There is a ton of geotechnical simulation software out there. However, only a small fraction is suitable for rockfall simulations. We have to remember that rockfall simulation software does not mean rock slope stability simulation. Unlike other software lists I provide, this one is not limited to open-source software.
If nothing works for us, then we should have a look at DEM software and build it ourselves. The DEM approach has the advantage that we can model all mitigation structures as well. I general it is questionable to use 2D rockfall simulations because we decide the rockfall path along an axis by selecting a profile of a slope. This is not acceptable with today’s computational power.