U.S. Std. Sieve Size and No.
Hydrometer
3/
3
4
10 20 40
140 200
4
0
100
20
80
40
60
60
40
80
20
100
0
1000
100
10
1
0.1
0.01
0.001
Grain Size (mm)
Figure 3. Typical grain size distribution for
soil collected from pond bottom in Eagle River
Gravel
Sand
Cobbles
Silt or Clay
Flats, Alaska (from Lawson and Brockett 1993).
Coarse
Fine
C'rse Medium
Fine
Table 1. Properties of geotextiles tested.
AOS1
Permittivity2
(sec1)
Geotextile
Product
Construction
(mm)
A
Texel F-300
NW PET
0.040.05
0.31
B
Texel Geo 9
NW PET,
0.060.125
1.72
reinforced
C
Amoco L17811
NW PP
0.075
not available
D
Amoco 4551
NW PP
0.150
1.9
1
Apparent opening size: A property that indicates the approximate largest
particle diameter that would effectively pass through the geotextile.
2 Permittivity of geotextiles refers to the volumetric flow rate of water per
unit cross-sectional area per unit head under laminar flow conditions, in the
normal direction.
Notes: NW = nonwoven, PET = polyester, PP = polypropylene
Several means of sampling soil-laden water for
PROCEDURE
total suspended solids (TSS) were tested before
The testing for this project consisted of two
the start of the experimental program by mixing
150 g of dry soil with 500 mL of water in a labora-
parts. Part I tests were conducted according to
tory blender before adding it to 49.5 L of water.
ASTM D 5141, Standard Test Method for Determin-
ing Filtering Efficiency and Flow Rate of a Geotextile
(These are the amounts of soil and water recom-
for Silt Fence Application Using Site-Specific Soil
mended by ASTM D 5141.) The soilwater mix-
ture was placed in a 0.5-m-diameter 0.75-m-
(ASTM 1992). Thus, an accepted engineering stan-
dard was used to compare candidate geotextiles.
high plastic container, and vigorously stirred with
Part II tests simulated field conditions, and were
a 0.25-m-wide paint stirrer attached to an electric
conducted to determine whether the candidate
drill. Samples were collected with a commercially
geotextile selected from the Part I tests was likely
available 250-mL-capacity water sampler while
to perform well. Procedures followed in both ex-
the water was still being agitated. This resulted in
periments are included in Appendix A. Figure 4 is
TSS determinations within 2% of the known TSS
a diagram of the flume used for the tests, includ-
from the quantity of oven-dry soil added to the
ing a gate that was added for Part II tests.
water. The PVC Coliwasa water sampler used is
3
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