1、BSI Standards PublicationBS ISO 18325:2015Geosynthetics Test methodfor the determination ofwater discharge capacity forprefabricated vertical drainsBS ISO 18325:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18325:2015.The UK participation in its preparat
2、ion was entrusted to TechnicalCommittee B/553, Geosynthetics.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The
3、British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 80710 7ICS 59.080.70Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 Nov
4、ember 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 18325:2015 ISO 2015Geosynthetics Test method for the determination of water discharge capacity for prefabricated vertical drainsGosynthtiques Mthode dessai pour la dtermination de la capacit de dcharge deau d
5、es drains verticaux prfabriqusINTERNATIONAL STANDARDISO18325First edition2015-11-15Reference numberISO 18325:2015(E)BS ISO 18325:2015ISO 18325:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part
6、 of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member bod
7、y in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18325:2015ISO 18325:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definition
8、s . 14 Principle 25 Apparatus and materials 26 Test specimens 56.1 Handling 56.2 Selection 56.3 Number and dimensions 56.4 Specimen condition 57 Test procedure 58 Calculations and expressions of results . 79 Test report . 7Annex A (informative) Determination of the correction factor RTfor conversion
9、 to a water temperature of 20 C 8Bibliography .10 ISO 2015 All rights reserved iiiContents PageBS ISO 18325:2015ISO 18325:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internat
10、ional 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-governmental, in liaison with I
11、SO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Pa
12、rt 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the
13、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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations rec
14、eived (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs ad
15、herence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 221, Geosynthetics.iv ISO 2015 All rights reservedBS ISO 18325:2015ISO 18325:2015(E)IntroductionPrefabricated vertic
16、al drains (PVDs) are used to accelerate the settlement of soils under a given surcharge loading. Discharge capacity is, therefore, one of the most important properties for PVDs. The discharge capacity decreases gradually due to alteration in shape of core materials under soil pressure and deformatio
17、n of the geotextile filter into the core structure as time passes.In highly compressible soils (e.g. peat and gyttja) the relative compression that takes place during the consolidation process, may cause more or less significant buckling of the drains.In less compressible soils (settlements lower th
18、an 20 %), the buckled test is not relevant. ISO 2015 All rights reserved vBS ISO 18325:2015BS ISO 18325:2015Geosynthetics Test method for the determination of water discharge capacity for prefabricated vertical drains1 ScopeThis International Standard specifies a test method for determining the wate
19、r discharge capacity of prefabricated vertical drains (PVDs), which can be used for conformance and acceptance testing.This is an index test.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For
20、dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 5813, Water quality Determination of dissolved oxygen Iodometric methodISO 9862, Geosynthetics Sampling and preparation of test specimensEN 1
21、5237, Execution of special geotechnical works Vertical drainage3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1prefabricated vertical drainPVDdrainage composite with a rectangular cross-section, with a width of typically 100 mm installed vertica
22、lly into soil to provide drainage for accelerated consolidation of soils usually consisting of a central core with a channel system surrounded by a filter sleeve or with a filter adhered to itNote 1 to entry: Other wordings like wick drain, band drain, strip drain are also used.3.2confined lengthlen
23、gth of the part of the specimen exposed to pressure3.3filter lengthlength of the filter around or on the specimen3.4index discharge capacity of a PVDqwvolume of water which flows out of the PVD per unit time under a specified hydraulic gradientNote 1 to entry: It is expressed in ml/s.INTERNATIONAL S
24、TANDARD ISO 18325:2015(E) ISO 2015 All rights reserved 1BS ISO 18325:2015ISO 18325:2015(E)3.5hydraulic gradientiratio of the total head loss across the specimen to the filter length in the flow directionNote 1 to entry: The filter length would be shorter than the core length and longer than the conf
25、ined length.4 PrincipleThe factors affecting the discharge capacity of PVDs measured according to this International Standard are limited to the intrusion of the filter into the core linked to the filter stiffness, the drainage core stiffness, creep and geometry of the core to some extent and creep
26、of the geotextile filter to some extent, confining pressure, and hydraulic gradient.PVD is enveloped by a flexible rubber membrane to simulate the deformation of the geotextile filter into the core structure and the discharge capacity is determined in straight and buckled conditions.5 Apparatus and
27、materials5.1 Discharge capacity apparatus5.1.1 The discharge capacity apparatus satisfies the following requirements.a) The apparatus shall be capable of maintaining a constant head loss at different water levels, at least those corresponding to hydraulic gradients of 0,1 and 1,0, simulating the pre
28、ssure arising from the earth mass when PVDs are mounted vertically within the ground to serve as discharging interstitial water, and testing PVDs in straight and buckled conditions.b) The apparatus is mainly comprised of a pressure cell, a water supply portion (see Figure 1) and buckling device (see
29、 Figure 2). The buckling device is used to simulate the deformation of PVDs due to the relative compression in highly compressible soils. The pressure cell shall be capable of inserting the buckling device and maintain mounted specimens in straight and buckled conditions.c) The distance between the
