Maximum value of shear stress that can be resisted by the soil is termed as shear strength.
The determination of shear strength is very difficult because it is not only property of soil, it also depend upon load hence there are two variable involved, that’s why it is difficult to determine.
A soil may derive its shear strength by following mechanism:
1. Interlocking between the particles (Gravel and Sand)
2. Friction between the particles due to sliding and rolling. (Sand, Gravel and Silt)
If keep increasing tangential force, resistance of friction also increases this process is called Mobilization of shear. and this process keep increasing up to reach at maximum value of resisting force and this is known as Resistance Mobilized. same concept apply for the soil but instead of μ, write tanϕ.
3. Intermolecular attraction due to cohesion (clay, silt)
