Geotechnical investigation and testing — Field testing — Part 9: Field vane test (FVT and FVT-F)

This document deals with the equipment requirements, execution and reporting of field vane tests for the measurement of peak and remoulded vane shear strength together with the sensitivity of fine-grained soils. In addition, post-peak shear strength behaviour can be evaluated. Two types of field vane test are described: the ordinary field vane test (FVT) and the fast field vane test (FVT-F). The uncertainties of the vane test result are described in Annex D. NOTE 1 This document fulfils the requirements for field vane tests as part of the geotechnical investigation and testing according to EN 1997-1 and EN 1997-2. NOTE 2 This document covers onshore and nearshore field vane testing.

Reconnaissance et essais géotechniques — Essais en place — Partie 9: Essais au scissomètre de chantier (FVT et FVT-F)

Le présent document traite des exigences en matière d'équipement, d'exécution et de compte-rendu des essais sur le terrain pour la mesure de la résistance au cisaillement maximale et résiduelle du sol, ainsi que de la sensibilité des sols à grains fins. En outre, le comportement de la résistance au cisaillement après le pic peut être évalué. Deux types d'essais au scissomètre de chantier sont décrits: l'essai scissométrique ordinaire (FVT) et l'essai scissométrique rapide (FVT-F). Les incertitudes du résultat de l'essai au scissomètre de chantier sont décrites à l'Annexe D. NOTE 1 Le présent document répond aux exigences relatives aux essais scissométriques dans le cadre de l'étude et des essais géotechniques conformément aux normes EN 1997-1 et EN 1997-2. NOTE 2 Le présent document porte sur les essais scissométriques à terre et à proximité du littoral.

General Information

Status
Published
Publication Date
06-Sep-2020
Current Stage
6060 - International Standard published
Start Date
07-Sep-2020
Completion Date
07-Sep-2020
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INTERNATIONAL ISO
STANDARD 22476-9
First edition
2020-09
Geotechnical investigation and
testing — Field testing —
Part 9:
Field vane test (FVT and FVT-F)
Reconnaissance et essais géotechniques — Essais en place —
Partie 9: Essai au scissomètre de chantier
Reference number
ISO 22476-9:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 22476-9:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22476-9:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and symbols ............................................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Symbols ......................................................................................................................................................................................................... 4

4 Equipment and configurations .............................................................................................................................................................. 6

4.1 Test equipment ....................................................................................................................................................................................... 6

4.1.1 Vane and vane shaft ....................................................................................................................................................... 6

4.1.2 Friction reducer ................................................................................................................................................................ 7

4.1.3 Slip coupling ........................................................................................................................................................................ 7

4.1.4 Extension rods, protective casings, protection shoe ......................................................................... 7

4.1.5 Rotation unit ........................................................................................................................................................................ 8

4.1.6 Equipment for measuring rotation and torque ..................................................................................... 8

4.2 Test configurations .............................................................................................................................................................................. 8

5 Selection of equipment and test configuration ..................................................................................................................10

5.1 Selection of equipment .................................................................................................................................................................10

5.2 Selection of test configuration ................................................................................................................................................11

6 Test procedure .....................................................................................................................................................................................................12

6.1 Equipment checks and calibrations ...................................................................................................................................12

6.2 Position and inclination of thrust machine .................................................................................................................12

6.3 Test depths ..............................................................................................................................................................................................12

6.4 Internal friction torque reading prior to testing .....................................................................................................12

6.5 Methods for reaching the level for insertion of the vane .................................................................................12

6.6 Insertion of the vane .......................................................................................................................................................................14

6.7 External friction torque reading ...........................................................................................................................................15

6.8 Vane shear test .....................................................................................................................................................................................15

6.9 Internal friction torque reading after the test ......... ..................................................................................................16

7 Test results ...............................................................................................................................................................................................................16

8 Reporting ...................................................................................................................................................................................................................17

8.1 General ........................................................................................................................................................................................................17

8.2 Reporting of test results ...............................................................................................................................................................17

8.2.1 General information ...................................................................................................................................................17

8.2.2 Location of the test .................. ......................................................................................................................... ...........18

8.2.3 Test equipment ...............................................................................................................................................................18

8.2.4 Test procedure ................................................................................................................................................................18

8.2.5 Test results .........................................................................................................................................................................19

8.3 Presentation of test plots ............................................................................................................................................................19

Annex A (informative) Test phases ......................................................................................................................................................................20

Annex B (informative) Example of field report for field vane test ......................................................................................21

Annex C (normative) Maintenance, checks and calibration ......................................................................................................23

Annex D (informative) Uncertainties in field vane testing .........................................................................................................26

Annex E (normative) General interpretation and explanation for tapered and rectangular

vanes with H/D ratios differing from 2 ......................................................................................................................................28

Annex F (informative) Interpretation and explanation for a rectangular vane with rounded

corners .........................................................................................................................................................................................................................31

Annex G (informative) Calculation of test depth corrected for inclination ...............................................................33

© ISO 2020 – All rights reserved iii
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ISO 22476-9:2020(E)

Annex H (informative) Example of estimation of post-peak behaviour .......................................................................34

Bibliography .............................................................................................................................................................................................................................35

iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22476-9:2020(E)
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 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 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 received (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 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).
A list of all parts in the ISO 22476 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.
© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 22476-9:2020(E)
Introduction

The field vane test is used to determine the vane shear strength of soils in the undrained condition,

by insertion of a rectangular vane into fine-grained soil and rotating it. During the rotation, the

torque and rotation can be measured, depending on the test configuration. From the measured torque

and the dimensions of the vane, the peak shear strength, an indication of post-peak behaviour, and

the remoulded shear strength can be derived by a limit equilibrium analysis. Soil sensitivity can be

ascertained if peak and remoulded shear strengths have been determined.

The tests are carried out in boreholes, in trial pits and with pushed-in equipment. The torque and

rotation are measured either above the ground surface using extension rods, or directly above the vane.

The field vane test is mainly applicable to saturated fine-grained soil. The vane shear strength

determined by the test is commonly corrected before geotechnical analysis, using factors based on

local experience.
vi © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22476-9:2020(E)
Geotechnical investigation and testing — Field testing —
Part 9:
Field vane test (FVT and FVT-F)
1 Scope

This document deals with the equipment requirements, execution and reporting of field vane tests

for the measurement of peak and remoulded vane shear strength together with the sensitivity of fine-

grained soils. In addition, post-peak shear strength behaviour can be evaluated. Two types of field vane

test are described: the ordinary field vane test (FVT) and the fast field vane test (FVT-F).

The uncertainties of the vane test result are described in Annex D.

NOTE 1 This document fulfils the requirements for field vane tests as part of the geotechnical investigation

and testing according to EN 1997-1 and EN 1997-2.
NOTE 2 This document covers onshore and nearshore field vane testing.
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 10012, Measurement management systems — Requirements for measurement processes and measuring

equipment
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1.1
cased extension rod

extension rod that is sleeved inside of protective casings (3.1.11) during vane (3.1.23) testing

3.1.2
cased borehole

borehole that is cased to prevent collapse and minimize friction between the extension rods and soil

3.1.3
centralizer
equipment to keep the extension rods straight and prevent buckling
© ISO 2020 – All rights reserved 1
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ISO 22476-9:2020(E)
3.1.4
data acquisition system
measuring system, which converts physical quantities to digital format

Note 1 to entry: The system typically includes sensors, signal conditioning, an analogue-to-digital converter and

recording unit.
3.1.5
downhole test
test configuration whereby the torque is measured close to the vane (3.1.23)

Note 1 to entry: The rotation (3.1.14) can be measured close to the vane or above the ground surface.

