Estimate earthwork volumes for grading and excavation using the average end area method.
The average end area method is a standard approximation for earthwork volume between two surveyed cross-sections. For highly irregular terrain, more sections or a 3D survey method gives better accuracy.
Two sections measuring 120m² and 95m², 20m apart, with 25% swell:
Use this for estimating cut or fill quantities between two surveyed cross-sections on a grading, road, or site development project.
Not a substitute for full 3D earthwork takeoff software on complex sites with many irregular sections. For tender-level quantities, use proper survey-based volume calculations.
Bank volume is material as it sits undisturbed in the ground. Loose volume is the same material after excavation, when it expands (swells) due to air gaps between particles — this is what fills a truck bed.
These typically come from a survey or design drawing showing the cut/fill area at each station along the alignment. A surveyor or engineer usually provides these.
Clay typically swells 25-35% when excavated. Always verify with a geotechnical report if available, since swell varies significantly with moisture content and clay type.