Civil Engineering Reference
In-Depth Information
Fig. 8.14
Example
8.3.
Minimum depth is required, and since F
p
=
2.0 has already been applied to the pressure dis-
tribution (see Section
8.6.1
),
5
d
3
9
2 5
d
3
0
0
=
=
1
10
9
(
+
d
)
3
3
(
5
+
d
)
0
0
d
=
.
7 7
m
0
To obtain the design depth, d, d
0
is increased by an amount equal to the extent required to
generate a net passive resistance force below the point of rotation at least as large as R. (R is
obtained from simple horizontal force equilibrium). This demands additional calculations and it
is common practice to avoid this by simply increasing d
0
by 20 per cent to give d.
i e d
. .,
= ×
d
0
1 2
.
=
7 7 1 2
.
×
.
=
9 24
.
m
.
8.6.3 Anchored and propped walls
When the top of a sheet pile wall is anchored, a considerable reduction in the embedment depth can be
obtained. Due to this anchorage the lateral yield in the upper part of the wall is similar to the yield in a
timbered trench (see Section
8.7)
, whereas in the lower part the yield is similar to that of a retaining wall
yielding by rotation. As a result the pressure distribution on the back of an anchored sheet pile is a com-
bination of the totally active and the arching-active cases, the probable pressure distribution is indicated
in Fig.
8.15b
. In practice the pressure distribution behind the wall is assumed to be totally active.
T
T
A
A
h
l
p
l
a
P
a
P
p
d
(a) Anchored sheet pile wall
(b) Distribution assumed for design
Fig. 8.15
Free earth support method for anchored sheet piled walls.
