What is the angle of repose?

What is the angle of repose?

• A. The angle at which soil will begin to slide
• B. The angle at which soil will no longer slide
• C. The angle at which soil will float
• D. The angle of maximum slope stability

Answer: (B)

The angle of repose is the steepest slope at which a pile of loose material can come to rest without continuing to slide. It represents the balance between the downslope component of gravity and the friction (and cohesion, if present) between particles. When the slope is at this angle, the pile is on the verge of movement: any more tilt and grains will begin to flow or avalanche until the slope returns to the repose angle. This is described as the maximum slope stability. The other options describe onset of sliding, an unrelated notion like floating, or misstate the stability concept.

The angle of repose is the steepest slope at which a pile of loose material can come to rest without continuing to slide. It represents the balance between the downslope component of gravity and the friction (and cohesion, if present) between particles. When the slope is at this angle, the pile is on the verge of movement: any more tilt and grains will begin to flow or avalanche until the slope returns to the repose angle. This is described as the maximum slope stability. The other options describe onset of sliding, an unrelated notion like floating, or misstate the stability concept.