1、BRITISH STANDARD BS EN ISO 12957-2:2005 Geosynthetics Determination of friction characteristics Part 2: Inclined plane test The European Standard EN ISO 12957-2:2005 has the status of a British Standard ICS 59.080.70 BS EN ISO 12957-2:2005 This British Standard was published under the authority of t
2、he Standards Policy and Strategy Committee on 8 March 2005 BSI 8 March 2005 ISBN 0 580 45586 6 National foreword This British Standard is the official English language version of EN ISO 12957-2:2005. It is identical with ISO 12957-2:2005. The UK participation in its preparation was entrusted to Tech
3、nical Committee B/553, Geosynthetics, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be
4、found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are r
5、esponsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and ke
6、ep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, pages 2 to 13 and a back cover. The BSI copyright notice displayed in this docume
7、nt indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 12957-2 February 2005 ICS 59.080.70 English version Geosynthetics - Determination of friction characteristics - Part 2: Inclined plane t
8、est (ISO 12957-2:2005) Gosynthtiques - Dtermination des caractristiques de frottement - Partie 2: Essai sur plan inclin (ISO 12957- 2:2005) Geokunststoffe - Bestimmung der Reibungseigenschaften - Teil 2: Schiefe-Ebene-Versuch (ISO 12957-2:2005) This European Standard was approved by CEN on 15 Novemb
9、er 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 obta
10、ined 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 Secr
11、etariat 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, Po
12、rtugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means rese
13、rved worldwide for CEN national Members. Ref. No. EN ISO 12957-2:2005: EEN ISO 12957-2:2005 (E) 2 Contents page Foreword3 1 Scope.4 2 Normative references.4 3 Terms and definitions 4 4 Principle.4 5 Test specimens.5 6 Conditioning .5 7 Apparatus5 8 Procedure8 9 Calculations 9 10 Test Report10 EN ISO
14、 12957-2:2005 (E) 3 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 n
15、ational 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 c
16、ountries 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, Swit
17、zerland and United Kingdom. EN ISO 12957-2:2005 (E) 4 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 appara
18、tus. 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 N
19、ormative 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
20、 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,
21、 the following terms and definitions apply. 3.1 normal stress ( n,o ) normal force (N) divided by the area of the specimen, in kilopascals n,o indicates the normal stress with the table in horizontal position; n,calcindicates the calculated normal stress at slippage failure with angle of slipping ()
22、. 3.2 angle of friction ( 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 ( ) angle, in degrees, at which the boxs displacement attains 50 mm 4 Principle The angle of friction for the soil/geosynthetic
23、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 geosyntheti
24、cs 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. EN ISO 12957-2:2005 (E)
25、5 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
26、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 i
27、n 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 App
28、aratus 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 geosy
29、nthetic. 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
30、 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
31、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 sha
32、ll 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
33、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 acco
34、rding to ISO 6344-2 (in case of testing with a rigid support). EN ISO 12957-2:2005 (E) 6 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 s 7 D max 50 mm, whe
35、re H s : depth of soil in the box, in millimetres; D max : maximum particle size of soil being used in the test, in millimetres. When testing geogrids, the minimum size of the apparatus shall be such that not less than two full ribs and three full longitudinal members are contained within the area o
36、f the box. In addition the upper box shall be able to accommodate a system of weights possibly used to apply the normal load to the soil. The upper box shall assure that the line of action of the normal force passes through the centre of gravity of the upper box when the apparatus is tilted, e.g. by
37、 wedges or inclinable walls. The standard shall be set at an angle of 27 degrees. NOTE Other angles may be used for geosynthetics with an angle significantly outside the range of 20 degrees to 35 degrees. The upper box may be fitted with rollers which bear on runners set outside of the geosynthetic
38、specimen. In this case the inside of the upper box shall be lined with smooth steel or a low friction surface to reduce friction between the soil and the sides of the box. In the case where the upper box is not fitted with rollers, shims shall be used to ensure a gap between the geosynthetic and the
39、 box; the shims are removed prior to inclining the apparatus. When shims are used, the friction between the soil and the upper box shall be sufficient to prevent the upper box from settling onto the specimen during the test. The gap between the base of the upper box and the geosynthetic shall be adj
40、ustable or set so that the upper box does not bear upon the specimen. The gap shall be between 0,5 mm and 1,5 mm to minimize the loss of soil during the test. The displacement of the upper box shall be measured during the test to a precision of 0,05 mm. Displacement readings shall be taken at interv
41、als not exceeding 30 s. 7.3 Soil filled base apparatus (Figure 3) 7.3.1 Lower soil box The lower box shall be a rigid box with the following minimum internal dimensions: - length: 400 mm; - width: 325 mm; - depth: H s 7 D max 50 mm, where H s : depth of soil in the box, in millimetres; D max : maxim
42、um particle size of soil being used in the test, in millimetres. The inclined plane apparatus shall be fitted with an angle measurement system which allows to measure the inclination angle of the lower soil box to the horizontal with a precision of 0,5 degrees. EN ISO 12957-2:2005 (E) 7 7.3.2 Upper
43、soil box (see Figure 4) The upper box shall be a rigid box with the following minimum internal dimensions: - length: 300 mm; - width: 300 mm; - depth: H s 7 D max 50 mm, where H s : depth of soil in the box, in millimetres; D max : maximum particle size of soil being used in the test, in millimetres
44、. When testing geogrids, the minimum size of the apparatus shall be such that not less than two full ribs and three full longitudinal members are contained within the area of the box. In addition, the upper box shall be able to accommodate a system of weights used to apply the normal load to the soi
45、l. The upper box shall assure that the line of action of the normal force passes through the centre of gravity of the upper box when the apparatus is inclined (e.g. by wedges or inclinable walls). The standard shall be set at an angle of 27 degrees. NOTE Other angles may be used for geosynthetics wh
46、ich exhibit an angle of slipping () significantly outside the range of 20 degrees to 35 degrees. The upper box may be fitted with rollers which bear on runners set outside of the geosynthetic specimen ; in this case, the inside of the upper box shall be lined with smooth steel or a low friction surf
47、ace to reduce friction between the soil and the sides of the box. In the case where the upper box is not fitted with rollers, shims shall be foreseen to ensure a gap between the geosynthetic and the box ; the shims are removed prior to inclining the apparatus. When shims are used, the friction betwe
48、en the soil and the upper box shall be sufficient to prevent the upper box from settling onto the specimen during the test. The gap between the base of the upper box and the geosynthetic shall be adjustable or set so that the upper box does not bear upon the specimen. The gap shall be inside the ran
49、ge of 0,5 mm to 1,5 mm to minimize the loss of soil during the test. The displacement of the upper box shall be measured during the test to a precision of 0,05 mm. Displacement readings shall be taken at intervals not exceeding 30 s. 7.4 Application of the normal force (for both types of apparatus) The normal force shall be applied by any method ensuring an even distribution of the pressure over the whole area of the specimen. NOTE A rig
