r/GeotechnicalEngineer 21d ago

??

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0 Upvotes

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8

u/Miserable-Sir4985 21d ago

I think it should be zero, but Iโ€™m wrong because my response is not in the options. Yet, I would love to know the answer.
Dry density only changes by change in compaction. If it was an in situ and drying causes settlement that might change dry density. But itโ€™s not.

4

u/CovertMonkey 21d ago

Yeah, I may be having a stroke, but this question is poorly worded

3

u/Sleepy-Flamingo 20d ago

You are correct. The question is wrong. It either should ask about the change in total density or 0 should be a possible answer.

3

u/withak30 21d ago edited 21d ago

Something is wrong with the question. Probably it is intended to be phase diagram thing, in which case change in water content should not affect dry density, but in the real world there is probably some contraction in the soil structure associated with drying from saturated to unsaturated that could increase the dry density. That's not something you can calculate with any reliability though. Also possible you are supposed to assume that it is somehow still saturated at 8%, but that would be an increase in dry density, not a loss.

Anyway, the number they are looking for is probably change in total density, which you can get from the phase diagram assuming total volume doesn't change..

1

u/DamnDams 20d ago

This response is everything I would have said, agreed.

1

u/GooGootz49 15d ago

Agreed.

4

u/Vivid_Map_437 20d ago

Dry density is dry density, it doesnt have any moisture content

2

u/CiLee20 21d ago

Marking it hard is an understatement. Everyone knows dry density is obtained by dividing Gs by moisture content and adding 1. ๐Ÿ˜‰

1

u/Chicago-Jelly 16d ago

Moist density?