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1、a Date: 5 August 2008 Origin: European Latest date for receipt of comments: 30 November 2008 Project no.: 2007/02773 Responsible committee: B/553 Geotextiles and geomembranes Interested committees: Title: Draft BS EN 14151 Geosynthetics - Determination of burst strength Supersession information: If
2、this document is published as a standard, the UK implementation of it will supersede NONE and partially supersede. NONE If you are aware of a current national standard which may be affected, please notify the secretary (contact details below). WARNING: THIS IS A DRAFT AND MUST NOT BE REGARDED OR USE
3、D AS A BRITISH STANDARD. THIS DRAFT IS NOT CURRENT BEYOND 30 November 2008. This draft is issued to allow comments from interested parties; all comments will be given consideration prior to publication. No acknowledgement will normally be sent. See overleaf for information on commenting. No copying
4、is allowed, in any form, without prior written permission from BSI except as permitted under the Copyright, Designs and Patent Act 1988 or for circulation within a nominating organization for briefing purposes. Electronic circulation is limited to dissemination by e-mail within such an organization
5、by committee members. Further copies of this draft may be purchased from BSI Customer Services, Tel: +44(0) 20 8996 9001 or email . British, International and foreign standards are also available from BSI Customer Services. Information on the co-operating organizations represented on the committees
6、referenced above may be obtained from the responsible committee secretary. Cross-references The British Standards which implement International or European publications referred to in this draft may be found via the British Standards Online Service on the BSI web site http:/. Direct tel: Responsible
7、 Committee Secretary: Mr M Awaleh (BSI) E-mail: Draft for Public Comment Head Office 389 Chiswick High Road London W4 4AL Telephone: +44(0)20 8996 9000 Fax: +44(0)20 8996 7001 Form 36 Version 8.0 DPC: 08/30172827 DC Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy,
8、(c) BSI b Introduction This draft standard is based on European discussions in which the UK has taken an active part. Your comments on this draft are welcome and will assist in the preparation of the consequent British Standard. If no comments are received to the contrary, then the UK will approve t
9、his draft and implement it as a British Standard. Comment is particularly welcome on national, legislative or similar deviations that may be necessary. Even if this draft standard is not approved by the UK, if it receives the necessary support in Europe, the UK will be obliged to publish the officia
10、l English Language text unchanged as a British Standard and to withdraw any conflicting standard. UK Vote Please indicate whether you consider the UK should submit a negative (with reasons) or positive vote on this draft. Submission The guidance given below is intended to ensure that all comments re
11、ceive efficient and appropriate attention by the responsible BSI committee. Annotated drafts are not acceptable and will be rejected. All comments must be submitted, preferably electronically, to the Responsible Committee Secretary at the address given on the front cover. Comments should be compatib
12、le with Version 6.0 or Version 97 of Microsoft Word for Windows, if possible; otherwise comments in ASCII text format are acceptable. Any comments not submitted electronically should still adhere to these format requirements. All comments submitted should be presented as given in the example below.
13、Further information on submitting comments and how to obtain a blank electronic version of a comment form are available from the BSI web site at: http:/ Template for comments and secretariat observations Date: xx/xx/200x Document: ISO/DIS xxxxx 1 2 (3) 4 5 (6) (7) MB Clause No./ Subclause No./ Annex
14、 (e.g. 3.1) Paragraph/ Figure/Table/ Note (e.g. Table 1) Type of com- ment Comment (justification for change) by the MB Proposed change by the MB Secretariat observations on each comment submitted 3.1 Definition 1 ed Definition is ambiguous and needs clarifying. Amend to read . so that the mains con
15、nector to which no connection . 6.4 Paragraph 2 te The use of the UV photometer as an alternative cannot be supported as serious problems have been encountered in its use in the UK. Delete reference to UV photometer. Microsoft and MS-DOS are registered trademarks, and Windows is a trademark of Micro
16、soft Corporation. Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM DRAFT prEN 14151 July 2008 ICS English Version Geosynthetics - Determination of burst strength Gosynthtiques - Dtermination de la rsistance l
17、clatement Geokunststoffe - Bestimmung der Berstdruckfestigkeit This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 189. If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Re
18、gulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the
19、 responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hunga
20、ry, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of whi
21、ch they are aware and to provide supporting documentation. Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN D
22、E NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. prEN 14151:2008: E Licensed CopyChinese University of Hong Kong, 21/10/2008 07:5
23、1, Uncontrolled Copy, (c) BSI prEN 14151:2008 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references4 3 Terms and definitions .4 4 Principle4 5 Apparatus .4 5.1 General4 5.2 Cell 5 5.3 Deflection measurement.6 5.4 Pressure measurement.6 5.5 Volume controlled method .6 5.6 Strain controlled m
24、ethod 6 6 Specimens6 7 Conditioning.6 8 Procedure .7 8.1 General7 8.2 Volume controlled test7 8.3 Strain controlled test.7 8.4 Diaphragm Correction.7 9 Calculations7 10 Test report9 Bibliography10 Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI prEN 14151:2
25、008 (E) 3 Foreword This document (prEN 14151:2008) has been prepared by Technical Committee CEN/TC 189 “Geosynthetics”, the secretariat of which is held by NBN. This document is currently submitted to the CEN Enquiry. Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy,
26、 (c) BSI prEN 14151:2008 (E) 4 1 Scope This European Standard specifies a method for the determination of bi-axial properties (burst strength) of geosynthetics. This method applies to geotextiles, geomembranes and their related products. It applies to geosynthetic clay liners only when tested in dry
27、 conditions. 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. EN ISO 10318,
