Mobilized strength variable (in percentages) shows the level of mobilized soil/rock shear strength. If Rmob = 100%, material reached the plastic state – the shear strength is fully mobilized.
The general equation for calculation of Rmob:
the current mobilized shear strength [-]
the shear strength (slope of plasticity/failure surface) [-]
Determination (calculation) of Mcur and M depends on the adopted constitutive model. Both variables (Mcur a M) are defined in σ‘m-J space (refer to picture below).
Mobilized shear strength in σ‘m-J space
Simply, for the case of 3ax compression:
Mobilized shear strength in σ‘-τ space