Angle of Repose

Synonyms

Critical angle of repose; Dynamic angle of repose

Definition

Theoretically, the maximum angle at which grains in a heap of sediment can remain in place without becoming unstable. The angle of repose of granular materials is relevant in various applications of science and engineering, such as sedimentology, geomorphology, hydraulic, and chemical engineering. It can be used in the descriptions of initial motion of sediment grains and sediment transport process, and in the investigations of bank stability, riprap protection, and reservoir sediment removal.

The angle of repose is measured using different methods (Carrigy 1970; Francis 1986), of which some are illustrated in Figs. 1, 2, 3, and 4. For example, it can be determined by pouring sand grains to form a conical pile (Fig. 1). Two different slopes can be differentiated during the pile formation. As grains are gradually added to a heap, they can pile up to an upper angle of repose. Once masses slump, a new surface will form...