1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Geotechnical investigation and testing - Laboratory testing of soilPart 8: Unconsolidated undrained triaxial testBS EN ISO 178928:2018National forewordThis British Standard is the UK implementation of EN ISO 178928:2018
2、. It is identical to ISO 178928:2018. It partially supersedes BS 13777:1990, specifically clause 7.The UK participation in its preparation was entrusted to Technical Committee B/526/3, Site investigation and ground testing.A list of organizations represented on this committee can be obtained on requ
3、est to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 94086 6ICS 93.020; 13.080.20Compliance with a
4、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 April 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 178928:2018EUROPEAN STANDAR
5、DNORME EUROPENNEEUROPISCHE NORMEN ISO 17892-8March 2018ICS 13.080.20; 93.020 Supersedes CEN ISO/TS 178928:2004, CEN ISO/EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No.
6、 EN ISO 178928:2018: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersGeotechnical investigation and testing Laboratory testing of soil Part 8: Unconsolidated undrained triaxial test (ISO 178928:2018)Reconnaissance et essais gotechniques Essais de l
7、aboratoire sur les sols Partie 8: Essai triaxial non consolid non drain (ISO 178928:2018)Geotechnische Erkundung und Untersuchung Laborversuche an Bodenproben Teil 8: Unkonsolidierter undrnierter Triaxialversuch (ISO 178928:2018)This European Standard was approved by CEN on 18 January 2018.CEN membe
8、rs 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. Uptodate lists and bibliographical references concerning such national standards may be obtained on application
9、to the CENCENELEC 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 notified to the CENCENELEC Management Ce
10、ntre 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuan
11、ia, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionEN ISO 17892-8:2018 (E)European forewordThis document (EN ISO 178928:2018) has been prepared by Technical Committee ISO/TC 182 “Geot
12、echnics“ in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and Testing” the secretariat of which is held by BSI.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 Septe
13、mber 2018, and conflicting national standards shall be withdrawn at the latest by September 2018.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This
14、document supersedes CEN ISO/TS 178928:2004.According to the CENCENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Y
15、ugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 1789
16、28:2018 has been approved by CEN as EN ISO 178928:2018 without any modification.2BS EN ISO 178928:2018ISO 17892-8:2018Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols 25 Apparatus . 35.1 General . 35.2 Triaxial cell . 45.3 Confining membrane . 55.4 Cel
17、l pressure system 55.5 Load frame 55.6 Measuring devices 55.6.1 Load measuring device . 55.6.2 Pressure measuring device . 55.6.3 Vertical displacement measuring device 65.7 Cell pressure fluids 65.8 Ancillary apparatus . 66 Test procedure 66.1 General requirements and equipment preparation 66.2 Pre
18、paration of specimens 66.3 Application of cell pressure and initial readings . 76.4 Shearing 86.5 Dismounting 87 Test results 97.1 Bulk density, dry density and water content 97.2 Stage prior to shearing . 97.3 Shearing 97.3.1 Corrected crosssectional area 97.3.2 Deviator stress . 97.3.3 Vertical st
19、rain . 107.3.4 Undrained shear strength . 107.4 Correction for elastic membrane . 108 Test report 108.1 Mandatory reporting 108.2 Optional reporting 11Annex A (normative) Calibration, maintenance and checks 12Bibliography .14 ISO 2018 All rights reserved iiiContents PageBS EN ISO 178928:2018ISO 1789
20、2-8:2018ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for wh
21、ich a technical committee has been established has the right to be represented on that committee. International organizations, governmental and nongovernmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all m
22、atters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This
23、 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 elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or a
24、ll 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 received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users an
25、d does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to
26、 Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by the European Committee for Standardization (CEN) Technical Committee CEN/TC 341, Geotechnical investigation and testing, in collaboration with ISO Technical Committee TC 182, Geotechnics, in accordance wi
27、th the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).This first edition of ISO 178928 cancels and replaces ISO/TS 178928:2004 and ISO/TS 178928:2004/Cor.1:2006.A list of all the parts in the ISO 17892 series can be found on the ISO website.iv ISO 2018 All rights reservedB
28、S EN ISO 178928:2018ISO 17892-8:2018IntroductionThis document covers areas in the international field of geotechnical engineering never previously standardized. It is intended that this document presents broad good practice throughout the world and significant differences with national documents is
29、not anticipated. It is based on international practice (see Reference 1). ISO 2018 All rights reserved vBS EN ISO 178928:2018This page deliberately left blankGeotechnical investigation and testing - Laboratory testing of soil Part 8: Unconsolidated undrained triaxial test1 ScopeThis document specifi
