Geotechnical investigation and testing - Field testing - Part 1: Electrical cone and piezocone penetration test (ISO 22476-1:2022)

This document establishes equipment, procedural and reporting requirements and recommendations on cone and piezocone penetration tests.
NOTE       This document fulfils the requirements for cone and piezocone penetration tests as part of geotechnical investigation and testing according to the EN 1997 series.
This document specifies the following features:
a)    type of cone penetration test;
b)    cone penetrometer class according to Table 2;
c)    test categories according to Table 3;
d)    penetration length or penetration depth;
e)    elevation of the ground surface or the underwater ground surface at the location of the cone penetration test with reference to a datum;
f)     location of the cone penetration test relative to a reproducible fixed location reference point;
g)    pore pressure dissipation tests.
This document covers onshore and nearshore cone penetration test (CPT). For requirements for offshore CPT, see ISO 19901-8.

Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 1: Drucksondierungen mit elektrischen Messwertaufnehmern und Messeinrichtungen für den Porenwasserdruck (ISO 22476-1:2022)

Dieses Dokument legt Anforderungen an die Ausrüstung und die Verfahren für sowie die Ergebnisdarstellung von Drucksondierungen mit Messwertaufnehmern und Messeinrichtungen für den Porenwasserdruck fest.
ANMERKUNG   Dieses Dokument erfüllt die Anforderungen für Drucksondierungen mit Messwertaufnehmern und Messeinrichtungen für den Porenwasserdruck als Teil von geotechnischen Untersuchungen und Versuchen nach der Normenreihe EN 1997
Dieses Dokument legt die folgenden Aspekte fest:
a)   Typ der Drucksondierung;
b)   Klasse der Drucksondierspitze nach Tabelle 2;
c)   Prüfkategorien nach Tabelle 3;
d)   die erreichbare Sondierlänge oder Sondiertiefe;
e)   die Höhe der Geländeoberfläche oder die Gewässergrundoberfläche am Ort der Drucksondierung mit Verweis auf eine Bezugshöhe;
f)   die Lage der Drucksondierung mit Bezug zu einem reproduzierbaren örtlich festgelegten Lagebezugspunkt;
g)   Porenwasserdruck-Dissipationsversuche.
Dieses Dokument behandelt CPT-Sondierungen an Land und im Nearshore-Bereich. Für Anforderungen an CPT-Sondierungen in Offshore-Bereichen siehe ISO 19901 8.

Reconnaissance et essais géotechniques - Essais en place - Partie 1: Essais de pénétration au cône électrique et au piézocône (ISO 22476-1:2022)

Geotehnično preiskovanje in preskušanje - Preskušanje na terenu - 1. del: Konusni penetracijski preizkus z ali brez merjenja pornih tlakov (ISO/FDIS 22476-1:2022)

General Information

Status
Published
Publication Date
10-Jan-2023
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
16-Feb-2021
Completion Date
11-Jan-2023

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SLOVENSKI STANDARD
oSIST prEN ISO 22476-1:2021
01-september-2021
Geotehnično preiskovanje in preskušanje - Preskušanje na terenu - 1. del:
Konusni penetracijski preizkus z ali brez merjenja pornih tlakov (ISO/DIS 22476-
1:2021)

Geotechnical investigation and testing - Field testing - Part 1: Electrical cone and

piezocone penetration test (ISO/DIS 22476-1:2021)
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 1:
Drucksondierungen mit elektrischen Messwertaufnehmern und Messeinrichtungen für
den Porenwasserdruck (ISO/DIS 22476-1:2021)
Reconnaissance et essais géotechniques - Essais en place - Partie 1: Essais de
pénétration au cône électrique et au piézocône (ISO/DIS 22476-1:2021)
Ta slovenski standard je istoveten z: prEN ISO 22476-1
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN ISO 22476-1:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 22476-1:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 22476-1:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22476-1
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
2021-06-29 2021-09-21
Geotechnical investigation and testing — Field testing —
Part 1:
Electrical cone and piezocone penetration test
Reconnaissance et essais géotechniques — Essais en place —
Partie 1: Essais de pénétration au cône électrique et au piézocône
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 22476-1:2021(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 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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.
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Published in Switzerland
ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
Contents Page

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

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

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

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

3 Terms, definitions and symbols ............................................................................................................................................................ 2

3.1 Terms and definitions ....................................................................................................................................................................... 2

3.2 Symbols ......................................................................................................................................................................................................... 8

4 Equipment ................................................................................................................................................................................................................... 9

4.1 Cone penetrometer ............................................................................................................................................................................. 9

4.2 Tolerances ................................................................................................................................................................................................... 9

4.3 Surface roughness and hardness ............................................................................................................................................. 9

4.4 Cone ...............................................................................................................................................................................................................10

4.5 Friction sleeve .......................................................................................................................................................................................11

4.6 Filter element ........................................................................................................................................................................................12

4.6.1 General filter location ...............................................................................................................................................12

4.6.2 Pore pressure u ..............................................................................................................................................................

