SPT Correlation to Pressuremeter deformation modulus and strength Reduction Factor

[moe333]

Hi Guys,
The subject title says it all!
There is a project requirement for this information, and I have never worked with the Pressuremeter before.
Are the correlations (if they exist) very reliable?
Thanks

 

[BigH]

Moe333 - have you referenced any of Paul Nayne's work?

 

[BigH]

http://geosystems.ce.gatech.edu/Faculty/Mayne/papers/Equivalent CPT-DMT Settlement Method.pdf

Paul's web site:

http://geosystems.ce.gatech.edu/Faculty/Mayne/papers/index.html

 

[BigH]

Also you might contact Paul. He was a classmate of mine. He would likely send you inthe right direction while you wait on McCoy.

 

[BigHarvey]

Most of the publications about pressuremeter are in french. Two books are quite interesting :
" Les essais in-situ en Mécanique des sols " by Maurice Cassan, Editions Eyrolles;1978. Vol 1 describes the different methods ( SPT, pressuremeter, CPT, etc )and corrélations between them and Vol 2 treats the design method associated to the various tests.

" The Pressuremeter and Foundation Engineering " by Baguelin, Jezequel and Shields, Trans Tech Publications,1978

From Cassan : N/(pl-p0) = 20 to 40 in clays, 30 in silts and 30 to 50 in sands (unit = MPa)
and N/Em =0.8 to 1.1 in clays, 3 in silts, and 2 to 6 in sands

don't forget Em is related to Young's modulus via the rheological factor 1/alpha

Menard proposed corrélations with CPT but not with SPT.

 

[BigHarvey]

moe333

I didn't comment about reliability... Given the ranges you can assume it's not so good. In sands the correlation dépends on the angle of frtiction. If you have both parameters, I would say you are better off computing settlements with pressuremeter values. The only situation where it can be optimistic is in very soft clays where I personnally prefer to work with lab parameters.

 

[Mccoy]

BigH, that's one piece of equipment which is not used at all, pretty rarely anyway, in Italy. France as BigHarvey says is the main user in Europe.
I wonder what's exactly the cited strenght reduction factor, something related to the pressiometer or some general concept...

 

[moe333]

Thanks to all!
I need to spend some time looking at available literature.
Cheers!

 

[BigH]

moe333 my iPad was small print and my fingers accidently touched red flag which I wouldn't do. I hope I wasable to cancel. Dang nabit!

 

[BigH]

moe333 my iPad was small print and my fingers accidently touched red flag which I wouldn't do. I hope I wasable to cancel. Dang nabit!