Sitework, Excavation, and Foundations
Soil and site characterization
Understand soil classification (USCS groups such as GW, SP, CL, CH), Atterberg limits, moisture content, compaction (Standard versus Modified Proctor), and bearing capacity. Know that expansive clays, organic soils, and fill require special treatment. Questions often test the difference between bank, loose, and compacted volumes using swell and shrinkage factors.
Earthwork quantities
Cut and fill balance, the average end area method, and the prismoidal correction appear frequently. Traps: applying a swell factor to compacted fill (shrinkage applies instead), ignoring topsoil stripping, and forgetting that a 1:1 slope is 45 degrees while 2:1 is flatter than it looks.
Excavation and shoring
Know OSHA excavation rules: 5 ft trigger for protective systems, 4 ft for ladder access, 20 ft for engineered systems, spoil piles at least 2 ft from the edge, and daily competent-person inspections. Understand trench boxes, benching, sloping soil types A, B, and C, and dewatering methods.
Foundations
Compare spread footings, mat, pile, drilled pier, and caisson systems. Know pile capacity components (skin friction plus end bearing) and the purpose of test piles and load tests. Waterproofing versus dampproofing and drainage board placement are common traps.
Worked example
A trench 6 ft deep in Type B soil requires a protective system because it exceeds 5 ft. If the crew uses sloping, Type B allows 1:1 (45 degrees); a 6 ft depth needs a 6 ft horizontal offset per side. A trench box is the alternative where right-of-way is limited.
Rule of thumb
Always strip topsoil before cut/fill balance, and never use swell on fill placed in lifts.