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Figure 20
Continued.
that an impermeable facing as used in the RRR method could be an effective
countermeasure.
Figure 20a and b show the measured and calculated contours of water
contents for Section 3-A of the test embankment at the end-of-infiltration test. It
is seen that the influenced zone (the area bounded by the contour of initial
volumetric water content u
26%) was underestimated in the analysis in both
vertical and horizontal directions. The underestimation for the extent of
influenced zone might result from the unrealistic permeability coefficients
obtained in the in-lab permeability test. It is considered that the voids and the
bedding planes that control the seepage characteristics of compacted clay in the
embankment may not be properly simulated in the in-lab permeability tests.
Calibration for the input parameters based on the measured water content
distribution on Section 3-A was performed. A trial-and-error process was adopted
to modify the calculated values of vertical permeability and horizontal
permeability coefficients, k
0
v
and k
0
h
. Fig. 20c shows an example of calculated
distribution of water content similar to that shown in Fig. 20a. In this case,
k
0
v
=
6
20, k
0
h
=
16 (k
v
and k
h
: the permeability coefficients measured in-lab
using undisturbed samples from Section 3-A), in order to obtain a similar pattern
of water content distribution to that observed in the field.
k
v
¼
k
h
¼
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