EN ISO 22477-6:2026

Geotechnical investigation and testing - Testing of geotechnical structures - Part 6: Load testing of soil nails and rock bolts (ISO 22477-6:2026)

This document establishes the specifications for the execution of tension tests to be carried out on soil nails and rock bolts.
NOTE 1      Soil nails and rock bolts are referred to as elements in the scope of this document.
NOTE 2      This document covers but is not limited to grouted soil nails and rock bolts.
NOTE 3      This document does not provide specification for the number of tests, the type of test, the Test Method, the value of the proof load and the limiting criteria. These aspects reside in EN 1997-3 and its national annex or in similar standards.
This document provides specifications for three types of tension tests: investigation tests, suitability tests and acceptance tests.
Two methods of testing are recognised by this document. Test Method A involves step-loaded maintained load tension tests. Test Method B involves constant displacement rate tension tests.
This document provides specifications for the experimental devices, the measurement apparatus, the test procedures, the definition and the presentation of the test results and the content of records, aiming at:
a)      measuring the pull-out resistance of a soil nail or a rock bolt;
NOTE 4      A loading test performed using this document provides the pulled-out resistance along the bonded length, that will possibly differ from the pull-out resistance considered in design.
b)      checking that a soil nail or rock bolt behaves as designed.

Geotechnische Erkundung und Untersuchung - Prüfung von geotechnischen Bauwerken und Bauwerksteilen - Teil 6: Belastungsprüfung von Bodennägeln und Felsankern (ISO 22477-6:2026)

Reconnaissance et essais géotechniques - Essais de structures géotechniques - Partie 6: Essai de chargement des clous et des boulons (ISO 22477-6:2026)

Geotehnično preiskovanje in preskušanje - Preskušanje geotehničnih konstrukcij - 6. del: Obremenilni preskus zemeljskih žebljev in skalnih vijakov (ISO 22477-6:2026)

Ta dokument določa specifikacije za izvedbo nateznih preizkusov, ki se izvajajo na zemeljskih žebljih in kamninskih sidrih.
OPOMBA 1 Zemeljski žeblji in kamninska sidra so v obsegu tega dokumenta navedeni kot elementi.
OPOMBA 2 Ta dokument zajema, vendar ni omejen na injektirane zemeljske žeblje in kamninska sidra.
OPOMBA 3 Ta dokument ne določa specifikacij za število preizkusov, vrsto preizkusa, preizkusno metodo, vrednost kontrolne obremenitve in mejna merila. Ti vidiki so zajeti v EN 1997-3 in njenem nacionalnem dodatku ali v podobnih standardih.
Ta dokument določa specifikacije za tri vrste nateznih preizkusov: raziskovalne preizkuse, preizkuse primernosti in sprejemne preizkuse.
Ta dokument priznava dve metodi preizkušanja. Preizkusna metoda A vključuje postopno obremenjene natezne preizkuse z vzdrževanjem obremenitve. Preizkusna metoda B vključuje natezne preizkuse s konstantno hitrostjo premika.
Ta dokument določa specifikacije za eksperimentalne naprave, merilne aparate, preizkusne postopke, definicijo in predstavitev rezultatov preizkusov ter vsebino zapisov, z namenom:
a) merjenja odpornosti proti izvleku zemeljskega žeblja ali kamninskega sidra;
OPOMBA 4 Obremenitveni preizkus, izveden v skladu s tem dokumentom, zagotavlja odpornost proti izvleku vzdolž vezane dolžine, ki se lahko razlikuje od odpornosti proti izvleku, upoštevane pri načrtovanju.
b) preverjanja, da zemeljski žebelj ali kamninsko sidro deluje skladno z načrtom.

General Information

• Status: Published
• Publication Date: 24-Mar-2026
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: CEN/TC 341 - Geotechnical Investigation and Testing
• Drafting Committee: CEN/TC 341 - Geotechnical Investigation and Testing
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 25-Mar-2026
• Due Date: 15-Aug-2026
• Completion Date: 25-Mar-2026
• Ref Project: SIST EN ISO 22477-6:2026 - Geotechnical investigation and testing - Testing of geotechnical structures - Part 6: Load testing of soil nails and rock bolts (ISO 22477-6:2026)

Relations

• Refers: EN 1992-1-1:2023 - Eurocode 2 - Design of concrete structures - Part 1-1: General rules and rules for buildings, bridges and civil engineering structures
• Effective Date: 08-Apr-2026
• Refers: EN 1993-5:2025 - Eurocode 3 - Design of steel structures - Part 5: Piling
• Effective Date: 08-Apr-2026
• Refers: EN 1997-1:2024 - Eurocode 7 - Geotechnical design - Part 1: General rules
• Effective Date: 08-Apr-2026
• Refers: EN 1990-2:2026 - Eurocode - Basis of structural and geotechnical design - Part 2: Assessment of existing structures
• Effective Date: 08-Apr-2026
• Refers: ISO 7500-1:2018 - Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Calibration and verification of the force-measuring system
• Effective Date: 08-Apr-2026
• Refers: EN 1997-2:2024 - Eurocode 7 - Geotechnical design - Part 2: Ground properties
• Effective Date: 08-Apr-2026
• Referred By: EN 12063:2024 - Execution of special geotechnical work - Sheet pile walls, combined pile walls, high modulus walls
• Effective Date: 01-Apr-2026
• Consolidated By: ISO 22477-6:2026 - Geotechnical investigation and testing — Testing of geotechnical structures — Part 6: Load testing of soil nails and rock bolts
• Effective Date: 12-Feb-2026

