This reinforced soil wall was constructed in 1999 using Keystone blocks with geogrid reinforcements near Sacramento, California.
This photo shows a lower row of Keystone blocks, with the geogrid reinforcement extending to the right side.
Coarse sand is packed in and around the blocks. The top surfaces of the blocks must be swept free of soil before the next level of blocks can be placed. Dowels are placed in the small-diameter holes in the blocks, and connect the upper blocks to the lower blocks in an overlapping sequence.
Sheets of geosynthetic “geogrid” are the reinforcement for the soil backfill. The front-end loader was used to place coarse sand / pea gravel directly behind the keystone blocks (left side of photo) to act as a drainage layer.
The geogrid is sandwiched between the facing blocks, and is hooked over the dowels that connect the blocks.
A view of the exposed face of the wall as construction progresses.
The wall is stepped-back at this location. The white PVC pipes are drain lines that connect to the drainage layer directly behind the blocks.
Geogrids are being laid out over a completed row of blocks. The two scrapers (earth-moving equipment in the upper left) are placing fill soils behind the geogrids.
The backhoe in the background spreads the fill materials out over the geogrid. Care must be taken not to damage the geogrids by driving equipment over the unprotected grid. Wood stakes are used to stretch the geogrid flat and hold it in place while the soil is placed over it.
Another row of blocks is being placed, with the geogrid sandwiched between the overlapping blocks. The front-end loader is placing the drainage layer in the background.