boulders during dig

Hi folks,

Im doing a totally DIY freeform steel wall pool with an 8 foot deep end, 9radius sloping to 5 foot radius at the bottom. On the deep end, i had to remove several very large sand stone rocks from my heavy clay soil that were simply too thick to break. Most of the wall looks pretty good and shelf integrity is good. But where i pulled out the big rocks (20 x30 inch) sized rocks there are sunken in cavities where the rocks once rested.

My question is how to bring those cavities back up to wall? Is it ok to Use existing clay soil, wet it a bit and tamp it in? Or maybe tamped 2RC or washed 2B? Concrete maybe? or is it ok to go heavy on the pool base?

Any help is appreciated and thank you!
 

jamjam

Well-known member
Jun 25, 2020
637
NY
Pool Size
25000
Surface
Vinyl
Chlorine
Salt Water Generator
not an expert but I would think if you did 2 inch lifts of crushed stone tamped between layers you should be good. you could probably get away with tamping the clay really well but crushed stone will assure you it won’t settle. Are the voids in the middle or close to the sides?
 
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thanks for the reply! Voids are in the sloping wall of the deep end. Ive pick mattocked my way to the proper slope and it looks great except where those boulders were. My thought was a washed stone base then something like 2RC tamped well on top, but needed someone else to say something similar...thanks again.
 

Brianf60

Well-known member
May 18, 2017
186
Bradford ontario
Flowable fill would be a choice. Basically weak concrete used to fill things like this. It won't settle. The other option would be excavate the whole depth to the lowest point and build up with gravel from there.
 
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jimmythegreek

TFP Expert
Bronze Supporter
In The Industry
Aug 10, 2017
3,796
Morris Cnty NJ
Flowable fill wont work on a slope. I use dry mixed concrete for sloped shaping. 50# bags are easy to put in pool and I just throw plywood down and open bag and flip with shovel and a hose just making it sticky, not wet. Fling it in and shape it up. Poolcrete will hide it all. Never use soil for fill inside a pool, either clean 3/4 gravel or road base if you can tamp it mechanically
 
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Flowable.fill wont work on a slope. I use dry mixed concrete for sloped shaping. 50# bags are easy to out in pool amd I just throw plywood down amd open bag amd flip with shovel and a hose just making it sticky, not wet. Fling it in amd shape it up. Poolcrete will hide it all. Never use soil for fill inside a pool, either clean 3/4 gravel or road base of you can tamp it mechanically

That's a good idea, thank you... Havent gotten to dealing with patching the holes yet as im flying solo on this right now and turned my attention to leveling and plumbing the steel walls and running the main drains plumbing so i can get the collar poured..this sounds like a simple and quick solution once i circle back to it...rain on monday, gonna have to tarp the deep end so i dont lose a week to the weather, maybe a good job to do while hiding under the tarp. PS and my poor case 580, got a knock the other day, and it's a bearing. nothing seized though. this project did a number on her, but ill drop the pan and get er back in shape.
 
Hi there, @Pittdave79. I'd love to see some pictures of your patched up pool bottom if you have any available.

I looked and all i have are some pre patch pics and post vermiculite. What i ended up doing was using my own formula of 1b limestone, clay, and 4000 psi sacks of concrete mixed together with some water, and kept a very light mist on the sidewalls while applying. I really packed the stuff in there, wore double leathered gloves and just went at it then shaped it to spec using a 2x i cut to length from the bottom radius to the bottom wall radius.

I have to do some touch up vermiculite work before i drop the liner to smooth out some lumps on the slope, but im pretty pleased otherwise.
 
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