3.1.6
external friction torque

torque due to friction outside the measuring equipment during rotation (3.1.14) excluding torque

caused by shearing of soil

Note 1 to entry: External friction is mainly caused by friction acting on extension rods, and it can be estimated

with a slip coupling (3.1.16) immediately before engagement of the vane (3.1.23).

3.1.7
friction reducer

ring inserted between the vane (3.1.23) and the extension rods to reduce friction along uncased

extension rods (3.1.20)
3.1.8
insertion length

distance from the ground surface or base of (bore)hole or trial pit to mid-height of the vane (3.1.23),

measured along the axis of the extension rods
3.1.9
internal friction torque

torque due to friction inside the measuring equipment during rotation (3.1.14) when there is no torque

acting on the vane (3.1.23) and no friction acting on the extension rods
3.1.10
protection shoe
equipment to protect the vane (3.1.23) while pushing into the soil

Note 1 to entry: It assists with the insertion of the vane without drilling. Usually, the tip of the protection shoe

consists of four plate slots allowing the vane plates (3.1.24) to retract inside of the protective casing (3.1.11).

3.1.11
protective casing

tube that isolates the extension rods from the soil and gives support against buckling

3.1.12
protrusion length

distance between the bottom of the protective casing/shoe and the mid-height of the vane (3.1.23)

when pushed to the test depth (3.1.17), measured along the axis of the rods
3.1.13
push-in equipment
equipment to push the vane (3.1.23) into the soil without predrilling.
3.1.14
rotation
change of angle by the circular movement of the vane (3.1.23) around its axis

Note 1 to entry: Apparent rotation is the rotation recorded by the rotation measurement equipment.

2 © ISO 2020 – All rights reserved
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ISO 22476-9:2020(E)
3.1.15
rotation rate
rate of angular rotation (3.1.14) of the vane (3.1.23)
3.1.16
slip coupling

mechanism that allows the extension rods to rotate freely while the vane (3.1.23) remains stationary

Note 1 to entry: The function of slip coupling is to separate the rod friction from vane torque resistance. A slip

coupling mechanism shall provide free rotation with minimal friction.
3.1.17
test depth

vertical distance from the ground surface, reference level or datum to the mid-height of the vane (3.1.23)

Note 1 to entry: According to Annex G, the insertion length (3.1.8) can be corrected with inclinometer

measurements to correspond to the corrected test depth. Otherwise, the test depth is based on the sum of the

lengths of the extension rods from reference level or datum owing to the uncertainty of inclination.

3.1.18
test location
plan position of a test or series of tests
3.1.19
time to failure

time from the beginning of application of torque to the vane (3.1.23) until the maximum torque is reached

3.1.20
uncased extension rod

extension rod that is not protected by protective casing allowing friction to develop between the

extension rods and the soil
3.1.21
uncased vane
vane (3.1.23) pushed into the ground without protection
3.1.22
uphole test
test configuration whereby the torque is measured above the ground surface

Note 1 to entry: The rotation (3.1.14) is applied and measurements registered above the ground surface.

3.1.23
vane
device formed by four vane plates (3.1.24) fixed at 90° to each other
3.1.24
vane plate
thin and flat rectangular plate

Note 1 to entry: Most vanes (3.1.23) have a (nearly) rectangular shape. For practical reasons, vanes without

protection shoes (3.1.10) often have slightly tapered lower ends of the vane plates or with rounded corners. Some

equipment using uncased extension rods (3.1.20) and a slip coupling (3.1.16) to separate the rod friction from the

torque on the vane are designed with slightly tapered, sharpened, pointed or conical, vane plates in order to

disengage the slip coupling during the pushing stroke.
3.1.25
vane shaft

cylindrical element of the vane (3.1.23) to which the vane plates (3.1.24) are fixed

Note 1 to entry: The vane shaft may be connected directly to the force or torque measurement equipment in a

downhole test (3.1.5) or connected to it via extension rods in an uphole test (3.1.22).

© ISO 2020 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 22476-9:2020(E)
3.1.26
waiting time

time between reaching the test depth (3.1.17) and beginning of application of the torque to the vane

3.1.27
zero shift

difference between the internal friction torque (3.1.9) readings of the measuring equipment prior to and

after completion of the test
3.1.28
sensitivity
ratio between the undisturbed and remoulded undrained shear strengths
3.2 Symbols
Symbol Name Description Unit
A Lateral shear surface area of the bottom cone mm
cone,bott
A Lateral shear surface area of the top cone mm
cone,top
A Lateral shear surface area of the cylinder mm
cylinder
α Measured total angle between the vertical axis and the axis of °
the vane
β Measured angle between the vertical axis and the projection of the °
axis of the field vane on a fixed vertical plane
β Measured angle between the vertical axis and the projection of the °
axis of the field vane on a vertical plane that is perpendicular to
the plane of angle β
C Protective casing Defined by term 3.1.11

c Undrained shear Shear resistance of fine-grained soils in the undrained condition kPa

strength
c Field vane Peak shear strength of soil, derived from the maximum torque kPa
strength measured by field vane test

c Fast field vane Peak shear strength of soil, derived from the maximum torque kPa

fv-f
strength measured by fast field vane test

c Post-peak field Post-peak shear strength of soil, selected after desired rotation kPa

vane strength after field vane strength

c Remoulded field Shear strength, as measured by field vane test, after remoulding kPa

vane strength the soil

D Downhole meas- Equipment for measuring torque and rotation are located close to

uring equipment the vane
D* Downhole meas- Equipment for measuring torque is located close to the vane,
uring equipment but equipment for measuring rotation is located above the
ground surface
D Diameter of the vane mm
d Diameter of vane shaft immediately behind vane mm
D Diameter of lower end of protective casing mm
D Diameter of protection shoe mm
F Friction reducer Defined by term 3.1.7
H Height of the vane mm
H The height of the vertical side of the tapered vane excluding mm
the height influence of tapering(s).
i Angle of the taper at vane top °
i Angle of the taper at vane bottom °
4 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 22476-9:2020(E)
Symbol Name Description Unit
R Rotation unit Rotation unit can be located close to the vane or above the
ground surface
R Area ratio Cross-sectional area ratio of vane and vane shaft compared to —
circular shear surface
r Radius of the rounded corner of the vane plate mm
r Lever arm of the lateral surface of the bottom cone of shear surface mm
cone,bott
r Lever arm of the lateral surface of the top cone mm
cone,top
r Lever arm of the lateral surface of the cylinder mm
cylinder
S Slip coupling Defined by term 3.1.16
Field vane The ratio between the field vane and remoulded field vane —
sensitivity strengths
s Thickness of the vane plates mm
T Torque Torque measured during vane rotation, corrected for external Nm
friction torque reading
T Component of torque required to shear the bottom cone of the Nm
cone,bott
shear surface
T Component of torque required to shear the top cone of the shear Nm
cone,top
surface
T Component of torque required to shear a quarter circular shear Nm
corner
surface
T Component of torque required to shear the side surface of the Nm
cylinder
cylinder

