Séminaire de Ian C. Bourg (Princeton University) :
Clay, water, and salt : hydro-chemo-mechanical coupling in fine-grained soils and sedimentary rocks
le vendredi 26 avril 2019 à 10h, salle 101, couloir 32-42, 1er étage (salle des conseils de l’UFR de chimie).
Résumé
A recurrent theme in the use of the subsurface for water, energy, or carbon mitigation is the importance of fine-grained (clay-rich) soils and sedimentary rocks. Fine-grained rocks (shale, mudstone) are used as caprocks, host rocks, and source rocks in a range of low-carbon energy technologies including carbon capture and storage, high-level radioactive waste storage, and shale hydrocarbon extraction. Fine-grained soils play an equally outsized role in agriculture and soil carbon storage. This importance ofclay-rich media derives largely from their distinct hydrologic and mechanical properties (ultra-low permeability, swelling-shrinking and cracking). Here, we review existing data on the hydrologic and mechanical properties of fined grained soils and sedimentary rocks. We show that these properties are controlled by chemo-mechanical-chemical couplings at two key scales : a nanoscale defined by the aggregation and swelling of clay (nano)particles and a mesoscale defined by the assemblage of larger grains. We present recent advances in modeling the distinct properties of clay-rich media on these two length scales using molecular dynamics (MD) and computational fluid dynamics (CFD) simulations.
