Residual friction values for soft clay Phi res

[ac4u2nv]

Dear all
My understanding is for pile design - using the peak value would not be appropriate as the clays become highly distrubed and displaced during piles installation (CFa piles).
BS8002 makes mention of phi res but doesnt provide any values. Where can i get values for phi res for soft clays?

Thank you

 

[fattdad]

run a normally consolidated drained direct shear test and take the peak values as fully softened and the residual values as residual values.

Tim Stark at the University of Illinois has research on correlations to fully-softened and residual strength based on clay content and other stuff. Can't recall.

f-d

ípapß gordo ainÆt no madre flaca!

 

[ac4u2nv]

FAtdad
if there are no lab tests available - there are cpt tests and n values from Cable percussive boreholes?

 

[Okiryu]

Here is the spreadsheet from Prof. Tim Stark. You can download it from his website. You need LL and FC to get the residual friction angle.