Short height correction for unconfined compression test.

[oldestguy]

I've been asked for a reference or formula for correcting unconfined compression tests on samples shorter than twice the diameter. I used to have that in my files, but now no luck. I understand there is such a correction for short concrete cylinders, but I can't even find that now. Help.

 

[BigH]

ASTM C42:

Ratio of Length
to Diameter (L/D)
Strength
Correction Factor
1.75 0.98
1.50 0.96
1.25 0.93
1.00 0.87

I've not seen anything for soils before.