Dangers of jetting "compaction" 2

[oldestguy]

I need some technical publication articles, papers, etc. citing problems with jetting new fill in attached garages. I have exhausted many attempts to find such articles in ASCE and other sources. Purpose is to show my neighbor builder it is very dangerous. He has built many a house and regularly jets the loose fill in the attached garages with no problems YET.. My reason is some years ago a similar contractor had his basement wall cave into the house basement causing such damage that the whole house had to be demolished. Since this is near me and the 66 year old builder probably won't listen to my verbal advice and it is for his retirement house. He thinks two horizontal re-bars in a 7-1/2" thick basement wall poured and still in below freezing weather is OK. One can have good luck on many previous houses built, but this sure looks bad. Plan is to jet in the Spring under a completed house. Yikes!!!

 

[epoxybot]

This really doesn't directly address your quest but it does provide a lot of food for thought.
Link

 

[oldestguy]

Thanks. I'm near their campus and it probably is too late, but I'd ask a question. Measure lateral pressure from the sand when saturated. I find it strange that this topic has not been published as a study. Perhaps because most engineers shy away from treatments like this knowing the dangers. Been thinking. I'll ask for permission to photograph all of his house from outside when I hear he about to jet. Seems pretty intelligent and if he asks why, it will to get the before condition on record for his insurance com0pany. Both the before and after shots will be free.

 

[epoxybot]

That is what I thought you were concerned about. Especially if the surrounding soil is clayey/silty, both the vertical & horizontal hydraulic gradient could degrade rather quickly. Throw in too many fines, that migrate to the surface during jetting and restrict draw down, like a finger on a straw, filled with water; it is easy to see how one might run into trouble, even though they had done jetting many times before.

I wonder if the DNR uses the percolation tests they get from property owners to build a generalized map of soil permeability for given areas.

 

[dhengr]

Oldestguy:
You’ve put your finger on an/the age-old problem facing thinking engineers. The contractor doesn’t really want to hear what you think, he wants you to bless what he’s done or wants to do. You can’t find an irrefutable answer/explanation for him, under all conditions, but your gut or judgement tells you something might happen under the right/wrong conditions, and he doesn’t want to hear it. He should get the local bishop to bless things, that’s what they do, with no technical knowledge, and you should worry less and enjoy your retirement. The problem may not happen at all, and then you’ve wasted your time and breath, for no pay, and if something does go wrong that will be a far greater teacher than all your verbiage. I’d tell him once, and if he doesn’t want to listen to the potential problems, forget it.

 

[cvg]

https://wisconsindot.gov/documents2/research/WisDOT-WHRP-project-0092-11-03-brief1.pdf

 

[BigH]

I've used jetting before behind a major retaining wall along a mass transit depressed section. However! We used clean river sand AND the water had somewhere to drain at the base of the fill - and drain quickly without build-up. In other words as the water was poured into the river sand backfill, the permeability was great enough that the water drained just as fast. Seems to have worked out - this was something like 35 years ago and haven't heard of any issues.

 

[oldestguy]

Update. So far it appears this builder will not do any jetting. BigH no drainage at all, other than maybe soaking down, but it is unlikely that is anywhere near suitable and no sideways drainage. I bought up a few things that would happen should there be s failure. No insurance will cover when they bring in an expert. (I won't testify). Next, wife will either kill him or divorce. Being that he is Norwegian extraction and I'm Swede and I communicate with a Swede every Sunday via ham radio, the word will soon be all over Europe. A real true Norske joke this would be. I think that last one will be the straw breaking the camel's back. Last I heard, no jetting.