# SOIL SHRINKAGE FACTOR



## barracus79 (Sep 18, 2011)

Is it:

bank dry density / compacted dry density

or

compacted dry density / bank dry density

I have a couple of sources that say bdd/cdd and I have one that says cdd/bdd*.

Just in common sense terms, shrinkage factors are typically 0.8-1.0, and for soil, compacted dry density is going to be higher bank dry density, so using typical shrinkage factors of &lt;1, the compacted dry density should be in the denominator and bdd/cdd should be correct.

*the one source is the new construction afternoon depth reference that came out this summer.


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## Ambrug20 (Sep 19, 2011)

barracus79 said:


> Is it:
> bank dry density / compacted dry density
> 
> or
> ...



Kaplan " Civil engineering Pe Licence Review" 17 th ed page 493

Swell factor = Loose unit wt/ Bank unit wt

Shrink factor = bank unit weght/Bank unit weght

in my notes (from CERM p 79-1 11th ed) Shrink. factor = dry density (field) / dry density (compacted) -1


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