To reply to KESServices I can simply say that your idea is not an accepted standard in these areas, all trenches under and road, residential industrial comercial, are ALWAYS backfilled with sand. Native material is then lost on site, or hualed of site. Frost is a concern, I'm replying form MI...
This will be used as a budget figure, to account for the compaction I have been simply figuring that a compacted yard = 1.3 x Loose yard. Native backfill will not be allowed for most cases since most of the pipe runs under the road.
Depth of trench varies, no complete design as of yet put I would assume that the we will see nothing deeper than 20' and backfill quantites for shallow depths are of little concern. No ground water is expected.
I am wondering what the best way to calculate backfill quantites for a trench, clay site with utilities under a road, I would assume that the side slopes would have to meet some standard and that also a box may affect the situation at some depth. I'm looking for a cubic yardage per lineal foot...
My only experience is with a program called Qwest estimating solutions, is was the norm for the contracting company I was hired in to. I would not recomend this program at all, it seems to be designed for the guys driving the dozers. Very few options and all in all a very poorly designed...