Angle of Repose

What does Angle of Repose Mean?

Definition of Angle of Repose in Construction: The angle of repose is the normal and natural angle that dirt, sand, gravel, stone, or other natural site-work material will take, if left to seek its own equilibrium. If an excavator is digging in a damp clay material, and there is a natural ability for the material to stand on its own, there could be a 90 degree angle of repose, initially. If this material is allowed to sit in the sun, it will dry out, and could hold that angle of repose indefinitely. However, if that material is subject to a heavy rain, the 90 degrees may end up being 0 degrees, due to a full slippage of the material. The angle of repose is extremely important when excavating a large excavation or a small trench. OSHA has specific standards for the maximum angles of repose for certain materials and different depth of excavation. The angle of repose is also a very temporary angle with many materials, such as clay, silt, sand, etc. However the angle of repose can also be a very permanent, static angle, as in large slopes of rip rap and stone. Structural engineers use the angle of repose to anticipate the loading on a shoring scheme or the loading of a footing on another structure. The term angle of repose is important within the construction industry and the term is used as a field identification or description, as well as an engineering characteristic of materials.