1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 10773:2011Clay geosynthetic barriers Determination of permeabilityto gases (ISO 10773:2011)BS EN ISO 10773:2011 BRITISH STANDARDNational forewordThis British Standard i
2、s the UK implementation of EN ISO 10773:2011.At Formal Vote, the UK National Committee B/553 abstained from voting because it could not achieve consensus over whether the test is reproducible and repeatable, and whether Nitrogen should be replaced as a test gas by Methane or Carbon Dioxide.The UK pa
3、rticipation in its preparation was entrusted to Technical Committee B/553, Geotextiles and geomembranes.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are
4、 responsible for its correct application. BSI 2011 ISBN 978 0 580 61349 4 ICS 59.080.70 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2011.Amendments i
5、ssued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 10773 May 2011 ICS 59.080.70 English Version Clay geosynthetic barriers - Determination of permeability to gases (ISO 10773:2011) Gosynthtiques bentonitiques - Dtermination de la permabilit aux gaz (ISO
6、 10773:2011) Geosynthetische Tondichtungsbahnen - Bestimmung der Gasdurchlssigkeit (ISO 10773:2011) This European Standard was approved by CEN on 28 April 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
7、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 CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, Fr
8、ench, 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 CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgari
9、a, 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, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR ST
10、ANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 10773:2011: EBS EN ISO 10773:2011 EN ISO 1077
11、3:2011 (E) 3 Foreword This document (EN ISO 10773:2011) has been prepared by Technical Committee ISO/TC 221 “Geosynthetics“ in collaboration with 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 sta
12、ndard, either by publication of an identical text or by endorsement, at the latest by November 2011, and conflicting national standards shall be withdrawn at the latest by November 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig
13、hts. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
14、Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of IS
15、O 10773:2011 has been approved by CEN as a EN ISO 10773:2011 without any modification. BS EN ISO 10773:2011ISO 10773:2011(E) ISO 2011 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). T
16、he work of preparing International Standards 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-go
17、vernmental, in liaison with ISO, also take 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.
18、 The main task of technical committees 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 v
19、ote. Attention is drawn to the possibility 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 10773 was prepared by Technical Committee ISO/TC 221, Geosynthetics. BS EN ISO 10773:2011BS
20、EN ISO 10773:2011INTERNATIONAL STANDARD ISO 10773:2011(E) ISO 2011 All rights reserved 1Clay geosynthetic barriers Determination of permeability to gases 1 Scope This International Standard specifies a method for measuring gas flow through a clay geosynthetic barrier. As clay geosynthetic barriers a
21、re used to contain gases in long-term applications, this test especially focuses on the steady state of the phenomenon. The test is conducted with nitrogen, e.g. N2( = 1,75 105Pas, = 1,15 kg/m3at 20 C). The test method and described apparatus allow the measurement of gas flows in the range 0,1 ml/mi
22、n to 5 l/min on specimens with moisture contents in the range of 90 % to 130 %. 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 re
23、ferenced document (including any amendments) applies. ISO 554, Standard atmospheres for conditioning and/or testing Specifications 3 Principle Clay geosynthetic barrier specimens are hydrated in a controlled manner before testing. From the plot of gas flow to moisture content under a normal load of
24、20 kPa and a differential pressure equal to 15 kPa, a gas flow index, GFI110/15, is determined, which is the gas flow at 110 % moisture content. 4 Apparatus 4.1 General The apparatus includes: a device allowing to load the specimen at a constant normal stress of 20 kPa (see 4.2); a test cell (see 4.
25、3); a device to apply inlet pressure in the upstream chamber (in contact with the upper face of the sample) (see 4.4); a device for measuring gas flow (see 4.5). 4.2 Loading device The loading device shall allow the application of the normal stress of 20 kPa with a tolerance of 5 % either by direct
26、loading or with a controlled air supply. BS EN ISO 10773:2011ISO 10773:2011(E) 2 ISO 2011 All rights reserved4.3 Test cell The test cell presented in Figure 1 shall allow: the testing of a specimen representative of the bulk clay geosynthetic barrier, where the diameter Duof the flow cross-section i
27、s greater than or equal to 150 mm which makes it possible to study needle-punched and stitch geosynthetic clay barriers; the measurement of thickness reduction under a 20 kPa normal stress until stabilization; after stabilization of the thickness, the measurements of the evolution of the gas flow at
28、 the outlet with time. The test cell shall have two chambers, one on each side of the specimen to accommodate the support material (lower chamber) and containment material (upper chamber). This material shall consist of glass beads, 1 mm to 2 mm diameter, likely to adapt to the variations of the spe
29、cimen thickness. The edges of the clay geosynthetic barrier specimen shall be confined by a cylinder (part 9 in Figure 1), fixed to the base. The side sealing in the edge of the cell shall be achieved by adding a bentonite paste on top of the specimen. The absence of a leak can be checked by a soapy
30、 liquid on the circumference. 1151314342167111098121516Key 1 gas tank 9 cylinder for specimen edge containment 2 inlet pressure regulator 10 containment material 3 inlet pressure gauge 11 valve for purge 4 valve for inlet gas 12 base 5 gas tank 13 valve for outlet gas 6 normal stress 14 gas flow met