30、two slots used to insert the specimen in the cell shall be (300 10) mm.5.1.2 A system allowing to adjust the head loss up to 500 mm shall be used.5.1.3 The buckling device satisfies the following requirements.a) The device is capable of buckling the specimen and maintaining the shape of the buckled
31、specimen. It is mainly comprised of supporters, guide frames, central and fixing pins and pushing rod (see Figure 2).b) The guide frame shall be fixed and supported inside the pressure cell.c) The guide frames shall consist of two holes and one slit to tie fixing pins and move the central pin. The d
32、istance between two holes shall be (60 0,1) mm and the length of slit should be greater than 60 mm in order to set up 60 mm and 55 mm of A and B respectively.d) The diameters of fixing pins and central pin shall be (5 0,5) mm.NOTE Other pin diameters can be selected with the agreement of all concern
33、ed persons or parties, provided that the pin diameter used is given in the test report.2 ISO 2015 All rights reservedBS ISO 18325:2015ISO 18325:2015(E)Key1 water reservoir 8 specimen (PVD)2 water inlet 9 pressure controller3 water outlet 10 slots4 equipment for determining the amount of water 11 man
34、ometers5 pressure cell 12 confined length, (300 10) mm6 supporters 13 head loss (h)7 flexible membraneFigure 1 Example of discharge capacity apparatus ISO 2015 All rights reserved 3BS ISO 18325:2015ISO 18325:2015(E)Key1 supporters 7 slit2 guide frames 8 flexible membrane3 central pin 9 specimen (PVD
35、)4 fixing pins 10 confined length5 pushing rod A 60 mm6 holes B 55 mmFigure 2 Example of buckling device5.2 Flexible membraneA cylinder- or oval shaped membrane with a thickness less than 0,7 mm made of synthetic rubber shall be used.The membrane shall be sufficiently flexible to not limit geotextil
36、e deformation and intrusion into the drain channels.5.3 WaterThe water shall be at a temperature between 18 C and 22 C and the water temperature should preferably be at or above the ambient temperature of the test laboratory. The oxygen content shall not exceed 10 mg/kg, when measured at the point w
37、here the water enters the apparatus. The water shall be filtered if suspended solids are visible to the naked eye or if solids accumulate on or in the specimen thus reducing the flow with time.4 ISO 2015 All rights reservedBS ISO 18325:2015ISO 18325:2015(E)As the temperature correction (see Annex A)
38、 relates only to laminar flow, it is advisable to work at temperatures as close as possible to 20 C to minimize inaccuracies associated with inappropriate correction factors, should the flow be non-laminar.NOTE The biological activity in the water is the one of facts for air bubbles, which will affe
39、ct the index discharge capacity in a negative way. Some biocides have been shown to reduce the biological activity. Demineralized water of grade 2 according to ISO 3696 can also be used to prevent this risk of biological activity.5.4 Pressure controllerThe pressure controller shall be provided for c
40、ontrolling the pressure of (10 300) kPa applied to the mounted specimen to an accuracy of 5 %. It shall be capable of maintaining the proposed pressure on the PVDs without any deformation which would influence the test results.5.5 Equipment for determining the amount of waterWhen the amount of water
41、 is determined by measurements of volume, a measuring vessel for determining the volume to an accuracy of 1 % is required. When the volume is determined by weighing, it shall be determined to an accuracy of 1 %.5.6 Dissolved-oxygen meter, or apparatus in accordance with ISO 5813.5.7 Stopwatch, for m
42、easuring time to an accuracy of 0,1 s.5.8 Thermometer, to determine the water temperature used for the flow measurements to an accuracy of 0,2 C.6 Test specimens6.1 HandlingThe sample shall not be folded and shall be handled as infrequently as possible to avoid disturbance to its structure. The samp
43、le shall be kept in a flat position without any load.6.2 SelectionTake specimens from the sample in accordance with ISO 9862.6.3 Number and dimensionsCut three test specimens from the sample with the length parallel to the machine direction. The full width of the product shall be tested.6.4 Specimen
44、 conditionThe specimens shall be clean, free from surface deposits and without visible damage or folding marks.7 Test procedure7.1 Cut the test specimens from the sample exposed to a temperature of (20 2) C for 24 h. The specimens shall be longer than the confined length. The geotextile portion that
45、 is unexposed to the pressure should be cut to ensure smooth entry and exit of water flow through the specimen. ISO 2015 All rights reserved 5BS ISO 18325:2015ISO 18325:2015(E)7.2 Place the specimens under water containing a wetting agent at laboratory temperature, gently stir to remove air bubbles
46、and leave to saturate for at least 12 h. Use an aryl alkyl sodium sulfonate at a concentration of 0,1 % by volume as the wetting agent.7.3 For specimen installation in straight condition, use the procedure described in 7.3.1 and 7.3.2.7.3.1 Wrap the specimen with flexible membrane except top and bot
47、tom parts. Place the specimen in the pressure cell and insert it into the slots. The specimen shall be mounted in a straight line.7.3.2 Cover the top and bottom parts of specimen with flexible membrane so as to ensure no wrinkles are formed. See that the membrane wrapped to the specimen is watertigh
48、t without leakage. The confined length of the PVD exposed to pressure shall be (300 10) mm for tests in straight condition.7.4 For specimen installation in buckled condition, use the procedure described in 7.4.1 to 7.4.4.7.4.1 Fix the guide frames to the supporters in the pressure cell. Insert two f
49、ixing pins into the holes and tie them to a value of A of (60 1) mm in guide frames. Insert the central pin into the slit and place to the left end.7.4.2 Wrap the specimen with flexible membrane except top and bottom parts. Place the specimen behind the fixing pins and in front of the central pin of guide frames in the pressure cell and insert it into the slots (see Figure 2). Move the centre of specimen at a constant speed of (120 10) mm/min using the central pin until B becomes 55 mm (using the pu
