Civil Engineering Reference
In-Depth Information
FIGURE 9.18
The shear force and normal force acting between each slice for the pseudostatic slope sta-
bility analysis. These forces are also known as the interslice forces. The SLOPE/W computer program was
used to generate the plot (Geo-Slope 1991).
2.
Peak ground acceleration a
max
: The peak ground acceleration
a
max
represents the high-
est value of the horizontal ground acceleration. In essence, this is the amplitude of the
maximum acceleration pulse. The greater the difference between the peak ground accel-
eration
a
max
and the horizontal yield acceleration
a
y
,
the larger the downslope move-
ment.
3.
Length of time:
The longer the earthquake acceleration exceeds the horizontal yield
acceleration
a
y
,
the larger the downslope deformation. Considering the combined effects
of items 2 and 3, it can be concluded that the larger the shaded area shown in Fig. 9.19
a,
the greater the downslope movement.
4.
Number of acceleration pulses:
The larger the number of acceleration pulses that
exceed the horizontal yield acceleration
a
y
,
the greater the cumulative downslope move-
ment during the earthquake.
Many different equations have been developed utilizing the basic Newmark
(1965) method as outlined above. One simple equation that is based on the use of two
