9.6.1 Hardin-Drnevich and Ramberg-Osgood Models

This section describes the input syntax of the Hardin-Drnevich and Ramberg-Osgood simple soil models. These models may be applied in a nonlinear analysis with Module NONLIN [Vol. Analysis Procedures]. For background theory, see Chapter 23.

The Hardin-Drnevich and Ramberg-Osgood soil models are coordinate dependent material models. In the elements in which these material models are applied, one of the local element axes should point in vertical direction.

    (syntax)

SOIL

starts the input of a simple soil model. The model specifier may be one of the following.

HARDRN

for the Hardin-Drnevich model [§9.6.1.1].

RAOSGO

for the Ramberg-Osgood model [§9.6.1.2].

data

are additional data records to specify the properties of a specific simple soil model.

9.6.1.1 Hardin-Drnevich

For a summary of the background theory of the Hardin-Drnevich model see §23.1. The input data of the Hardin-Drnevich model starts with the HARDRN model specifier.

    (syntax)

GAMMAR

gammar is the characteristic shear strain $\gamma_{\mathrm}^{}$r . ( $\gamma_{\mathrm}^{}$r > 0 )

BULKMO

specifies the method used to determine the bulk modulus K : INISTF for the bulk modulus based on the initial stiffness, and CURSHE for the bulk modulus based on the current shear modulus. [INISTF]

9.6.1.2 Ramberg-Osgood

For a summary of the background theory of the Ramberg-Osgood model see §23.2. The input data of the Ramberg-Osgood model starts with the RAOSGO model specifier.

    (syntax)

GAMMAR

gammar is the characteristic shear strain $\gamma_{\mathrm}^{}$r . ( $\gamma_{\mathrm}^{}$r > 0 )

ALPHA

alpha is the material parameter $\alpha$ . ( $\alpha$$\ge$ 0 )

BETA

beta is the material parameter $\beta$ . ( $\beta$ > 0 )

BULKMO

specifies the method used to determine the bulk modulus K : INISTF for the bulk modulus based on the initial stiffness, and CURSHE for the bulk modulus based on the current shear modulus. [INISTF]