Overview

FprEN ISO 22477-6 (ISO/DIS 22477-6:2025) specifies how to perform axial static load tests on single soil nails and rock bolts to determine their load–displacement behaviour. Prepared by ISO/TC 182 in collaboration with CEN, this part of the ISO 22477 series covers test equipment, procedures, measurement, data presentation and reporting for investigation, suitability and acceptance tension tests. The document applies to grouted and other types of soil nails and rock bolts and is intended for use in geotechnical investigation, construction QA/QC and research.

Key Topics

• Scope of testing: Single-element axial tension (pull-out) tests on soil nails and rock bolts to measure pull-out resistance and verify designed behaviour.
• Types of tests:
  • Investigation tests
  • Suitability tests
  • Acceptance tests
• Test methods:
  • Test Method A: Step-loaded, maintained-load (incremental) tension tests.
  • Test Method B: Constant displacement-rate tension tests.
• Equipment and setup: Requirements for test set-up, reaction systems, loading devices, force and displacement measurement, and environmental/time monitoring.
• Test element types: Differentiation between sacrificial and production elements and guidance on timing between installation and testing.
• Execution details: Test preparation, proof load, datum load, check of de-bonded length, measurement checks and data interpretation.
• Reporting: Required content for data reports and interpretative reports to document results and conclusions.
• Creep assessment: Includes provisions (Annex A) on creep rate and critical creep load for long-term behaviour assessment.
• Limitations: The standard does not set the number of tests, proof load values or acceptance criteria - those are provided by EN 1997-3 or relevant national application documents.

Applications

• Quality control and acceptance testing during excavation, slope stabilisation and tunnel or underground works.
• Design verification and site investigation to confirm soil nail or rock bolt performance.
• Laboratory and field testing by geotechnical testing laboratories, contractors, and engineering consultants.
• Research into load–displacement and creep behaviour of anchored elements in soils and rock.

Who should use it

• Geotechnical engineers, rock mechanics specialists, site testing teams, construction QA/QC personnel, and standards/specification authors involved in foundation construction, earthworks and underground works.

Related Standards

• EN 1997 (Eurocode 7: Geotechnical design) - application rules, test frequency and acceptance criteria.
• EN 1990 (Basis of structural design) - general design principles.
• ISO 7500-1 - calibration and verification of force-measuring systems.
• Other parts of the ISO 22477 series for testing of geotechnical structures.

Keywords: ISO 22477-6, soil nails, rock bolts, load testing, geotechnical investigation, tension tests, load–displacement, Test Method A, Test Method B, EN 1997.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2026
Geotehnično preiskovanje in preskušanje - Preskušanje geotehničnih konstrukcij
- 6. del: Obremenilni preskus zemeljskih žebljev in skalnih vijakov (ISO 22477-
6:2026)
Geotechnical investigation and testing - Testing of geotechnical structures - Part 6: Load
testing of soil nails and rock bolts (ISO 22477-6:2026)
Geotechnische Erkundung und Untersuchung - Prüfung von geotechnischen Bauwerken
und Bauwerksteilen - Teil 6: Belastungsprüfung von Bodennägeln und Felsankern (ISO
22477-6:2026)
Reconnaissance et essais géotechniques - Essais de structures géotechniques - Partie
6: Essai de chargement de clous et de boulons (ISO 22477-6:2026)
Ta slovenski standard je istoveten z: EN ISO 22477-6:2026
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22477-6
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2026
EUROPÄISCHE NORM
ICS 93.020
English Version
Geotechnical investigation and testing - Testing of
geotechnical structures - Part 6: Load testing of soil nails
and rock bolts (ISO 22477-6:2026)
Reconnaissance et essais géotechniques - Essais de Geotechnische Erkundung und Untersuchung - Prüfung
structures géotechniques - Partie 6: Essai de von geotechnischen Bauwerken und Bauwerksteilen -
chargement des clous et des boulons (ISO 22477- Teil 6: Belastungsprüfung von Bodennägeln und
6:2026) Felsankern (ISO 22477-6:2026)
This European Standard was approved by CEN on 2 March 2026.

