Evaluating Seismic Stability of Embankment Dams - Multiscale Geomechanics: From Soil to Engineering Projects - page 375

test the sensibility of the seismic resistance of the embankment to the state of the
alluvium controlled by its relative density. This type of calculation should give us
elements for defining the seismic risk in various zones of the embankment. Indeed,
the relative density of the materials constituting the embankment and its foundation
can easily be determined by an extensive series of penetrometer tests. According to
the test results, it will be possible to characterize the seismic risk for a given
embankment at a first attempt.
The numerical model studied is presented in Figure 10.16. The embankment is
assumed to be homogeneous and constructed with soils coming from the foundation.
The embankment is 8 m high and its slope is H/V = 3/1. The model is made of 3,102
quadrilateral elements and 3,254 nodes, and is 217 m long and 33 m high.
Figure 10.16. Geometry and meshing of the numerical model
The mechanical properties have been simplified on purpose. The relative density
is assumed to be identical in the foundation and in the embankment. Four values
were used: 30%, 50%, 70%, and 100%. The mechanical properties, dependent on
the relative density, are provided in Table 10.5.
The failure criterion is expressed as follows:
tan ϕ = 0.22*log( p'c/p' ) + 0.726
The hydraulic characteristics are the following: for the alluviums a horizontal
permeability of 2 -3 m/s and a vertical permeability of 5 -4 m/s, assumed to be the same
for the embankment and the foundation and independent of the relative density.