Environmental Engineering Reference
In-Depth Information
The stiffness coefficients are calculated according to Table
12.2
in Sect.
12.2.3
.
For example, the stiffness and damping coefficients for the translational degree of
freedom of the platform over soft soil are obtained as
¼
8
3
10
6
11
:
3
2
0
:
35
K
x
¼
8G
S
r
F
2
t
S
¼
1
:
644
10
8
N/m
ð
12
:
21
Þ
p
3
10
6
1600
p
G
S
q
S
C
x
¼
4
:
6r
F
2
t
S
¼
4
:
6
11
:
3
2
2
0
:
35
¼
2
:
466
10
7
Ns/m
ð
12
:
22
Þ
Repeating the calculation for each of the six degrees of freedom, the stiffness
and damping matrices for the soft soil can be completed (Eq.
12.23
-
12.24
).
Table
12.10
contains the whole set of spring-dashpot coefficients for the three
different soil types.
2
3
0
:
164
0
:
164
4
5
sym
0
0
0
:
209
10
9
N
=
m
K
¼
ð
12
:
23
Þ
17
:
759
0
0
0
17
:
759
0
0
0
0
0
0
0
0
0
23
:
086
2
4
3
5
0
:
025
0
:
025
sym
0
0
0
:
046
10
9
N
s
=
m
C
¼
ð
12
:
24
Þ
0
0
0
1
:
303
0
0
0
0
1
:
303
0
0
0
0
0
0
:
918
Table 12.10
Spring-dashpot coefficients for the three soil types
Soil type
DOF
Stiffness K [N/m]
Damping C [N s/m]
1.644
10
8
2.466
10
7
Soft soil
Horizontal
2.086
10
8
4.627
10
7
Vertical
1.776
10
10
1.303
10
9
Rocking
2.309
10
10
9.178
10
8
Torsional
6.381
10
9
1.650
10
8
Medium hard soil
Horizontal
7.749
10
9
2.961
10
8
Vertical
6.596
10
11
8.337
10
9
Rocking
9.235
10
11
6.325
10
9
Torsional
2.583
10
11
1.300
10
9
Hard soil
Horizontal
3.013
10
11
2.242
10
9
Vertical
2.565
10
13
6.468
10
10
Rocking
3.848
10
13
4.949
10
10
Torsional
