Warren Lecture with Kimberly Hill

"'Granular Mud' in Natural and Human Infrastructure Materials" with Kimberly Hill

Kimberly Hill
Civil, Environmental, and Geo- Engineering, University of Minnesota
"'Granular Mud' in Natural and Human Infrastructure Materials"

ABSTRACT: “Granular mud,” i.e., mixtures of particles and viscous-like fluids are ubiquitous in natural and man-made systems, from muddy geophysical flows to hot mixed asphalt and concrete. As we strive toward a “greener economy,” predicting their behaviors in asphalt compaction toward efficient processing becomes increasingly important given the wide-spread use of asphalt in our roadways. At the same time, and at a much greater scale, predicting behaviors of this granular mud in the form of rocky/muddy geophysical flows (debris flows) would help with hazard mitigation, particularly critical in the face of their increasing frequency and intensity under recent higher intensity storms. While we don’t typically think of such vastly different materials in the same context, we have found that considering them in a similar multiscale framework sheds light on both problems. 

Hill first presents these issues in the context of hot mixed asphalt compaction, particularly in mixture design toward increasing compaction efficiency. Likely because of the wide range of particle sizes, we find that a simple single phase model is not effective in capturing the mechanistic influence of specific components. However, when we model the particle dynamics specifically at two different scales using our new two-scale discrete (or distinct) element method approach we capture changes of the compaction efficiency to material additives and grain size distributions. At the same time, because of the nature of the DEM approach in representing the motion of and forces on individual particles, the model provides intuition on the mechanics involved. Hill ends with a brief discussion of her research team's ongoing experimental and field research in which they have begun to apply this approach to understand behaviors of debris flows (large rocky/muddy flows in steep regions) and various channelization signatures on alluvial fans.  

Start date
Friday, Sept. 17, 2021, 10:10 a.m.
End date
Friday, Sept. 17, 2021, 11:15 a.m.
Location

(Recording not available)

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