1、BS EN ISO12956:2010ICS 59.080.70NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDGeotextiles andgeotextile-relatedproducts Determination of thecharacteristic openingsize (ISO 12956:2010)This British Standardwas published under theauthority of the StandardsPolicy
2、and StrategyCommittee on 31 May 2010 BSI 2010ISBN 978 0 580 67998 8Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 12956:2010National forewordThis British Standard is the UK implementation of EN ISO 12956:2010.It supersedes BS EN ISO 12956:1999 which is withdrawn.The UK particip
3、ation in its preparation was entrusted to TechnicalCommittee B/553, Geotextiles and geomembranes.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsi
4、ble for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 12956 April 2010 ICS 59.080.70 Supersedes EN ISO 12956:1999English Version Geotextiles and geotextile-related products - Determinat
5、ion of the characteristic opening size (ISO 12956:2010) Gotextiles et produits apparents - Dtermination de louverture de filtration caractristique (ISO 12956:2010) Geotextilien und geotextilverwandte Produkte - Bestimmung der charakteristischen ffnungsweite (ISO 12956:2010) This European Standard wa
6、s approved by CEN on 22 March 2010. 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 nat
7、ional standards may be obtained on application to the CEN Management Centre 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
8、 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, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
9、Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All
10、 rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 12956:2010: EBS EN ISO 12956:2010EN ISO 12956:2010 (E) 3 Foreword This document (EN ISO 12956:2010) has been prepared by Technical Committee ISO/TC 221 “Geosynthetics“ in collaboration w
11、ith Technical Committee CEN/TC 189 “Geosynthetics”, the secretariat of which is held by NBN. 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 October 2010, and conflicting national standards shall
12、be withdrawn at the latest by October 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 12956:1999
13、. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countrie
14、s are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia
15、, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 12956:2010 has been approved by CEN as a EN ISO 12956:2010 without any modification. BS EN ISO 12956:2010ISO 12956:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Normative references
16、1 3 Symbols1 4 Principle1 5 Apparatus and materials.2 6 Test specimens3 6.1 Handling .3 6.2 Selection.3 6.3 Number and dimensions.3 6.4 Specimen condition 3 7 Procedure.3 8 Calculation and expression of results 4 9 Test report4 Annex A (normative) Mesh sizes.7 Annex B (informative) Example of the de
17、termination of the characteristic opening size.8 BS EN ISO 12956:2010ISO 12956:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stan
18、dards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also t
19、ake part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees
20、is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibil
21、ity that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 12956 was prepared by Technical Committee ISO/TC 221, Geosynthetics. This second edition cancels and replaces the first edition (IS
22、O 12956:1999), which has been technically revised. BS EN ISO 12956:2010INTERNATIONAL STANDARD ISO 12956:2010(E) ISO 2010 All rights reserved 1Geotextiles and geotextile-related products Determination of the characteristic opening size 1 Scope This International Standard specifies a method for the de
23、termination of the characteristic size of the openings of a single layer of a geotextile or geotextile-related product using the wet-sieving principle. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edi
24、tion cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 9862, Geosynthetics Sampling and preparation of test specimens ISO 10320, Geotextiles and geotextile-related products Identification on site ISO 565, Test sieves Metal wi
25、re cloth, perforated metal plate and electroformed sheet Nominal sizes of openings ISO 2591-1, Test sieving Part 1: Methods using test sieves of woven wire cloth and perforated metal plate 3 Symbols For the purposes of this document, the following symbols apply. 3.1 dnparticle size for which n % mas
26、s fraction is smaller than the mass of measured particles 3.2 O90size of opening which is equal to the particle of size d90of the granular material which passes through the geotextile or geotextile-related product 3.3 Cucoefficient of uniformity, defined as d60/d104 Principle The particle size distr
27、ibution of a graded granular material (usually soil) is determined after washing through a single layer of the geotextile or geotextile-related product used as a sieve, without load. The characteristic opening size corresponds to a specified size of the granular material passed. BS EN ISO 12956:2010
28、ISO 12956:2010(E) 2 ISO 2010 All rights reserved5 Apparatus and materials 5.1 Sieving apparatus, composed of the following elements. 5.1.1 Sieving unit, allowing for the testing of a specimen with an exposed sieving area corresponding to a minimum diameter of 130 mm, complying with the following req
29、uirements: a) sieving device, with a frequency of 50 Hz to 60 Hz; b) predominantly vertical sieve motion capable of maintaining a 1,5 mm amplitude (3 mm swing height) over the period of test. 5.1.2 Water supply system. 5.1.3 Spray nozzle(s), to ensure even wetting of the test specimen, enclosed in a
30、 transparent cylinder or covering cap to avoid soil or granular material loss; It is recommended that the nozzle(s) be capable of a water discharge of approximately 0,5 l/min at a working pressure of about 300 kPa. 5.1.4 Specimen clamping device. 5.1.5 Pan, affixed to the sieving apparatus, with a t
31、ube connection to the device for collection of the water and granular material passing through the specimen. NOTE Typical sieving equipment is represented in Figure 1. 5.1.6 Grid, with wire of 1 mm in diameter and a mesh size of (10 1) mm to support the specimen during the test, to avoid excessive d
32、eformation of the specimen under the weight of the granular material. 5.2 Granular material, complying with the following requirements: a) It should be cohesion-less, i.e. particles shall not aggregate in water. If there is no visible agglomeration of particles during the test, the results are accep
33、table. If not, the test has to be performed again. b) It shall not be gap-graded and the particles shall be essentially round, and sharp-edged flaky particles shall be avoided. c) 3 u Cuu 20. d) To improve the accuracy of the characteristic opening size determination, the granular material shall be
34、such that d20u O90u d80; the zone for the graded granular material and the range of O90values which are applicable are given in Figure 2. 5.3 Filter paper, to collect the passed granular material. If the graded material contains a silt fraction, the filter paper used should have a maximum opening si
35、ze of 10 m. 5.4 Drying oven, capable of maintaining temperatures of between 50 C and 110 C. 5.5 Set of sieves, in accordance with ISO 565, size R 20 (see Annex A). 5.6 Balance, for determining the mass of the granular to an accuracy of 0,03 g. 5.7 Stopwatch, for measuring time to an accuracy of 1 s.