1 13

4.6.3 Pore pressure u ..............................................................................................................................................................

2 13

4.6.4 Pore pressure u ..............................................................................................................................................................

3 13

4.7 Gaps and soil seals ............................................................................................................................................................................13

4.8 Pushrods ....................................................................................................................................................................................................13

4.9 Measuring system ..............................................................................................................................................................................14

4.9.1 Accuracy ...............................................................................................................................................................................14

4.9.2 Sensors for cone resistance and sleeve friction .................................................................................14

4.9.3 Sensor for pore pressure .......................................................................................................................................14

4.9.4 Sensor for inclination................................................................................................................................................14

4.9.5 Sensor for temperature ...........................................................................................................................................14

4.9.6 Measuring of penetration length ....................................................................................................................14

4.9.7 Raw data ...............................................................................................................................................................................15

4.10 Thrust machine....................................................................................................................................................................................15

5 Test procedures ..................................................................................................................................................................................................15

5.1 Selection of equipment, procedures and evaluation of results ..................................................................15

5.1.1 Calibrations required for determining cone penetrometer class .......................................15

5.1.2 Cone penetrometer class conformity assessment ...........................................................................16

5.2 Position and level of thrust machine .................................................................................................................................18

5.3 Preparation of the test ...................................................................................................................................................................18

5.4 Pushing of the cone penetrometer ......................................................................................................................................19

5.5 Use of friction reducing techniques ...................................................................................................................................19

5.6 Frequency of logging parameters ........................................................................................................................................19

5.7 Registration of penetration length ......................................................................................................................................19

5.8 Dissipation test (DPT) ...................................................................................................................................................................20

5.9 Test completion ...................................................................................................................................................................................20

5.10 Evaluation of CPT/CPTU data and test category ....................................................................................................21

5.11 Equipment checks and calibrations ...................................................................................................................................22

5.12 Safety requirements ........................................................................................................................................................................22

6 Test results ...............................................................................................................................................................................................................22

6.1 Measured parameters ....................................................................................................................................................................22

6.2 Correction of parameters ............................................................................................................................................................23

6.3 Calculated parameters ...................................................................................................................................................................24

7 Reporting ...................................................................................................................................................................................................................25

7.1 General ........................................................................................................................................................................................................25

7.2 Reporting of test results ...............................................................................................................................................................26

7.3 Presentation of test results .......................................................................................................................................................27

© ISO 2021 – All rights reserved iii
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)

7.4 Presentation of results and calculated parameters ..............................................................................................28

Annex A (informative) Suitability of test methods ..............................................................................................................................30

Annex B (normative) Maintenance, checks and calibration .....................................................................................................33

Annex C (Informative) Calibration report example ...........................................................................................................................51

Annex D (normative) Calculation of penetration depth ................................................................................................................59

Annex E (informative) Correction of sleeve friction for water pressure ......................................................................60

Annex F (informative) Preparation of the piezocone .......................................................................................................................61

Annex G (informative) Friction reduction Techniques ...................................................................................................................62

Bibliography .............................................................................................................................................................................................................................63

iv © ISO 2021 – All rights reserved
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(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 the European Committee for Standardization (CEN) Technical

Committee CEN/TC 341, Geotechnical investigation and testing, in collaboration with Technical

Committee ISO/TC 182, Geotechnics, Subcommittee SC 1, Geotechnical investigation and testing, in

accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 22476-1:2012), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Dimensional tolerances of cone penetrometer

— Accuracy class scheme has been replaced by cone penetrometer class and test category classification

scheme
— Addition of normative requirements for the calibration of cone penetrometers
— Minor updates to figures and text
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 2021 – All rights reserved v
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
Introduction

The electrical cone penetration test (CPT) consists of pushing a cone penetrometer using a series of

pushrods into the soil at a constant rate of penetration. During penetration, measurements of cone

resistance and sleeve friction are recorded. The piezocone penetration test (CPTU) also includes the

measurement of pore pressures around the cone. The test results can be used for interpretation of

stratification, classification of soil type and evaluation of engineering soil parameters. Two International

Standards define cone penetration tests: ISO 22476-1 defines CPT and CPTU practice using electronic

transducers; ISO 22476 12 defines CPT practice using mechanical measuring systems.

