CAREER: Impact of Liquefaction-Induced Water Layers on Forward and Inverse Geoengineering Analyses

这个教师早期职业发展（Career）项目的研究目标是评估地震中水层的演变，以及它对工程结构的影响。与液化有关的地面破坏（例如，横向扩散、建筑物沉降/倾斜、埋藏结构的浮动、水流滑动）是地震造成经济损失的一个重要且日益增长的来源。这些故障几乎破坏了所有形式的基础设施，包括生命线和交通设施、建筑地基、水坝和防洪堤以及滨水结构。了解和减轻这些后果对于在大地震后保持恢复能力至关重要。然而，一些研究表明，在地震期间，地下可能会形成离散的水层。水层?可能造成了很大比例的基础设施损坏。因此，地质学专业人士必须回答以下问题：地震期间水层是如何形成的，在哪里形成的？如果形成水层，它们有多持久和连续？水层如何影响工程结构和我们对史前地震的解释？为了回答这些问题，将进行综合现场，实验室和离心机研究，以评估地震震动期间水层的演变及其对工程结构的影响。实地研究将通过检查加利福尼亚中部和南部的许多液化点以及新马德里和沃巴什谷地震带的古液化点来寻找水层特征，这些地点有助于在地震期间（或之后）形成水层。实验室和离心机研究将在更广泛的控制条件下评估水层的形成。该教育计划的重点是通过一门课程来培养学生的工程判断力。综合问题评估？将实践演示（使用为本项目构建的实验室设备）、专家论坛、问题学习、合作学习和创造性思维与传统的讲座和讨论相结合的方法。这种综合方法将使学生更好地为工程实践做好准备，在工程实践中，与来自多个学科的专家合作开发创造性的工程解决方案是司空见惯的。这项研究的更广泛影响包括：(1)通过开发评估水层形成的工具，减少与地震有关的经济损失，以便采取适当的缓解措施；(2)为以古液化研究为主要基础的美国地区（如美国中部和东部）的地震危险性分析提供基础输入；(3)培养融合多学科（包括岩土工程、地震工程、工程地质学、工程地震学、沉积学、水文学和工程力学）专业知识的新型工程师和学生。工程判断吗?然后呢?综合问题评估？应对地质灾害并减轻其影响。

The research objective of this Faculty Early Career Development (CAREER) project is evaluate water layer evolution during seismic shaking, as well as its impact on engineered structures. Ground failures related to liquefaction (e.g., lateral spreads, building settlement/tilting, floating of buried structures, flow slides) represent a significant and growing source of economic loss resulting from earthquakes. These failures damage nearly all forms of infrastructure, including lifeline and transportation facilities, building foundations, dams and levees, and waterfront structures. Understanding and mitigating these consequences is critical to maintaining resiliency following a major earthquake. However, some studies show that discrete layers of water may form within the subsurface during earthquakes, and these poorly understood ?water layers? may be responsible for a significant percentage of infrastructure damage. Therefore, it is imperative that the geo-profession answer questions such as: How and where do water layers form during earthquakes? If water layers form, how persistent and continuous are they? How do water layers influence engineering structures and our interpretation of prehistoric earthquakes?To answer these questions, an integrated field, laboratory, and centrifuge study will be undertaken to evaluate water layer evolution during seismic shaking, as well as its impact on engineered structures. The field studies will search for water layer signatures by examining numerous liquefaction sites in central and southern California and paleoliquefaction sites in the New Madrid and Wabash Valley seismic zones that are conducive to forming water layers during (or after) shaking. The laboratory and centrifuge studies will evaluate water layer formation under a wider variety of controlled conditions. The educational plan focuses on building engineering judgment in students through an ?integrated problem assessment? approach that involves fusing hands-on demonstrations (employing the laboratory equipment constructed for this project), expert-based forums, problem-based learning, cooperative learning, and creative thinking with traditional lectures and discussions. This integrated approach will better prepare students for engineering practice, where working in teams with experts from multiple disciplines to develop creative engineering solutions is commonplace. The broader impacts from this study include: (1) reducing economic losses related to earthquakes by developing tools to assess water layer formation so that proper mitigation measures can be adopted; (2) providing fundamental input to seismic hazard analysis in regions of the United States (such as the central and eastern U.S.) where paleoliquefaction studies provide the primary basis for these analyses; and (3) developing a new breed of engineers and students who blend expertise from multiple disciplines (including geotechnical engineering, earthquake engineering, engineering geology, engineering seismology, sedimentology, hydrology, and engineering mechanics) using ?engineering judgment? and ?integrated problem assessment? to address geohazards and mitigate their impacts.