What is the Mohr-Coulomb failure criterion used for?

The Mohr-Coulomb failure criterion is a fundamental concept in soil mechanics and is primarily used to predict the shear strength of soil based on two key parameters: normal stress and cohesion. This criterion helps in establishing a failure envelope for soil, which defines the relationship between shear stress and normal stress at failure.

In practical terms, the Mohr-Coulomb equation forms the basis for analyzing soil behavior under various loading conditions. It incorporates the internal friction angle of the soil and its cohesion, allowing engineers to determine how much shear stress the soil can withstand before failure occurs. This prediction is crucial for designing stable slopes, foundations, and retaining structures, among other applications in geotechnical engineering.

The other options relate to different aspects of soil mechanics but do not accurately describe the primary function of the Mohr-Coulomb failure criterion. Assessing permeability involves fluid dynamics in soil, predicting settlement pertains to volume change under loading, and evaluating compaction levels focuses on soil density and moisture content—none of which directly relate to the shear strength predictions provided by the Mohr-Coulomb criterion.