General Contractor License Site Work and Excavation 3 — Questions and Answers
Question 1: What does the term 'cut and fill' refer to in site grading operations?
- Cutting utility lines and filling them with conduit
- Excavating high areas and using that material to fill low areas to achieve desired grade (Correct answer)
- Cutting tree stumps and filling the holes with gravel
- Removing topsoil and replacing it with engineered fill
Correct answer: Excavating high areas and using that material to fill low areas to achieve desired grade
Cut and fill balances earthwork by excavating (cutting) elevated areas and using that soil to raise (fill) lower areas, minimizing the need to import or export material.
Question 2: Which document specifies the required compaction percentage for engineered fill on a construction project?
- Building permit
- Geotechnical (soils) report (Correct answer)
- Survey plat
- Zoning variance
Correct answer: Geotechnical (soils) report
The geotechnical or soils report prepared by a licensed engineer specifies required compaction percentages, typically expressed as a percentage of Modified Proctor density.
Question 3: During excavation, encountering unexpected soft or unstable soil (unsuitable material) at subgrade requires the contractor to:
- Compact it aggressively with a vibratory roller
- Over-excavate and replace with engineered fill or structural aggregate (Correct answer)
- Cover it immediately with the foundation slab
- Add water to stabilize the material
Correct answer: Over-excavate and replace with engineered fill or structural aggregate
Unsuitable material must be removed and replaced with approved engineered fill or crushed stone to provide stable bearing capacity for foundations.
Question 4: What is 'underpinning' as it relates to excavation near existing structures?
- Installing drainage pipes under a foundation
- Temporarily or permanently strengthening an existing foundation to support excavation next to it (Correct answer)
- Placing waterproofing membrane under a slab
- Installing anchor bolts into an existing foundation
Correct answer: Temporarily or permanently strengthening an existing foundation to support excavation next to it
Underpinning extends or strengthens an existing foundation so that nearby excavation does not undermine its bearing capacity or cause settlement.
Question 5: What is the primary purpose of installing silt fencing around an excavation site?
- To mark the boundary of the construction zone for safety
- To control sediment runoff and protect adjacent waterways from erosion (Correct answer)
- To prevent unauthorized vehicle access to the site
- To reduce noise levels from excavation equipment
Correct answer: To control sediment runoff and protect adjacent waterways from erosion
Silt fencing is an erosion and sediment control best management practice (BMP) required by stormwater permits to prevent disturbed soil from entering waterways.
Question 6: A contractor discovers archaeological artifacts while excavating. What is the required immediate action?
- Continue excavating carefully to document the find
- Stop work, secure the area, and notify the appropriate authorities (Correct answer)
- Remove artifacts and store them on-site
- Photograph the artifacts and resume work
Correct answer: Stop work, secure the area, and notify the appropriate authorities
Federal and state laws (including the National Historic Preservation Act) require stopping work and notifying authorities when suspected archaeological or cultural resources are discovered.
Question 7: What is 'benching' as an alternative to sloping in trench excavation?
- Installing horizontal timber planks at the trench bottom
- Cutting the trench wall into a series of horizontal steps or levels (Correct answer)
- Placing concrete benches at each side of a trench for worker safety
- Using a bench saw to cut through rock in the trench
Correct answer: Cutting the trench wall into a series of horizontal steps or levels
Benching creates a series of horizontal steps in the trench wall to prevent soil from sliding into the excavation, and is allowed in certain soil types per OSHA standards.
General Contractor License Site Work and Excavation 3
What does the term 'cut and fill' refer to in site grading operations?