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BRITISH STANDARD BS EN 918:1996

Geotextiles and geotextile-related products —Dynamic perforation test (cone drop test)

The European Standard EN 918:1995 has the status of a British Standard

ICS 59.080.70

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BS EN 918:1996

This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 July 1996

© BSI 02-1999

The following BSI references relate to the work on this standard:Committee reference TCI/35Draft for comment 92/48135 DC

ISBN 0 580 26249 9

Committees responsible for this British Standard

The preparation of this British Standard was entrusted to Technical Committee TCI/35, Geotextiles, upon which the following bodies were represented:

Association of Consulting EngineersBritish Geotechnical SocietyBritish Polyolefin Textiles AssociationBritish Textile Technology GroupChemical Industries AssociationDepartment of the Environment (Building Research Establishment)Department of Transport (Highways Agency)Department of Transport (Transport Research Laboratory)ERA Technology Ltd.Federation of Civil Engineering ContractorsInstitute of Asphalt TechnologyInstitute of Wastes ManagementInstitution of Chemical EngineersInstitution of Civil EngineersNational Rivers AuthoritySociety of Engineers Incorporated

Amendments issued since publication

Amd. No. Date Comments

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BS EN 918:1996

© BSI 02-1999 i

Contents

PageCommittees responsible Inside front coverNational foreword ii

Foreword 21 Scope 32 Normative references 33 Definition 34 Principle 35 Apparatus 36 Specimens 37 Conditioning 48 Procedure 89 Calculation 8

10 Test report 8

Figure 1 — Example of clamping rings and of guide block use 4Figure 2 — Typical cone drop framework with safety screen 5Figure 3 — Example of cone and guide rod 6Figure 4 — Example of measuring cone 7

List of references Inside back cover

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BS EN 918:1996

ii © BSI 02-1999

National foreword

This British Standard has been prepared by Technical Committee TCI/35 and is the English language version of EN 918 Geotextiles and geotextile-related products — Dynamic perforation test (cone drop test) published by the European Committee for Standardization (CEN).EN 918 was prepared as a result of international discussions in which the UK took an active part.This British Standard supersedes BS 6906-6:1990 which is withdrawn.

A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Cross-references

Publication referred to Corresponding British Standard

EN 963:1995 BS EN 963:1995 Geotextiles and geotextile-related products — Sampling and preparation of test specimens

EN 30320:1992 BS EN 30320:1993 Geotextiles — Identification on siteISO 2854:1976 BS 2846 Guide to statistical interpretation of data

Part 4:1976 Techniques of estimation and tests relating to means and variances

Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, an inside back cover and a back cover.This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.

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EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 918

December 1995

ICS 59.080.70

Descriptors: Textiles, geotextiles, mechanical tests, drop tests, perforating tests, perforating strength

English version

Geotextiles and geotextile-related products — Dynamic perforation test (cone drop test)

Géotextiles et produits apparentés — Essai de perforation dynamique (essai par chute d’un cône)

Geotextilien und geotextilverwandte Produkte — Dynamischer Durchschlagversuch (Kegelfallversuch)

This European Standard was approved by CEN on 1995-12-01. CEN membersare bound to comply with the CEN/CENELEC Internal Regulations whichstipulate the conditions for giving this European Standard the status of anational standard without any alteration.Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to anyCEN member.This European Standard exists in three official versions (English, French,German). A version in any other language made by translation under theresponsibility of a CEN member into its own language and notified to theCentral Secretariat has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium,Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland andUnited Kingdom.

CEN

European Committee for StandardizationComité Européen de NormalisationEuropäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members Ref. No. EN 918:1995 E

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EN 918:1995

© BSI 02-19992

Foreword

This European Standard has been prepared by the Technical Committee CEN/TC 189, Geotextiles and geotextile-related products, of which the Secretariat is held by IBN.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 June 1996, and conflicting national standards shall be withdrawn at the latest by June 1996.ISO/CS is presently preparing ISO/DIS 13433 that will deal with the same subject as pr EN 918.According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Gemany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

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EN 918:1995

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1 ScopeThis European Standard specifies the determination of the resistance of geotextiles and geotextile-related products to the penetration by a steel cone dropped from a fixed height. The degree of penetration is an indication of the behaviour of the product likely to be caused by dropping sharp stones onto the geotextile surface.The method is generally applicable to geotextiles and geotextile-related products. The validity of this test for some types of products (e.g. geogrids) should be considered carefully, as the principle of the test may not be applicable for these materials.

2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies.EN 963, Geotextiles and geotextile-related products — Sampling and preparation of test specimens. EN 30320, Geotextiles — Identification on site. (ISO 10320:1991)ISO 554, Standard atmospheres for conditioning and/or testing —Specifications. ISO 2854, Statistical interpretation of data — Techniques of estimation and tests relating to means and variances.

