This is a rebuild of an particle erosion file I did two years ago in Houdini. It has particles affecting geometry based on an erosion and depositing principle. In the end it is simply displacing the surface in the surface normal based on the particle attributes.
The cool thing is that the particles start to carve out paths in the geometry because of the feedback between the particles and the surface.
Sopsolver for deformation, popsolver for particles.
The file can be found here: