In which scenarios is rock excavation commonly required?

Rock excavation is commonly required in scenarios where bedrock lies beneath the surface grading elevation. In construction, especially in highway projects, encountering bedrock can significantly affect the site preparation process. When bedrock is below the grading elevation, it must be removed to ensure a stable foundation for structures or roadways. This typically involves using heavy machinery and specialized techniques to break and remove the rock.

Loose soil, while it may necessitate certain excavation techniques, does not specifically require rock excavation. Flood control operations generally involve managing water flow and drainage rather than dealing with bedrock. The installation of underground utilities might involve various types of excavation, but it does not inherently require rock excavation unless it encounters bedrock in the process. Therefore, the condition of having bedrock beneath the grading elevation is a clear indicator of the need for rock excavation.