3 DefinitionFor the purposes of this standard the following definition applies.

3.1 hole size

the diameter in millimetres of the hole made by the cone in penetrating the specimen

4 PrincipleThe geotextile specimen is clamped horizontally between two steel rings. A stainless steel cone is dropped, point first, from a distance of 500 mm onto the centre of the specimen. The degree of penetration is measured by insertion of a narrow-angle graduated cone into the hole.

5 Apparatus5.1 Clamping system

The clamping system (see Figure 1) shall prevent pre-tensioning of the specimen before, and slippage during the test. The internal diameter of the clamping rings shall be (150 ± 0,5) mm. An example of a clamping system is shown in Figure 1. The clamping rings and the guide block are also shown in Figure 1.5.2 Frame for supporting the clamped specimen, and a means of releasing the cone from a distance of (500 ± 2) mm, point first, onto the centre of the specimen (see Figure 2). The frame shall be mounted on a hard, non-resilient surface.NOTE 1 The cone should fall vertically point first. This can be achieved either by using guides which do not limit the rate of fall, or by an appropriate release mechanism ensuring free fall without rotation.NOTE 2 Safety: Figure 2 shows a safety screen to protect the operator from injury by the falling cone.

5.3 A stainless steel cone, of 45° tip angle, with a smooth polished surface and a mass of (1 000 ± 5) g including the guide rod, having detailed dimensions as shown in Figure 3.5.4 Means for ensuring the test specimen is horizontal and the cone axis vertical (e.g. spirit level and adjusting screws).5.5 Measuring cone with the dimensions given in Figure 4 and with a mass of (600 ± 5) g including grip.

6 Specimens6.1 Sampling

Take specimens in accordance with EN 963.

6.2 Number and dimension of specimens

Cut 10 test specimens from the sample, each of suitable dimensions for the apparatus used.If the material to be tested is known to have different characteristics on the two faces, (e.g. physical characteristics or as a consequence of the manufacturing process), then the complete test shall be carried out separately on each face using 10 specimens.The test report shall include details of this extension of the test procedure and separate results for each face shall be given.

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EN 918:1995

4 © BSI 02-1999

7 ConditioningCondition the specimens, and conduct the tests in the standard atmosphere as defined in ISO 554. The specimens can be considered to have been conditioned when the change in mass of the specimen in successive weighings made at intervals of not less than 2 h does not exceed 0,25 % of the mass of the test specimens.

Conditioning and/or testing at a specified relative humidity may be omitted if it can be shown that the results are not affected.

NOTE 1 This figure is not to scale.NOTE 2 Number of screws to suit the clamping rings being used.

Dimensions in mm

Figure 1 — Example of clamping rings and of guide block use

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EN 918:1995

© BSI 02-1999 5

NOTE This figure is note to scale.

Dimensions in mm

Figure 2 — Typical cone drop framework with safety screen

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EN 918:1995

6 © BSI 02-1999

NOTE This figure is not to scale.

Dimensions in mm

Figure 3 — Example of cone and guide rod

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EN 918:1995

© BSI 02-1999 7

NOTE This figure is not to scale.

Dimensions in mm

Figure 4 — Example of measuring cone

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EN 918:1995

8 © BSI 02-1999

8 Procedure8.1 Ensure that the clamping rings (see 5.1) are horizontal in the frame (see 5.2) using a suitable means (see 5.4).8.2 Secure one specimen between the clamping rings of the clamping system free of slack (see Figure 2) (e.g. using a guide block, see Figure 1). Place the specimen and clamping system in the testing machine.8.3 Release the cone (see 5.3) so that it falls smoothly from (500 ± 2) mm onto the surface of the specimen. Record any unusual occurrences such as the cone bouncing off the specimen and making a new hole on its second fall. In this event measure the size of the larger hole.NOTE A light dusting of talcum powder on the surface of the specimen can help to indicate the site of the first strike by the cone.

8.4 Immediately place the measuring cone (see 5.5) into the hole. Wait 10 s, then measure the diameter of the hole to the nearest millimetre. The value determined shall be the maximum visible diameter of the measuring cone when the cone is in a vertical position. If the material is very anisotropic, i.e. different properties across and along the machine direction, it can be necessary to make assessments of the hole diameter from two or more positions at right angles on the periphery of the cone.

9 CalculationCalculate the mean hole diameter in millimetres to an accuracy of 0,1 mm and the coefficient of variation in percentage in accordance with ISO 2854.NOTE If the falling cone totally penetrates one or more specimens resulting in a hole of 50 mm, then the mean and the coefficient of variation should not be calculated. In this case, the individual results should be quoted in the test report, and special comment on this behaviour should be made.

10 Test reportThe test report shall include the following particulars:

a) number and date of this standard;b) identification of the sample tested according to EN 30320, date of receipt and date of testing;c) conditioning atmosphere;d) mean hole diameter;e) coefficient of variation of hole diameter in percentage;f) any unusual behaviour, such as secondary penetration;g) indication of the degree of anisotropy of the material from observations of the hole shape;h) any deviation from the procedure.

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BS EN 918:1996

© BSI 02-1999

List of references

See national foreword.

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