Hypoplastic model for granular materials

Parameters are specified in the PLAXIS input in the following order:

State variables:

The routine uses 14 state variables:

The hypoplastic model for granular materials is implemented via user defined subroutine usermod. To use the model in PLAXIS, copy the files UDSM_HPS.dll and UDSM_HPS64.dll into the PLAXIS installation directory. Then, select "user-defined model" from the Material model combo box in the General tab sheet (Fig. 4.1).

Figure: Selecting user defined model in the Material model combo box.
Image udefmod
(Fig. 4.1). After selecting the user-defined model, correct user-defined dynamic library (typically UDSM_HPS.dll) needs to be selected in the "Available DLL's" combo box under "Parameters" tab sheet. In the "Models in DLL" combo box, model with ID 1 (Hypoplas. - sand) must be selected. The parameters can then be input into the parameter table (Fig. 4.2).
Figure: Selecting sand hypoplasticity model in the "Parameters" tab sheet.
Image sandhypo

Parameters of the sand hypoplastic model for different soils have been evaluated by Herle and Gudehus [2]. They are given in Table 4.1. Parameters of the intergranular strain concept for granular materials are in Tab. 4.2.


Table 4.1: Typical parameters of the hypoplastic model for granular materials (Herle and Gudehus [2])
  $ \varphi_c$ $ h_s$ $ n$ $ e_{d0}$ $ e_{c0}$ $ e_{i0}$ $ \alpha$ $ \beta$
Hochstetten gravel 36$ ^\circ$ 32 $ \times 10^6$ kPa 0.18 0.26 0.45 0.5 0.1 1.9
Hochstetten sand 33$ ^\circ$ 1.5 $ \times 10^6$ kPa 0.28 0.55 0.95 1.05 0.25 1.5
Hostun sand 31$ ^\circ$ 1.0 $ \times 10^6$ kPa 0.29 0.61 0.96 1.09 0.13 2
Karlsruhe sand 30$ ^\circ$ 5.8 $ \times 10^6$ kPa 0.28 0.53 0.84 1 0.13 1
Lausitz sand 33$ ^\circ$ 1.6 $ \times 10^6$ kPa 0.19 0.44 0.85 1 0.25 1
Toyoura sand 30$ ^\circ$ 2.6 $ \times 10^6$ kPa 0.27 0.61 0.98 1.1 0.18 1.1



Table 4.2: Parameters of the intergranular strain concept for sandy soils (Niemunis and Herle [8])
  $ R$ $ m_R$ $ m_T$ $ \beta_r$ $ \chi$
Hochstetten sand 1.e-4 5.0 2.0 0.5 6


David Masin 2017-09-12