The
behaviour
of
compacted
bentonite upon hydration is n
umerically investigated
here
by
simu-
lating
a
swelling pressure test
on
a
MX
-
80 bentonite
sample
. Two constitutive models
are
employed in the
analysis
:
the “Imperial College Single
-
Structure Model” (ICSSM)
and
the “Imperial College Double
-
Structure
Model” (
ICDSM), the latter
specifically developed for expansive clays. It is shown that the latter exhibits a
considerably improved performance as it
is able
to
accurately
capture the swelling pressure developed
in
the
material
upon wetting
. Nevertheless,
a
limite
d knowledge
of the evolution
of the material’s fabric, notably at
the micro
-
scale,
is an obstacle for deriving with certainty some of the model parameters
.
This issue is high-
lighted
here
by
performing analyses of
the
swelling pressure test with two
sets of
material characterisations,
with model parameters
differ
ing
i
n
the
derivation of the
microstructural
component
.
B
oth analyses
show
a
very good match with the test
data
,
but it is difficult to justify one set of microstructural parameters
over
the
other.
T
he paper emphasises what aspects of experimental research could be helpful in studying the fabric of
compacted bentonite upon wetting, and hence improve the calibration
procedure of the
double
-
structure mod-
el.