Shear Strength, Friction Angle, Joint Roughness Coefficient
Shear force is applied along a shear plane while maintaining a constant normal force to cause shear displacement. The shear plane is along an open discontinuity, foliation, joint surface, bedding plane, etc. The shear force is recorded and used to calculate friction angle. Any specimen orientation can be tested.
3 or 4
In most cases, the least cross-sectional dimension of the specimen should be at least 10 times the largest grain size in the specimen. The test plane should have a minimum area of 1900 mm2 (3 in2). Specimen should fit within 6" diameter shear rings.
Asperity, direct shear strength, discontinuity, displacement, rock, roughness, sliding friction, stress