3D Runout Analysis

DAN3D is a Windows-based program for the dynamic analysis of rapid flow slides, debris flows and avalanches over three-dimensional terrain, based on the numerical model developped by McDougall and Hungr (2004, 2005).

A depth-averaged Lagrangian solution is implemented using meshless smooth particles hydrodynamics.

The software accepts as input the 3D path and initial sliding mass topographies, as well as the optional distribution of erodible materials throughout the topography. Materials are based on five different rheologies: frictional, plastic, Newtonian, Bingham and Voellmy.

The slide mass is animated on the screen as the numerical simulation progresses.

Data input

• Streamlined problem setup
• Slope path and sliding mass input as ASCII grid files (.dat)
• Up to 20 materials along slide path
• Choice of 5 material rheologies (Frictional, Plastic, Newtonian, Bingham, Voellmy)

Analysis

• On-screen animation of the slide’s thickness, velocity or volume
• Entrainment of material along bed surface (erosion and deposition)
• Erosion thickness and impact area plots

Data output

• Slide location, velocity and volume statistics
• Export profile and velocity plots compatible with Grapher and Excel

Equivalent fluid

DAN3D uses the "equivalent fluid,“ depth-averaging approach, as described by Hungr (1995). The flowing mass of the landslide is simulated as a mass of simple fluid which is always frictional internally, but with a basal flow resistance developed according to one of several alternative rheological models.

Back-analysis

The rheological properties of the "equivalent fluid" must be determined by back-analysis of real landslide precedents. Back-analysis involves the assessment of the model’s performance in terms of runout distance, length of deposit, deposit thickness distribution, flow duration and distribution of flow velocities, where known in the field, as described in Hungr (1996).

Shallow flow

DAN3D is based on shallow flow assumptions and is best suited to shallow mass movements, where the flow thickness is at least an order of magnitude less than the length of the moving mass and the movement vectors are approximately parallel with the bed.