Power Conduit Abandonment

 

Challenge:

 A utility contractor in Rochester, New York, was tasked with abandoning nearly 30,000LF of 8″ oil-filled steel power conduit.  After pulling the electrical lines and removing the oil, the contractor had to completely fill the lines with grout.

Limits:

There are very few access points for high voltage power conduits.  There were multiple runs over 3,500LF on this project, and it was neither safe nor practical to excavate down to the line at the frequent intervals required to fill the conduit with flowable fill.  

The Solution:

CJGeo proposed abandoning the conduit with cellular concrete.  Cellular concrete is an exceptionally high mobility grout, and can easily be pumped thousands of feet at a time, at low pressure.  Through careful planning with the client, CJGeo broke down the placement into 9 different runs, ranging from 200LF to 3800LF.  Each placement utilized existing access points, such as vaults & terminations.

Result:

CJGeo successfully abandoned each run of conduit.  Pumping pressures never exceeded 30psi, and uniform grout showed at the vent end of each run to confirm complete fill.  The work was performed over the winter, including multiple placements below freezing, and during snow.  The cellular concrete was generated using Aerlite preformed foam, by Aerix Industries, and continuous generation wet batching.