NSF Award
2400391
Permafrost, the permanently frozen ground found in cold regions, is rapidly thawing due to climate change, posing significant risks to buildings, roads, and ecosystems in Arctic and sub-Arctic regions. Despite its importance, scientists still struggle to predict how permafrost will respond to warming temperatures over time. This research project aims to bridge that knowledge gap by examining permafrost at multiple scales - from tiny ice crystals to vast frozen landscapes. Using advanced imaging techniques, innovative laboratory experiments, and powerful computer simulations, the team will uncover how the internal structure of frozen soil influences its behavior as it thaws. The project will also engage students and the public through educational programs about permafrost in both southern states and alpine regions, helping to raise awareness about this critical but often overlooked component of our changing climate.<br/><br/>The specific goal of the research is to enhance our understanding of the temporal interactions between climatic temperatures and the physical processes that influence permafrost dynamics and stability. This project seeks to answer three fundamental questions: (1) How do microstructural features like grain size, ice content, and void structure affect permafrost's macroscale mechanical properties? (2) How do different environmental conditions (temperature, degree of saturation) and loading parameters (mechanical load, strain rate) affect the thermo-mechanical behavior of permafrost and frozen soil? (3) How do long-term climate changes impact permafrost stability and deformation? To address these questions, the research will employ a multiscale approach combining X-ray computed tomography (CT) scanning, geotechnical centrifuge testing, and integrated discrete element-finite element (DEM-FEM) modeling. CT scanning will provide detailed imaging and analysis of frozen soil microstructure. Geotechnical centrifuge testing at the Natural Hazard Engineering Research Infrastructure (NHERI) UC Davis Center for Geotechnical Modeling will simulate long-term climate change impacts on permafrost at an accelerated timescale. The coupled Discrete Element Modeling (DEM) and Finite Element Modeling (FEM) will bridge microscale and macroscale behaviors, integrating data from both imaging and physical experiments. This comprehensive approach will yield high-quality data for developing and validating multiscale numerical models to predict permafrost thaw trajectories and impacts on infrastructure in cold regions. The project will advance the knowledge base in frozen soil mechanics, physical modeling, and multiscale computational methods while training the next generation of researchers in cold region engineering.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
