Abstract: Many of the natural hazards that threaten infrastructure and communities are driven by particulate interactions and particle kinematics. Land surface hazards like landslides and earthquake surface rupture occur in particulate systems of sands and rocks. Coastal scour and erosion occur one grain of sand at a time. Even wildfire spread into communities at the wildland urban interface occurs through the wind-driven flow of millions of discrete firebrand particles. This presentation will showcase how our research group represents various hazards as fundamentally discontinuous particulate systems using the discrete element method (DEM). DEM uses relatively simple contact physics to model how discrete particles interact and the motions of these particles resulting from their interactions. With the aid of modern high-performance computing systems, we model discontinuous systems composed of millions of discrete particles, including particles of irregular shape and size to elucidate how these factors affect the macroscopic properties traditionally used to characterize material behaviors in constitutive models. Our simulations show how with simple boundary conditions, we can replicate complex mechanics of landslide runout, shear rupture propagation through soil, and firebrand accumulation in simulations validated not only on laboratory experiments but also on observed case histories. Our virtual experiments advance the understanding of natural hazards in a broad range of fields including civil engineering, mechanics, geology, and seismology.

Contact: Silas Alben