Geomembrane patching? Landfill cooling?
Puncture protection?

Questions and answers from the GMA Techline

Using geosynthetics with existing foundation wall
The goal of [our] project is to demolish a commercial building and use one of the existing concrete foundation walls as a retaining wall to allow for the construction
of a parking lot above. The wall would
be approximately 6.5ft high, 10in. wide,
120ft long.

My question is if you have seen similar projects or know of a way I can find more information on a similar project. Also, more specifically, since segmented blocks are
not being used, what is the most effective means of attaching the material to the foundation wall.

Thank you.

(Nick | New York)

Dear Nick,

My thoughts go in two directions:

(1) Insert concrete anchors with large protruding eyebolts and thread a pipe through them of at least 3 inches diameter parallel to the wall and about 2in.–3in. away from the back face. As you place each soil lift, take twice the required length of geogrid reinforcement and wrap it around the pipe so half the length is in one soil lift and the other half is in the next higher soil lift. The key is to have good connection of the anchors to the host
concrete wall.

(2) Construct a completely independent “wrap-around” geotextile or geogrid wall as close to the back of the concrete wall as possible. Let it settle and perhaps proof-roll it somewhat for stabilization purposes. Then fill the remaining space with a compressible foam.

Both techniques have been used when rock outcrops get in the way of the required geosynthetic reinforcement layers.

Bob Koerner | GMA Techline