Model – Modified Hardening Soil

Input Dialog Box

The modified hardening soil requires the following input parameters.

• φ – Friction angle
• c – Cohesion
• ψ – Dilatancy angle

• p_ref – Reference stress
• m – Power for stress dependency

• E_oed,ref – Reference value of the oedometric tangent modulus for initial loading
• C_SH – Material constant for control of shear hardening

• E_ur,ref – Reference value of the secant modulus for unloading and reloading
• ν – Poisson's ratio for unloading and reloading

• p^POP/η^POP – Preconsolidation stress / Preconsolidation ratio

These parameters are defined in the specific input tab shown in the image below.

Input Dialog Box – Modified Hardening Soil Model

Additional Notes

Cohesion

When using numerical methods, such as FEM, in geotechnical engineering, it is recommended to always apply a non-zero cohesion. Therefore, a small cohesion between 0.5 and 1.0 kN/m² can be applied even for non-cohesive soils.

Power for Stress Dependency

The usual value for sand is m = 0.5, and for clay m = 1.0.