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Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
Displacements-time profile at the toe and the crest obtained
by the analysis are in good agreement with the test results as
shown in Figure 10. Figure 11 shows the distribution of
at
the end of the dynamic loading, in which
/
(
: plastic deviatoric strain increment). It can be seen that the
several strain localization zones appear from the toe of the
embankment to the crest. In addition, another strain localization
zone can be seen in the base ground, which is consistent with
the test results (Figure 4).
The distribution of pore water pressure is shown in Figure
12. It is seen that the pore water pressure increases in the
seepage area. Figure 13 shows the skeleton stress decreasing
ratio SSDR (defined as
1
⁄
,
: current mean skeleton
stress,
: initial mean skeleton stress) at the end of the
dynamic loading. The higher SSDR is observed just below the
toe of the embankment. This suggests that the decrease in the
mean skeleton stress due to the increase in pore pressure
induces the large deformation of the embankment with water
infiltration.
4 CONCLUSIONS
Dynamic behaviors of unsaturated embankment considering
seepage flow have been studied through the centrifugal model
tests and their numerical simulation. For the seepage process,
the unsaturated seepage flow has been observed in the
experiment, and the seepage area of numerical simulation has
been similar to that of experiment. It is found in the dynamic
loading process that the infiltration of water into the unsaturated
embankment has induced the large deformation in the seepage
area due to the generation of pore water pressure in the
embankment. The numerical results have provided that the
increase in the pore pressure leads to the decrease in the mean
skeleton stress in the seepage area, in particular, just below the
toe of the embankment.
5 ACKNOWLEDGEMENTS
This research was supported in part by the National Institute for
Land and Infrastructure Management, MLIT, Japan (Grant for
research and development of technologies for improving the
quality of road policy, No. 21-4, 2009-2012).
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.
Figure 8. Pore water pressure-time profile during the seepage process
Figure 9. Distribution of pore water pressure at 24 hours of the seepage
process (unit: kPa)
Figure 10. Displacements-time profile during the dynamic loading
process
Figure 11 Distribution of
at 30 seconds of the dynamic loading
process (max: 0.240)
Figure 12 Distribution of the pore water pressure at 30 seconds of the
dynamic loading process (Unit: kPa, max: 109.0kPa)
Figure 13 Distribution of SSDR at 30 seconds of the dynamic loading
process
0
4
8 12 16 20 24
0
10
20
30
40
50
P4
P3
P2
P1
P2
P3
P4
Pore pressure (kPa)
Time (hour)
P1
0
5 10 15 20 25 30
-0.4
-0.3
-0.2
-0.1
0.0
0.1
Vertical disp. (Crest, sim.)
Vertical disp. (Crest, exp.)
Vertical disp. (Toe, sim.)
Vertical disp. (Toe, exp.)
Horizontal disp. (Toe, sim.)
Horizontal disp. (Toe, exp.)
Displacement (m)
Time (sec)