T External friction Stable output of measuring equipment during rotation when there Nm

ext
torque reading is no torque acting on the vane (usually measured prior to the
vane engagement by slip coupling)

T External friction Stable output of measuring equipment during rotation after Nm

ext*
torque reading remoulding the soil when there is no torque acting on the vane

after remoulding (usually measured prior to the vane engagement by slip coupling)

the soil

T Internal friction Stable output of measuring equipment during rotation when there Nm

int

torque reading is no torque acting on the vane and no friction acting on the exten-

prior to test sion rods

T Maximum torque Torque required to obtain failure in the soil around the vane, Nm

max
corrected for internal and external friction torque reading(s) if
relevant
T Maximum Measured torque required to obtain failure in the soil around the Nm
meas,max
measured torque vane, including external friction. The maximum torque (T ) can
max
be calculated by subtracting T from
ext
T (T = T – T ) otherwise T is T
meas,max max meas,max ext meas,max max

T Measured post- Measured post-peak torque selected after the desired rotation Nm

meas,pv
peak torque (post peak strength measurement) including external friction
torque. The post-peak torque is calculated by subtracting T from
ext
T (T = T – T ) otherwise T is T
meas,pv pv meas,pv ext meas,pv pv

T Measured torque The constant measured torque value after remoulding including Nm

meas,rv
for remoulded external friction torque. The torque for the remoulded condition
conditions is calculated by subtracting T from T (T = T – T )
ext meas,rv rv meas,rv ext
otherwise T is T
meas,rv rv
T Torque caused by shearing of circular plate shear surface Nm
plate

T Post-peak torque Post-peak torque selected after maximum torque, corrected for Nm

internal and external friction torque reading(s) if relevant

T Torque for Measured constant torque value after remoulding the soil, correct- Nm

remoulded ed for internal and external friction torque reading(s) if relevant
conditions
© ISO 2020 – All rights reserved 5
---------------------- Page: 11 ----------------------
ISO 22476-9:2020(E)
Symbol Name Description Unit

τ Shear stress Stress acting along the failure surface due to external shear force kPa

U Uphole A continuous torque measuring equipment located above the
measuring ground surface at the point for insertion of the vane
equipment
W Mechanical A torque wrench or a dial indicator spring with variable lever arm
measuring
device

X Protective casing Protective casing defined by term 3.1.11 and accordingly protec-

with protection tive shoe by term 3.1.10
shoe
4 Equipment and configurations
4.1 Test equipment

The test equipment shall include a vane and vane shaft, extension rods, rotation unit and a rotation/

torque measuring equipment.
Accessories to the test equipment may include:
— a friction reducer;
— a slip coupling;
— a protective casing;
— a protective casing with protection shoe,

which are used to increase the insertion length that can be achieved and will reduce or enable to

measure the friction in the system.
4.1.1 Vane and vane shaft

The vane shall consist of four identical vane plates fixed at 90° to each other with a tolerance of ±1°, see

Figure 1.

NOTE 1 For practical reasons, uncased vanes can have rounded corners or can be tapered.

The shape should be rectangular with an H/D ratio of 2.

NOTE 2 An example of a mould to measure and verify the dimensions and H/D ratio requirements of the vane

is given in Annex C.
Figure 1 — Principal design of the vane
6 © ISO 2020 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 22476-9:2020(E)

For testing of soils with a sensitivity more than 30, the vane plate thickness s shall not exceed 2 mm.

For testing of soils with a sensitivity less than 30, the vane plate thickness may be thicker but shall not

exceed 3 mm. For vane plates with a plate thickness exceeding 2 mm, the vane edges shall be sharpened

with 45° edges, as shown in Figure 2.
Dimensions in millimetres
Key
1 rotation direction
Figure 2 — Principle for sharpening the vane blades for rectangular vane

The diameter of the vane shaft immediately behind the vane should be less than 16 mm for testing soils

with a sensitivity more than 15 and at a maximum 20 mm for testing soils with sensitivity less than 15.

The diameter of the vane shaft, including welding seams in the centre of the vane, shall be small enough

to minimize the effects of disturbance on the measured torque.

NOTE 3 Disturbance causes a loss of peak shear strength of fine-grained soil, which increases with increasing

sensitivity of the soil.

The length of the vane shaft above the vane shall be at least 5 times the difference of the diameter of the

friction reducer/slip coupling/extension rod and the diameter of the vane shaft for testing soils with a

sensitivity higher than 15.

NOTE 4 For non-sensitive soils, the friction due to the vane shaft can be reduced by assembling a friction

reducer or slip coupling close to the vane, as the disturbance is not as relevant.

The diameter of the vane shaft can gradually in
...

NORME ISO
INTERNATIONALE 22476-9
Première édition
2020-09
Reconnaissance et essais
géotechniques — Essais en place —
Partie 9:
Essais au scissomètre de chantier
(FVT et FVT-F)
Geotechnical investigation and testing — Field testing —
Part 9: Field vane test (FVT and FVT-F)
Numéro de référence
ISO 22476-9:2020(F)
© ISO 2020
---------------------- Page: 1 ----------------------
ISO 22476-9:2020(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2020

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,

y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut

être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.

ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: +41 22 749 01 11
E-mail: copyright@iso.org
Web: www.iso.org
Publié en Suisse
© ISO 2020 – Tous droits réservés
---------------------- Page: 2 ----------------------
ISO 22476-9:2020(F)
Sommaire Page

Avant-propos ...............................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

1 Domaine d'application ...................................................................................................................................................................................1

2 Références normatives ..................................................................................................................................................................................1

3 Termes, définitions et symboles ......................................................................................................................................................... 1

3.1 Termes et définitions ........................................................................................................................................................................ 1

3.2 Symboles ...................................................................................................................................................................................................... 4

4 Matériel et configurations .........................................................................................................................................................................6

4.1 Matériel d'essai ....................................................................................................................................................................................... 6

4.1.1 Moulinet et axe du moulinet..................................................................................................................................... 7

4.1.2 Réducteur de frottement ............................................................................................................................................. 8

4.1.3 Raccord à glissement ...................................................................................................................................................... 8

4.1.4 Tiges, gaines de protection, sabot de protection ................................................................................... 8

4.1.5 Unité de rotation ................................................................................................................................................................ 8

4.1.6 Équipement pour la mesure de la rotation et du couple ................................................................. 9

4.2 Configurations d'essai ........................................................................................................................................... ........................... 9

5 Sélection du matériel et configuration d’essai ..................................................................................................................11

5.1 Sélection du matériel ..................................................................................................................................................................... 11

5.2 Sélection de la configuration d’essai ................................................................................................................................12

6 Procédure d’essai .............................................................................................................................................................................................13

6.1 Contrôles et étalonnages de l’équipement .................................................................................................................. 13

6.2 Position et inclinaison de la machine de poussée ................................................................................................. 13

6.3 Profondeurs d'essai ......................................................................................................................................................................... 13

6.4 Lecture du couple de frottement interne avant essai ....................................................................................... 13

6.5 Méthodes pour atteindre le niveau d'insertion du moulinet ......................................................................13

6.6 Insertion du moulinet .................................................................................................................................................................... 15

6.7 Lecture du couple de frottement externe .................................................................................................................... 15

6.8 Essai de cisaillement au scissomètre ............................................................................................................................... 15