28、 Geosynthetics Terms and definitions (ISO 10318:2005) ISO 554, Standard atmospheres for conditioning and/or testing Specifications. 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN ISO 10318 apply. 4 Principle A circular specimen, clamped around its ed
29、ge, is subjected to a gradually increasing normal hydraulic stress until rupture occurs. NOTE 1 This test is normally performed with a constant rate of increase of volume. However, the test may be performed with a constant rate of strain. Strain control is obtained by using real time calculations en
30、abling constant readjustment of the pressure under the specimen. NOTE 2 These calculations are based on the assumption of spherical deformation. The main parameters measured during the test are the hydraulic pressure under the specimen and the deflection of the specimen. For geotextiles, dry geosynt
31、hetic clay liners and products with apertures, e.g. geogrids, it is necessary to use an appropriately thin, impermeable and deformable membrane (diaphragm) under the specimen. 5 Apparatus 5.1 General The equipment is composed of: a test cell with two parts; a deflection measuring device; a pressure
32、measuring device; Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI prEN 14151:2008 (E) 5 a means of controlling flow rate An example is shown in figure 1. Dimensions in mm Key 1 air 2 pneumatic servovalve 3 computer 4 displacement sensor 5 water vessel 6 spe
33、cimen 7 clamping ring 8 pressure transducer 9 base Figure 1 Example of testing apparatus 5.2 Cell The cell is composed of a base and a clamping ring. The inner diameter (D) of the ring, shall be between 100 mm and 300 mm. This diameter is the effective diameter of the tested specimen. The lower inne
34、r edge of the clamping ring shall be rounded (3 mm in radius). The bottom (base) of the cell, maintained horizontally, can be either flat or recessed With a liquid inlet at its centre. The cell shall be designed so that no deformation occurs even for water pressure up to 1 Mpa. The clamping device s
35、hall be designed in order to avoid any slippage of the specimen during the test. Clamping shall not damage the specimen. Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI prEN 14151:2008 (E) 6 5.3 Deflection measurement The deflection of the centre of the spe
36、cimen is measured with a deflection measuring device. Any measuring method meeting the following criteria is acceptable: ability to measure deflection up to the diameter of the cell; an accuracy of 0,5 mm; creation of negligible stress on the specimen. This measurement is used to calculate the defor
37、mation of the specimen. 5.4 Pressure measurement For both methods, a pressure measuring device with an accuracy of 1 % shall be used to measure the liquid pressure in the cell. The temperature of the liquid shall be (23 2)C and shall be maintained constant during the test. 5.5 Volume controlled meth
38、od For the volume controlled test, the equipment shall allow control of the incoming liquid flow. 5.6 Strain controlled method For the strain controlled test, the apparatus used shall permit continuous readjustment of fluid pressure under the specimen up to rupture, thus enabling the rate of strain
39、to be maintained constant. 6 Specimens Five specimens shall be cut from the test sample. They shall be clean and without any visible defects. NOTE 1 If the surface of the specimen is rough, it may be necessary to smooth the clamping area in order to ensure a perfect seal. NOTE 2 Geosynthetic clay li
40、ners may only be tested in dry condition. 7 Conditioning The test specimens shall be conditioned in the standard atmosphere for testing (20C 2C at 65% 5% RH) as defined in ISO 554. The specimens can be considered to have been conditioned when the change in mass in successive weightings made at inter
41、vals of not less than 2 h does not exceed 0,25% of the mass of the test specimen. Conditioning and/or testing in standard atmosphere may only be omitted when it can be shown that results obtained for the same specific type of product (both structure and polymer type) are not affected by changes in t
42、emperature and humidity exceeding the limits. Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI prEN 14151:2008 (E) 7 8 Procedure 8.1 General If the cell is not flat, fill the base up to its flange with water. Put the specimen on the base of the cell and, if
43、necessary, put the thin membrane (diaphragm) under it. NOTE The mechanical properties of the thin membrane in theory should not affect the measurements. Its bi-axial mechanical strength should be negligible compared with the tested geosynthetic. However, the influence of the membrane should be taken
44、 into account for calculations. If the cell is flat, apply a little vacuum under the specimen before clamping. Place the deflection measuring device in the centre of the specimen. If the specimen is not flat, the zero deflection is determined by the level of the lower face of the clamping ring. Non-
45、spherical or non-symmetrical deformation, e.g. as it occurs with anisotropic materials, shall be reported. The test is not valid if the specimen breaks at the edge of the clamping ring. 8.2 Volume controlled test When using a cell with an inner diameter of 200 mm, conduct the test with an incoming f
46、low rate of 3 cm3/s. For a cell with a diameter (D) other than 200 mm, use a flow rate (q) calculated as follows: q = 3,00 (D/200)3 cm3/s (1) Ensure no slippage or fluid leakage has occurred around the perimeter of the clamp. 8.3 Strain controlled test Conduct the test with a strain rate of 5% per m
47、inute until rupture occurs. Rupture is defined as a sudden loss in pressure. Ensure no slippage or fluid leakage has occurred around the perimeter of the clamp. 8.4 Diaphragm Correction With the same rate of liquid flow as employed in the tests, distend the diaphragm (without the presence of the spe
48、cimen) and note the pressure required to distend it by an amount equal to the average distension of the specimens. This pressure is the “diaphragm correction”. 9 Calculations Strain and stress calculations are based on the following assumptions (see also figure 2): spherical deformation; constant an
49、d uniform thickness of the specimen. Geometrical considerations lead to : H D H R 2 4 + = 2 2 (2) Licensed CopyChinese University of Hong Kong, 21/10/2008 07:51, Uncontrolled Copy, (c) BSI prEN 14151:2008 (E) 8 where: D : inner diameter of the cell (in m), H : deflection of the specimen at the centre (in m), R : radius of the sphere (in m), = R HR Arccos (3) where: H : deflecti