×
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

Passive soil pressure above a retaining wall rock socket

Passive soil pressure above a retaining wall rock socket

Passive soil pressure above a retaining wall rock socket

(OP)
I am doing a redesign on a soldier pile retaining wall due to additional soil information encountered during construction.  Rock was discovered between 7' to 16' below the front finished grade.  I know that the wall needs to deflect to attain the passive soil condition.  But at the rock there is no deflection.  I am wondering if anyone has any ideas on how much passive soil pressure, if any, I can use above the rock.

The piles have already been delevered to the job site and if I use no passive soil pressure the piles are underdesigned.  I am looking into using cover plates on the piles if I need to.  

Thanks in advance for any help on this.

Scott

RE: Passive soil pressure above a retaining wall rock socket

In order to generate passive pressure the pile must deflect, although the required deflection for the passive pressire is less than that for active. The rock socket will prevent any deflection near the top of the socket as you basically have a fixed end condition. However, depending on your rock conditions and socketing details, you can develop some moment at the conection, which may drop your overall moment somewhat. Otherwise some other ideas would be to use a brace or anchors, unload a few feet at the top (be sure to go past the active zone, or if possible install piles on a slight batter to reduce lateral earth pressure - I know this works with driven piles but have never seen it with drilled in piles - talk to the driller.
Cover plates may be the simpest answer.

RE: Passive soil pressure above a retaining wall rock socket

(OP)
Thanks.

I will check into battering the pile, although I don't think it will provide enough resistance to prevent me from using cover plates.  I have already taken out the possibility of tiebacks because the area behind the wall is a landfill.  Otherwise, that would have been a more cost effective solution.

Scott

RE: Passive soil pressure above a retaining wall rock socket

Can you provide all the dimensions of the proposed temporary wall section with soil type and rock RQD data?? Perhaps a closer pile spacing is warranted, than the typical 8 feet c/c I normally use.

RE: Passive soil pressure above a retaining wall rock socket

(OP)
The pile spacings are just over 8 foot centers.  However, they have already gotten precast pannels for the wall.  

The RQD's are fairly low.  They range from 0 to 68.

We have decided to increase the pile section to account for the increased moment due to the fixed pile at the rock.  I then designed the rock socket assuming a course gravel instead of the rock.  This should provide me with a conservative design both with the rock socket design and the pile design.

Scott

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