The angle of repose is defined as the angle at which soil will no longer slide. Which statement best describes this concept?

The angle of repose is defined as the angle at which soil will no longer slide. Which statement best describes this concept?

• A. The angle at which soil slides continuously
• B. The angle at which soil will no longer slide
• C. The angle at which soil becomes non-cohesive
• D. The angle of soil contact with the ditch

Answer: (B)

The angle of repose is the steepest slope at which a pile of soil can stay intact without sliding, determined by the balance between gravity pulling grains downward and friction and cohesion between them resisting motion. In other words, it’s the stability limit: at this angle the material is on the edge of movement, and if the slope becomes any steeper, sliding or flowing occurs. That’s why the statement describing the angle as the point at which soil will no longer slide best captures the idea—beyond it, sliding starts; at it, the slope is just stable. The other statements describe conditions that aren’t about this stability boundary: continuous sliding, non-cohesiveness, or soil contacting the ditch, which don’t define the maximum stable angle. Factors like particle shape, size, moisture, and density influence the exact angle of repose in a given soil.

The angle of repose is the steepest slope at which a pile of soil can stay intact without sliding, determined by the balance between gravity pulling grains downward and friction and cohesion between them resisting motion. In other words, it’s the stability limit: at this angle the material is on the edge of movement, and if the slope becomes any steeper, sliding or flowing occurs. That’s why the statement describing the angle as the point at which soil will no longer slide best captures the idea—beyond it, sliding starts; at it, the slope is just stable. The other statements describe conditions that aren’t about this stability boundary: continuous sliding, non-cohesiveness, or soil contacting the ditch, which don’t define the maximum stable angle. Factors like particle shape, size, moisture, and density influence the exact angle of repose in a given soil.