Geoscience Reference
In-Depth Information
Stability of stacking
For the entire (assumed) horizontal width of the stacking, three times the width
of a geotextile container is maintained:
B
tot
25.2 m;
For the height of the shear susceptible layer of geotextile containers,
D
t
=
3
⋅
b
=
=
b
⋅
sin(
α
)
=
2.7 m must be maintained;
H
s
=
3 m will be evaluated;
b/D
car
=
5.25. Choose formula (6.17) for safety purposes:
⎛
⎞
⎛
⎞
⎟
Φ
D
Φ
27
25 2
=
ln
0
31
⎛
t
0
04
100
Φ
0
31
⎛
⎝
004
1000
40
+
⎠
+
⇒
⇒
+
⎠
+
=
⎛
⎜
⎛
⎝
t
+
.
0
⋅
=
⋅
⎜
⇒
0
.
000
.
H
⎝
B
H
.
s
tot
H
s
Φ=
04
H
s
12
m
⋅
=
4
1
.
According to formula (6.20):
gh
1000 9. 11
⋅
28
⋅
ρ
⋅
g
⋅
t
.
300 kN
/
m
F
w
g
s
=
=
=
sin(
18
F
sin
.)
α
To determine the submerged weight
G
, the entire layer of containers has to be
considered: the total height of the stacking
h
st
10 m formed by the six stacked geo-
textile containers (each container is proximally 1.6 m in height).
The downward force
G
of the containers under water per metre run can now be
found using:
=
number of containers
(
n
(
)
gA
⋅
−
⋅
g
⋅
ρ
s
w
s
w
=−
(
1
0 4
. ) (
⋅
2650
−
1000
)
⋅
9 81 10 8 6
.
⋅
.
⋅
=
629 kN/m
For the stability of the stacking formula (6.19) applies:
sin
sin(
18
43
F
GF
300
.)
α
⋅
⋅
0 275
.
f
F
=
=
=
629
m
300
cos(
18
.)
43
α
cos
F
⋅
−⋅
F
According to formula (6.21):
complies
f
<
30
°
35
°=
0. 8070
tan
°
t
⇒
an
.
Placement accuracy at 10 m water depth
The placement accuracy can be determined in two ways (see Appendix H):
1
s
h
32
08
.m
8
−=
h
3
p
2
chD
07
10 16
280
s
80
m
c
⋅
D
=
=
⋅
⋅
50
7
10 1
p
0.8 m is based on the formula derived from measurements obtained at
Kandia dam during the placement of geotextile containers. If the drop area under
The
s
p
=
