When may the trench be excavated to grade if the trench bottom does not contain stone larger than one inch and bedrock is not encountered?

• A. Where the trench bottom does not contain stone larger than one inch in size or bedrock is not encountered.
• B. Only if stone is larger than one inch.
• C. Only if bedrock is encountered.
• D. Only if the trench is dry for several days.

Answer: (A)

The key idea is that a trench can be excavated to the finished grade only when the bottom is suitable for backfill and support, meaning it is free of large stones and there is no bedrock present. Stones bigger than one inch can create unstable spots and voids that complicate backfill and grading, while encountering bedrock would require additional rock removal or different methods beyond ordinary trenching to grade. When these conditions are met—no stones larger than one inch and no bedrock—the trench can be brought to grade safely and with a stable base. The other options describe conditions that would not reliably allow grading, such as needing large stones, requiring bedrock, or focusing on dryness, which isn’t the standard basis for when to grade a trench.