leachate flow in leakage collection layers due to defects in ...

GIROUD et al. D Leachate Flow in Leakage Collection Layers Due to Geomembrane Defects
t
avg L
=
A
wmax
Vmax
/cosb
(158)
It should be noted that the notation used for the average leachate thickness is t avg L (for
x = L), and not t avg max , since a large wetted zone leads to a relatively small value (not
a maximum value) of t avg .
Combining Equations 62, 157 and 158 gives:
t = ( 3/ 2) Lsinb
avg L
(159)
( + 32
1 2Lsin b / t ) / - 1
Combining Equations 10 and 159 gives the following equation for the case where the
leakage collection layer is not full:
t
avg L
=
( 3/ 2) Lsinb
32 /
1+ 2Lsin b k / Q)
-1
d
o
i
(160)
Combining Equations 17 and 159 gives the following equation for the case where the
leakage collection layer is full:
t
avg L
=
L
N
M
1 +
t
LCL
( 3/ 2) L sinb
4 L sinb
F Q
1 +
2
kt
HG
LCL
O
I
KJ
Q
P
32 /
- 1
(161)
5.1.4 Leachate Thickness in Case II
Case II (Figure 13b) is a case that may frequently occur. Since it is not easy to develop
an analytical solution for this case for the reasons indicated in Section 5.1.1, an interpolation
method is proposed.
The limit situation between Cases I and II (Figure 13) is illustrated in Figure 14a. This
situation occurs when:
to
F mI x = L - = L 1 - K J
(162)
2 sinb 2
HG
Combining Equations 154 and 162 gives:
L sinb
5
-
3 to
to
18
tavg lim
=
32 /
2 F 2 L sinbI
t
HG
o
KJ
(163)
260 GEOSYNTHETICS INTERNATIONAL S 1997, VOL. 4, NOS. 3-4