Am I too close to the edge of my excavation?

[AK-]

What the retaining wall will do is prevent the soil from washing out from below the pool. It won’t help with lose dirt settling.

The question you should ask yourself is how comfortable do you feel about the filled area.
We can give you some advice and share some concerns, but the ultimate decision is yours to make.
My pool was built pretty much in the opposite of what is recommended, but I felt comfortable with what I was doing.

 

[Mdragger88]

It’s definitely too close- there’s supposed to be at least a foot of leveled ground all the way around the pool. I am no retaining wall engineer but the way it stands now you are risking the integrity of the pool with the 1st rain.

 

[Toxophilite]

If you are going to fence, could you not just cut into the hill till the other side is near ground level and hanging side would now be below slope level? A slope is always going to have the potential for wash-out/slide, but virgin, unexposed, soil will be much more reliably stable. You could then backfill around to the natural slope of hill for run-off.

 

[Nofronts]

One thing that I didn't mention was that after the excavation the excavator did go over and compacted the whole area with a piece of equipment. So the ground was packed down before the pool was put up. I know it will settle more but this should have helped?

 

[Toxophilite]

One thing that I didn't mention was that after the excavation the excavator did go over and compacted the whole area with a piece of equipment. So the ground was packed down before the pool was put up. I know it will settle more but this should have helped?

It most certainly probably did help with compaction. From looking at the picture, what I would more want to know about is did the natural slope of the hill get enhanced. IOW, it is very hard to cheat mother nature. That hill formed, and still forming over very, very, long timeframe, from natural forces. Any time there's a raised issue on a slope, it stand very little chance of survival to the same forces in the sort term. Anything below the natural slope is greatly protected from surface changes.

 

[JamesW]

This will probably begin to sink immediately.

Can you dig down to solid undisturbed ground?

You can't really build up without doing it correctly with the right materials, good compaction, a wide margin away from the pool and probably a retaining wall.

 

[kimkats]

That raised are is an accident waiting to happen I am sorry to say. You need to go down to raw dirt NOT raise up. There will THOUSHANDS of pounds of water on that soft dirt that will go squish

 

[Toxophilite]

There might be the impression that a lost pool and water down a hill is cost of risk. It's not. If your family and friends are in that pool and the wall caves without warning, tonnage of water will be carrying them and crushing them against sharp metal, easily leading to folks being stitched up, spinal injuries, or even death. It happens all the time. A few more feet in the ground would ensure nothing, and no person's safety, is dependent on the integrity of a formed ledge over a hill.

 

[Newdude]

There will THOUSHANDS of pounds of water on that soft dirt that will go squish

142,817.9 lbs for a 27ft round with 4 ft of water, with said weight sloshing around from VIPs having a good time in the pool.

 

[Toxophilite]

Having to take back down to scratch must be some right of passage for AB pool owners. Common enough. My first was just finished filling and out of level just enough to aggravate the eye. After much internal debate, it came back down for another try. If this one were mine, I could call a landscaping contractor and 6 men with shovels and wheel borrows would show up. Within a few hours they would have hand dug that hole a few feet deeper, keeping the circle circumference, and down to a perfectly level bottom.

 

[Casey]

What I want to know is, who lives below you? If no one, proceed, but if you have a neighbors, I would hire an excavator and dig more dirt out , especially if you own more of that land and push it down towards the property line and tier the yard closest to the house n trees.

 

[merc123]

I'm not an expert or soil engineer but I had top soil brought in and filled an area with about 3' to level off the spot. It had quite a bit of clay. My prep for it was to spray water on it and run back and forth with my tractor until it didn't leave tire marks. I did this for a few days and kept saturating the area with water. Then I covered over it with plastic and rocks to help with washout. I did this in May 2020 and it's still holding and still level. No apparent settling of the legs.

I do want to point out when I buried the plumbing I had to use the backhoe because the clay was so hard you couldn't shovel it. I also made sure I had 8-12" of stand off from the legs so they aren't right on the edge. Yours seem pretty close and I'd be concerned.

Here's my build.

18x48 Coleman Vista 2 Build - Doing (most) everything wrong

This is my first time doing an AGP and it seems I've done alot wrong, but time will tell for sure! :) 1st thing that we did wrong was we built up instead of down. We built up ALOT. I brought in fill dirt and topsoil (another no-no) and we put around 1.5 tandem loads of dirt into the area. I...

www.troublefreepool.com

 

[phonedave]

You all know I need to chime in here in order to dispel some soils myths:

1) I am (or to be more accurate) was a soils engineer. BS and MS in Civil Engineering, concentration in soils, and ground modification. Worked as a geotechnical engineer when I first got of out college. Don't do that now, but that is how life goes. It's like the guy in Margin Call who was a NASA propulsion engineer but is now a financial risk assessor "it's all just adding up numbers. Just what you are adding up is different"
2) Without performing an analysis of the soil(s) in question the best anybody is doing is guessing. Soil is a natural material. The word "clay" especially in the parlance used here, can mean dozens of things, all with wildly different characteristics. You would not go to an auto parts store and ask for brake pads for "car" or even for a "Ford" you need a specific make, model, and year. Saying you have "clay" is like buying brakes for a "car"
3) The greatest single factor when it comes to compaction of soils is moisture content. If you don't have you soil at the right moisture content you can compact it with whatever you choose, for as long as you want, and guess what, once it dries out or gets wet and gets to that optimum moisture content, it will settle some more. Optimum moisture content is not "I sprayed it real good with a hose". You need to run tests on your soil to determine the optimum moisture content.
4) As I said in #3, moisture content matters, you cannot drive a heavy truck on it, track it in real good, or rent the largest vibratory plate that Home Depot has. There are different types of compactors for different types of soil, for silty clays, or clayey silts, or clays, or silts or organic clays or whatever it is you have, a vibratory plate can do more harm than good.
5) A pool is a horrible thing to build a foundation for. It is a giant, very heavy, unstable bag of water. Aside from the balanced static loading of the wall, there is no structural support for that bag of water that is your pool. Once it gets out of level, it is going to continue to push in that direction as it gets more out of level. An ABG is an unstable system, if you push it to the side, it does not move back to center - it keeps going to the side.
6) Designing a retaining wall to hold back serious loads also requires a solid design. Not just a "lets stack this up and add some tiebacks, that will be good" attitude.

A word on stone dust and QP (and other quarry products). They are usually graded to certain standards, and so you can make assumptions about their compaction curves. QP is especially forgiving with very flat proctor curves, so it is easy to get it to a good compaction percent. But again, for things like a pool foundation, you need to get somebody who knows what they are doing.

Also, when it comes to how water flows through soils and what sort of uplift or heave it causes, that is a whole soil mechanics course on just that subject. Not that it is likely to happen in your pool foundation, but if you get enough rain moving through the soil, it is not just washing away of soils, but also soil liquefaction that can occur.