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 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, 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 CEN-CENELEC 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, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22477-6:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22477-6:2026) has been prepared by Technical Committee ISO/TC 182
"Geotechnics" 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 September 2026, and conflicting national standards
shall be withdrawn at the latest by September 2026.
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.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 22477-6:2026 has been approved by CEN as EN ISO 22477-6:2026 without any
modification.
International
Standard
ISO 22477-6
First edition
Geotechnical investigation and
2026-03
testing — Testing of geotechnical
structures —
Part 6:
Load testing of soil nails and rock
bolts
Reconnaissance et essais géotechniques – Essais de structures
géotechniques —
Partie 6: Essai de chargement des clous et des boulons
Reference number
ISO 22477-6:2026(en) © ISO 2026

ISO 22477-6:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part 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 ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 22477-6:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms, definitions .2
3.2 Symbols .3
4 Equipment . 3
4.1 Test set-up .3
4.2 Reaction system .4
4.3 Loading device .4
4.4 Load measurement .5
4.5 Displacement measurement .5
4.6 Time and temperature measurement .5
5 Test elements . 5
5.1 General .5
5.2 Sacrificial elements .6
5.3 Production elements .6
6 Execution of the test . 6
6.1 Time period between installation of test element and testing.6
6.2 Test preparation .6
6.3 Proof load .6
6.4 Datum load .7
6.5 Check of the de-bonded length .7
7 Test report . 7
7.1 General .7
7.2 Data report .7
7.3 Interpretative report .8
8 Test Method A . 8
8.1 General .8
8.2 Investigation test .8
8.2.1 Loading procedure .8
8.2.2 Measurement and checks .9
8.2.3 Interpretation of data .9
8.3 Suitability test .11
8.3.1 Loading procedure .11
8.3.2 Measurement and checks . 12
8.3.3 Interpretation of data . 12
8.4 Acceptance test . 13
8.4.1 Loading procedure . 13
8.4.2 Measurement and checks .14
8.4.3 Interpretation of data .14
9 Test Method B . 14
9.1 General .14
9.2 Loading procedure . 15
9.3 Measurement and checks .17
9.4 Interpretation of data .17
Annex A (informative) Creep rate α and critical creep load P .18
c
Bibliography . 19

iii
ISO 22477-6:2026(en)
Foreword
ISO (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 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 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, Part 1. In particular, the different approval criteria needed for the different types
of ISO document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 182, Geotechnics, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 341, Geotechnical
Investigation and Testing, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
A list of all parts in the ISO 22477 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 22477-6:2026(en)
Geotechnical investigation and testing — Testing of
geotechnical structures —
Part 6:
Load testing of soil nails and rock bolts
1 Scope
This document establishes the specifications for the execution of tension tests to be carried out on soil nails
and rock bolts.
NOTE 1 Soil nails and rock bolts are referred to as elements in the scope of this document.
NOTE 2 This document covers but is not limited to grouted soil nails and rock bolts.
NOTE 3 This document does not provide specification for the number of tests, the type of test, the Test Method, the
value of the proof load and the limiting criteria. These aspects reside in EN 1997-3 and its national annex or in similar
standards.
This document provides specifications for three types of tension tests: investigation tests, suitability tests
and acceptance tests.
Two methods of testing are recognised by this document. Test Method A involves step-loaded maintained
load tension tests. Test Method B involves constant displacement rate tension tests.
This document provides specifications for the experimental devices, the measurement apparatus, the test
procedures, the definition and the presentation of the test results and the content of records, aiming at:
a) measuring the pull-out resistance of a soil nail or a rock bolt;
NOTE 4 A loading test performed using this document provides the pulled-out resistance along the bonded
length, that will possibly differ from the pull-out resistance considered in design.
b) checking that a soil nail or rock bolt behaves as designed.
2 Normative references
The 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 amendments) applies.
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
EN 1990 (series), Eurocode: Basis of structural and geotechnical design
EN 1992-1-1, Eurocode 2: Design of concrete structures
EN 1993-5, Eurocode 3: Design of steel structures
EN 1997 (series), Eurocode 7: Geotechnical design

ISO 22477-6:2026(en)
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in the EN 1990 series and the EN 1997
series and the following terms apply. ISO and IEC maintain terminology databases for use in standardization
at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms, definitions
3.1.1
applied load
P
tension load applied to the tendon head during the test
3.1.2
proof load
P
p
maximum load to which a test element is subjected in a particular load test
3.1.3
measured pull-out resistance
R
t,m
measured value of the pull-out resistance at the element-ground interface
3.1.4
tendon
soil nail or rock bolt reinforcing element
Note 1 to entry: Steel, fibreglass, etc.
3.1.5
test element
element on which a test is performed
3.1.6
sacrificial element
test element installed in the same way as production elements, but not forming part of the completed
reinforced ground structure
3.1.7
production element
test element which forms part of the completed reinforced ground structure
3.1.8
investigation test
load test to establish the geotechnical ultimate load resistance of a soil nail or rock bolt at the interface
between the element and the ground and to determine the behaviour of the element in the working load
range
3.1.9
suitability test
load test to confirm that a particular soil nail or rock bolt design will be adequate in particular ground
conditions
3.1.10
acceptance test
load test to confirm that an individual soil nail or rock bolt conforms with its acceptance criteria
...