31、er 7 piston 15 specimen 8 screws to fix cylinder to base 16 o-ring NOTE In cases where there is a high degree of certainty that no leaks will occur, the use of the cylinder can be avoided. In such circumstances a simpler test cell may be used. An example of such a cell is provided in Annex A. Figure
32、 1 Scheme of gas flow apparatus BS EN ISO 10773:2011ISO 10773:2011(E) ISO 2011 All rights reserved 34.4 Device for applying inlet gas pressure The application of a constant inlet gas pressure in the upstream chamber shall be ensured by a bottle of nitrogen equipped with a pressure reducer and a pres
33、sure meter connected to the piston. The inlet gas pressure shall be measured with a tolerance of 5 %. 4.5 Device for measuring gas flow When a constant pressure difference (p = 15 kPa) is imposed between both sides of the specimen, a gas flow through the specimen is generated, which shall be measure
34、d by a gas flow meter connected to the base. It shall allow the measurement of a gas flow ranging between 0,1 ml/min and 5 l/min. 5 Samples The samples shall be clean and free from any visible defects. Samples shall be conditioned according to ISO 554 for a minimum period of 24 hours unless it can b
35、e shown that omitting this step has no influence on the test result. The test shall then be performed in the same conditions. 6 Testing procedure 6.1 Preparation and characterisation of samples 6.1.1 Cut three samples of geosynthetic clay barrier and bring them to three distinct values of water cont
36、ent close to 110 %, e.g. 100 %, 110 % and 120 %. Ensure that the values of bentonite water content are between 90 % and 130 % and are spaced at least 20 % between the lowest and the greatest value. Complete the following steps: choose a representative section from the roll, undisturbed by transport,
37、 storage, and handling. cut a sample sufficient to accommodate (Dr+ 0,05) m, where Dris the specimen diameter. determine the mass per unit area, its thickness under load of the sample and the water content of the bentonite. immerse the sample for a controlled duration in deionized water. NOTE Absorp
38、tion curves might be prepared to determine the immersion time necessary to reach the desired water content. remove the excess water on both faces using an absorbing paper when removing the clay geosynthetic barrier sample from the water, and then insert the sample in a plastic bag and seal it. load
39、the sample under 20 kPa for one week. 6.1.2 Complete the following prior to the gas flow test: remove the sample from the plastic bag and cut out the specimen to the diameter Dr. determine the specimen weight. Quickly perform the above operations in order to prevent free swell of the specimens. BS E
40、N ISO 10773:2011ISO 10773:2011(E) 4 ISO 2011 All rights reserved6.2 Specimen set-up 6.2.1 Fill the lower chamber of the base with glass beads (1 mm to 2 mm diameter). Protect the hole for outlet gas flow with a geotextile if required. Adjust the quantity of beads so that they fill the cavity present
41、 under the specimen. 6.2.2 Put the specimen in the base. NOTE If the test is conducted on a stitched clay geosynthetic barrier, make sure that a representative portion of clay geosynthetic barrier is selected for testing. 6.2.3 Add bentonite paste on the edges of the specimen. 6.2.4 Assemble the bas
42、e with the cylinder, sealing the joint between the base and the cylinder with bentonite paste. 6.2.5 Fill the cylinder with glass beads (1 mm to 2 mm diameter) to a thickness greater than or equal to 10 mm. Smooth off the beads. 6.2.6 Install the piston and the displacement gauge to measure the vert
43、ical deformation of specimen and beads. 6.2.7 Apply a 20 kPa load. 6.3 Flow measurement 6.3.1 Measure the volumetric gas flow for a constant pressure difference across the specimen with the downstream pressure being atmospheric pressure, and pressure applied in the upstream chamber remaining constan
44、t during the test. 6.3.2 Set the difference between upstream and downstream pressures to 15 kPa. 6.3.3 Increase the normal stress by 15 kPa in order to avoid the piston rising when one applies a differential pressure (p) of 15 kPa. 6.3.4 Follow the outlet volumetric gas flow versus time until its st
45、abilisation. The time to obtain steady flow is a function of the bentonite water content. 6.4 Analysis of the specimen 6.4.1 Immediately at the end of the test, disassemble the cell and retrieve the specimen. Clean off all beads. 6.4.2 Weigh the specimen. 6.4.3 Dry the specimen and measure its dry m
46、ass. 6.4.4 Calculate the final water content of the specimen. BS EN ISO 10773:2011ISO 10773:2011(E) ISO 2011 All rights reserved 57 Calculation of the index flow GFI110/15The steady-state gas flow is measured for the three specimens at three distinct final water contents close to 110 %, e.g. 100 %,
47、110 % and 120 %, and the gas flux, qV, is calculated according to Equation (1): VQqA= (1) where Q is the outlet volumetric gas flow at the atmospheric pressure; A is the flow section of the specimen of diameter Du. Plot the log of the gas flux, qV, against the water content of the bentonite, wi, as
48、shown in Figure 2, and select the best-fit curve. NOTE The gas flux at 110 % final water content is the gas flow index GFI110/15, where 110 % is the water content for the index flux and 15 kPa is the differential gas pressure. 115110 125 1309590 100 105 120qVwiKey wiwater content of bentonite, perce
49、ntage qVgas flux, metres per second Figure 2 Evolution of gas flow, qV, versus bentonite water content, wi8 Test report The test report shall include the following information: a) reference to this International Standard, e.g. ISO 10773:2011; b) identification of the clay geosynthetic barrier, including type; c) name of the product; d) references of the sample; BS EN ISO 10773:2011ISO 10773:2011(E) 6 ISO 2011 All rights reservede) date of reception of the sample; f) total mass per unit area at recepti
