ρw ag
scale factor squared if the seepage force is to be
k=κ
(A26)
w
scaled like the weight force.
where ρw and w are, respectively, the density
and the viscosity of the fluid phase, and κ is de-
CENTRIFUGE TECHNIQUE
fined as the absolute permeability, which depends
only on the geometry of the soil skeleton. Because
The centrifuge is used to approximate the con-
ρw, w and κ do not depend on gravity, it follows
dition of eq A10 by subjecting a model to the con-
stant angular velocity Ω such that the following
that
km ag m
approximate relation holds:
1
=
=
.
(A27)
kp
ag p
Kl
r Ω2
ag m
1
≈
=
(A30)
Thus eq A25 becomes
ag p
Kl
ag p
Kl4
=
KFs
.
(A28)
Kt
ity, r is a representative radius of the model from
the axis of rotation (Cooke 1991), and rΩ2 is the
Because KFs must equal KF = Kl2 , then
radial centripetal acceleration of the model at this
Kt = Kl2 .
radius. In the centrifuge modeling literature, N
(A29)
or n is often used as the symbol for the inverse of
That is, the time scale factor is equal to the length
the length scale factor, i.e., 1/Kl.
13
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