×
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

Subgrade at Tunnel Construction

Subgrade at Tunnel Construction

Subgrade at Tunnel Construction

(OP)
We are building a tunnel that is about 40 feet deep. Ground water has saturated the fat clay subgrade and now the subgrade will not meet the 2000 psf required per the drawings. One option would be to bridge the subgrade by undercutting 12" (This is the max we can undercut, since anything more would undermine the soldier piles) placing geogrid, and 12" of #2 stone. However, there was a guy representing the owner at the meeting we had this morning that said "we really don't have to attain the 2000 psf, the tunnel is sitting a mat foundation, we only needed to have a stable subgrade"

Is this a true statement? I still think that if don't get the 2000 psf, we should undercut and bridge it. Any thoughts?

RE: Subgrade at Tunnel Construction

Not enough information for an informed answer.  A cross-section of the tunnel would help.  Also a better description of the material under and around the tunnel.

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