Sitework and Earthwork
What is tested
Sitework and earthwork covers soil behavior, cut and fill, compaction, grading, erosion control, and underground work. Questions often turn on bank, loose, and compacted volumes.
Core rules
- Bank cubic yard (BCY) is in-place soil; loose cubic yard (LCY) is excavated and bulked by swell; compacted cubic yard (CCY) is placed and compacted and requires more bank soil because of shrinkage.
- Swell % = (LCY − BCY) ÷ BCY × 100. Shrinkage % = (BCY − CCY) ÷ BCY × 100.
- Compaction is measured against a Proctor maximum dry density; relative compaction = field dry density ÷ maximum dry density.
- Trench rules: a protective system is required at 5 ft or deeper unless a competent person determines stable rock; keep spoil piles and equipment back from the edge.
- Stormwater: SWPPP, silt fence, stabilized entrance, concrete washout, and inspection after rain.
Worked example
Cut = 10,000 BCY; swell = 25%, so haul = 12,500 LCY. Fill = 8,000 CCY; shrinkage = 10%, so borrow = 8,000 ÷ 0.90 = 8,889 BCY. Net surplus = 10,000 − 8,889 = 1,111 BCY to dispose of as bank volume. Reasoning: shrinkage means 1 BCY does not make 1 CCY; divide by (1 − shrink).
Traps
Adding shrink instead of dividing; comparing LCY directly with CCY; ignoring topsoil stripping; using the wrong Proctor; assuming excavated volume equals hauled volume.