David L George

D-Claw: a granular-fluid model for landslides, debris flows, and their interactions with water bodies

D-Claw is a depth-averaged, two-phase, mathematical model originally developed for dense granular flows, such as landslides and debris flows (Iverson & George, 2014). A key property of the model is the incorporation of granular dilatancy, which regulates the coupled evolution of solid-volume fractions and pore-fluid pressure, and thereby mediates flow resistance. Model properties were motivated by our desire to simulate landslide initiation and resolve the evolving downslope mobility based on theoretically quantifiable sediment material properties, rather than utilize artificial rheological rules that predetermine mobility and require unrealistic initial force balances. More recently, by utilizing D-Claw's solid-fluid evolution, we have extended it to hybrid problems that involve the interaction of granular material and water bodies (e.g., landslide-generated tsunamis, dam breaching and erosion).

D-Claw is implemented in the open-source software framework of Clawpack (clawpack.org), and employs algorithms that facilitate the computation of large-scale problems (e.g., AMR, dynamic DEM integration), similar to the related tsunami modeling software, GeoClaw (George, 2006). I will describe key aspects of the D-Claw mathematical model and present some recent hybrid applications that utilize the software for hazard assessment.