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MCC

Warning

Obsolete/outdated, better use the Modified-Cam-Clay implementation (however, only MCC is linked with the HCA model for clay)

*Mechanical = MCC 
nu [-], kappa [-], lambda [-], varphi [-], K^w [F/A]
Parameters of the MCC model:

  • \(\nu\) is the Poisson's ratio. This parameter has no unit. Typical range: \(0-0.499\).

  • \(\kappa\) [-] is the swelling index. This parameter has no unit.

  • \(\lambda\) [-] is the compression index. This parameter has no unit.

  • \(\varphi\) is the friction angle. This parameter is given in degree.

  • \(K^w\) is the bulk modulus of pore water, should be kept to zero since ideally undrained conditions should be assumed with this implementation

State variables

In addition to the (effective) stress, the Modified Cam-Clay constitutive model takes additional state variables. Performing simulations with this model requires the prescription of those. The following state variables are contained in the model:

  • Void ratio: \(e\), void_ratio

  • Preconsolidation stress: Pre_stress

  • Pore water pressure: \(p^w\), Pw. Only in case of ideally undrained conditions \(K^w>0\). If no value for \(p^w\) is prescribed, \(p^w_0=0\) kPa is assumed.

The state variables can be initialized in two different ways:

  • Using the *Initial conditions, type = state variables command in the input file, e.g.

    *Initial conditions, type = state variables
    element_set_name, Pre_stress, <value>

  • Using the interface for user-defined initial state variables. In this approach, the vector holding the state variables is filled directly in a Fortran user routine. The position of the state variable in the associated vector is as follows:

    • statev(1) = \(e\)

    • statev(2) = Pre_stress

    • statev(3) = \(p^w\)

Additional output variables

The following additional output variables are available in the *Output command (see here):

  • Void ratio \(e\): void_ratio

  • Preconsolidation pressure \(p_c\): Pre_stress

  • Plastic strain: plastic_strain

  • Overconsolidation ratio OCR: OCR

  • Pore water pressure \(p^w\) (for ideally undrained simulations with \(K^w > 0\)): Pw