Annular Space Grouting–Dam Rehab

Annular Space Grouting–Dam Rehab, Waynesboro, Virginia


The liner pipe selected for slip lining the outflow of a dam 2.5 miles up the side of a mountain in a national forest required annular space grouting at less than 2 psi.


2 psi grout installation required by slip line pipe manufacturer.  Annular space was only 3/4 inch, and pipe was 165 feet long.  Lastly, the job was literally on the side of a mountain, yet the dam being rehabilitated was subjected to stormwater flow from multiple square miles of terrain, so logistics coordination and adequate dewatering were critical.  Terminal end mid stream in existing pipe (and 40 feet under the dam) prevented capping and filling the liner pipe with water during grouting.


Lightweight cellular concrete was chosen for the void filling because it is easily pumped through small orifices, is non-segregating, and was easy to transport to the job site.


CJGeo placed the lightweight cellular concrete to fill the annular space to the engineer’s specification.