Geosynthetics August/September 2020 - 23

with a geotextile, a drainage layer is created between the geotextile and IDS geomembrane sheet, as shown in Figure 2.
AGRU Super Gripnet 50-mil (1.25mm) HDPE liner was selected as the
IDS geomembrane and Agrutex 081, a
nonwoven IDS geotextile, was selected
for the test pad. AGRU specifications
require the geotextile overlying the IDS
geomembrane to be nonwoven.
Subgrade protrusions of 1 inch (2.5
cm) and final cover soil rocks up to 9
inches (22.9 cm) in dimension were used
in the test pad to determine whether these
features would damage the IDS geotextile
or puncture the IDS geomembrane. One
half of the test pad was constructed in
two lifts: 12-inch (30.5-cm) lift overlain
by a 6-inch (15.2-cm) lift (Figure 3), and
one half of the test pad was constructed in
one 18-inch (45.7-cm) lift (Figure 4). The

additional 18 inches placed over the lower
bench (Figures 3 and 4) will be discussed
in Part 2 of this article. The test pad was
two geomembrane roll widths wide, minus
overlaps to seam. As the roll width of the
IDS geomembrane is 23 feet (7.0 m), the
test pad is 46-feet (14.0-m) wide. It is recommended by the GRI Guide GS11 that
the test pad width be at least 100% greater
than the equipment width for each tested
condition. The crawler tractor (dozer)
used on the test pad was 8.2-feet (2.5-m)
wide; therefore, the GS11 guidance on
width was met for the use of the dozer.
The test pad length consisted of one
20-foot (6.1-m) wide upper bench, a
63-foot (19.2-m) slope length, plus one
20-foot (6.1-m) wide lower bench, for
a total length of 103 feet (31.4 m). The
slope length of 63 feet (19.2 m) exceeded
the GS11 length requirement of 300% of

Subgrade protrusions
of 1 inch (2.5 cm) and
final cover soil rocks
up to 9 inches (22.9
cm) in dimension were
used in the test pad
to determine whether
these features would
damage the IDS
geotextile or puncture
the IDS geomembrane.

FIGURE 4 Test pad cross section,
subareas D, F and B

8 oz/yd2 (271 g/m2) Nonwoven Geotextile
(Installed in Contact with the IDS
Geomembrane)
IDS Geomembrane (Installed in Contact with the Subgrade)
Prepared Subgrade
Temporary Soil Cover
Upper Bench
Top of CCR
Top

al
of Fin

r Soil

Cove

rea B

8 oz/yd2 (271 g/m2) Nonwoven Geotextile

Suba

20 ft (6.1 m)
6.1 m (20 ft)

SUBAREA DD
Subarea

18 in (46 cm)
Lifts
Unprocessed
Soil (see
Note 1)

SUBAREA F
Subarea
F

IDS Geomembrane

Top of CCR

See Detail A

Min. 6 in (15 cm)Temporary Cover Soil
Prepared Subgrade
See Detail A
20'
20 ft (6.1
m)

Prepared Subgrade
Added Protrusion (No. 57 Aggregate)
Added Protrusion
IDS Geomembrane
Nonwoven Geotextile
Hard Angular Rock, Approximate Maximum Dimension
9 in (23 cm)

Note:
1. Unprocessed soil had rocks and woody material
greater than 9 in (23 cm) in any dimension removed
prior to placement.

GAI FILE NUMBER:

FIGURE: 3

GAI DRAWING NUMBER:

C130109-05-A2-003

003

www.GeosyntheticsMagazine.com
23
DRAWN
BY: CHECKED BY: APPROVED BY:

PROJECT

CLIENT

MAYHOEJ

TEST PAD CROSS SECTION

APPALACHIAN POWER CO.

SHEET NO.:

SCALE:

SUBAREAS D, F, AND B

JOHN E. AMOS LANDFILL

OF

N.T.S

Figure 3. Test Pad Cross Section Subareas D, F, and B
0820GS_p20-27.indd 23

ISSUE DATE:

7/22/20 9:30 PM
© 2019 GAI Consultants
http://www.GeosyntheticsMagazine.com
Geosynthetics August/September 2020

Table of Contents for the Digital Edition of Geosynthetics August/September 2020
