ASTM D6706-01
(Test Method)Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil
Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil
SCOPE
1.1 Resistance of a geosynthetic to pullout from soil is determined using a laboratory pullout box.
1.2 The test method is intended to be a performance test conducted as closely as possible to replicate design or as-built conditions. It can also be used to compare different geosynthetics, soil types, etc., and thereby be used as a research and development test procedure.
1.3 The values stated in SI units are to be regarded as standard. The values stated in parentheses are provided for information only.
1.4 This standard may involve hazardous materials, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D6706–01
Standard Test Method for
Measuring Geosynthetic Pullout Resistance in Soil
This standard is issued under the fixed designation D 6706; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.3 cross-machine direction, n—the direction in the plane
of the geosynthetic perpendicular to the direction of manufac-
1.1 Resistance of a geosynthetic to pullout from soil is
ture.
determined using a laboratory pullout box.
3.1.4 failure, n—a defined point at which a material ceases
1.2 The test method is intended to be a performance test
to be functionally capable of its intended use.
conducted as closely as possible to replicate design or as-built
3.1.5 geosynthetic, n—a planar product manufactured from
conditions. It can also be used to compare different geosyn-
polymeric material used with soil, rock, earth, or other geo-
thetics, soil types, etc., and thereby be used as a research and
technical engineering related material as an integral part of a
development test procedure.
man-made project, structure, or system. (D 4439)
1.3 The values stated in SI units are to be regarded as
3.1.6 junction, n—thepointwheregeogridribsareintercon-
standard. The values stated in parentheses are provided for
nected in order to provide structure and dimensional stability.
information only.
3.1.7 machine direction, n—the direction in the plane of the
1.4 This standard may involve hazardous materials, and
geosynthetic parallel to the direction of manufacture.
equipment. This standard does not purport to address all of the
3.1.8 pullout, n—the movement of a geosynthetic over its
safety concerns, if any, associated with its use. It is the
entire embedded length, with initial pullout occurring when the
responsibility of the user of this standard to establish appro-
back of the specimen moves, and ultimate pullout occurring
priate safety and health practices and determine the applica-
when the movement is uniform over the entire embedded
bility of regulatory limitations prior to use.
length.
2. Referenced Documents
3.1.9 pullout force, (kN), n—force required to pull a geo-
synthetic out of the soil during a pullout test.
2.1 ASTM Standards:
3.1.10 pullout resistance, (kN/m), n—the pullout force per
D 123 Definitions of Terms Relating to Textiles
width of geosynthetic measured at a specified condition of
D 653 Terminology Relating to Soil, Rock and Contained
displacement.
Fluids
3.1.11 rib, n—the continuous elements of a geogrid which
D 2905 Statement on Number of Specimens Required to
are either in the machine or cross-machine direction as
Determine the Average Quality of Textiles
manufactured.
D 3080 Method for Direct Shear Test of Soils Under Con-
3.1.12 ultimate pullout resistance, (kN/m), n—the maxi-
solidated Drained Conditions
mum pullout resistance measured during a pullout test.
D 4354 Practice for the Sampling of Geotextiles
3.1.13 wire gage, n—a displacement gage consisting of a
D 4439 Terminology for Geotextiles
non extensible wire attached to the geosynthetic and monitored
3. Terminology
by connection to a dial extensometer, or electronic displace-
ment transducer.
3.1 Definitions of Terms Specific to This Standard:
3.2 For definitions of other terms used in this test method
3.1.1 apertures, n—the open spaces in geogrids which
refer to Terminology D 123, D 653, and D 4439.
enable soil interlocking to occur.
3.1.2 atmosphere for testing geosynthetics, n—air main-
4. Summary of Test Method
tained at a relative humidity of 60 6 10 % and a temperature
4.1 Inthismethod,ageosyntheticisembeddedbetweentwo
of 21 6 2°C (70 6 4°F).
layers of soil, horizontal force is applied to the geosynthetic
and the force required to pull the geosynthetic out of the soil is
This test method is under the jurisdiction of ASTM Committee D35 on
recorded.
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
4.2 Pullout resistance is obtained by dividing the maximum
cal Properties.
Current edition approved Sept. 10, 2001. Published October 2001. load by the test specimen width.
Annual Book of ASTM Standards, Vol 07.01.
4.3 The test is performed while subjected to normal com-
Annual Book of ASTM Standards, Vol 04.08.
4 pressive stresses which are applied to the top soil layer.
