Civil Engineering Reference
In-Depth Information
v
24. The shear modulus of the bearing chalk, allowing for disturbance due to pile
installation, may be taken as
G
=
0
.
=
36 MPa (Lord, 1976). Young's modulus of the piles
is
E
p
=
28 000 MPa.
The various parameters may be calculated as
G
L
=
12 MPa
;
ρ
=
0
.
5
;
ξ
=
G
L
/
G
b
=
0
.
33
;
l
=
E
p
/
G
L
=
2333
tanh(
μ
L
)
L
d
=
L
/
d
=
23
.
5
;
ζ
=
3
.
1(from equation (4.40))
;
μ
L
=
0
.
78
;
19
.
6
μ
L
Thus
2
2
π
×
0
.
5
33
+
×
19
.
6
P
t
0
.
76
×
0
.
3
.
1
w
t
=
dG
L
×
=
157 kN/mm
1
π
l
8
1
+
33
×
19
.
6
0
.
76
×
0
.
For a working load of l000 kN, the settlement will therefore be 1000/157
=
6.4 mm.
4.2.3 Layered soil profiles
The solution described above may be extended or adapted to different conditions,
such as to deal with step-tapered piles or piles that penetrate more than one soil type
(with widely differing soil stiffnesses). Essentially each section of the pile shaft may be
treated independently, retaining compatibility of displacement of the pile shaft between
each section (see Figure 4.29). Effectively, the load settlement ratio for the pile base
Figure 4.29
Modelling of pile in layered soil.
