One possibility for raising soil and other types of fill material higher on walls is with an auger. The photo above shows a grain auger, which may or may not be sufficiently robust for augering moist, heavy soil, but you can see the general concept. This idea may only be worthwhile on large projects and/or projects with tall walls/second stories. The basic idea is simple – dump the material into a hopper and a screw forces it up the auger. You’d have to experiment to work out the details. I know it’s possible because rammed earth builders use similar equipment, which you may be able to rent. Please let us know if you try this and report your results.
Image source: Kimball Sales Company