Pipe Trench Backfill Calculator

Inputs

View results
Measured trench centerline length.
ft
Usable trench width at pipe bedding elevation.
in
Depth from surface grade to trench bottom.
in
Horizontal widening per unit vertical depth. Use 0 for vertical sides.
H:V
Actual pipe outside diameter used for displacement and clearance.
in
Number of parallel pipes in the same trench.
pipes
Clear space between parallel pipes. Ignored for a single pipe except for future layout checks.
in
Bedding thickness below the pipe.
in
Initial embedment or bedding-zone cover above the pipe crown.
in
Allowance added to the calculated bedding material volume.
%
Share of remaining compacted backfill supplied by reusable excavated soil.
%
Allowance added to imported backfill material.
%
Loose spoil volume increase after excavation.
%
Loose native spoil needed to create one compacted backfill volume.
%
Bulk density used to estimate imported backfill mass.
lb/ft³
Bulk density used to estimate bedding material mass.
lb/ft³

Results

Default result
Edit inputs
Excavation volume(V_exc)
1,200ft³

Trapezoid trench section times measured run length.

Also computed

Bedding to buy(V_b_buy)567.4ft³

10.0% bedding allowance added.

Import backfill to buy(V_i_buy)214.3ft³

10.0% import allowance added.

Loose spoil haul-off(V_haul)995ft³

Loose spoil after swell, minus retained native backfill needed for compaction.

Compacted fill volume(V_fill)1,165ft³

Excavation volume minus pipe displacement.

Bedding compacted volume(V_b)515.8ft³

Bedding-zone volume before waste, limited by trench depth if needed.

Native backfill compacted(V_native)454.5ft³

70.0% of remaining compacted backfill.

Pipe trench backfill preview: excavation 34.0 cubic meters, haul-off 28.2 loose cubic metersPipe trench takeoffExcavation, bedding, pipe displacement, backfill and haul-offexcavation34.0 m3haul-off loose28.2 m3FillBedding shareQuantity screen only. Final trench work needs utility locates, shoring/slope safety, bedding spec, compaction testing, groundwater, traffic and restoration requirements.
Method notes 4 notes
  • Excavation uses a trapezoid trench section: top width = bottom width + 2 x side slope x depth.
  • Bedding material is the lower bedding envelope minus pipe OD displacement; remaining backfill is above that envelope.
  • Haul-off is loose excavated spoil after swell minus loose native material retained to compact into the selected native reuse volume.
  • This is a quantity takeoff only. Final trench work needs utility locates, trench safety/shoring or sloping, bedding class, lift thickness, compaction testing, groundwater, pavement restoration, traffic control, disposal rules and utility-owner specifications.

Powered by MachineCalcs ↗