The project calls for a retaining wall to be built 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 does it need to be proof compacted? If it does, what percentage should it be compacted to?” 90%?
95% density unless your wall is very close to the building. If the wall is within 8’ of the building, I would use 98%.
“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?
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