Nice!
I'd be curious, but don't understand the math and physics involved at how much outward pressure some stacked blocks could withstand. If I were to use them as swimming pond walls for, I dunno, 15' x 25' x 10' deep would I need to back fill to keep them standing? I think back filling would be acceptable if kept below the water surface for plants and junk on the outside of the swimming portion.
Wet dirt is heavier than water. I expect walls to buckle over time.
A house basement ithstands pressure from outside for a few reasons:
It isn't real tall, typically less than 8'.
It has a concrete floor poured between the walls preventing soil pressure from buckling the walls at bottom where pressure is greatest.
The wooden floor structure is bolted to the top of the foundation wall, helping to support from the top.
Dirt is usually not as tall as the wall.
Poured concrete foundations include steel & have some strength.
Dirt weighs approximately 100 LBS per cubic feet, wet dirt more, it's more plastic. Ten feet down, that is more than 1000 PSF against the bottom of your wall. Water weighs about 55 LBS per cubic foot. Ten feet down pressure is 550 PSF. That's about 450 PSF differential pushing on every square foot of surface That's 5400 pounds force against each mafia block.
A small enough structure would gain strength from the corners. Long, tall walls won't do as well.
Wet dirt one side, water on the other, these blocks displace water, about 1700 LBS per block. Under water they don't weigh as much, only about half as much as they do in air.
