×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

(OP)
I am trying to get some clarification regarding the Soil-Friction Angle (Friction Angle for Foundation Surface). Have seen different calculations from the different sources, for example NavFac 7.2 - Table 1 (and other sources) uses a friction factor of tan (delta), with no Safety Factor. Coduto, uses mu_allowable = mu/F, where F = 1.5 or 2 and mu = tan (0.7*phi). Have seen suggestions to use (tan(dela))/2, where 2 is the safety factor.

Appreciate your guidance in trying to clarify the friction angle for foundation surface.

Thanks

RE: Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

Others might disagree, but I would use the angle of internal friction (phi) as it is and apply a safety factor to the system of its use. For instance, if you are doing slope stability, use an overall safety factor for the stability of the slope, with consideration of other factors, not just the phi angle used in your calcs.

RE: Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

(OP)
I am looking into this in terms of the soil-foundation friction underneath the footing of a concrete retaining wall or concrete U-channel.

RE: Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

For the coefficient of friction to resist sliding, I use the tangent of the angle of internal friction, divided by 1.5.

DaveAtkins

RE: Soil-Foundation Friction Angle (Friction Angle for Foundation Surface)

I use tan(2/3*phi) as the friction angle between the foundation and the soil. If you are looking at plane in the soil, such as with a shear key, then I would use tan(phi).

With either analysis, an appropriate factor of safety should be used.

Mike Lambert

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources