Soil Mechanics with ADINA
ADINA is used widely in many fields of applications, including the field of geomechanics.
Currently, ADINA offers the following geotechnical material models: DruckerPrager,
MohrCoulomb, Camclay, and a curve description model. These models can be combined
with the following ADINA features:
 two and threedimensional solid elements;
 birth and death of elements (useful for tunneltype studies);
 initial stresses and strains;
 gravity loading;
 small and large deformations; and
 associated or nonassociated flow rules.
To illustrate the use of ADINA in the field of geomechanics, we present the solutions of
two common soil mechanics problems using the MohrCoulomb material model. The
first problem is the classical strip footing problem on a soil foundation, in which
a uniformly distributed pressure is applied to model the effect
of the footing (see Fig. 1 below).
Figure 1. Schematic of first problem
Due to vertical symmetry, only half of the domain is
considered. The finite element mesh consists of 9node twodimensional solid elements
deforming in plane strain. Fig. 2 below shows the loaddisplacement curves obtained
for the associated and nonassociated analyses, with two runs presented for each case.
The movie above shows the evolution of the effective stress in the foundation for the
nonassociated analysis.
Figure 2. Results of first problem: loaddisplacement curves
The second problem considers a tunnel in which the initial support of the tunnel roof
is gradually removed (see Fig. 3 below). The objective is to establish
the displacement of the tunnel roof as the support is being removed. The support
is modeled as a radial pressure.
Figure 3. Schematic of second problem
The results obtained show that plastification
starts occurring between 50% and 55% of pressure removal and that the final plastic radius (i.e., when
there is no pressure in the tunnel) is 8.85 m (see Fig. 4 below). Finally, Fig. 5 shows
the evolution of the radial displacement of the tunnel as it is unloaded.
Figure 4. Results of second problem: band plot of MohrCoulomb flag in Region A of Fig. 3
Figure 5. Results of second problem: evolution of tunnel's radial displacement
These examples illustrate only some of the powerful analysis capabilities of ADINA for solving
geomechanics problems.
