CSLB C-27 Landscaping ContractorSite Preparation and DrainageMedium
A C-27 contractor is preparing a site for a new residential landscape. The design calls for a retaining wall that is 4 feet high. According to general engineering principles and safety standards, what is the minimum distance the excavated material (spoil pile) should be kept from the edge of the excavation?
- A2 feet
- B4 feet
- C1 foot
- D3 feet
Show answer & explanationAnswer & explanation
Correct answer: A. 2 feet
OSHA regulations and good safety practices dictate that excavated material (spoil pile) should be kept at least 2 feet from the edge of an excavation. This prevents material from falling back into the trench and reduces lateral pressure on the trench wall.
Why the other options are wrong
- B. 4 feet is even safer but exceeds the minimum required distance for spoil piles.
- C. 1 foot is generally insufficient to prevent material from falling back into the excavation or adding undue pressure to the trench wall.
- D. 3 feet is a safer distance but not the minimum required for general excavation by OSHA.
Spoil Pile Distance
The minimum safe distance excavated material (spoil pile) must be kept from the edge of an excavation to prevent material from falling back in and to reduce lateral pressure on trench walls.
- Minimum distance is 2 feet (0.6 meters) from the edge.
- Prevents material from falling into the excavation.
- Reduces surcharge load on the excavation walls, preventing collapse.
- Applies to trenches, foundations, and other excavations.
Memory trick: Two feet away, the spoil pile must stay, to keep the trench safe today.