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.

这项美日合作快速响应研究资助 (RAPID) 奖项将调查 2016 年 4 月日本熊本地震序列 (KES) 后观察到的意料之外且知之甚少的岩土现象。岩土极端事件勘察（GEER）组织在 KES 发生后立即动员了一支美国勘察队探索受影响地区。美国团队与日本调查人员合作，发现了一些重要的案例历史，由于其独特的、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，需要进一步调查。这些案例包括：阿苏山火山口内一个无法解释的 10 公里长的洼地，对建筑物和输电线路造成了严重损坏；断层破裂，穿过蓄满水库的大坝溢洪道；令人惊讶的是，对土壤液化及其对这种规模的地震和明显场地条件的影响的观察非常有限。该 RAPID 奖项通过以下方式支持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、土壤变形和结构沉降或倾斜信息； (2) 从感兴趣的潜在案例历史地点收集初步岩土、地震、地质和地形信息； (3) 对回收的样品进行一套全面的实验室测试，然后进行初步模拟，以评估土壤的抗液化性和循环荷载下的响应。在此过程中，该奖项有助于提高岩土地震工程关键领域的知识和实践水平，从而提高全球岩土结构和基础设施的复原力。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与合作，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。这笔赠款将通过增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 项目将能够从日本 2016 年 KES 中收集与山体滑坡、液化触发和影响以及地震引起的地面变形相关的有价值且易腐烂的信息。 KES 之后观察到的许多现象无法用现有的知识状态或当前的分析和/或经验预测模型来解释。这些现象可能对美国具有类似地质和地貌的地点的抗震设计产生重要影响。从受影响地点收集的信息，然后进行实验室测试和分析，将增加我们对 KES 后观察到的岩土现象的根本原因的理解，这最终将影响岩土地震工程实践的状态。工程界将受益于了解为什么该地区土壤液化没有达到预测的程度。使用基于无人机的航空摄影和地面 LiDAR 技术联合应用 3D 数字表面建模将推动岩土工程遥感科学和艺术的发展，并将改善收集岩土地震现象表面证据的方式。此外，从该 RAPID 收集的初步现场和实验室数据将指导和激发更大规模的国际合作研究工作，以更彻底地调查观察到的这一系列地震的独特岩土现象和损害。