1604
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
3 SPECIFICATION OF E-DEFENSE
Table 1 shows a specification of E-Defense. E-Defense is the
world’s largest shaking table having the size of 20 m by 20 m,
which can simulate high level ground motions. The maximum
payload is reaced to 12 MN so that various full-scale models
can be tested by this equipment.
4 LARGE SLOPE MODEL
Two large slope models having one layer and three layers were
constructed for the shaking table test. One layered slope model
was constructed to evaluate the response characteristics during
seismic excitation. Three layered slope model was constructed
to evaluate the deformation characteristics during seismic
excitation and confirm the failure mode. In this paper, only the
shaking table test using one layered slope model is described.
Figure 1 shows the slope model configuration and arrangement
of measurement equipments. The height and width of this model
are 3.8 m and 4.5 m, respectively. This model was consists of
general soil and reinforced soil layers assumed as weathered
layers on the hard rock layer as shown in Table 2. The hard rock
layer was constructed using cement-mixed gravel which
consisted of a weight ratio of 100:4:7 of gravel, cement and
water. The target wet density was 19.6 kN/cm
3
. The general
layer consisted of a weight ratio of 100:7:10 of silica sand,
bentonite and water. The target wet density was 16.2 kN/cm
3
.
The reinforced layer consisted of a weight ratio of 100:10:10 of
silica sand, bentonite and water. The target wet density was
16.2 kN/cm
3
. In this test, the slip surface was ssumed to be
generated in the general soil layers so that geogrids having
strength of 30 kN/m were installed in the reinforced layers.
5 INPUT WAVES
At first, the shaking table tests were carried out with the
sinusoidal wave having only the horizontal component and both
the horizontal and vertical components in series to investigate
the basic effect of vertical acceleration against the dynamic
Table 1. Specification of E-Defense.
Table size
20 m × 15 m
Payload
12 MN
Shaking direction
Horizontal
Vertical
Max. acceleration
900 gal
1,500 gal
Max. velocity
200 cm/s
70 cm/s
Max. displacement
100 cm
50 cm
Figure 1. Slope model configuration and arrangement of measurement
equipment.
response of the slope. Subsequently, a seismic wave recorded at
the Niigataken Chuetsu-oki Earthquake having both the
horizontal and vertical components was applied to the slope
model to investigate the effect of iregular motion having both
the horizontal and vertical components. Figure 2a) shows orbits
in cases of sinusoidal seismic waves without phase difference
and with a phase difference of 180 in degrees. Figure 2b) shows
the orbit of recorded seismic excitation used in this study. For
positive and negative direction of accelerations, a forward of
slope is positive in the horizontal direction and a upward is
positive in the vertical direction. Here, the sliding failure
probably occures along the slope inclination, therefore it can be
considered that the most effective direction in the inertia force
caused by seismic load against the sliding failure is the parallel
direction of slope inclination. This means that the phase
difference between the horizontal and vertical directions
becomes 180 in degrees as shown in Figure 2a). Figure 3 shows
time histories of horizontal and vertical accelerations of the
recorded seismic excitation. The target horizontal and vertical
acceleration were 700 and 470 gal, respectively. In the shaking
table tests, the horizontal acceleration was applied with a step of
100 gal from the start of the horizontal acceleration level of 100
gal.
Table 2. Strength property.
Peak state
Residual state
Material
Friction
angle
(in degrees)
Cohesion
(kPa)
Friction
angle
(in degrees)
Cohesion
(kPa)
General
soil
31.4
11.06
32.8
4.45
Reinforced
soil
29.3
13.38
31.4
5.55
-400 -200 0 200 400
-400
-200
0
200
400
a)
Vertical acceleration (gal)
Horizontal acceleration (gal)
Phase difference of
180 in degrees
No phase difference
-1000 -500 0 500 1000
-1000
-500
0
500
1000
b)
-654 gal
625 gal
-455 gal
537 gal
Vertical acceleration (gal)
Horizontal acceleration (gal)
Figure 2. Orbits between horizontal and vertical accelerations on the
shaking table; a) sinusoidal excitation, b) recorded seismic excitation.
12 14 16 18 20 22 24 26 28 30
-1000
-500
0
500
1000
Horizontal
acceleration (gal)
Time (s)
a) Horizontal acceleration.
b) Vertical acceleration.
Figure 3. Record seismic wave with amplitude adjustment.
450
4500
400
550 550 650 700 500
300@8
□ × 19
■ × 13
○ × 4
△ × 19
▲ × 13
× 8
× 16
□
Horizontal accelerometer (2G)
△
Vertical accelerometer (2G)
■
Horizontal acceleration in the back (2G)
▲
Vertical acceleration in the back (2G)
○
Piezoelectric accelerometer
Displacement transducer
Laser displacement sensor
12 14 16 18 20 22 24 26 28 30
-1000
-500
0
500
1000
Vertical
acceleration (gal)
Time (s)
Reinforced soil
