When is it appropriate to use Vesic's formula for bearing capacity determination (cohesive, cohesionless, or both) and is it ever appropriate to exclude the phi=0 condition for foundations on clay?
AASHTO, with exceptions, has adopted Vesic's bearing capacity method. It's interesting to note, however, that when the USACOE wrote its program CBEAR, they adopted Meyerhof's method as the more conservative one: