Backfilling a trench with a drain line
We had to move a 4″ drain line from the house to the street, and it is now under the driveway. What is the best way to make sure the pipe is not damaged when we fill the trench back up?
I am concerned about the joints, and any streches of pipe that are not
sitting on solid earth.
Put about 12" of sand around the pipe and back fill in 6" or 8"lifts. compact each lift. Should be good to go.
The proper and normal way to backfill be to shade the pipe. The pipe should be fully supported by having the bottom of the trench properly sloped. (The bad way is have piles of dirt supporting it every 5' to 10'). Then get a tamper or 4 X 4 and pack the dirt on both sides of the pipe. After testing / Inspection, pack down a foot of dirt on top of the pipe and continue to compact in layers. In years past (and now), the dirt was simply pushed loosely into the trench and then the better guys would get a pipe and water hose and "Jet" the loose dirt to settle.
Laziness and bad practices cause the dirt to settle years later, causing driveway and sidewalk damage. So now some Localities require Soil Engineers compaction Reports.