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

University Of California-Irvine, Irvine CA

Investigators

Abstract

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.