Lock-Block Retaining Walls

[GeoGrouting]

During an excavation for foundations, lock blocks were placed to support the neighboring excavated profile. The total height of lock blocks is about 3.5 m. (5 rows). The blocks were positioned on top of each other with no reinforcement by a contractor. The gap between the lock block and the sloping ground has not been back filled except partially.

I am looking for a methodology to reinforce the existing lock-blocks to provide additional lateral support for the blocks without being have to remove the lock blocks. Thank you.

 

[RFreund]

I'm not exactly sure what the lock block system is but I'm assuming they are large segmental precast blocks. You could use geogrid. To avoid taking down courses to install the grid. You could drill some threaded rod into the back of the blocks say 4-6' on center and run steel pipe (6" dia maybe) continuously across the back of the units. Then wrap geogrid around the pipe and extend it back however far you need to to resist external and internal forces. Also you may want to check the pipe for bending and the threaded rod for pullout.


EIT

 

[RFreund]

Also I found the manufactures to be very helpful so you may also want to contact LockBlock. They may have some suggestions.

EIT

 

[oldestguy]

This is a possible place for drilled-in tie-backs, grouted rods. However, the rigs that do that usually are heavy and they usually stand on the base of an excavation. That means probably filling against the outside of that wall for that support on a temporary basis.

Apparently the "wall" is not holding back much other than lower backfilled area. Seems like a cheaper way would be to remove blocks down as far as possible and then install soil nails by hand held drills. Not the best alternative, short of cantlevered sheet piles.

If there is some serious risk of losing the adjacent land, I'd fill the hole and start over doing it right.