Article ID Journal Published Year Pages File Type
4577070 Journal of Hydrology 2012 6 Pages PDF
Abstract

SummaryClay rock formations, and compacted clay (e.g., bentonite) used as backfill within disposal drifts, have been considered as natural and engineered barriers, respectively, for isolating high-level nuclear wastes in mined geologic repositories. Accurately modeling unsaturated flow in those clay materials is important for assessing the performance of a geological repository. While the non-Darcian behavior of water flow in clay materials has been demonstrated in the literature, a systematic study of modeling unsaturated non-Darcian flow is still lacking. Based on a hypothesis that pore water in clay becomes non-Newtonian as a result of water–clay interaction, we propose new constitutive relationships for unsaturated flow, including a relationship between water flux and hydraulic gradient and those among capillary pressure, water saturation, and hydraulic conductivity. An evaluation based on a set of laboratory experimental observations supports the usefulness of the proposed relationships. More experimental studies are desirable for further confirming the non-Newtonian water flow behavior in clay materials and evaluating the proposed relationships.

► Pore water in clay may become non-Newtonian as a result of water–clay interaction. ► We propose constitutive relationships for unsaturated flow of non-Newtonian fluids. ► Experimental observations support the usefulness of our results.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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