×
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

Retaining wall freeboard height design

Retaining wall freeboard height design

Retaining wall freeboard height design

(OP)
We are designing a 26' high retaining wall. We have been required to substantiate the freeboard height and impact load we recommended (5.0', 125 pcf), based on possible future debris flow.

The ascending slope is about 1.5:1.0; the max. depth of sloughing has been postulated at 3.0'. I am assuming that at most only about 1/3 of the length of the upslope could slough down at any one time. It appears that a graphical solution would be most practical, but that's just a guess.

Any and all help appreciated.

RE: Retaining wall freeboard height design

(OP)
You are correct; assume a natural angle of repose of 2.75:1.00 H:V for collected material starting at the top of the 5' freeboard and project upslope. Use geometry to determine the volume per foot of wall. That "1/3 length of slope" won't work for very long or tall slopes; get your project geologist to provide input re: size/depth of sloughs and slumps typical to the project area and/or slope.

The 125 pcf is derived by assuming the modeled sloughed material against the freeboard essentially has no shear strength; that's about what you get when you plug C=0 and PHI=0 into the failure wedge analysis.

Hope this helps

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