6.9 Lecture du couple de frottement interne après l’essai .................................................................................... 16

7 Résultats d’essai ................................................................................................................................................................................................16

8 Consignation dans un rapport ............................................................................................................................................................18

8.1 Généralités .............................................................................................................................................................................................. 18

8.2 Communication des résultats des essais ...................................................................................................................... 18

8.2.1 Informations générales.............................................................................................................................................. 18

8.2.2 Localisation de l'essai ................................................................................................................................................. 18

8.2.3 Matériels d'essai ............................................................................................................................................................... 18

8.2.4 Procédure d’essai ............................................................................................................................................................ 19

8.2.5 Résultats d’essai ............................................................................................................................................................... 19

8.3 Présentation des points d'essai ............................................................................................................................................ 20

Annexe A (informative) Phases d'essai ..........................................................................................................................................................21

Annexe B (informative) Exemple de rapport de terrain pour l'essai scissométrique .................................22

Annexe C (normative) Maintenance, contrôles et étalonnage ...............................................................................................24

Annexe D (informative) Incertitudes dans les essais scissométriques .......................................................................27

Annexe E (normative) Interprétation et explication générales pour les moulinets coniques

et rectangulaires dont le rapport H/D diffère de 2 ......................................................................................................29

Annexe F (informative) Interprétation et explication d'un moulinet rectangulaire à coins

arrondis ......................................................................................................................................................................................................................32

Annexe G (informative) Calcul de la profondeur d'essai corrigée de l'inclinaison .........................................34

iii
© ISO 2020 – Tous droits réservés
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ISO 22476-9:2020(F)

Annexe H (informative) Exemple d'estimation du comportement post-pic ............................................................35

Bibliographie ...........................................................................................................................................................................................................................36

© ISO 2020 – Tous droits réservés
---------------------- Page: 4 ----------------------
ISO 22476-9:2020(F)
Avant-propos

L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes

nationaux de normalisation (organismes membres de l'ISO). Le travail de préparation des normes

internationales est normalement effectué par les comités techniques de l'ISO. Chaque organisme

membre intéressé par un sujet pour lequel un comité technique a été créé a le droit d'être représenté

au sein de ce comité. Les organisations internationales, gouvernementales et non gouvernementales, en

liaison avec l'ISO, participent également aux travaux. L'ISO collabore étroitement avec la Commission

électrotechnique internationale (CEI) sur toutes les questions de normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents

critères d'approbation requis pour les différents types de documents ISO. Le présent document a

été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir

www.iso.org/directives).

L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de

droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de

brevets reçues par l'ISO (voir www.iso.org/brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion

de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir www.iso.org/avant-propos.

Le présent document a été élaboré par le comité technique ISO/TC 182, Géotechnique, en collaboration

avec le comité technique CEN/TC 341, Investigations et essais géotechniques, du Comité européen de

normalisation (CEN), conformément à l'Accord de coopération technique entre l'ISO et le CEN (Accord

de Vienne).

Une liste de toutes les parties de la série ISO 22476 est disponible sur le site web de l'ISO.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

se trouve à l’adresse www.iso.org/fr/members.html.
© ISO 2020 – Tous droits réservés
---------------------- Page: 5 ----------------------
ISO 22476-9:2020(F)
Introduction

L'essai au scissomètre de chantier est utilisé pour déterminer la résistance au cisaillement des sols à

l'état non drainé, par l'insertion d'un moulinet rectangulaire dans un sol à grain fin et par sa rotation.

Pendant la rotation, le couple et la rotation peuvent être mesurés, en fonction de la configuration de

l'essai. À partir du couple mesuré et des dimensions du moulinet, la force maximale de cisaillement,

une indication du comportement après le pic, et la force de cisaillement après restructuration du sol

peuvent être dérivées par une analyse d'équilibre limite. La sensibilité du sol peut être vérifiée si les

forces de cisaillement maximale et résiduelle ont été déterminées.

Les essais sont effectués dans des trous de forage, dans des puits d'essai et avec un matériel de fonçage.

Le couple et la rotation sont mesurés soit au-dessus de la surface du sol à l'aide de tiges, soit directement

au-dessus du moulinet.

L'essai au scissomètre de chantier est principalement adapté aux sols saturés à grains fins. La résistance

au cisaillement déterminée par l'essai est généralement corrigée avant l'analyse géotechnique, en

utilisant des facteurs basés sur l'expérience locale.
© ISO 2020 – Tous droits réservés
---------------------- Page: 6 ----------------------
NORME INTERNATIONALE ISO 22476-9:2020(F)
Reconnaissance et essais géotechniques — Essais en
place —
Partie 9:
Essais au scissomètre de chantier (FVT et FVT-F)
1 Domaine d'application

Le présent document traite des exigences en matière d'équipement, d'exécution et de compte-rendu des

essais sur le terrain pour la mesure de la résistance au cisaillement maximale et résiduelle du sol, ainsi

que de la sensibilité des sols à grains fins. En outre, le comportement de la résistance au cisaillement

après le pic peut être évalué. Deux types d'essais au scissomètre de chantier sont décrits: l'essai

scissométrique ordinaire (FVT) et l'essai scissométrique rapide (FVT-F).

Les incertitudes du résultat de l'essai au scissomètre de chantier sont décrites à l'Annexe D.

NOTE 1 Le présent document répond aux exigences relatives aux essais scissométriques dans le cadre de

l'étude et des essais géotechniques conformément aux normes EN 1997-1 et EN 1997-2.

NOTE 2 Le présent document porte sur les essais scissométriques à terre et à proximité du littoral.

2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.

Pour les références non datées, la dernière édition du document de référence s'applique (y compris les

éventuels amendements).

ISO 10012, Systèmes de management de la mesure — Exigences pour les processus et les équipements de

mesure
3 Termes, définitions et symboles
3.1 Termes et définitions

Pour les besoins du présent document, les termes et définitions suivants s'appliquent.

L'ISO et la CEI tiennent à jour des bases de données terminologiques destinées à la normalisation aux

adresses suivantes:

— ISO Online browsing platform: disponible à l'adresse https:// www .iso .org/ obp

— IEC Electropedia: disponible à l'adresse https:// www .electropedia .org/
3.1.1
tige gainée

rallonge qui est glissée à l'intérieur de tubages de protection (3.1.11) pendant l'essai au scissomètre

(3.1.23)
3.1.2
forage tubé

trou de forage qui est tubé pour éviter l'effondrement et minimiser la friction entre les tiges et le sol

© ISO 2020 – Tous droits réservés
---------------------- Page: 7 ----------------------
ISO 22476-9:2020(F)
3.1.3
centreur
équipement permettant de maintenir les tiges droites et de prévenir le flambage
3.1.4
système d'acquisition de données
système de mesure, qui convertit les quantités physiques en format numérique

Note 1 à l'article: Le système comprend généralement des capteurs, un traitement du signal, un convertisseur

analogique-numérique et une unité d'enregistrement.
3.1.5
essai en fond de trou

configuration d'essai dans laquelle le couple est mesuré à proximité du moulinet (3.1.23)

Note 1 à l'article: La rotation (3.1.14) peut être mesurée à proximité du moulinet ou au-dessus de la surface du sol.

