Modified Mohr-Coulomb (MCM)
The model requires inputting the following parameters: modulus of elasticity E, the Poisson's ratio, angle of internal friction and cohesion. The latter two parameters serve to define the yield condition. The formulation of constitutive equations assumes effective parameters of angle of internal friction φeff and cohesion ceff. The angle of dilation must also be specified.
Similarly to the DP model the Modified Mohr-Coulomb model smoothes out the corners of the MC yield surface. As suggested in the Figure the projection of the MCM yield surface into the deviatoric plane passes through all corners of the Mohr-Coulomb hexagon and as the MC yield function the MCM yield function depends on the effective mean stress σm and the Lode angle θ. With reference to its definition a slightly stiffer response of the material can be expected with the MCM plasticity model when compared to the MC and DP models.
MCM and MC yield surfaces in the deviatoric plane