Explain with sketch Mohr-Coulomb failure theory.
Mohr presented a theory for rupture in materials. The failure along a plane in a material occurs by a critical combination of normal and shear stresses, and not by normal or shear stress alone. The functional relation between normal and shear stress on the failure plane can be given by
Where c is cohesion and Φ is the angle of friction of the soil equation
2) is generally referred to as the Mohr-Coulomb failure criteria. If data from several tests, carried out on different samples up to failure is available, a series of Mohr circles can be plotted. It is convenient to show only the upper half of the Mohr circle. A line tangential to the Mohr circles can be drawn, and is called the Mohr-Coulomb failure envelope.