Best way to compact soil under a slab overhang

"MiamiCuse" wrote in news:8J-dnaGmyLYl6aTWnZ2dnUVZ snipped-for-privacy@dsli.com:

In other apps I'll often toss some in then soak with water. When it goes down, add more and repeat. Bit late now for that for you and probably not practical in your case.

Water. Wet the sand and tamp it in. flow more sand in and wet it. Pack it and let it dry. If it settles, put some more "slurry" in and let it settle. Then pour your concrete over it. The watering will wash sand down into the gravel below too, so it won't sift down later.

"MiamiCuse" wrote in news:8J-dnaGmyLYl6aTWnZ2dnUVZ snipped-for-privacy@dsli.com:

Use a low strength concrete wet mix - about a third to a quarter as much cement powder as when you want a proper strong mix. Pour it or shovel it in. It won't shrink at all but it can settle if you don't work it a bit into the cracks and crevices or prevent it from sloughing out the front opening.

Concrete yards know this as a "six sack mix". You can get it with sand or fine gravel aggregate. I've used it often to fill undermined slabs even in structural settings (even driveway ramps in gas stations).

-Zz