Annual Book of ASTM Standards, Vol 04.13.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6706–01
4.4 A plot of maximum pullout resistance versus applied the front as defined by the direction of applied pullout force.A
normal stress is obtained by conducting a series of such tests. typical box is shown in Fig. 1.
6.1.1 The box should be square or rectangular with mini-
5. Significance and Use
mum dimensions 610 mm (24 in.) long by 460 mm (18 in.)
5.1 The pullout test method is intended as a performance
wide by 305 mm (12 in.) deep, if sidewall friction is mini-
test to provide the user with a set of design values for the test
mized, otherwise the minimum width should be 760 mm (30
conditions examined.
in.). The dimensions should be increased, if necessary, so that
5.1.1 The test method is applicable to all geosynthetics and
minimum width is the greater of 20 times the D85 of the soil
all soils.
or 6 times the maximum soil particle size, and the minimum
5.1.2 Thistestmethodproducestestdata,whichcanbeused
length greater than 5 times the maximum geosynthetic aperture
inthedesignofgeosynthetic-reinforcedretainingwalls,slopes,
size. The box shall allow for a minimum depth of 150 mm (6
and embankments, or in other applications where resistance of
in.) above and below the geosynthetic. The depth of the soil in
a geosynthetic to pullout under simulated field conditions is
theboxaboveorbelowthegeosyntheticshallbeaminimumof
important.
6 times the D85 of the soil or 3 times the maximum particle
5.1.3 The test results may also provide information related
size of the soil, whichever is greater.The box must allow for at
to the in-soil stress-strain response of a geosynthetic under
least 610 mm (24 in.) embedment length beyond the load
confined loading conditions.
transfer sleeve and a minimum specimen length to width ratio
5.2 Thepulloutresistanceversusnormalstressplotobtained
of 2.0. It should be understood that when testing large aperture
from this test is a function of soil gradation, plasticity,
geosynthetics the actual pullout box may have to be larger than
as-placed dry unit weight, moisture content, length and surface
the stated minimum dimensions.
characteristics of the geosynthetic and other test parameters.
NOTE 1—To remove side wall friction as much as possible a high
Therefore, results are expressed in terms of the actual test
density polyethylene (HDPE) geomembrane should be bonded to the
conditions.The test measures the net effect of a combination of
inside surfaces of the pullout box.The sidewalls may also be covered with
pullout mechanisms, which may vary depending on type of
a layer of silk fabric, which has been shown to eliminate adhesion and has
geosynthetic specimen, embedment length, relative opening
a very low friction value. Alternatively, a lubricant can be spread on the
size, soil type, displacement rate, normal stress, and other
sidewalls of the box and thin sheets of polyethylene film used to minimize
factors. the side wall friction. It should be also noted that the effect of sidewall
friction on the soil-geosynthetic interface can also be eliminated if a
5.3 Information between laboratories on precision is incom-
minimum distance is kept between the specimen and the side wall. This
plete. In cases of dispute, comparative tests to determine if
minimum distance is recommended to be 150 mm (6 in.).
there is a statistical bias between laboratories may be advis-
able.
6.1.2 The box shall be fitted with a metal sleeve at the
entrance of the box to transfer the force into the soil to a
6. Apparatus
sufficient horizontal distance so as to significantly reduce the
6.1 Pullout Box—An open rigid box consisting of two stress on the door of the box. The sleeve, as shown in Fig. 2,
smooth parallel sides, a back wall, a horizontal split removable shall consist of two thin plates (no more than 13 mm (0.5 in.)
door, a bottom plate, and a load transfer sleeve. The door is at thick) extending the full width of the pullout box and into the
FIG. 1 Experimental Set-Up for Geosynthetic Pullout Testing
D6706–01
FIG. 2 Cross-Sectional Detail View for Geosynthetic Pullout Setup
pullout box a minimum distance of 150 mm (6 in.) but it is should be monitored during testing, see Note 2.Also, a device
recommendedthatthisdistanceequalthetotalsoildepthabove
to measure the pullout force such as a load cell or proving ring
orbelowthegeosynthetic.Theplatesshallbetaperedasshown
must be incorporated into the system and shall be accurate
in Fig. 2, such that at the point of load application in the soil,
within 60.5 % of its full-scale range.
the plates forming the sleeve are no more then 3 mm (0.12 in.)
