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10° 10' 1
Frequency (Hz)
10° 10 1 Fig.9 Acceleration Time History of
Frequency (Hz)
/ n^wr Motion
c
Fig. 8 Spectral Ratio to Doubled Input Motion
Fig. 10 Parameters describing the shape
of sliding Surface
surface is generated only inside the model, which means size of sliding block is limited by some
reasons in an actual slope. While Fig. 12 shows the critical surface when no limitation is considered.
The safety factor with the limitation is 2.38 and the safety factor without the limitation is 2.20. For the
comparison, 2-d analysis is also performed, and the obtained safety factor is 2.14, In the case without
the limitation, the shape of sliding surface is close to the shape obtained by 2-d analysis and the
directions of excitation and sliding are close to the direction of the steepest of the slope. This result
suggests us that the critical state without the limitation is close to the state of two dimensional analysis.
On the other hand, Fig. 11 suggests that the shape of sliding surface, directions of excitation and sliding
becomes complicated, if there is some limitations with respect to the area of sliding surface.
The same analysis for Type-2 model with the limitation is performed. The critical surface is shown
in Fig. 13. The direction of sliding and excitation are close to the steepest direction of the slope
although the limitation is considered. It can be interpreted that the response around the 3-d comer of
the slope of Type-2 is smaller than that of 2-d slope so that the critical slope tends to be formed to
avoid 3-d corner of the slope. The obtained safety factor for Type-2 slope is 2.60, which is larger than
that of Type-1 model.
Table 1 Properties of Model
Upper
Lower
Unit Weight
(kN/m 3 )
17.8
16.8
Poisson's
Ratio
0.48
0.45
Shear
Velocity
(m/s)
338.0
499.0
Cohesion
(kPa)
98.1
1500.0
Internal Friction
(degree)
38.6
0.0
Tensile Strength
(kPa)
0.0
222.0