3.1.6
couple de frottement externe

couple dû au frottement à l'extérieur du matériel de mesure pendant la rotation (3.1.14), à l'exclusion du

couple dû au cisaillement du sol

Note 1 à l'article: Le frottement externe est principalement causé par la friction agissant sur les tiges, et il peut

être estimé avec un raccord à glissement (3.1.16) immédiatement avant l'engagement du moulinet (3.1.23).

3.1.7
réducteur de frottement

anneau inséré entre le moulinet (3.1.23) et les tiges pour réduire le frottement le long des tiges non

gainées (3.1.20)
3.1.8
longueur d'insertion

distance entre la surface du sol ou la base du trou (de forage) ou du puits d'essai et la mi-hauteur du

moulinet (3.1.23), mesurée le long de l'axe des allonges
3.1.9
couple de frottement interne

couple dû au frottement à l'intérieur du matériel de mesure pendant la rotation (3.1.14) lorsqu'il n'y a

pas de couple agissant sur le moulinet (3.1.23) et pas de frottement agissant sur les tiges

3.1.10
sabot de protection
équipement de protection du moulinet (3.1.23) lors de l'enfoncement dans le sol

Note 1 à l'article: Il aide à l'insertion du moulinet sans perçage. Habituellement, l'extrémité du sabot de protection

est constituée de quatre fentes permettant aux plaquettes (3.1.24) de se rétracter à l'intérieur du boîtier de

protection (3.1.11).
3.1.11
tubage de protection
tube qui isole les tiges du sol et les soutient contre le flambage
3.1.12
longueur de saillie

distance entre le fond du tubage/sabot de protection et la mi-hauteur du moulinet (3.1.23) lorsqu'il est

poussé à la profondeur d'essai (3.1.17), mesurée le long de l'axe des tiges
3.1.13
matériel de fonçage
équipement permettant de pousser le moulinet (3.1.23) dans le sol sans préforage
© ISO 2020 – Tous droits réservés
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ISO 22476-9:2020(F)
3.1.14
rotation

changement d'angle par le mouvement circulaire du moulinet (3.1.23) autour de son axe

Note 1 à l'article: La rotation apparente est la rotation enregistrée par l'appareil de mesure de la rotation.

3.1.15
vitesse de rotation
vitesse de rotation (3.1.14) angulaire du moulinet (3.1.23)
3.1.16
raccord à glissement

mécanisme qui permet aux tiges de tourner librement alors que le moulinet (3.1.23) reste immobile

Note 1 à l'article: La fonction du raccord à glissement est de séparer la résistance au frottement de la tige de

la résistance au cisaillement du moulinet. Un raccord à glissement doit permettre une rotation libre avec un

frottement minimal.
3.1.17
profondeur d'essai

distance verticale entre la surface du sol, le niveau de référence ou le point de référence et la mi-hauteur

du moulinet (3.1.23)

Note 1 à l'article: Conformément à l'Annexe G, la longueur d'insertion (3.1.8) peut être corrigée par des mesures

inclinométriques pour correspondre à la profondeur d'essai corrigée. Sinon, la profondeur d'essai est basée

sur la somme des longueurs des tiges par rapport au niveau de référence ou au point de référence en raison de

l'incertitude de l'inclinaison.
3.1.18
localisation de l'essai
position d'un essai ou d'une série d'essais
3.1.19
délai de rupture

temps écoulé entre le début de l'application du couple au moulinet (3.1.23) et le moment où le couple

maximal est atteint
3.1.20
tige non gainée

rallonge non protégée par une enveloppe de protection permettant le développement d'un frottement

entre les tiges et le sol
3.1.21
moulinet non gainée
moulinet (3.1.23) enfoncé dans le sol sans protection
3.1.22
essai en surface

configuration d'essai dans laquelle le couple est mesuré au-dessus de la surface du sol

Note 1 à l'article: La rotation (3.1.14) est appliquée et les mesures sont enregistrées au-dessus de la surface du

sol.
3.1.23
moulinet

dispositif formé par quatre plaquettes (3.1.24) fixées à 90° les unes par rapport aux autres

© ISO 2020 – Tous droits réservés
---------------------- Page: 9 ----------------------
ISO 22476-9:2020(F)
3.1.24
plaquettes
plaque rectangulaire mince et plate

Note 1 à l'article: La plupart des moulinets (3.1.23) ont une forme (presque) rectangulaire. Pour des raisons

pratiques, les moulinets sans sabots de protection (3.1.10) ont souvent les extrémités inférieures des plaquettes

légèrement effilées ou avec des coins arrondis. Certains équipements utilisant des tiges non gainées (3.1.20) et

un raccord à glissement (3.1.16) pour séparer le frottement de la tige du couple sur le moulinet sont conçus avec

des plaquettes légèrement effilées, aiguisées, pointues ou coniques, afin de désengager le raccord à glissement

pendant l'enfoncement.
3.1.25
axe du moulinet

élément cylindrique du moulinet (3.1.23) sur lequel sont fixées les plaquettes (3.1.24)

Note 1 à l'article: L'axe du moulinet peut être relié directement à l'appareil de mesure de la force ou du couple

dans un essai en fond de trou (3.1.5) ou relié à celui-ci par des tiges dans un essai en surface (3.1.22).

3.1.26
temps d'attente

durée entre l'atteinte de la profondeur d'essai (3.1.17) et le début de l'application du couple au moulinet

3.1.27
décalage du zéro

différence entre les lectures du couple de frottement interne (3.1.9) du matériel de mesure avant et après

l'achèvement de l'essai
3.1.28
sensibilité

rapport entre la résistance au cisaillement non drainée du sol non remanié et celle du sol remanié

3.2 Symboles
Symbole Nom Description Unité
A Surface de cisaillement latérale du cône inférieur mm
cone,bott
A Surface de cisaillement latérale du cône supérieur mm
cone,top
A Surface de cisaillement latérale du cylindre mm
cylinder
α Angle total mesuré entre l'axe vertical et l'axe du moulinet °
β Angle mesuré entre l'axe vertical et la projection de l'axe du scis- °
somètre de chantier sur un plan vertical fixe
β Angle mesuré entre l'axe vertical et la projection de l'axe du scis- °
somètre de chantier sur un plan vertical perpendiculaire au plan
d'angle β
C Tubage de protec- Défini par le terme 3.1.11
tion

c Résistance au Résistance au cisaillement des sols à grain fin à l'état non drainé kPa

cisaillement non
drainée

c Résistance au Résistance maximale au cisaillement du sol, dérivée du couple kPa

cisaillement maximal mesuré par l'essai au scissomètre de chantier

c Résistance au Résistance maximale au cisaillement du sol, dérivée du couple kPa

fv-f
cisaillement rapide maximal mesuré par l'essai rapide au scissomètre de chantier

c Résistance post-pic Résistance post-pic au cisaillement du sol, retenue après la rota- kPa

au cisaillement tion souhaitée une fois la résistance maximale au cisaillement
dépassée
© ISO 2020 – Tous droits réservés
---------------------- Page: 10 ----------------------
ISO 22476-9:2020(F)
Symbole Nom Description Unité

c Résistance au Résistance au cisaillement, mesurée par l'essai au scissomètre de kPa

cisaillement rési- chantier, après remaniement du sol
duelle

D Appareil de mesure Les appareils de mesure du couple et de la rotation sont situés à

en fond de trou proximité du moulinet

D* Appareil de mesure L'appareil de mesure du couple est situé près du moulinet, mais

en fond de trou l'appareil de mesure de la rotation est situé au-dessus de la sur-

face du sol
D Diamètre du moulinet mm
d Diamètre de l'axe du moulinet immédiatement derrière celui-ci mm
D Diamètre de l'extrémité inférieure du tubage de protection mm
D Diamètre du sabot de protection mm
F Réducteur de frot- Défini par le terme 3.1.7
tement
H Hauteur du moulinet mm
H Hauteur du côté vertical du moulinet conique sans tenir compte mm
de la hauteur du ou des cônes.
i Angle du cône au sommet du moulinet °
i Angle du cône à la base du moulinet °

R Dispositif de rota- Le dispositif de rotation peut être situé à proximité du moulinet

tion ou au-dessus du sol

R Rapport de surface Rapport de la section transversale du moulinet et de l'axe du mou- —

linet par rapport à la surface de cisaillement circulaire
r Rayon de l'angle arrondi du moulinet mm
r Bras de levier de la surface latérale du cône inférieur de la surface mm
cone,bott
de cisaillement
r Bras de levier de la surface latérale du cône supérieur mm
cone,top
r Bras de levier de la surface latérale du cylindre mm
cylinder
S Raccord à glisse- Défini par le terme 3.1.16
ment

Sensibilité scisso- Le rapport entre la résistance au cisaillement et la résistance au —

métrique cisaillement résiduelle
s Épaisseur des plaquettes mm
T Couple Couple mesuré pendant la rotation du moulinet, corrigé en fonc- Nm
tion de la lecture du couple de frottement externe
T Composante du couple nécessaire pour cisailler le cône inférieur Nm
cone,bott
de la surface de cisaillement
T Composante du couple nécessaire pour cisailler le cône supérieur Nm
cone,haut
de la surface de cisaillement
T Composante du couple nécessaire pour cisailler une surface de Nm
corner
cisaillement d'un quart de cercle
T Composante du couple nécessaire pour cisailler la surface latérale Nm
cylinder
du cylindre

T Lecture du couple Sortie stable du matériel de mesure pendant la rotation lorsqu'au- Nm

ext
de frottement cun couple n'agit sur le moulinet (généralement mesurée avant
externe l'engagement du moulinet par le raccord à glissement)

T Lecture du couple Sortie stable du matériel de mesure pendant la rotation après Nm

ext*
de frottement remaniement du sol lorsqu'aucun couple n'agit sur le moulinet
externe après (généralement mesuré avant l'engagement du moulinet par le
remaniement du sol raccord à glissement)
© ISO 2020 – Tous droits réservés
---------------------- Page: 11 ----------------------
ISO 22476-9:2020(F)
Symbole Nom Description Unité

T Lecture du couple Sortie stable du matériel de mesure pendant la rotation lorsqu'au- Nm

int

de frottement cun couple n'agit sur le moulinet et qu'aucun frottement n'agit sur

interne avant le test les tiges

T Couple maximal Couple nécessaire pour obtenir une rupture dans le sol autour Nm

max
du moulinet, corrigé pour tenir compte de la ou des lectures du
couple de frottement interne et externe, le cas échéant

T Couple maximal Mesure du couple nécessaire pour obtenir une rupture dans le sol Nm

mes,max
mesuré autour du moulinet, y compris le frottement externe. Le couple
maximum (Tmax) peut être calculé en soustrayant T de T
ext mes,max
(T = T - T ) sinon T est Tmax
max mes,max ext mes,max

T Couple post-pic Couple mesuré après le pic, retenu après la rotation souhaitée Nm

mes,pv
mesuré (mesure de la résistance résiduelle), y compris le couple de frotte-
ment externe. Le couple post-pic est calculé en soustrayant le T
ext
de T (T = T - T ), sinon T est T
mes,pv pv mes,pv ext mes,pv pv
T Couple mesuré La valeur constante du couple mesurée après le remaniement du Nm
mes,rv

dans des conditions sol, y compris le couple de frottement externe. Le couple pour des

remaniées conditions remaniées est calculé en soustrayant le T de T
ext mes,rv
(T = T - T ) sinon T est T
rv mes,rv ext mes,rv rv
T Couple causé par le cisaillement de la surface de cisaillement Nm
plate
circulaire de la plaquette

T Couple post-pic Couple après le pic, retenu après le couple maximal, corrigé pour Nm

tenir compte de la ou des lectures du couple de frottement interne
et externe, le cas échéant

T Couple dans des Valeur de couple constante mesurée après le remaniement du sol, Nm

conditions rema- corrigée en fonction de la ou des lectures de couple de frottement

niées interne et externe, le cas échéant

τ Contrainte de Contrainte agissant le long de la surface de rupture en raison kPa

cisaillement d'une force de cisaillement externe

U Matériel de mesure Un appareil de mesure du couple en continu situé au-dessus de la

en surface surface du sol au point d'insertion du moulinet
W Dispositive de Une clé dynamométrique ou un cadran indicateur de couple à
mesure mécanique ressort avec un bras de levier variable

X Tubage de protec- Tubage de protection définie par le terme 3.1.11 avec sabot de

tion avec sabot de protection défini par le terme 3.1.10
protection
4 Matériel et configurations
4.1 Matériel d'essai

Le matériel d'essai doit comprendre un moulinet et son axe, des tiges, une unité de rotation et un

appareil de mesure de la rotation/couple.
Les accessoires du matériel d'essai peuvent inclure:
— un réducteur de frottement;
— un raccord à glissement;
— un tubage de protection;
— un tubage avec un sabot de protection
...

DRAFT INTERNATIONAL STANDARD
ISO/DIS 22476-9
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
2019-08-01 2019-10-24
Ground investigation and testing — Field testing —
Part 9:
Field vane test (FVT and FVT-F)
Reconnaissance et essais géotechniques — Essais en place —
Partie 9: Essai au scissomètre de chantier
ICS: 93.020
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22476-9:2019(E)
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 SUPPORTING DOCUMENTATION. ISO 2019
---------------------- Page: 1 ----------------------
ISO/DIS 22476-9:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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
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Phone: +41 22 749 01 11
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/DIS 22476-9:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 General ........................................................................................................................................................................................................... 1

3.2 Symbols ......................................................................................................................................................................................................... 4

4 Equipment ................................................................................................................................................................................................................... 5

4.1 Test configurations .............................................................................................................................................................................. 5

4.2 Vane .................................................................................................................................................................................................................. 8

4.2.1 General...................................................................................................................................................................................... 8

4.2.2 Dimensional requirements ..................................................................................................................................... 8

4.3 Vane shaft and friction reducer .............................................................................................................................................10

4.4 Slip coupling ...........................................................................................................................................................................................10

4.5 Extension rods, protective casings, protection shoe ...........................................................................................10

4.6 Equipment for applying rotation ..........................................................................................................................................11

4.7 Equipment for measuring rotation and torque .......................................................................................................11

5 Selection of test and test configuration .....................................................................................................................................11

5.1 Selection of shear strengths to be measured .............................................................................................................11

5.2 Selection of equipment and procedures related to soil conditions ........................................................13

6 Test procedure .....................................................................................................................................................................................................13

6.1 Equipment checks and calibrations ...................................................................................................................................13

6.2 Position and inclination of thrust machine .................................................................................................................14

6.3 Test depths ..............................................................................................................................................................................................14

6.4 Internal friction torque reading prior to testing .....................................................................................................14

6.5 Methods for reaching the level for insertion of vane ..........................................................................................14

6.6 Insertion of the vane .......................................................................................................................................................................16

6.7 External friction torque reading ...........................................................................................................................................16

6.8 Vane shear test .....................................................................................................................................................................................16

6.9 Internal friction torque reading after the test ......... ..................................................................................................17

7 Test results ...............................................................................................................................................................................................................17

8 Reporting ...................................................................................................................................................................................................................18

8.1 General ........................................................................................................................................................................................................18

8.2 Reporting of test results ...............................................................................................................................................................19

8.2.1 General information ...................................................................................................................................................19

8.2.2 Location of the test .................. ......................................................................................................................... ...........19

8.2.3 Test equipment ...............................................................................................................................................................20

8.2.4 Test procedure ................................................................................................................................................................20

8.2.5 Test results .........................................................................................................................................................................20

8.3 Presentation of test plots ............................................................................................................................................................20

Annex A (informative) Example of field record for field vane test .....................................................................................22

Annex B (normative) Maintenance, checks and calibration .....................................................................................................24

Annex C (informative) Uncertainties in field vane testing ..........................................................................................................27

Annex D (normative) General interpretation and explanation for tapered and rectangular

vanes with H/D ratios differring from 2 ...................................................................................................................................29

Annex E (informative) Interpretation and explanation for a rectangular vane with rounded

corners .........................................................................................................................................................................................................................32

Annex F (normative) Calculation of test depth .......................................................................................................................................34

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Annex G (informative) Example of estimation of post-peak behaviour ........................................................................35

Bibliography .............................................................................................................................................................................................................................36

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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 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 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 received (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 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.
A list of all parts in the ISO 22476- 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.
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ISO/DIS 22476-9:2019(E)
Introduction

The field vane test is used to determine the vane shear strength of soils in the undrained condition,

by insertion of a rectangular vane into fine-grained soil and rotating it. During rotation, the torque

and rotation can be measured, depending on the test configuration. From the measured torque and the

dimensions of the vane, the peak shear strength, an indication of post-peak behaviour and the remoulded

shear strength can be derived by limit equilibrium analysis. Soil sensitivity can be ascertained if peak

and remoulded shear strengths have been determined.

The tests are carried out in boreholes, in trial pits and with pushed-in equipment. Torque and rotation

are measured either above the ground surface using extension rods; or directly above the vane.

The field vane test is mainly applicable to saturated fine-grained soil. The vane shear strength

determined by the test is commonly corrected before geotechnical analysis, using factors based on

local experience.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 22476-9:2019(E)
Ground investigation and testing — Field testing —
Part 9:
Field vane test (FVT and FVT-F)
1 Scope

This standard deals with the equipment requirements, execution and reporting of field vane tests for

the measurement of peak and remoulded vane shear strength together with the sensitivity of fine-

grained soils. In addition, post-peak shear strength behaviour can be evaluated. Two types of field vane

test are described; the ordinary field vane test (FVT) and the fast field vane test (FVT-F).

The uncertainties of the vane test result are described in Annex C.

NOTE 1 This part of ISO 22476 fulfils the requirements for field vane tests as part of the geotechnical

investigation and testing according to EN 1997-1 and EN 1997-2
NOTE 2 This part of ISO 22476 covers onshore and nearshore field vane testing
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 referenced

document (including any amendments) applies.

ISO 10012:2003, Measurement management systems — Requirements for measurement processes and

measuring equipment

ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:

Identification and description

ISO 14688-2, Geotechnical investigation and testing — Identification and classification of soil — Part 2:

Principles for a classification

ISO 22475-1, Geotechnical investigation and testing – Sampling methods and groundwater measurements

– Part 1: Technical principles for execution
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General
3.1.1
Cased extension rod

Extension rods that are sleeved inside of protective casings during vane testing.

3.1.2
Cased borehole

Borehole that is cased to prevent collapse and minimize friction between the extension rods and soil.

3.1.3
Centralizer
Equipment to keep the extension rods straight and prevent buckling.
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3.1.4
Data acquisition system
Measuring system, which converts physical quantities to digital format.

Note 1 to entry: The system typically includes sensors, signal conditioning, AD converter and recording unit.

3.1.5
Downhole test

Test configuration whereby the torque is measured close to the vane. The rotation can be measured

close to the vane or above the ground surface.
3.1.6
External friction torque

Torque due to friction outside the measuring equipment during rotation excluding torque caused by

shearing of soil. External friction is mainly caused by friction acting on extension rods and it can be

estimated with a slip coupling immediately before engagement of the vane.
3.1.7
Friction reducer

A ring inserted between the vane and the extension rods to reduce friction along uncased extension rods.

3.1.8
Insertion length

Distance from the ground surface or base of (bore)hole or trial pit to mid-height of the vane, measured

along the axis of the extension rods.
3.1.9
Internal friction torque

Torque due to friction inside the measuring equipment during rotation when there is no torque acting

on the vane and no friction acting on the extension rods.
3.1.10
Penetration length

Sum of the lengths of the extension rods, the vane shaft and the distance to mid-height of the vane,

relative to a fixed horizontal plane (normally the ground surface).
3.1.11
Protection shoe

Equipment to protect the vane while pushing into the soil. It assists with the insertion of the vane

without drilling. Usually, the tip of the protection shoe consists of four plate slots allowing the vane

plates to retract inside of the protective casing.
3.1.12
Protective casing

Tubes that isolate the extension rods from the soil and give support against buckling.

3.1.13
Protrusion length

Distance between the bottom of the protective casing/shoe and the mid-height of the vane when pushed

to the test depth, measured along the axis of the rods.
3.1.14
Push-in equipment
Equipment to push the vane into the soil without predrilling.
3.1.15
Rotation
Change of angle by the circular movement of the vane around its axis.

Note 1 to entry: Apparent rotation is the rotation recorded by the rotation measurement equipment.

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3.1.16
Rotation rate
Rate of angular rotation of the vane.
3.1.17
Slip coupling

Mechanism that allows the extension rods to rotate freely while the vane remains stationary.

3.1.18
Test depth

Vertical distance from the ground surface, reference level or datum to mid-height of the vane.

Note 1 to entry: According to Annex F, the penetration length can be corrected with inclinometer measurements

to correspond the test depth. Otherwise, the test depth is based on the penetration length owing to the

uncertainty of inclination.
3.1.19
Test location
Plan position of a test or series of tests.
3.1.20
Test type

Two types of field vanes test can be distinguished; ordinary field vane test (FVT) and fast field vane

test (FVT-F).
3.1.21
Time to failure

Time from the beginning of application of torque to the vane until the maximum torque is reached.

3.1.22
Uncased extension rods

Extension rods that are not protected by protective casing allowing friction to develop between the

extension rods and the soil.
3.1.23
Uncased vane
The vane pushed into the ground without protection.
3.1.24
Uphole test

Test configuration whereby the torque is measured above the ground surface. The rotation is applied

and measurements registered above the ground surface.
3.1.25
Vane
Four vane plates fixed at 90˚ to each other.
3.1.26
Vane plate
Thin and flat rectangular plate.

Note 1 to entry: Most vanes have a (nearly) rectangular shape. For practical reasons, vanes without protection

shoes often have slightly tapered lower ends of the vane plates or with rounded corners. Some equipment using

uncased extension rods and a slip coupling to separate the rod friction from the torque on the vane are designed

with slightly tapered, sharpened, pointed or conical, vane plates in order to disengage the slip coupling during

the pushing stroke.
3.1.27
Vane shaft

Cylindrical element of the vane to which the vane plates are fixed. The vane shaft may be connected

directly to the force or torque measurement equipment in a downhole test or connected to it via

extension rods in an uphole test.
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3.1.28
Waiting time

Time between reaching the test depth and beginning of application of the torque to the vane.

3.1.29
Zero shift

Difference between the internal friction torque readings of the measuring equipment prior and after

completion of the test.
3.1.30
Sensitivity
The ratio between the undisturbed and remoulded undrained shear strengths.
3.2 Symbols
Symbol Name Description Unit
A Lateral shear surface area of the bottom cone mm
cone,bott
A Lateral shear surface area of the top cone mm
cone,top
A Lateral shear surface area of the cylinder mm
cylinder

c Undrained shear Shear resistance of fine-grained soils in the undrained condition kPa

strength
c Field vane Peak shear strength of soil, derived from the maximum torque kPa
strength measured by field vane test

c Post-peak field Post-peak shear strength of soil, selected after desired rotation after kPa

vane strength field vane strength

c Remoulded field Shear strength, as measured by field vane test, after remoulding kPa

vane strength the soil

c Fast field vane Peak shear strength of soil, derived from the maximum torque kPa

fv-f
strength measured by fast field vane test
D Diameter of the vane mm
d Diameter of vane shaft immediately behind vane mm
D Diameter of lower end of protective casing mm
D Diameter of protection shoe mm
H Height of the vane mm
H The height of the vertical side of the tapered vane excluding mm
the height influence of tapering(s).
i Angle of taper at vane top ˚
i Angle of taper at vane bottom ˚

l Penetration sum of the lengths of the extension rods, the vane shaft and the dis- m

length tance to mid-height of the vane, relative to a fixed horizontal plane

R Area ratio Cross sectional area ratio of vane and vane shaft compared to circular -

shear surface
r Radius of rounded corner of the vane plate mm
r Lever arm of lateral surface of the bottom cone of shear surface mm
cone,bott
r Lever arm of lateral surface of the top cone mm
cone,top
r Lever arm of lateral surface of the cylinder mm
cylinder

Field vane The ratio between the field vane and remoulded field vane strengths -

sensitivity
s Thickness of the vane plates mm

T Internal friction Stable output of a measuring equipment during rotation when there Nm

int

torque reading is no torque acting on the vane and no friction acting on the exten-

prior to test sion rods
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Symbol Name Description Unit

T External friction Stable output of a measuring equipment during rotation when there Nm

ext

torque reading is no torque acting on the vane (usually measured prior to the vane

engagement by slip coupling)
τ Shear stress kPa
T Torque measured during vane rotation, corrected for external friction Nm
torque reading
T Torque caused by shearing of bottom cone of shear surface Nm
cone,bott
T Torque caused by shearing of top cone of shear surface Nm
cone,top
T Torque caused by shearing of cylindrical shear surface Nm
cylinder
T Torque caused by shearing of a quarter circular shear surface Nm
corner

T Maximum torque Torque required to obtain failure in soil around the vane, corrected for Nm

max
internal and external friction torque reading(s) if relevant

T Maximum Measured torque required to obtain failure in soil around the vane in- Nm

meas,max

measured torque cluding external friction. The maximum torque (T ) can be calculate

max
by subtracting T from T (T = T – T ) otherwise
ext meas,max max meas,max ext
T is T
meas,max max
T Torque caused by shearing of circular plate shear surface Nm
plate

T Post-peak torque Post-peak torque selected after maximum torque, corrected for inter- Nm

nal and external friction torque reading(s) if relevant

T Measured post- Measured post-peak torque selected after desired rotation after Nm

meas,pv
peak torque maximum torque including external friction torque. The post-peak
torque is calculated by subtracting T from T (T = T –
ext meas,pv pv meas,pv
T ) otherwise T is T
ext meas,pv pv

T Torque for Measured constant torque value after remoulding the soil, corrected Nm

remoulded for internal and external friction torque reading(s) if relevant
conditions

T Measured torque The constant measured torque value after remoulding including Nm

meas,rv

for remoulded external friction torque. The torque for remoulded condition is calcu-

conditions lated by subtracting T from T (T = T – T ) otherwise
ext meas,rv rv meas,rv ext
T is T
meas,rv rv
α measured total angle between the vertical axis and the axis of the vane °
β measured angle between the vertical axis and the projection of the °
axis of the vane on a fixed vertical plane
β measured angle between the vertical axis and the projection of the °
axis of the cone penetrometer on a vertical plane that is perpendicular
to the plane of angle β
4 Equipment
4.1 Test configurations

The test equipment includes a vane and vane shaft, extension rods, rotation equipment and a rotation/

torque measuring equipment, configured in a number of combinations, see Figure 1.

Accessories to the vane equipment may include:
— a protective casing (C)
— a protective casing with protection shoe (X)
— friction reducer (F)
— a slip coupling (S)
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ISO/DIS 22476-9:2019(E)

which are used to increase the insertion or the penetration length that can be achieved and also will

reduce the friction in the system. In addition, borehole casing may be used to allow predrilling prior to

the insertion of the vane.

Vane test may be performed in either uphole or downhole configurations. Typical configurations

are illustrated in Figure 1 and locations of torque and rotation measurements, torque transfers and

accuracy of rotation measurements are explained in Table 1.

In the uphole configuration, torque (T) can be measured by a torque wrench or a dial indicator spring

with variable lever arm (W) or by a continuous torque measuring equipment (U) located above ground

surface at the point for insertion of the vane. For reading with an indicator spring, correction is needed

due to the variation of the lever arm.

In the downhole configuration, the torque measuring equipment is located close to the vane, but the

rotation can be measured either close to the vane (D*) or above ground surface (D). The rotation unit

can be located close to the vane (R) or above the ground surface.

In the downhole configuration, the measuring unit can be covered by larger protective casing and the

unit is installed between the vane shaft and the extension rods.
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Figure 1 — Typical configurations for vane test

NOTE All configurations without slip coupling and protection shoe may be equipped with friction reducer.

Table 1 — Configurations of field vane test
Torque and
Configurations Measurement Torque transfer
rotation
W Uphole measurement of maximum Transfer of torque by uncased Maximum torque
torque extension rods without slip
coupling

WS Uphole measurement of maximum Transfer of torque by uncased ex- Maximum torque

torque tension rods with a slip coupling
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Table 1 (continued)
Torque and
Configurations Measurement Torque transfer
rotation

U Continuous uphole measurement of Transfer of torque by uncased Torque – apparent

torque versus rotation extension rods without slip rotation
coupling

US Continuous uphole measurement of Transfer of torque by uncased ex- Torque – apparent

torque versus rotation tension rods with a slip coupling rotation

UC Continuous uphole measurement of Transfer of torque by cased Torque – apparent

torque versus rotation extension rods rotation

UX Continuous uphole measurement of Transfer of torque by cased Torque – apparent

torque versus rotation extension rods rotation

D Continuous downhole measurement Transfer of torque by uncased Torque – apparent

of torque and continuous
...

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