Friction angle together with cohesion defines the shear strength parameters of soil. Its definition is derived from the Mohr-Coulomb failure criterion. It can be determined in the laboratory by direct shear test or triaxial tests or from theoretical correlations with density or N SPT number.

The current tool sets the rules to calculate friction angle for granular soils based on N SPT number. You can activate the tool and then go back to the project page to plot the friction angle with depth.