why the lengthdiameter should be more than 31 for a caisso

huangyhg

why the length:diameter should be more than 3:1 for a caisso
why the length:diameter should be more than 3:1 for a caisson to be a caisson.
what is the difference of caisson and augered shallow foundation.
thanks
can you give reference to back up the "caisson" definition? - i.e., where did you see 3:1??  traditionally, the l/d ratio is taken as 4 to 5 for acting as 'deep foundations' compared to acting as a shallow foundation (see original terzaghi bearing capacity equations).  subsequent improvements such as hansen suggests that bearing factors are now "independent" of the l/d ratio.  for piles, i still stick with the berentzev values.