SIST EN ISO 12957-2:2005

SLOVENSKI STANDARD
SIST EN ISO 12957-2:2005
01-maj-2005
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,62
Geosynthetics - Determination of friction characteristics - Part 2: Inclined plane test (ISO
12957-2:2005)
Geokunststoffe - Bestimmung der Reibungseigenschaften - Teil 2: Schiefe-Ebene-
Versuch (ISO 12957-2:2005)
Géosynthétiques - Détermination des caractéristiques de frottement - Partie 2: Essai sur
plan incliné (ISO 12957-2:2005)
Ta slovenski standard je istoveten z: EN ISO 12957-2:2005
ICS:
59.080.70 Geotekstilije Geotextiles
SIST EN ISO 12957-2:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 12957-2:2005

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SIST EN ISO 12957-2:2005



EUROPEAN STANDARD
EN ISO 12957-2

NORME EUROPÉENNE

EUROPÄISCHE NORM
February 2005
ICS 59.080.70
English version
Geosynthetics - Determination of friction characteristics - Part 2:
Inclined plane test (ISO 12957-2:2005)
Géosynthétiques - Détermination des caractéristiques de Geokunststoffe - Bestimmung der Reibungseigenschaften -
frottement - Partie 2: Essai sur plan incliné (ISO 12957- Teil 2: Schiefe-Ebene-Versuch (ISO 12957-2:2005)
2:2005)
This European Standard was approved by CEN on 15 November 2004.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.




EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12957-2:2005: E
worldwide for CEN national Members.

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SIST EN ISO 12957-2:2005
EN ISO 12957-2:2005 (E)
Contents
page
Foreword.3
1 Scope.4
2 Normative references.4
3 Terms and definitions .4
4 Principle.4
5 Test specimens.5
6 Conditioning .5
7 Apparatus.5
8 Procedure.8
9 Calculations .9
10 Test Report.10

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SIST EN ISO 12957-2:2005
EN ISO 12957-2:2005 (E)
Foreword
This document (EN ISO 12957-2:2005) has been prepared by Technical Committee CEN/TC 189 “Geosynthetics",
the secretariat of which is held by IBN, in collaboration with Technical Committee ISO/TC 221 “Geosynthetics".
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by August 2005, and conflicting national standards shall be withdrawn at the latest by
August 2005.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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SIST EN ISO 12957-2:2005
EN ISO 12957-2:2005 (E)
1 Scope
This document describes a method to determine the friction characteristics of geosynthetics (geotextiles and
geotextile-related products, geosynthetic barriers), in contact with soils, at low normal stress, using an inclining
plane apparatus.
This test method is primarily intended as a performance test to be used with site specific soils but may also be used as
an index test with standard sand.
Test data obtained for geogrids tested with a rigid support are not necessarily realistic as the results depend on the
friction support.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 554, Standard atmospheres for conditioning and/or testing – Specifications.
ISO 6344-2, Coated abrasives – Grain size analysis – Part 2: Determination of grain size distribution of macrogrits
P 12 to P 220.
ISO 9862, Geotextiles – Sampling and preparation of test specimens.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
normal stress (σσσσ )
n,o
normal force (N) divided by the area of the specimen, in kilopascals

σ indicates the normal stress with the table in horizontal position; σ indicates the calculated normal stress at
n,o n,calc
slippage failure with angle of slipping (β).
3.2
angle of friction (φφφφ )
gp
angle of friction between geosynthetic and soil, in degrees, defined as the average of the values recorded in the
test
3.3
angle of slipping (ββββ)
angle, in degrees, at which the box’s displacement attains 50 mm
4 Principle
The angle of friction for the soil/geosynthetic system is determined by measuring the angle at which a soil filled box
(with possible additional weights) slides when the base supporting the geosynthetic is inclined at a constant speed.
NOTE  Variations to the test described in this document can be used to measure friction properties of geosynthetics in non-
standard conditions, e.g.:
a) a second layer of geosynthetic can be fitted in the upper part of the shear box to measure geosynthetic on geomembrane friction;
b) normal pressures different from the standard values can be applied to simulate actual site conditions.
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SIST EN ISO 12957-2:2005
EN ISO 12957-2:2005 (E)
5 Test specimens
5.1 Sampling
Take specimens in accordance with ISO 9862.
5.2 Number and dimensions of test specimens
Cut three specimens from the test sample, for each direction to be tested. The size of the specimens shall suit the
dimensions of the apparatus.
If the two faces of the sample are different, both faces shall be tested. Three specimens shall be tested for each
face.
6 Conditioning
Condition the test specimens and conduct the tests in the standard atmosphere for testing, defined in ISO 554, i.e. at a
relative humidity of (65 ± 2) % and a temperature of (20 ± 2) °C until the change in mass between two successive
readings made at intervals of not less than two hours does not exceed 0,25 % of the mass of the test specimens.
NOTE Conditioning and/or testing at a specified relative humidity may be ommitted if it can be shown that the results are not
affected by this omission.
7 Apparatus
7.1 General
Two types of apparatus are possible, one with the upper box supported by rollers, the other without support of the
box. A diagrammatic representation of suitable equipment is shown in Figures 1, 2, 3 and 4. Figures 1 and 2
illustrate an apparatus with a rigid support for the geosynthetic. Figure 3 illustrates an apparatus in which the
geosynthetic is supported by a lower box filled with soil. Figure 4 gives the minimum dimensions of the upper
sliding box to be used with both methods.
7.2 Rigid base apparatus (see Figures 1 and 2)
7.2.1 Rigid base
The inclined plane apparatus consists of a rigid smooth plate hinged at one end. The apparatus shall be fitted with a
mechanism which allows the plane to be raised smoothly at a rate of (3 ± 0,5) degrees per minute. The inclined plane
apparatus shall be horizontal in all directions at the start of each test. Spirit levels shall be fitted to allow checking of the
inclination before each test.
The mechanism used to raise the inclined plane shall be fitted with a trip-switch which will automatically stop the raising
of the table when the displacement of the upper soil filled box exceeds 50 mm.
The inclined plane apparatus shall be fitted with an angle measurement system which allows to measure the inclination
angle of the table to the horizontal with a precision of ± 0,5 degrees.
The geosynthetic shall be fixed to the inclined plane apparatus to limit any relative displacement between the
geosynthetic and the plane.
NOTE  This may be obtained by one of the following techniques:
- stitching or gluing;
- use of a rough high friction support;
- anchoring the geosynthetic outside the contact area.
For geogrids and geotextiles with open structures the support used shall be either soil or an emery cloth abradant
P 100 according to ISO 6344-2 (in case of testing with a rigid support).
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SIST EN ISO 12957-2:2005
EN ISO 12957-2:2005 (E)
7.2.2 Upper soil box (see Figure 4)
The upper soil box shall be of rigid construction with the following minimum internal dimensions:
- length: 300 mm;
- width: 300 mm;
- depth: soil depth H > 7 × D' > 50 mm, where
s max
H : depth of soil in the box, in millimetres;
s
D' : maximum particle size of soil being used in the test, in millimetres.
max
When testing geogrids, the minimum size of the apparatus shall be such that not less than two full ribs and three full
long
...