NOTE 2—Pullout tests may also be conducted using a constant stress
thick. The plates shall be rigidly separated at the sides with
loading approach. This approach can be achieved using one of the three
spacers and be sufficiently stiff such that normal stress is not
methods described: (1) Controlled Stress Rate Method (short-term loading
transferred to the geosynthetic between the plates.
condition) where the pullout force is applied to the geosynthetic under a
6.2 Normal Stress Loading Device—Normal stress applied
uniform rate of load application, not exceeding 2 kN/m/min until pullout
to the upper layer of soil above the geosynthetic must be
or failure of the geosynthetic is achieved; (2) Incremental Stress Method
constant and uniform for the duration of the test. To maintain
(short-term loading condition) where the pullout force is applied in
a uniform normal stress, a flexible pneumatic or hydraulic
uniform or doubling increments and held for a specific time before
diaphragm-loading device which is continuous over the entire
proceedingtothenextincrement,asagreedtobythepartiesinvolveduntil
pullout box area should be used and capable of maintaining the pullout or failure of the geosynthetic is achieved; and (3) Constant Stress
(Creep) Method (long-term loading condition) where the pullout force is
applied normal stress within 62 % of the required normal
applied using one of the first two methods mentioned above to achieve the
stress. Normal stresses utilized will depend on testing require-
required constant stress for the test. The constant stress is maintained and
ments, however, stresses up to 250 kPa (35 psi) should be
the test specimen is monitored over time for the duration of time agreed
anticipated.Arecommended normal stress-loading device is an
to by the parties involved (i.e., typically 100 to 10,000 h depending on
air bag is shown in Fig. 2.
application). It should be noted that the constant stress procedures
6.3 Pullout Force Loading Device—Pullout force must be
described above, have not been widely researched and comparisons with
supplied by a device with the ability to pull the geosynthetic
the constant strain method have not been determined.
horizontally out of the pullout box. The force must be at the
6.4 Displacement Indicators—Horizontal displacement of
same level with the specimen.The pullout system must be able
the geosynthetic is measured at the entrance of the pullout box
to apply the pullout force at a constant rate of displacement,
and at several locations on the embedded portion of the
slow enough to dissipate soil pore pressures as outlined in Test
specimen. Measurements outside the door at the pullout box
Method D 3080. If excess pore pressures are not anticipated
and in the absence of a material specification, apply the pullout
force at a rate of 1 mm/min 610 percent, and the pullout rate
D6706–01
entrance are made by a dial extensometer or electronic dis- 6.6 Soil Preparation Equipment—Use equipment as neces-
placement transducers (e.g. liner variable differential trans- sary for the placement of soils at desired conditions. This may
formers (LVDT’s) can be used) mounted to the box frame to include compaction devices such as vibratory or “jumping-
read against a plate attached to the specimen near the door. jack” type compaction, or hand compaction hammers. Soil
6.4.1 Determine the displacement of the geosynthetic at a container or hopper, leveling tools and soil placement/removal
minimum of three equally spaced distances from the clamping tools may be required.
plates. Displacement measurements within the box may em- 6.7 Miscellaneous Equipment—Measurement and trimming
ploy any of several methods, which place sensors or gauge equipment as necessary for geosynthetic preparation, a timing
connectors directly on the geosynthetic and monitor their device and soil property testing equipment if desired.
change in location remotely. One such device utilizes wire
7. Geosynthetic Sampling
gages,whichareprotectedfromnormalstressbyasurrounding
7.1 Lot Sample—Divide the product into lots and for any lot
tube, which runs from a location mounted on the specimen to
tobetested,takethelotsamplesasdirectedinPracticeD 4354,
the outside of the box where displacements are measured by a
see Note 4.
dial indicator or electronic displacement transducer. A typical
instrumentation setup is shown in Fig. 3.
NOTE 4—Lots of geosynthetics are usually designated by the producer
6.4.2 All dial gauges or electronic measurement devices during manufacture. While this test method does not attempt to establish
a frequency of testing for determination of design oriented data, the lot
must be accurate to 6 0.10 mm. Locations of the devices must
number of the laboratory sample should be identified. The lot number
be accurately determined and recorded. Minimum extension
should be unique to the raw material and manufacturing process for a
capabilities of 50 mm (2 in.) are recommended.
specific number of units (for example, rolls, panel, etc.) designated by the
6.5 Geosynthetic Clamping Devices—Clamps which con-
producer.
nect the specimen to the pullout force system without slipping,
7.2 Laboratory Sample—Consider the units in the lot
causing clamp breaks or weakening the material may be used,
sample as the units in the laboratory sample for the lot to be
see Note 3. The clamps shall be swiveled to allow the pulling
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