Angle of internal friction
Alternative term: Angle of shearing resistance
The limiting value of the angle between the reaction on a plane within a soil mass at which shearing may occur and the normal to that plane.
Note: The tangent of the angle of internal friction is the coefficient of friction for the soil.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM