Getch and Gravel for a Road Bed

Try digging out to 15" depth lay a 6" gravel bed then fill with you gretch and a 3" gavel topping compacted over the fill. If it should happen to rain the top gravel will prevent the gretch washing out; the under layer provides the drainage. The gretch just adds bulk and prevents the gravel rutting up too quickly.

There is the old MacAdam road fill method, from when came tarred MacAdam = tarmac

In essence it is a graded mixture of assorted gravel, crushed gravel and grit that is screened into sizes for the optimal filled space for the mixture.

Concrete is made the same way to get max strength and minumum use of cement.

Look at a few of these sites, they may give you some ideas.

http://www.google.com/search?hl=en&q=%22MacAdam+road+%22&btnG=Search

try adding some ash to the gravel mix it will provide a binder to hold the gravel tighter and slow the loss of rock into the earth below. good luck.