30、es a method for unconsolidated undrained triaxial compression tests.This document is applicable to the laboratory determination of undrained triaxial shear strength under compression loading within the scope of geotechnical investigations.The cylindrical specimen, which can comprise undisturbed, rec
31、ompacted, remoulded or reconstituted soil, is subjected to an isotropic stress under undrained conditions and thereafter is sheared under undrained conditions. The test allows the determination of shear strength and stressstrain relationships in terms of total stresses.Nonstandard procedures such as
32、 tests with the measurement of pore pressure or tests with filter drains are not covered in this document.NOTE This document fulfils the requirements of unconsolidated undrained triaxial compression tests for geotechnical investigation and testing in accordance with EN 19971 and EN 19972.2 Normative
33、 referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendme
34、nts) applies.ISO 146881, Geotechnical investigation and testing Identification and classification of soil Part 1: Identification and descriptionISO 178921, Geotechnical investigation and testing Laboratory testing of soil Part 1: Determination of water contentISO 178922, Geotechnical investigation a
35、nd testing Laboratory testing of soil Part 2: Determination of bulk densityISO 178923, Geotechnical investigation and testing Laboratory testing of soil Part 3: Determination of particle density3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO an
36、d IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obpINTERNATIONAL STANDARD ISO 17892-8:2018 ISO 2018 All rights reserved 1BS EN ISO 17
37、8928:2018ISO 17892-8:20183.1cell pressurepressure applied to the cell fluid3.2deviator stressdifference between the applied vertical total stress and the horizontal total stress at the mid height of the specimen3.3undrained shear strengthequal to one half of the deviator stress at failure in the unc
38、onsolidated undrained triaxial compression test3.4failurestress or strain condition at which one of the following criteria are met: peak deviator stress; a specified deformation criterion if a peak deviator stress has not been achieved, e.g., 15 % vertical strain.4 SymbolsAiinitial crosssectional ar
39、ea of the specimenAcorcrosssectional area of the specimen during sheara crosssectional area of the piston if an external load cell is usedcuundrained shear strengthDminitial internal diameter of membrane (before it is placed on the specimen)Emelastic modulus for the membrane, measured in tensionf fa
40、ctor relating the vertical strain to the specimen volumetric strainHsinitial height of the specimen prior to shearing (=HiHi)HiInitial height of specimen after preparationh distance from the top of the top cap to the mid height of the specimenP vertical load readingtminitial thickness of the unstres
41、sed membraneViinitial volume of the specimen after preparationW gravity force acting on the sum of the deadweight hanger (if used), the piston, the top cap and one half of the soil specimen unit weight of the cell fluidHiheight change prior to shearingHsheight change during shearing2 ISO 2018 All ri
42、ghts reservedBS EN ISO 178928:2018ISO 17892-8:2018(v)mcorrection to vertical total stress due to the membranevvertical strain(v)mvertical strain of the membraneccell pressure at the mid height of the specimenhhorizontal total stress at the mid height of the specimenvvertical total stress at the mid
43、height of the specimenV specimen volume change (with reduction in volume being a positive numerical value)5 Apparatus5.1 GeneralThe apparatus shall undergo regular maintenance, checks and calibration as specified in Annex A.A schematic diagram of a typical apparatus for triaxial compression testing
44、is shown in Figure 1. ISO 2018 All rights reserved 3BS EN ISO 178928:2018ISO 17892-8:2018Key1 alternative positions for load measuring device2 air bleed3 vertical displacement measuring device4 piston5 top cap6 soil specimen7 rubber membrane8 Orings9 device for control and measurement of cell pressu
45、re10 triaxial cellP vertical loadFigure 1 Schematic diagram of a typical unconsolidated undrained triaxial apparatus5.2 Triaxial cell5.2.1 The triaxial cell shall be able to withstand the applied cell pressure without leakage of cell fluid out of the cell. Transparent cells should be used where poss
46、ible.5.2.2 The sealing bushing and piston guide shall be designed such that the piston runs smoothly with minimal friction and maintains alignment.5.2.3 The material of the top cap and the pedestal and the connection between the top cap and the piston shall be such that their deformations are neglig
47、ible compared to the deformations of the soil specimen.5.2.4 The diameter of the top cap and of the pedestal should normally be equal to the diameter of the specimen. Specimens with diameters smaller than the diameter of the end caps may be tested provided cavities under the membrane at the ends of
48、the specimen can be avoided.4 ISO 2018 All rights reservedBS EN ISO 178928:2018ISO 17892-8:20185.2.5 The vertical stress applied to the specimen due to the weight of the top cap should not exceed 2 % of the estimated undrained shear strength of the specimen or 1 kPa, whichever is the greater.5.3 Con
49、fining membrane5.3.1 The soil specimen shall be confined by an elastic membrane which effectively prevents the cell fluid from penetrating into the specimen.NOTE Membranes with an elastic modulus of around 1 400 kPa have been found to be suitable.5.3.2 A confining membrane that gives a correction on the estimated undrained shear strength of less than 10 % at failure should be used (see 7.4).If rubber membranes are used, membranes with following properties sho