36、 BS EN ISO 12956:2010ISO 12956:2010(E) ISO 2010 All rights reserved 36 Test specimens 6.1 Handling The sample shall be handled as infrequently as possible and shall not be folded, in order to prevent disturbing its structure. Keep the sample in a flat position without any load. 6.2 Selection Take sp
37、ecimens from the sample in accordance with ISO 9862. 6.3 Number and dimensions Cut five test specimens from the sample, each of the dimensions suitable for the sieve apparatus to be used. 6.4 Specimen condition The specimens shall be clean, free from surface deposits and without visible damage or fo
38、lding marks. 7 Procedure 7.1 Determine and record the mass of the dry specimen to the nearest 0,1 g. The specimen is considered dry when there is a reduction in mass of less than 0,1 % between consecutive measurements with a time interval of 600 s. Drying should be carried out at a temperature of 70
39、 C or less, if the temperature affects the material. 7.2 Place the specimen under water containing a wetting agent at laboratory temperature and leave it to saturate for at least 12 h. The wetting agent used shall be an aryl alkyl sulfonate at 0,1 % volume. 7.3 Remove the specimen from the water and
40、 place it flat and without tension in the clamping device. Place the clamping device on the sieving apparatus. The specimen should be horizontal to avoid accumulation of granular material at one location on the specimen. 7.4 Determine the dry mass of the granular material to the nearest 0,1 g. Use e
41、nough granular material to achieve a mass per specimen equivalent to (7,0 0,1) kg/m2of exposed sieving area. However, if the amount passing during the test is insufficient, the total amount can be adapted in such a way that enough material is passed to carry out a particle size analysis. 7.5 Spread
42、the granular material evenly on the specimen. 7.6 Open the water supply and spray water uniformly over the whole specimen. Adjust the quantity of water with a regulating valve to ensure that granular particles are completely wetted, but do not allow the water level to rise above the granular materia
43、l. There shall be no standing water on the specimen. Maintain the water supply during the whole sieving operation. 7.7 Switch on the sieving device and slowly adjust the amplitude to 1,5 mm (3 mm swing height). 7.8 Collect the granular material which passes through the specimen. 7.9 After a sieving
44、time corresponding to 600 s, switch off the sieving device and turn off the water supply. 7.10 Collect the specimen together with any retained granular material. 7.11 Dry, separately, the passed granular materials (see 7.8) and the specimen with the retained granular material (see 7.10). 7.12 Obtain
45、 the dry mass of the retained granular material by weighing the specimen containing the retained granular material and subtracting the dry mass of the specimen. Determine to an accuracy of 0,1 g the dry mass of the retained granular material. Determine, also, the dry mass of the passed granular mate
46、rial. If the combined mass of the retained and passed granular material deviates more than 1 % from the initial total dry mass, the test is invalid and shall be repeated. BS EN ISO 12956:2010ISO 12956:2010(E) 4 ISO 2010 All rights reserved7.13 Repeat 7.1 to 7.12 until three of the five specimens hav
47、e been tested. 7.14 If any of the masses of granular materials passing through the specimen vary from the average by more than 25 %, then the two remaining specimens shall be tested. 7.15 Tabulate the initial amount of granular material, the material passed and retained, and calculate the percentage
48、s of material passed and lost as indicated in Table 1 or Table 2. Combine the granular material passed through the individual specimens and determine the particle size distribution. NOTE After selection of the required successive sieves as given in ISO 565, size R 20 (see Annex A), guidance for the
49、determination of the particle size distribution of the granular material, by sieving is given in ISO 2591-1. An example is given in Annex B. 7.16 If the amount of the passed granular material of three specimens is less than the amount required for sieving in accordance with ISO 2591-1, the two remaining specimens shall be tested and Table 2 completed. If the additional testing does not produce the required amount of passed granular material, the amount of granular material per square metre on the exposed sieving area is increased. I
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