Environmental Engineering Reference
In-Depth Information
Rowe [ROW 98] set up a calculation procedure that allows us to take the
presence of holes in correspondence to a wrinkle of the geomembrane into account
(see Figure 16.27). It assumes that the length (
L
w
) of the wrinkle is far greater than
the width (2b) so that the effect of leakage through a circular defect of radius
r
o
(m)
at the ends of the wrinkle can be neglected. The calculation of leakage can then be
carried out referring to the minimum value between the equations [16.11] and
[16.12] related to cases A and B, respectively. Case A corresponds to the situation
where the flow is not limited by the hole, while case B recognizes that the flow may
be controlled by: i) Bernoulli's equation, if the hydraulic conductivity of the sub-soil
is very high; and/or ii) by the capacity of the fluid to drain to the hole. The latter
corresponds to the case examined by Giroud [GIR 97] in which the flow is obtained
(iteratively) from equation [16.12].
Figure 16.27
.
Schematic showing a hole of radius r
0
in a wrinkle of a geomembrane
and the underlying strata together with the head distribution between the geomembrane
and clay liner [ROW 98]
