望国际参与。 已经开发了一项全面的新西兰提案，以进行额外的测试，以促进他们对罚款在液化触发和地面故障中的作用的理解。 他们渴望与美国研究人员合作。 通过既定程序触发液化的过度预测似乎是由于它们无法捕获粉质土壤反应的结果。 用于开发这些过程的经验数据库主要包括触发清洁砂站点的数据。 经验液化程序的保守主义也有助于过度预测液化。 为了最终评估低可塑性的液化潜力，需要先进的实验室测试。 随着基督城恢复的继续，工程师面临困境 - 如何使用已建立的液化触发程序在这些粉质土壤中对液化的预测与矛盾的观察结果调和，即在强烈的多个方面强烈摇动期间几乎没有观察到很少或没有观察到的液化损害几乎没有观察到？ 问题对于开发实用的工程解决方案非常重要，这些解决方案在风险和负担能力之间取得了明智的平衡。这项研究利用了在新西兰已经在指导基督城重建的大量工作。 新西兰政府资助机构只有可以迅速执行这项工作感兴趣，因此可以在重建过程中为工程师和计划者提供帮助。 因此，这项工作是紧迫的，美国的研究人员必须在压缩的NZ工作时间表中参加。 这项工作利用了由NSF资助的基督城的事先和当前的研究，并没有重复持续的努力。 通过这项研究开发的高质量案例研究以及相关的实验室测试和分析将推进有关粉质土壤液化的持续研究，并在全球范围内广泛利益。 在设计水平地震之后的观察结果中记录和学习对于促进我们对地震工程的理解是非常宝贵的。 研究粉质土壤液化的发生或不存在，并评估液化对建筑物和寿命的影响提供了宝贵的信息，这将是我们对土壤液化的理解的基准。 该项目将向全球研究界提供高质量的数据，从地震后观测，岩土研究和实验室测试。 可以将这些数据纳入现有的国际数据集中，以帮助改善有关土壤参数，液化触发和结果效应的经验相关性。 当前可用的大多数研究数据都与沙质土壤有关，因此，添加有关粉质土壤的信息将在很大程度上有助于扩大经验设计方法的适用性。 最后，拟议的研究支持了国际研究合作伙伴关系，该伙伴关系将在全球范围内推进液化工程知识，同时在紧急重建期间为新西兰工程师提供关键信息。