Geosynthetics April/May 2021 - 14

Modular geosynthetics construction

FIGURE 4 Irregular-shaped geomembrane panels
for a shale oil and gas development project

Hypalon geomembrane. Another example is shown in Figure 4 and consists
of factory-fabricated geomembranes of
various sizes and shapes for secondary
containment at a shale oil and gas development project. In addition to complex
panel geometries, factory fabrication
allows prefabrication of time-consuming
geomembrane accessories, such as pipe
boots, ballast tubes, vents and other custom appurtenances, which greatly reduce
field time and increase the quality of the
welding through the use of controlled
factory conditions and different types of
welding equipment for large and small
pieces (e.g., geomembrane accessories
and seaming). For example, dielectric
welding or seaming is efficient and produces high-quality welds in the factory,
but it cannot be used in the field due to
its size and power requirements. In the
factory, fabricators can also build custom
jigs and ways to weld and produce geomembrane panels and accessories more

FIGURE 5 Large wrinkles developed in a landfill expansion with irregular slopes-due to thermal
expansion-after the HDPE roll goods were deployed and covered with a geocomposite drainage layer.
14

Geosynthetics | April May 2021

efficiently than in the field, which can
significantly reduce costs to the owner.
Irregular geometries are particularly suited to factory-fabricated panels
because individual rolls of geomembrane require longer field time, which is
complicated by day-to-day temperature
fluctuations that result in significant
differential expansion/contraction. For
example, Figure 5 shows a small municipal solid waste landfill cell that was lined
with individual geomembrane rolls during the summer of 2020. Because the
installation required several days, worrisome wrinkles developed. As a result, the
geomembrane installer had to return to
the site one month later to cut out some
of the large wrinkles that had aggregated
even after the geosynthetic drainage
composite was installed above it.

Geomembranes used in
modular construction
Geomembranes that can be used in
modular construction are flexible but
still chemical resistant because they are
rolled or folded in the factory after they
are cut and seamed for shipping to the
site. However, this flexibility provides
many other advantages for the installation and long-term performance of
the geomembrane, including increased
ability to conform to subgrade changes;
increased deformability to subgrade protrusions, bumps and rocks; decreased
number and size of wrinkles because
of greater subgrade contact and lower
bending modulus; lower coefficient of
thermal expansion; and less leakage
because of greater intimate contact with
the underlying subgrade or compacted
soil. If desired, flexible geomembranes
also can be reinforced with a geotextile
scrim fabric to increase dimensional stability and increase intimate contact with
the subgrade to decrease wrinkles and
leakage, increase puncture resistance,



Geosynthetics April/May 2021

Table of Contents for the Digital Edition of Geosynthetics April/May 2021

Geosynthetics April/May 2021 - Cover1
Geosynthetics April/May 2021 - Cover2
Geosynthetics April/May 2021 - 1
Geosynthetics April/May 2021 - 2
Geosynthetics April/May 2021 - 3
Geosynthetics April/May 2021 - 4
Geosynthetics April/May 2021 - 5
Geosynthetics April/May 2021 - 6
Geosynthetics April/May 2021 - 7
Geosynthetics April/May 2021 - 8
Geosynthetics April/May 2021 - 9
Geosynthetics April/May 2021 - 10
Geosynthetics April/May 2021 - 11
Geosynthetics April/May 2021 - 12
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Geosynthetics April/May 2021 - 14
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Geosynthetics April/May 2021 - 20
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Geosynthetics April/May 2021 - 27
Geosynthetics April/May 2021 - 28
Geosynthetics April/May 2021 - 29
Geosynthetics April/May 2021 - 30
Geosynthetics April/May 2021 - 31
Geosynthetics April/May 2021 - 32
Geosynthetics April/May 2021 - 33
Geosynthetics April/May 2021 - 34
Geosynthetics April/May 2021 - 35
Geosynthetics April/May 2021 - 36
Geosynthetics April/May 2021 - 37
Geosynthetics April/May 2021 - 38
Geosynthetics April/May 2021 - 39
Geosynthetics April/May 2021 - 40
Geosynthetics April/May 2021 - 41
Geosynthetics April/May 2021 - 42
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Geosynthetics April/May 2021 - 44
Geosynthetics April/May 2021 - Cover3
Geosynthetics April/May 2021 - Cover4
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-december-2021-january-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-october-november-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-august-september-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-june-july-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-april-may-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-february-march-2021
https://www.nxtbook.com/ifai/geosynthetics/1220GS
https://www.nxtbook.com/ifai/geosynthetics/1020GS
https://www.nxtbook.com/ifai/geosynthetics/0820GS
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