The backfill pipe installation assembly uses a backfill hopper to simultaneously install {HEAD ~ drainage pipe} above the trench floor and envelop the drainage pipe in {TAIL ~ backfill material} to maintain the drainage pipe at a constant height above the trench floor 
The backfill pipe installation assembly uses a backfill hopper to simultaneously install { HEAD ~ drainage pipe } above the trench floor and envelop the drainage pipe in { TAIL ~ backfill material } to maintain the drainage pipe at a constant height above the trench floor
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH