The Mohr–Coulomb failure criterion is primarily applied to predict the shear failure of rocks. Here are the detailed explanations for each option:
Elastic behavior of rocks:
The elastic behavior of rocks refers to their ability to return to original shape after the stress is removed. The Mohr–Coulomb criterion does not describe this behavior, as it deals with failure, not elasticity.
Plastic flow of rocks:
Plastic flow is the deformation of materials that do not recover after the stress is removed. The Mohr–Coulomb criterion focuses on the conditions under which rocks fail in shear, rather than their ability to undergo plastic deformation.
Shear failure of rocks:
The correct answer. The Mohr–Coulomb failure criterion is a model describing the response of materials, like rock, soil, or other granular media, to shear stress. It helps in predicting the shear failure of these materials under different stress conditions. It is represented by the formula:
\tau = c + \sigma \tan(\phi)
where \tau is the shear stress, c is the cohesion, \sigma is the normal stress, and \phi is the angle of internal friction.
Tensile failure of rocks:
Tensile failure occurs when materials fail under tension. The Mohr–Coulomb criterion does not address tensile failure directly; it is mainly used for shear failure.
Thus, the Mohr–Coulomb failure criterion is mainly used to describe the shear failure of rocks.