rbtjr
Gold Member
This reply may be too late to help. As noted by prior posters, the goal is to protect the pipe from taking the load by having the load borne by the material beside the pipe. The first way to do that is to make the trench for the pipe as narrow as possible and still accommodate the pipe. This is a key. That way, the dirt walls on both sides of the pipe carry much of the load, especially with large tires passing over. Next, be sure to fill the sides of the trench outside the pipe with gravel. Fill a little at a time, then compact it, then fill more, and compact that new fill, etc. Then cover the whole thing with as much gravel as you can get on top, up to say 4". The gravel on top also helps to spread the down force on the pipe over a wider area. I have buried pipe in this manner, using only dirt to fill in the trench beside the pipe instead of gravel, and with maybe 4" of dirt fill above the pipe, and have had no problem running a 5,000+ lb tractor over it.