ISO/FDIS 22477-6

Geotechnical investigation and testing - Testing of geotechnical structures - Part 6: Load testing of soil nails and rock bolts

This document establishes the specifications for the execution of static load tests on soil nails or rock bolts, in which a single element (soil nail or rock bolt) is subjected to an axial static load in tension in order to define its load-displacement behaviour. Load tests on rock bolts are also covered by this document

Reconnaissance et essais géotechniques – Essais de structures géotechniques — Partie 6: Essai de chargement des clous et des boulons

General Information

• Status: Not Published
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: ISO/TC 182 - Geotechnics
• Drafting Committee: ISO/TC 182 - Geotechnics
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 04-Dec-2025
• Completion Date: 04-Dec-2025

Relations

• Consolidates: ISO/IEC 19075-6:2021 - Information technology - Guidance for the use of database language SQL - Part 6: Support for JSON
• Effective Date: 18-Nov-2023

Overview

ISO/FDIS 22477-6:2025 - "Geotechnical investigation and testing - Testing of geotechnical structures - Part 6: Load testing of soil nails and rock bolts" specifies how to carry out static axial tension load tests on individual soil nails and rock bolts to determine their load–displacement behaviour. The standard covers grouted and non‑grouted elements, defines required test equipment and measurement systems, and sets out procedures for three test types: investigation, suitability and acceptance tests. It focuses on single‑element static load testing and on producing reproducible, traceable test records.

Key topics and technical requirements

• Test scope and objectives
  • Measures pull‑out resistance and checks that an element behaves as designed.
  • Provides procedures for investigation, suitability and acceptance testing.
• Recognised test methods
  • Test Method A: step‑loaded, maintained load (creep monitoring).
  • Test Method B: constant displacement rate tension tests.
• Equipment and setup
  • Loading device (normally a hydraulic jack) applied axially; stroke sufficient to avoid reseating.
  • Reaction system must resist the proof load and not bias pull‑out measurements; facing should be disconnected where needed.
  • Displacement monitoring support must be remote and rigid to avoid interference.
• Measurement and calibration
  • Applied load measured by load cell or from jack pressure; devices calibrated and traceable per ISO 7500‑1.
  • Load measurement uncertainty: the larger of 2% of the proof load or 10 kN (as specified).
  • Displacement measurement minimum uncertainty requirement specified (e.g., < 0.1 mm and 1% of measured value).
  • Loading device and load cells/calibration valid within one year of test.
• Test execution and reporting
  • Timing between installation and testing, proof load application, datum loads, and checks of de‑bonded length are specified.
  • Test report must include both data and interpretative elements to support design and acceptance decisions.
• Limitations
  • The standard does not prescribe the number of tests, proof load magnitudes, or acceptance criteria - these are referenced to EN 1997‑3 / national annexes or project specifications.

Applications and users

• Practical uses: site investigation, design verification of soil nails and rock bolts, acceptance testing during construction, forensic post‑failure testing, quality assurance for slope stability, retaining structures, tunnels and rock anchors.
• Primary users: geotechnical engineers, testing laboratories, contractors and site supervisors, structural/geotechnical designers, and code compliance reviewers.

Related standards

• ISO 7500‑1 (calibration of force‑measuring systems)
• EN 1990 / EN 1997 (Eurocode - basis and geotechnical design)
• EN 1997‑3 (national annexes for testing frequencies and acceptance criteria)

Keywords: ISO/FDIS 22477-6, geotechnical investigation, load testing, soil nails, rock bolts, tension tests, load‑displacement, test method A, test method B, pull‑out resistance, calibration, EN 1997.

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 182
Geotechnical investigation and
Secretariat: BSI
testing — Testing of geotechnical
Voting begins on:
structures —
2025-12-04
Part 6:
Voting terminates on:
2026-01-29
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
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 182
Geotechnical investigation and
Secretariat: BSI
testing — Testing of geotechnical
Voting begins on:
structures —
Part 6:
Voting terminates on:
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
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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 Reference number
ii
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 .5
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 .6
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 and critical creep load P .18
c
Bibliography . 19

iii
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
FINAL DRAFT International Standard ISO/FDIS 22477-6:2025(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 Soils nails and rock bolts are referred 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 might 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 1997 (series), Eurocode 7: Geotechnical design

3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in EN 1990 series and 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 supporting 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

