Trench dimensions & excavation quantities
Soil conditions and piping specifications dictate widths (bottom) and depths of trenches in which pipes will lie and the amounts of material that will have to be excavated. Pipe diameters will affect amounts of backfill and surplus. In sand, sides of excavations will be sloped, whilst in shale vertical sides are possible, albeit with shoring. Cover of 3' or 1m is usually allowed for. For example, when excavating the trench for a 2" pipe that will have (say) approx 3ft or 1m cover after backfilling, the bottom of the trench will have to be 2.4ft or 700cm wide (for access purposes) and 4ft or 1.3m deep.
Backfilling & surpluses
Following the laying and backfilling of a pipe in the ground there will always be a surplus of material for disposal, roughly equal to the quantity displaced by the volume of the pipe. The larger the pipe's diameter, the greater the amount of surplus, which might have to be disposed of away from site. ie Small diameter pipe surplus will probably be spread locally.
Input trench dimensions per job specifications to obtain excavation, backfill and surplus quantities per line sizes. For a hypothetical example, click Real time sync at the foot of this tabulation, enter subsoil for the secret word and click connect.