Cut & Fill, Swell & Shrink, and Planning the Mass Haul

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Alright, Cut & Fill, Swell & Shrink, and Planning the Mass Haul. Don't let the plain title fool you. Here's the part that actually matters on the job: Dirt changes volume every time you move it, so a site balances only when you count bank yards, loose yards, and compacted yards as three different numbers and plan the haul around where the material actually has to go. Learn it well and you will know before the first truck rolls whether the job balances, imports, or exports, which is the knowledge that separates a crew lead from an operator.

The grading plan shows where the cut and fill are. This lesson is about how much, in what state, and how it gets from one to the other with the least machine time.

Three kinds of cubic yard

Earthwork is measured in three states, and mixing them up is the most common estimating error in sitework:

• Bank cubic yards (BCY) — material in place, undisturbed. Plans and takeoffs are usually in bank yards.
• Loose cubic yards (LCY) — material after it is dug. It fluffs up; this is what the bucket and the truck bed hold.
• Compacted cubic yards (CCY) — material after it is placed in lifts and compacted. It usually takes up less room than it did in the bank.

Swell is the increase from bank to loose. Published ranges run roughly 10 to 15 percent for sand and gravel, 20 to 30 percent for common earth, 30 to 40 percent for clay, and 50 percent or more for blasted rock. The load factor is the inverse: common earth at 25 percent swell has a load factor of 0.80, so a 10-yard truck of loose common earth carries about 8 bank yards. Shrinkage is the loss from bank to compacted, often 10 to 20 percent for soils, because the compacted fill is denser than the natural ground was. Rock does the opposite and bulks even after placement. Use the swell and shrink in the geotechnical report or from a test strip on the site, not a table, whenever you can.

Why the plan does not balance by itself

A takeoff that says 10,000 bank yards of cut and 10,000 of fill is not balanced. With 12 percent shrinkage the cut makes about 8,800 compacted yards, so the site is roughly 1,200 yards short before anything else happens. Then subtract what the cut cannot supply:

• Topsoil and organics, stripped first and stockpiled for landscaping, never structural fill.
• Unsuitable material in the cut: wet clay, soft layers, old fill, debris.
• Rock that must be blasted, hammered, or hauled as oversize.
• Trench and footing spoil that comes out later and cannot go back under slabs. Then add what the fill needs: stone under slabs and pavements is imported, and over-excavation under footings replaced with stone is more import. Crew leads work this out on paper before mobilization, and the operator who knows the site is 3,000 yards short understands why the superintendent cares about every truck of spoil leaving.

How volumes are computed

Two hand methods still matter. The average end area method, for roads and embankments, averages the cut or fill area at two cross sections, multiplies by the distance between, and divides by 27 for cubic yards. The grid method, for pads, finds cut or fill at each grid corner from existing and proposed elevations and averages by cell. Today most quantities come from surface-to-surface comparisons in software, existing ground against design subgrade. The field equivalent is a quick topo with a GPS rover or drone before and after a stage, which tells the crew what was actually moved and lets the lead compare progress to the plan every week.

The mass haul diagram

For a road or a long site, the estimator draws a mass haul diagram: cumulative cut minus fill plotted against station. Where the line rises the road is in cut; where it falls, in fill; where it crosses the baseline, the earthwork balances between those stations. The diagram tells you which direction the dirt moves, how far, and whether a section is net borrow or net waste. Free haul is the distance the estimate assumes; anything past that is overhaul and costs more per yard. A pad site does not need a formal diagram, but it needs the same thinking: which cut feeds which fill, in what order, so that you never haul over finished work.

Matching the haul to the machine

The haul distance decides the equipment, and this is where production and cost are won:

• Dozer push is efficient to roughly 300 feet, less uphill or in rock, and is the right choice for pushing cut into an adjacent fill.
• Scrapers work from about 300 feet to a mile or more, push-loaded by a dozer in harder material, and they spread as they dump, which helps lift control.
• Excavator or loader and trucks take over beyond that, on tight sites, in rock, and whenever material leaves the site. Articulated trucks handle soft haul roads and grades that would stop a rigid truck. Haul downhill loaded when the sequence allows, keep the haul road graded and watered, and set the fill up so trucks dump in a line the dozer can spread into a lift without stopping the cycle.

Sequencing the earthwork

A workable order on a typical site: erosion and sediment controls, strip and stockpile topsoil, cut the high areas and build the fills in lifts from the bottom up, keep positive drainage on cut and fill every night so a storm does not turn the fill into mud, then rough grade, utilities, and fine grade. Fills near structures need the most control, so plan the test frequency and the technician's time with the sequence.

Going Deeper (Intermediate)

Stockpiles have a cost: every yard handled twice costs the cycle twice. Place topsoil where it will not move again, keep structural fill close to the fill, and shape piles to shed water. Track quantities weekly against the takeoff with a rover topo; a site that was supposed to balance and is suddenly exporting is usually hiding unsuitable material, an unplanned undercut, or a pad built high. On import, know the source: fill from another site must meet the structural fill specification, is usually tested before it comes over the fence, and the geotechnical engineer approves the borrow.

Advanced / Pro-Level

Pros read the geotechnical report before planning the haul. The boring logs show where rock is, how wet the clay is, and whether the cut will even make usable fill; a seasonal high water table or a soft layer at footing depth changes the whole balance. They build the mass haul around weather windows, because clay cut in a wet month is not fill, and they price overhaul, double handling, and rock honestly. On large sites they watch the surface-to-surface quantity change daily in the machines and rovers, so the weekly report is measured, not guessed.

Practice Challenge

A pad site shows 15,000 bank yards of cut and 13,000 compacted yards of fill on the plan. The geotechnical report gives 25 percent swell and 15 percent shrinkage, and 2,500 bank yards of the cut is topsoil to be stripped. Does the site balance? (Answer: usable cut is 15,000 minus 2,500, or 12,500 bank yards; at 15 percent shrinkage that makes about 10,625 compacted yards, against 13,000 needed, so the site is short roughly 2,400 compacted yards and will need import of structural fill, before any stone, unsuitables, or trench spoil are considered. The swell figure sizes the trucks, not the balance.)

In Practice

A crew lead who works the swell and shrink and strips the topsoil out of the numbers tells the superintendent in week one that the site is short and gets the borrow lined up. A crew lead who takes the plan quantities at face value finds out in week six, with the pad half built and trucks sitting idle while someone finds dirt.

Common Mistakes to Avoid

• Treating bank, loose, and compacted yards as the same number
• Forgetting to subtract topsoil and unsuitable material from the usable cut
• Hauling uphill loaded or over work that is already at grade
• Building fill in a hole with no drainage, then losing it to a storm
• Using a dozer for a 1,000-foot push because it was already on site

Takeaway: Dirt changes volume every time you move it, so a site balances only when you count bank yards, loose yards, and compacted yards as three different numbers and plan the haul around where the material actually has to go.

Educational content only — not engineering, geotechnical design, or safety advice, and not a substitute for hands-on training, your employer's competent-person program, or a licensed engineer. Follow OSHA 29 CFR 1926 Subpart P and the other standards as adopted in your jurisdiction, the project drawings, specifications, and geotechnical report, the tabulated data for your protective systems, and the manufacturer's operator's manual for every machine. Editions and local adoption vary.