Earthwork quantities

Roads, railways, canals and embankments move huge volumes of earth, and earthwork is often the largest single item in their cost. Quantities come from cross sections taken at regular chainages along the centre line.

At each chainage, the area of cut or fill is worked out from the formation width, side slopes and the depth at the centre line, or by coordinates for irregular ground. Volumes between sections are then found by the average end area method, simple but slightly over-estimating for tapering shapes, or by the prismoidal formula, which is exact for prismoids and needs an odd number of sections at equal spacing.

A mass-haul diagram plots cumulative volume along the route. It shows where cut can be used as fill, the haul distances, and where borrow or disposal is needed. Bulking and shrinkage factors convert between bank, loose and compacted volumes.

Our earthwork calculator applies both methods so you can compare them.