Civil Engineering Reference
In-Depth Information
Figure 19.23
Trench supported by propped sheet piles.
Figure 19.24
Mechanism of collapse for trench in Figure 19.23.
(for a slice 1 m thick out of the page) are
Q
=
qH
=
80
×
5
=
400 kN
1
2
H
2
1
2
5
2
W
=
γ
=
×
20
×
=
250 kN
δ
=
From the displacement diagram, for
v
1,
√
2
δ
v
=
δ
h
=
1 and
δ
w
=
Hence, from Eq. (19.8), the work done by the external forces is
P
u
From Eq. (19.13), the work dissipated in the slip plane with length 5
√
2mis
δ
E
=
Q
δ
v
+
W
δ
v
−
P
u
δ
h
=
400
+
250
−
5
√
2
√
2
δ
W
=
s
u
L
δ
w
=
40
×
×
=
400
Hence, equation
δ
E
=
δ
W
,
P
u
=
400
+
250
−
400
=
250 kN
