earthbags as retaining walls on a slope

Hi,
I'm building a small Oehler style greenhouse into a 1:3 slope and intending to use bags to hold back earth on the downward sides (both south and west slope away).  Am I right in thinking that the lateral force against these walls will be quite small as the soil and water will want to push down the slope?  It's sand and sandstone below a spades depth of topsoil and the bags are being filled with the sand and smaller stones.  It will be about 5 ft deep to support and have visqueen covering over the bags.
Thanks

Hi Steve --
We've built a few such farm buildings on our similarly steep multi-angled sloped site using earth bags over a foundation layer of a few cement bags in place. No problems structurally -- however, be careful with surface water making sure to channel it away from the upper areas of the structure. We had a 16" cyclone hit soon after build and **thank goodness** we had first started with a French drain (a.k.a. mini swale) to channel water into a moat used for animal watering.... WHEW! SO -- poultry, swine, feed stores, and sprouting areas are in tact, have survived trials and tribulations, and remain in fine form (exactly as you mention!)
Good luck with your build!
Deo, P.E.

Be sure to use a plumb bob so your wall is set correctly for the slope.
You also want to have a "footing", at least one bag deep below the current soil surface (similar to a house foundation) so the wall is anchored and thus won't slip down the hill from the forces of gravity.
Steeper slopes do require a set back for every layer but I don't think yours will encounter those forces enough to worry about that sort of failure over time.  

Steve Mitchell wrote:Hi,
I'm building a small Oehler style greenhouse into a 1:3 slope and intending to use bags to hold back earth on the downward sides (both south and west slope away).  Am I right in thinking that the lateral force against these walls will be quite small as the soil and water will want to push down the slope?  It's sand and sandstone below a spades depth of topsoil and the bags are being filled with the sand and smaller stones.  It will be about 5 ft deep to support and have visqueen covering over the bags.
Thanks

I would say that your plan sounds good. Sand drains very well so the hydrostatic pressure will not have a chance build up much, and sandstone is stable in its own right. If it is practical, I would incline the bag wall a bit into the berm to help with stability.

Thanks all for the responses.  It's always good to have a sanity check from folks that know their stuff!  Good luck with the book Kelly.
Now, only a few more tons to shovel, sieve, bag....