3.2 Symbols
A Minimum cross section of the tendon, including the connecting parts
t
E elastic modulus of the tendon material
t
L bonded length of the test element
b
L debonded length of the test element
db
L external length of the tendon
e
P applied load
P datum load
a
P critical creep load
c
P’ intermediate parameter to derive the critical creep load P
c c
P proof load
p
R measured pull-out resistance
t,m
f (= f ) tensile strength
tk uk
f yield strength at 0,2 % strain
t0,2k
s axial displacement of tendon head
s axial displacement of tendon head at time t , for creep rate determination
1 1
s axial displacement of tendon head at time t , for creep rate determination
2 2
t time
t minimum load step duration for Test Method A
min
t time at the beginning of the interval used for creep rate determination
t time at the end of the interval used for creep rate determination
α creep rate (defined in Annex A)
α limiting criterion for creep rate for Test Method A
A
4 Equipment
4.1 Test set-up
The equipment comprises (non-exhaustive list) of one jack, used as a loading device, displacement and load
monitoring devices, a reaction system, associated locking nuts, tendon extension.
An example of test set-up is given in Figure 1.
The test set-up shall take into account the aim of the test, the ground conditions and the expected
displacement of the test element.
Where the facing system or the load test reaction system can influence the test result, then the test element
should be de-bonded over the zone of influence.

Key
1 facing
2 reaction structure
3 extension of tendon
4 locking nut and plate at top of jack
5 displacement monitoring of tendon end
6 jack
7 pressure gauge
8 load cell
9 hydraulic system (pump)
10 tendon
11 grout
12 borehole
Figure 1 — Schematic layout of test loading system
4.2 Reaction system
The reaction system shall be designed to resist the proof load P , according to the relevant design standards.
p
The reaction system should be designed so as not to affect the measured pull-out resistance of the test
eleme
...

ISO/DISFDIS 22477-6:2025(en)
ISO/TC182TC 182
Secretariat: BSI
Date: 2025-05-0711-19
Geotechnical investigation and 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 dedes clous et dedes boulons
FDIS stage
ISO/CEN PARAISO/CEN PARAISO/CEN PARAISO/CEN PARAISO/CEN PARAISO/CEN PARALLLLLLLLLLLLEL PREL PREL PREL PREL PREL PROCESSIOCESSIOCESSIOCESSIOCESSIOCESSINGNGNGNGNGNG

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: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
2 © ISO 2022 – All rights reserved
ii
ISO/DISFDIS 22477-6:2025(en)
Contents
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 . 5
4.3 Loading device . 5
4.4 Load measurement . 5
4.5 Displacement measurement . 5
4.6 Time and temperature measurement . 6
5 Test elements . 6
5.1 General . 6
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 . 7
6.3 Proof load . 7
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 . 9
8.1 General . 9
8.2 Investigation test . 9
8.3 Suitability test . 14
8.4 Acceptance test . 17
9 Test method B . 20
9.1 General . 20
9.2 Loading procedure . 20
9.3 Measurement and checks. 26
9.4 Interpretation of data . 26
Annex A (informative) Creep rate and critical creep load P . 27
c
Bibliography . 29

iii
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.
4 © ISO 2022 – All rights reserved
iv
DRAFT International Standard ISO/DIS 22477-6:2025(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 Soils nails and rock bolts are referred 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) 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 might differ from the pull-out resistance considered in design.
b) 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 1997 (series,), Eurocode 7: Geotechnical design
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in EN 1990 series and 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 3.1.1
applied load
P
tension load applied to the tendon head during the test
3.1.2 3.1.2
proof load
P
p
maximum load to which a test element is subjected in a particular load test
3.1.3 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 3.1.4
tendon
soil nail or rock bolt reinforcing element
Note 1 to entry: steel, fibreglass, etc.
3.1.5 3.1.5
test element
element on which a test is performed
3.1.6 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 3.1.7
production element
test element which forms part of the completed reinforced ground structure
3.1.8 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 supporting element and the ground and to determine the behaviour of the element in the working
load range
2 © ISO 2022 – All rights reserved
ISO/DISFDIS 22477-6:2025(en)
3.1.9 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 3.1.10
acceptance test
load test to confirm that an individual soil nail or rock bolt compliesconforms with its acceptance criteria
3.2 Symbols
A Minimum cross section of the tendon, including the connecting parts
t
E elastic modulus of the tendon material
t
L bonded length of the test element
b
L debonded length of the test element
db
L external length of the tendon
e
P applied load
P datum load
a
P critical creep load
c
P’ intermediate parameter to derive the critical creep load P
c c
P proof load
p
R measured pull-out resistance
t,m
f (= f ) tensile strength
tk uk
f yield strength at 0,2 % strain
t0,2k
s axial displacement of tendon head
s axial displacement of tendon head at time t , for creep rate determination
1 1
s axial displacement of tendon head at time t , for creep rate determination
2 2
t time
t minimum load step duration for Test Method A
min
t time at the beginning of the interval used for creep rate determination
t time at the end of the interval used for creep rate determination
α creep rate (defined in Annex AAnnex A))
α limiting criterion for creep rate for Test Method A
A
4 Equipment
4.1 Test set-up
The equipment comprises (non-exhaustive list) of one jack, used as a loading device, displacement and load
monitoring devices, a reaction system, associated locking nuts, tendon extension.
An example of test set-up is given in 0Figure 1.
The test set-up shall take into account the aim of the test, the ground conditions and the expected displacement
of the test element.
Where the facing system or the load test reaction system can influence the test result, then the test element
should be de-bonded over the zone of influence.

