Buried Blocks Retaining Wall Question

[suaf]

I need to build a retaining wall only abut 12 inches high about 6 feet out from my foundation. I have read in an article that you should start the first layer of blocks about 2/3 buried under the top soil. However, it did not say why and I have yet to understand why it is a necessary staep. My wall will only be a max of 2 blocks tall. The only reason I can think of is that it may help stabilize the wall, but it still doesn't make sense. It seems the only part stabilized would be the part below ground (the 1st layer)?? So is it simply for aesthetics or is there a structural purpose to doing this. Also, the area to build mine is flat already so I may need to tap the soil a bit to keep the wall straight but otherwise its a flat surface to begin with. Perhaps that is why they say to dig also...in order to create a flat surface??? Answers will be much appreciated...Thanks!

 

[rgt10]

Hi Suaf,

I will try and help you a bit. IF after building the wall, you are going to be putting any kind of granular fill in back of it, ie: dirt, sand, gravel, then you will need to bury the first course of block as you stated in your post. If you are just building it as a decorative seperation wall, with no fill behind, then there is no need to bury the block.

Roger

 

[suaf]

Thanks

Thanks Roger, I will be putting in about 6 inches of soil behind the wall, but I still don't understand how burying the first block keeps the wall more stable?

 

[rgt10]

Hi,

Think of packing a garbage bag. As you push more fill into it the sides balloon out. The same thing will happen with retaining walls if there is no "toe" to the first course. Probably wont happen with only 6" of soil, but if it was a taller wall, the bottom of the wall would push out over time.

Roger