Civil Engineering Reference
In-Depth Information
FIGURE 10.5c
Example problem (
continued
). Calculation of the maximum bearing stress and the factor
of safety for sliding. (
From Lambe and Whitman 1969, reproduced with permission of John Wiley & Sons.
)
with wall friction, the active earth pressure is still a triangular distribution acting upon the
retaining wall, and thus the location of the active earth pressure resultant force
P
A
is at a distance of
1
3
H
above the base of the wall, or 6.7 feet (2.0 m).
Passive Earth Pressure.
As shown in Fig. 10.5
a,
the passive earth pressure is developed
by the soil located at the front of the retaining wall. Usually wall friction is ignored for the
passive earth pressure calculations. For the example problem shown in Fig. 10.5, the passive
resultant force
P
p
was calculated by using Eqs. (10.3) and (10.4) and neglecting wall friction
and the slight slope of the front of the retaining wall (see Fig. 10.5
c
for passive earth pres-
sure calculations).