Key
1 facing
2 reaction structure
3 extension of tendon
4 locking nut and plate at top of jack
5 displacement monitoring of tendon end
6 jack
7 pressure gauge
4 © ISO 2022 – All rights reserved
ISO/DISFDIS 22477-6:2025(en)
7*8 load cell
89 hydraulic system (pump)
910 tendon
1011 grout
1112 borehole
Figure 1 — Schematic layout of test loading system
4.2 Reaction system
The reaction system shall be designed to resisttheresist the proof load P , according to the relevant design
p
standards. The reaction system should be designed so as not to affect the measured pull-out resistance of the
test element, or to impose bearing pressures in excess of the bearing capacity of the facing.
It shall ensure that the applied load remains purely axial.
The reaction system may comprise the facing and additional rigid reaction elements (such as plates, beams,
etc.).
When no de-bonded length can be implemented, special attention should be taken to the choice of the
minimum distance between the test element and the reaction structure to minimize the influence of the
reaction system. However, if a facing is present, it shall be strictly disconnected from the test element.
4.3 Loading device
The loading device, normally a hydraulic jack, shall have a capacity at least equal to 1,1 times the proof load
P .
p
The stroke of the jack shall be sufficient to avoid reseating during the test. The design of the loading device
shall permit the load to be applied smoothly, and axially to the test element, in both loading and unloading
phases.
The loading device shall be calibrated within one year prior to the test.
4.4 Load measurement
The applied load shall be measured with an appropriate device.
The applied load shall be either measured using a load cell or be derived from the pressure in the jack. In the
latter case, the pressure should be measured in a pressure gauge attached close to the jack.
The uncertainty on the measured load shall be the larger of 2 % of the proof load P or 10 kN.
p
Load cells, jack and pressure gauges used to measure the load shall be calibrated within one year prior to the
test.
The load measurement devices shall be calibrated against a suitable master device following ISO 7500-1,
giving full traceability to National Standardsnational standards.
4.5 Displacement measurement
The displacements of the element head shall be measured with an appropriate device.
The support for the displacement measurement devices shall be remote from the loading device and reaction
system and be sufficiently rigid so as not to be influenced by climatic effects or ground vibrations.
The minimum uncertainty on the displacement measurements shall be smaller than 0,1 mm and 1 % of the
measured value (whichever is the greatest).
Displacement devices shall be capable of monitoring the extension of the test element, throughout the test,
without the need for reseating.
The displacement devices used shall be calibrated within one year prior before carrying out the test.
4.6 Time and temperature measurement
The uncertainty of the measured time shall be less or equal to 1 s.
The uncertainty of the measured air temperature shall be less or equal to 1 °C.
5 Test elements
5.1 General
Load tests may be performed on either sacrificial elements or production elements, with different purposes
and requirements.
The execution and documentation of test elements shall conform with relevant execution standards.
NOTE EN 14490 can be used for the execution of soil nails.
When a facing is present, a de-bonded length shall be implemented to ensure disconnection between the test
element and the facing.
5.2 Sacrificial elements
Sacrificial elements, which are not part of a completed reinforced ground structure, are usually installed and
tested by investigation tests prior to the installation of production elements. Ground conditions at the test
location shall be
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