RAPID/Collaborative Research: Investigating Unanticipated Geotechnical Phenomena in Kumamoto, Japan, Observed from the April 2016 Earthquake Sequence

快速/协作研究：调查从 2016 年 4 月地震序列中观察到的日本熊本意外岩土现象

• 批准号: 1727593
• 负责人: Shideh Dashti
• 金额: $ 4.35万
• 依托单位: University of Colorado at Boulder
• 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: 2017-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1727593&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; Investigating; Unanticipated

This collaborative U.S.-Japan Grant for Rapid Response Research (RAPID) award will investigate unanticipated and poorly understood geotechnical phenomena observed following the April 2016 Kumamoto earthquake sequence (KES) in Japan. The Geotechnical Extreme Events Reconnaissance (GEER) organization mobilized a U.S. reconnaissance team to explore the affected area immediately following the KES. The U.S. team in collaboration with Japanese investigators identified significant case histories that warrant further investigation due to their unique, unanticipated, and poorly understood nature, as well as their important potential implications for seismic design and safety in the U.S. and around the world. These case histories include, among other things: an unexplained 10km-long depression zone within the Mount Aso volcano caldera that caused significant damage to structures and transmission lines; a fault rupture through the spillway of a large dam impounding a full reservoir; and surprisingly limited observations of soil liquefaction and its effects for an earthquake of this size and apparent site conditions. This RAPID award supports a detailed study of the underlying causes behind these observations through: (1) the use of state-of-the-art remote sensing techniques to collect perishable surface topology, soil deformation, and structure settlement or tilt information from known liquefaction and major landslide sites; (2) the collection of preliminary geotechnical, seismic, geologic, and topographic information from potential case history sites of interest; and (3) the performance of a comprehensive set of laboratory tests on retrieved samples followed by preliminary simulations to evaluate the soil's resistance to liquefaction and response under cyclic loading. In doing so, this award contributes to the state of knowledge and practice in critical areas of geotechnical earthquake engineering and hence, the resilience of geotechnical structures and infrastructure globally. Collaboration with Japanese researchers through this study will improve the relationship and cooperation between the two countries, and will provide valuable international research experience for the PIs and the graduate students involved in this project. This grant will advance the science and practice of geotechnical earthquake engineering by enhancing the fundamental understanding of seismic-induced ground deformations and liquefaction triggering. This RAPID project will enable the collection of valuable and perishable information related to landslides, liquefaction triggering and effects, and earthquake-induced ground deformations from the 2016 KES in Japan. There are a number of phenomena observed after the KES that cannot be explained by the existing state of knowledge or current analytical and/or empirical prediction models. These phenomena could have important implications for seismic design in locations with similar geology and geomorphology in the U.S. Information collected from the affected sites followed by laboratory testing and analysis will increase our understanding of the underlying causes of the geotechnical phenomena observed following the KES, which will ultimately impact the state of geotechnical earthquake engineering practice. The engineering community will benefit from learning why soil liquefaction did not occur to the extent that it was predicted in this region. Joint application of 3D digital surface modeling using UAV-based aerial photography and terrestrial LiDAR techniques will advance the science and art of remote sensing in geotechnical engineering and will improve the way surficial evidence of geotechnical earthquake phenomena is collected. Further, preliminary field and laboratory data collected from this RAPID will guide and inspire a larger international collaborative research effort to more thoroughly investigate the observed unique geotechnical phenomena and damage from this series of earthquakes.

这个合作的美国-日本快速反应研究基金（RAPID）将调查2016年4月日本熊本地震序列（KES）后观察到的意料之外和知之甚少的岩土现象。地质极端事件侦察（GEER）组织动员了一支美国侦察队在KES之后立即探索受影响的地区。美国研究小组与日本研究人员合作，确定了值得进一步调查的重要案例，因为它们具有独特的、不可预见的和知之甚少的性质，以及它们对美国和世界各地的抗震设计和安全的重要潜在影响。这些案例包括，除其他事项外：一个原因不明的10公里长的凹陷区内的阿索火山破火山口，造成重大损害的结构和输电线路;故障破裂，通过溢洪道的大坝蓄水满水库;和令人惊讶的有限的观测土壤液化及其影响的地震规模和明显的网站条件。该RAPID奖支持通过以下方式对这些观测背后的根本原因进行详细研究：（1）使用最先进的遥感技术从已知的液化和主要滑坡地点收集易腐烂的表面拓扑结构，土壤变形和结构沉降或倾斜信息;（2）从潜在的历史遗址收集初步的岩土工程、地震、地质和地形信息;及（3）对回收的样本进行一系列全面的实验室测试，然后进行初步模拟，以评估土壤的抗液化能力和在循环荷载下的反应。在这样做的过程中，该奖项有助于岩土地震工程关键领域的知识和实践状态，从而提高全球岩土结构和基础设施的恢复力。通过这项研究与日本研究人员的合作将改善两国之间的关系和合作，并将为参与该项目的PI和研究生提供宝贵的国际研究经验。该补助金将通过加强对地震引起的地面变形和液化触发的基本理解来推进岩土地震工程的科学和实践。该RAPID项目将能够从2016年日本KES收集与滑坡、液化触发和影响以及地震引起的地面变形有关的宝贵和易逝的信息。在KES之后观察到的一些现象无法用现有的知识或当前的分析和/或经验预测模型来解释。这些现象可能会有重要的影响，在美国类似的地质和地貌的位置，从受影响的网站收集的信息，然后通过实验室测试和分析，将增加我们的理解的根本原因的岩土工程现象观察KES后，这将最终影响国家的岩土地震工程实践。工程界将受益于了解为什么土壤液化没有发生的程度，它是预测在这个地区。使用基于无人机的航空摄影和地面激光雷达技术的3D数字表面建模的联合应用将推进岩土工程中的遥感科学和艺术，并将改善收集岩土地震现象的表面证据的方式。此外，从该RAPID收集的初步现场和实验室数据将指导和激励更大的国际合作研究工作，以更彻底地调查观察到的独特岩土工程现象和这一系列地震造成的损害。