The Linear-Elastic Perfectly-Plastic Mohr-Coulomb model involves five input parameters, i.e. Young's modulus E and Poisson's ratio nu (ν) for soil elasticity; cohesion c, friction angle phi (φ)  and dilatancy angle psi (ψ) for soil plasticity. The Mohr-Coulomb model represents a 'first-order' approximation of soil or rock behaviour. It is recommended to use this model for a first analysis of the problem considered. For each layer, one estimates a constant average stiffness. Due to this constant stiffness, computations tend to be relatively fast and one obtains a first estimate of deformations.