Has anyone looked into using Fly Ash from power plants to stabilise the soil. There was a study by NDSU at Carrington that was using fly ash in a feedlot to help with the mud. I'm not sure if it would suit your situation or what the cost would be but it seemed to make the soil more stable.

Links to the project-

http://www.ag.ndsu.edu/pubs/ansci/beef/as1258.pdf

http://www.ag.ndsu.nodak.edu/carringt/bison/Fly%20Ash%2002.htm