What describes the term 'Angle of Repose'?

The term 'Angle of Repose' specifically refers to the steepest angle at which a pile of granular material, such as sand or gravel, can maintain stability without collapsing. This angle is a critical concept in geology and materials science because it reflects the characteristics of the material, including its size, shape, and moisture content. When the angle exceeds this threshold, gravity overcomes the internal friction and cohesion of the particles, leading to a potential landslide or other forms of failure of the slope.

The angle of repose is variable, depending on factors like particle composition and surface texture. For instance, a pile of round gravel will typically have a lower angle of repose than a pile of angular sand, which tends to interlock more firmly. Understanding the angle of repose is essential for engineers, architects, and geologists when designing structures, assessing slope stability, and predicting mass wasting events.

The other choices do not accurately represent this geological concept, as they either refer to different aspects of slope stability or physical dimensions not related to granular materials.