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

该学院早期职业发展（CAREER）项目的研究目标是评估地震震动过程中水层的演变及其对工程结构的影响。 与液化有关的地面破坏（例如，横向扩展、建筑物沉降/倾斜、掩埋结构的漂浮、流动滑坡）代表了地震造成的经济损失的重要且不断增长的来源。 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，水坝和堤坝以及海滨结构。 了解和减轻这些后果对于在大地震后保持恢复力至关重要。 然而，一些研究表明，地震时地下可能会形成离散的水层，而这些都知之甚少。水层？可能造成了很大比例的基础设施损坏。 因此，地质专业人员必须回答这样的问题：地震期间水层是如何形成的？ 如果水层形成，它们的持久性和连续性如何？ 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，将进行一项综合的现场、实验室和离心研究，以评估地震震动过程中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州中部和南部的许多液化点以及新马德里和瓦巴什山谷地震带的古液化点来寻找水层特征，这些液化点有助于在震动期间（或之后）形成水层。 实验室和离心研究将在更广泛的受控条件下评价水层的形成。教育计划的重点是通过一个学生建设工程判断？综合问题评估？这种方法涉及融合动手示范（使用为本项目建造的实验室设备），专家论坛，基于问题的学习，合作学习和创造性思维与传统的讲座和讨论。 这种综合方法将更好地为学生的工程实践做好准备，在那里与来自多个学科的专家团队合作开发创造性的工程解决方案是司空见惯的。这项研究的更广泛的影响包括：（1）通过开发评估水层形成的工具来减少与地震有关的经济损失，以便采取适当的减灾措施;（2）为美国地区（如美国中部和东部）的地震危险性分析提供基本输入。其中古液化研究提供了这些分析的主要基础;和（3）开发一个新的工程师和学生谁混合多学科的专业知识（包括岩土工程，地震工程，工程地质，工程地震学，沉积学，水文学和工程力学）使用？工程判断？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.