General Contractor License Site Work and Excavation 4 — Questions and Answers
Question 1: Which piece of equipment is best suited for bulk earthmoving operations over long haul distances on a large grading project?
- Excavator with dump truck
- Scraper (motorized or push-pull) (Correct answer)
- Backhoe loader
- Skid-steer loader
Correct answer: Scraper (motorized or push-pull)
Self-loading scrapers efficiently cut, carry, and deposit large volumes of soil over longer distances in a single operation, making them ideal for mass grading.
Question 2: What does 'shrinkage factor' mean in earthwork calculations?
- The amount soil compresses when frozen
- The reduction in volume when loose soil is compacted relative to its bank volume (Correct answer)
- The percentage of moisture lost during excavation
- The decrease in trench width after shoring is installed
Correct answer: The reduction in volume when loose soil is compacted relative to its bank volume
Shrinkage factor accounts for the fact that compacted fill occupies less volume than the same material in its natural bank state, affecting fill quantity calculations.
Question 3: What is 'rock excavation' typically defined as in contract specifications?
- Any material that requires a backhoe to remove
- Material that cannot be excavated without blasting or hydraulic breaking due to its hardness (Correct answer)
- Soil with a high gravel content
- Any subsurface material below a specified depth
Correct answer: Material that cannot be excavated without blasting or hydraulic breaking due to its hardness
Contract specifications typically define rock excavation as material requiring mechanical breaking (hoe-ram) or blasting to remove, and it is usually paid at a higher unit price.
Question 4: In an urban excavation project, what is 'sheet piling' primarily used for?
- Temporarily storing excavated materials
- Creating a watertight vertical barrier to retain soil and groundwater around an excavation (Correct answer)
- Marking the perimeter of the excavation area
- Providing a working platform for excavation equipment
Correct answer: Creating a watertight vertical barrier to retain soil and groundwater around an excavation
Sheet piling consists of interlocking steel or vinyl sections driven into the ground to retain soil and groundwater, allowing excavation in tight urban spaces without sloping.
Question 5: What frequency of inspection is required for excavations by a competent person?
- Weekly only
- Monthly or after significant rainfall
- Daily and after any hazardous condition (rain, freeze-thaw, adjacent loads) (Correct answer)
- Only before work begins each morning
Correct answer: Daily and after any hazardous condition (rain, freeze-thaw, adjacent loads)
OSHA requires a competent person to inspect excavations daily before work begins and as needed throughout the shift, and after rain, freezing, or other events that could affect stability.
Question 6: What is the OSHA-required maximum depth for an unprotected trench in stable rock?
- Any depth is acceptable in stable rock without protection (Correct answer)
- No more than 4 feet without a protective system
- No more than 5 feet without a protective system
- No more than 20 feet without a protective system
Correct answer: Any depth is acceptable in stable rock without protection
OSHA allows vertical walls without protective systems only in stable rock because the rock itself provides the structural support that prevents collapse.
Question 7: When grading a site, a 'swale' is designed to:
- Retain stormwater on-site in a retention pond
- Direct surface water away from structures in a controlled path (Correct answer)
- Measure the elevation difference across the site
- Stabilize steep slopes with vegetation
Correct answer: Direct surface water away from structures in a controlled path
A swale is a shallow, vegetated or lined channel that collects and conveys stormwater away from buildings and across the site to a designated outlet.
General Contractor License Site Work and Excavation 4
Which piece of equipment is best suited for bulk earthmoving operations over long haul distances on a large grading project?