Skin Friction for Driven Piles

[ar9]

Hello,

I am looking into a project that will have driven piles due to the soils (very soft clays). I have a boring and lab test results which include the Unconfined Compressive Strength. This might be great for end bearing, I was wondering if someone could tell me if the following equation is correct for skin friction, and if not, if someone could assist/point me in the right direction.

Qs= alpha*Cuavg*As

where

alpha=adhesion
Cuavg=Avg unconfined compressive strength for length of pile
As= Side Surface Area

Thanks

 

[GeoPaveTraffic]

That equation is one way of estimating the friction capacity of a pile in clay. However, there is a lot more to it. For example how much settlement will occur and how the different layers will effect each other.

It appears that you do not have a lot of experience with piles in clay. Therefor, you really need to work with someone who as that exerience; such as the project geotechnical engineer.

Mike Lambert

 

[massagung]

I agree with Mike Lambert,

@ar9 : equation that you write is alpha method (undrained condition/total stress), for estimate friction method in cohessive soil there is many equation and method like beta and lambda method, you can read text book of soil mechanics and geotechnical engineering about that such as
1. [Braja_M._Das]_Principles_of_Foundation_Engineering_7th Ed_2011, 2. [Atkinson]_Mechanics_Soil_and_Foundations_2nd Ed_2007, 3. [M. J. Tomlinson] Foundation Design and Construction_7th Ed_2001, you can choose what equation that should you use in that book to get the right conclusion,

M.A.

 

[jasperrupp]

Though equations are helpful, many other factors can contribute to differences in the application. I agree with GeoPaveTraffic that you should work with someone who’s experienced with clay.

 

[geotechnicalenginee]

Touche! I agree with Mike Lambert.