Retaining Wall

[daviv]

The project calls for a retaining wall to be build around a building (See detail). The contractor will remove the concrete pavement and excavate to the sub-grade. The question is "can the retaining wall be poured on the undisturbed sub grade or it needs to be proof compacted. If it does, what percentage should it be compacted to? 90%?

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1550261070/tips/Wall_Details_fb5pfe.pdf[/url]

 

[bridgebuster]

If it’s truly undisturbed, no compaction necessary. Although you’ll still need to touch things up a bit. If you need to compact go to 95% density.

 

[Ron247]

I agree with the 95% density unless your wall is real close to the building. If the wall is within 8' of the building, I would use 98%.

What is "Warning Fabric"? I have never heard that term. Any particular reason your foundation does not have a "toe" extending out?

 

[daviv]

Ron,

This is a design from the consultant so I will have ask about the toe and warning fabric. So do you also agree that if it is undisturbed, no compaction is necessary?

 

[SlideRuleEra]

The contractor will remove the concrete pavement and excavate to the sub-grade.

Don't expect the sub-grade to be undisturbed, typical excavation is not that precise. Compact it.

Agree with Ron247, overall proportions of the retaining wall are questionable for the portion that is 6' high. Specifically, check it for overturning.

http://www.SlideRuleEra.net

 

[PEinc]

I would compact it also. Just because it is "undisturbed" doesn't mean it is not loose or won't consolidate when the fill is placed behind the wall.

http://www.PeirceEngineering.com

 

[Ron247]

Not disturbed is not enough for me to say 'No problem'. In most instances, not disturbed we talk about is the ground has not been disturbed in 2,000 years. They did uncontrolled fill 25 years ago is not the same thing. That is when living somewhere for 30 years is an advantage. I remember 15 years ago when this was Mr. Gilmore's hog farm. Since then, they dumped the 8' of soil they excavated from the Mall project and compacted it with a roller compacted after all of it was in place. Get the picture?