Collaborative Research: Resilience of Geotechnical Infrastructure under a Changing Climate: Quantitative Assessment for Extreme Events

该奖项资助了一个合作和跨学科的研究项目，重点是定量评估关键的岩土基础设施(即天然和工程地球结构)在当前和不断变化的气候下对极端气候和自然灾害的性能。虽然已经进行了几项大规模研究，以评估气候变化的影响，但在各种全球变化表现下，我们对岩土基础设施的区域和结构规模绩效评估的了解状况存在明显差距。在这个项目中，我们关注多种危害，包括极端降水事件强度的增加、海平面上升和极端温度。预计这项研究的结果将加强我们对我国基础设施在最近气候趋势下的复原力和可靠性的了解。此外，这项研究将通过评估与气候变化相关的风险，加强目前对现有岩土基础设施的分析，以及未来岩土基础设施的设计和实施。在这一项目方面，一些教育和外联工作(包括新的学习工具)将纳入调查人员教授的本科生和研究生课程。这个项目也将为有志于追求科学和工程事业的学生提供以项目为基础的学习机会。这个奖项将提供一个定量的评估，以评估岩土基础设施在不断变化的气候下对极端事件的适应能力。该项目将解决以下研究问题：(I)气候变化的速度和变异性如何影响气候极端事件和自然灾害的重复间隔(2)在气候调整极端事件施加的热-水力-机械(THM)过程中，土壤行为如何变化(3)气候极端事件和自然灾害如何影响岩土结构的短期和长期行为。为了妥善解决这些问题，我们将通过三个主要任务来量化气候变化对控制区域和结构性极端反应的因素的影响：供应(例如，土壤的抗剪强度和压缩性)和需求(例如，由于极端气候和自然灾害对结构施加的载荷)。任务1将扩展非平稳极值分析(NEVA)，以获得气候变化下极值的重现区间。使用Neva将解决类似研究中的主要缺陷之一，这些研究忽略了气候变暖中极端事件的非平稳性。任务2将包括使用NEVA的输出来评估极端气候对土壤在多物理过程下的剪切强度和压缩性的影响。在任务3中，前两个任务的结果将被集成到一组数值和分析模型中，以模拟岩土结构的短期和长期行为。工作假设是，变饱和土中温度和土壤水分的变化将控制岩土基础设施中的力学行为和土-结构相互作用。研究目标是了解气候变化下极端事件对岩土基础设施的影响，并将这些影响纳入现有岩土基础设施的工程分析以及未来岩土基础设施的设计。为实现这一目标，本项目的研究目标是：1)在非等温条件下表征土体的压缩和抗剪强度；2)利用THM数值模型和分析模型，评估极端气候和自然灾害对关键岩土结构性态的影响。

This award funds a collaborative and interdisciplinary research project focused on quantitatively assessing the performance of critical geotechnical infrastructure (i.e., natural and engineered earth structures) to climatic extremes and natural hazards under current and changing climate. While several large-scale studies have been conducted to evaluate implications of climate change, there is a clear gap in the state of our knowledge on regional- and structural-scale performance assessment of geotechnical infrastructure under myriad manifestations of global change. In this project, we focus on multiple hazards including increased intensity of extreme precipitation events, sea-level rise, and temperature extremes. The outcome of this research is expected to enhance our understanding about the resilience and reliability of our infrastructure under recent climate trends. In addition, this research will enhance the current analysis of existing geotechnical infrastructure, as well as the design and implementation of future geotechnical infrastructure by assessing the risks associated with a changing climate. In connection with this project, a number of educational and outreach efforts (including new learning tools) will be integrated into undergraduate and graduate courses taught by the investigators. This project will also provide the opportunity of project-based learning for students interested in pursuing science and engineering careers.This award will provide a quantitative assessment of the resilience of geotechnical infrastructure to extreme events under a changing climate. The project will address the following research questions: (I) How does the rate and variability of a changing climate affect recurrence intervals of climatic extremes and natural hazards (2) How does soil behavior vary under thermo-hydro-mechanical (THM) processes imposed by climate-adjusted extremes (3) How do climate extremes and natural hazards affect the short-term and long-term behavior of geotechnical structures. To properly address these questions, we will quantify the impact of climate change on both factors governing regional and structural responses to extremes: supplies (e.g., shear strength and compressibility of soil) and demands (e.g., loadings imposed to the structure due to climate extremes and natural hazards) through three main Tasks. Task 1 will extend the Non-stationary Extreme Value Analysis (NEVA) to obtain recurrence intervals of extremes under climate change. Employing NEVA will address one of the main shortcomings in similar studies that ignore the non-stationary nature of extremes in a warming climate. Task 2 will include using NEVA outputs to assess the impacts of climate extremes on the shear strength and compressibility of soil under multi-physics processes. In Task 3, the results from the first two tasks will be integrated in a set of numerical and analytical models to simulate short-term and long-term behaviors of geotechnical structures. The working hypothesis is that variations in temperature and soil moisture in variably saturated soil will govern the mechanical behavior and soil-structure interaction in geotechnical infrastructure. The research goal is to understand the impacts of extreme events under a changing climate on geotechnical infrastructure, and incorporate these impacts into the engineering analysis of existing geotechnical infrastructure as well as the design of future geotechnical infrastructure. In pursuit of this goal, the research objectives of this project are to: 1) Characterize the compressibility and shear strength of soil under non-isothermal conditions, and 2) Evaluate the impacts of climate extremes and natural hazards on the behavior of critical geotechnical structures using coupled THM numerical and analytical models.