Photobucket

Author Topic: Earthbag Retaining Wall  (Read 4553 times)

Offline Insidious

  • Senior Survivalist
  • ****
  • Posts: 277
  • Karma: 22
Earthbag Retaining Wall
« on: December 27, 2010, 09:02:05 PM »
Hi everyone!

I've been thinking about building some earthbag retaining walls to terrace my property and was wondering if anyone had any practical experience or info sources.

I have the book 'Ceramic Houses and Earth Architecture' and 'Eathbag Building' and have searched EarthbagBuilding.com and CalEarth.org without success. They mention retaining walls in passing but don't get into specifics.

My thought right now is to use one of the designs in 'Builders Guid to Drainage and Retaining Walls' for Concrete Block and substitute continuos earthbag tubes for the runs of block. I'd rather avoid stabilized earth for cost and flexibility reasons (if you want to turn the wall back into dirt, its a lot easier if its not mixed with concrete.

One of the other things I've been wondering about is root penetration from the trees growing on the slope above the wall. Are root barriers needed to protect the bags?

Any thoughts would be greatly appreciated.
An ounce of action is worth a ton of theory.

Please disagree, I learn more that way.

Offline monger20

  • Prepper
  • **
  • Posts: 52
  • Karma: 2
Re: Earthbag Retaining Wall
« Reply #1 on: December 27, 2010, 09:54:50 PM »
Wow, Insidious. Hitting the boards hard for a new guy. +1

I am a structural engineer in central CO & I have used many things to retain the rockies but never earthbags.

I am unfamiliar with the book you referenced & would need to see the type of wall your considering to construct. I would be more than happy the review your situation if you contact me personally. Lability sucks and in my world there is never a cover all situation.

Drainage is paramount. Hydrostatic pressure is an exponential function with height.

My first response would be to treat earthbags like a 'crib' retaining wall.
not a 'cantilevered' retaining wall.  
A house is not a home unless it contains food and fire for the mind as well as the body.

Offline Insidious

  • Senior Survivalist
  • ****
  • Posts: 277
  • Karma: 22
Re: Earthbag Retaining Wall
« Reply #2 on: December 27, 2010, 11:32:58 PM »
Thx monger! =) Its all that slack time between the holidays.


None of the walls I'm building will exceed 4' in height to avoid permitting requirements. Originally I was planning on cantelivered concrete/rebar, then started looking into gabions. Decided against them as I don't have a lot of loose stone (would need to be brought in) and increased wall thickness (wasted space).

A crib wall seems like it might be overkill for the height. I was thinking gravel fill behind the wall with subsoil drainage (daylighting the drain pipe is easy, nothings flat), with my only concern being the compression pushing the wall out of plumb over time. On the plus side, I'm not planning on any of the walls being straight, they'll all have slight curves into the hillside.

The crib wall design, particularly the angled concrete foundation is interesting. I thought it might be enough to just step the bags slightly (1/2-1 inch per row).

I completely understand the answer 'it depends..'
An ounce of action is worth a ton of theory.

Please disagree, I learn more that way.

Offline monger20

  • Prepper
  • **
  • Posts: 52
  • Karma: 2
Re: Earthbag Retaining Wall
« Reply #3 on: December 28, 2010, 08:00:15 PM »
Insidious

Retaining anything under 4' shouldn't be a problem with your proposed plan. The more curves you put in the wall the better. And if you are going to finish the face I would recommend strategic 'headers'. A partial crib so to speak, this will help with your pushing concern. If you leave the bags as your exposed face you should have a problem but I have a feeling they are going to move for the first year or two.

The crib wall digram I posted is designed for much larger retaining situations. I'm sure you have seen the railroad tie version around.
A house is not a home unless it contains food and fire for the mind as well as the body.

Offline dukejer

  • Prepper
  • **
  • Posts: 73
  • Karma: 6
Re: Earthbag Retaining Wall
« Reply #4 on: December 30, 2010, 02:44:23 PM »
How about creating and using compressed earth blocks, CEBs.  It could be less work using local soil and I think you can build a small manual press to make the bricks.  I have never built a CEB but I think they can be bonded with the a slurry using the same material that was used to create the bricks.

Here are some plans for building a manual compressed earth press called a CINVA Ram.  http://www.windward.org/notes/notes67/walt6720.htm

Here is a bigger automated machine with Open Source Plans a group made that creates 16 bricks a minute.

http://www.youtube.com/watch?v=nV_-ZzYmo3A#

- DukeJer

Offline EarthbagDude

  • Prepper
  • **
  • Posts: 53
  • Karma: 0
  • Husband Father Prepper Natural Builder Beer-Lover
    • My Earthbag Blog
Re: Earthbag Retaining Wall
« Reply #5 on: June 08, 2011, 03:08:18 PM »
Duke,
   CEB's can't stand up to rain, unless they're cemented over, or if they have a good overhang.  Which isn't really normal for a retaining wall, but hey you could if you like.
   As for earthbags for a retaining wall, it's the same as CEB's.  If you cement over, great.  If you earth plaster over it, it won't work normally.  If you create a great earthen plaster (after experimenting) mayyyybe you could get it to withstand the elements for a few years, depending on your climate....
    Depending on the angle the bags lay, would determine what would be the best solution.  If you have a straight wall, they would stand up for a long time if you don't have sideways rain often (if the bags were tamped well and cured well).  I did a garden bed this way, and learned the hard way that earthen plasters don't work outside without a sufficient 'hat' and 'boots'. 
    Hope that helps, I can give more advice if you like!