Cobble retaining wall repair

[BadgerPE]

We have a project in which a limestone cobble retaining wall has developed a bulge in it. The wall is approximately 8' tall and 2' wide. We have a proposed solution to draw the wall back into place and prevent future outward movement. However, I am wondering if anyone has any literature regarding the correcting/repair of a cobble retaining wall that needs to be drawn back into position. I am not looking for an additional solution, or literature that specifically shows a step by step solution or a whole series of calcs to run. I am merely looking for general information regarding the repair similar retaining walls so that I can have a better understanding of how the wall may react. Also, to head off any "Just stabilize the wall and leave the bulge" comments, this wall is part of a large municipal pool project that is about 80 years old. It is very architecturally appealing and the municipality would like the bulge corrected to enhance the appearance of the facility.

Thanks much in advance!

 

[RFreund]

Is this a rockery type wall?

If so look here for some info on rockery design :

http://www.vulcanhammer.net/geotechnical/FHWA-CFLTD-06-006.pdf

However I would think these would be similar to SRW type walls i.e. easy to put up, easy to take down, not so easy to repair.

EIT

http://www.HowToEngineer.com

 

[BadgerPE]

No it is a mortared wall. See attached picture. Thanks for the info though!

 

[shobroco]

Presumably the bulge is a result of loss of bond between the face stones and the core or back-up. Do you know if the wall is all stone or if there is a concrete back-up? Do you know if the space behind the bulge is full of debris & failing mortar? Do you know if the mortar is lime or portland cement based? All have a big impact on any repair. Was the wall tied by binding deeper masonry units, or with metal ties of some sort that have rusted off? The least intrusive repair depends upon the cavity being clean behind the bulge (highly unlikely) and on introducing new ties. If the cavity is clean, you can cut out a lot of the horizontal mortar joints, push the bulge in as far as possible with planks & hydraulic jacks, install stainless steel helical ties through the joints into the back-up, point with appropriate mortar, and low-pressure pump grout into the remaining cavity. I've repaired a lot of stone walls & this ideal scenario seems pretty unlikely to work for this repair, but maybe you'll get lucky.

 

[BadgerPE]

**Update**

Upon excavation, it was noted that approximately 60-70% of the wall section had been loss to degradation of the limestone. Backfill behind the wall was clay and the site had significant drainage ending up right behind the wall. Therefore, the decision was made to remove the wall and to construct a new RC retaining wall with limestone veneer. Thanks to all for the insight.