CAREER: Coupled Hydrology and Mechanics of Fine-Grained Soils and Sedimentary Rocks

点击翻译按钮获取中文摘要

Fine-grained rocks (shale, mudstone) exist as caprocks, host rocks, and source rocks for a range of subsurface water, energy, and carbon resources. They also represent a control on carbon capture and storage, high-level radioactive waste storage, groundwater sources and storage and shale hydrocarbon extraction. Fine-grained soils play an equally important role in agriculture and soil carbon storage. This importance of clay-rich media derives largely from their distinct hydrologic and mechanical properties (ultra-low permeability, swelling-shrinking and cracking). These properties are of singular importance in controlling fluid flow in the subsurface (where fine-grained rocks constitute roughly two-thirds of the sedimentary rock mass), yet they remain a sparsely charted frontier research area in groundwater hydrology. This project will develop a general theory of the hydrologic properties of fine-grained soils and sedimentary rocks. This goal requires understanding the coupled hydrologic, mechanical, and chemical properties of porous media on multiple scales, from the nanometer scale (where aggregation and swelling of clay particles takes place) to the 10-100s of meters that control the bulk mechanical and flow properties of the rock. The proposed research relies on a combination of simulation methodologies adapted to each length scale of interest, along with rigorous experimental validations at each scale. Key projected outcomes include detailed fundamental understanding of the meso- and nanoscale properties of fine-grained media and new constitutive relations describing the coupled hydrologic-mechanical-chemical properties of these media. The major education and outreach goal is to develop the use of molecular dynamics simulations as a pedagogical tool that can illustrate the fundamental basis of important scientific concepts and phenomena in an intuitive, and hands-on manner. This tool will be developed for both first year of the Environmental Engineering undergraduate curriculum and as part of a web-based interface (a Science Gateway) that will enable the broader community (e.g., high school students and teachers) to visualize and explore simulation results stored on the high-performance data storage systems at the National Energy Research Scientific Computing Center (NERSC).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.