The softening model consists of a linear region until it reaches the maximum shear strength. The softening region then enters a nonlinear region. Specify the Maximum residual strength, Residual strength and Softening rate to define the constitutional relationship below.

<Strain softening constitution relationship>

The main nonlinear parameters of the Softening model are as follows.

The maximum cohesion using the undrained shear strength and define residual cohesion, defined by the amount of stress reduction and softening rate to simulate the strength decrease with strain and bulk increase. In comparison with the Tresca model, the Tresca model behaves in a simple or perfectly plastic state for undrained conditions but this model decreases from the maximum strength and can simulate the effects of the residual strength.

<Softening behavior>