“Cone resistance” is the term used in practice and also in this part of ISO 22476, although “cone

penetration resistance” is a more correct description of the process.

The test results of this part of ISO 22476 are especially suited for the qualitative and/or quantitative

determination of a soil profile together with direct investigations (e.g. sampling according to

[2]
ISO 22475-1 ) or as a relative comparison of other in situ tests.

— The results from a cone penetration test are typically used to evaluate: stratification;

— soil behaviour type;
— geotechnical parameters such as:
— soil density;
— shear strength parameters
— deformation and consolidation characteristics
— Hydraulic conductivity and ground water pressure

— The results from a cone penetration test may also be used directly in geotechnical design

calculations.
vi © ISO 2021 – All rights reserved
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oSIST prEN ISO 22476-1:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 22476-1:2021(E)
Geotechnical investigation and testing — Field testing —
Part 1:
Electrical cone and piezocone penetration test
1 Scope

This part of ISO 22476 deals with equipment requirements, the execution of and reporting on electrical

cone and piezocone penetration tests.

NOTE 1 This part of ISO 22476 fulfils the requirements for electrical cone and piezocone penetration tests as

part of geotechnical investigation and testing according to EN 1997 (all parts)

Within the electrical cone and piezocone penetration test, two subcategories of the cone penetration

test are considered:

— electrical cone penetration test (CPT), which includes measurement of cone resistance and sleeve

friction.

— electrical piezocone test (CPTU), which is a cone penetration test with the additional measurement

of pore pressure.

The CPTU is performed like a CPT with the measurement of the pore pressure at one or several locations

on the penetrometer surface.

NOTE 2 CPT or CPTU can also be used without measurement of sleeve friction, but this is not covered in this

part of ISO 22476.
This part of ISO 22476 specifies the following features:
a) type of cone penetration test;
b) Cone penetrometer class according to Table 1;
c) Test categories according to Table 2;
d) penetration length or penetration depth;

e) elevation of the ground surface or the underwater ground surface at the location of the cone

penetration test with reference to a datum;

f) location of the cone penetration test relative to a reproducible fixed location reference point; and

g) pore pressure dissipation tests.

NOTE 3 This part of ISO 22476 covers onshore and nearshore CPT. For requirements for offshore CPT, see

ISO 19901-8.
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 17025, General requirements for the competence of testing and calibration laboratories

© ISO 2021 – All rights reserved 1
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
3 Terms, definitions and symbols
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 https:// www .electropedia .org/
3.1 Terms and definitions
3.1.1
average surface roughness

average deviation between the real surface of the cone penetrometer and a medium reference plane

placed along the surface of the cone penetrometer
3.1.2
cone

conical shaped bottom part of the cone penetrometer and the cylindrical extension

Note 1 to entry: When pushing the penetrometer into the ground, the cone resistance is transferred through the

cone to the load sensor.

Note 2 to entry: This part of ISO 22476 assumes that the cone is rigid, so when loaded its deformation is very

small relative to the deformation of other parts of the cone penetrometer.
3.1.3
base of the cone
cylindrical part of the cone directly behind the conical part of the cone tip
3.1.4
cone penetration test
CPT

pushing of a cone penetrometer at the end of a series of pushrods into the ground at a constant rate of

penetration and forces are measured electrically in the cone penetrometer
3.1.5
cone penetrometer

assembly containing the cone, friction sleeve, any other sensors and measuring systems as well as the

connection to the pushrods

Note 1 to entry: An example of a cone penetrometer is shown in Figure 1, for other filter locations, see Figure 2.

2 © ISO 2021 – All rights reserved
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)

a) Cone resistance and sleeve friction load cells b) Subtraction type cone penetrometer

in compression
Key
1 sleeve load cell
2 cone load cell
3 thread
4 soil seal
5 water seal
Figure 1 — Cross-section of an example of a cone penetrometer
3.1.6
cone resistance
cone penetration resistance
3.1.7
corrected cone resistance
measured cone resistance, q , corrected for pore pressure effects
Note 1 to entry: Also called total cone resistance.
3.1.8
corrected friction ratio

ratio of the measured or corrected sleeve friction to the corrected cone resistance measured at the

same depth

Note 1 to entry: Usually, the measured sleeve friction is used, however, if available, the corrected sleeve friction

is used.
© ISO 2021 – All rights reserved 3
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
3.1.9
corrected sleeve friction
measured sleeve friction, f , corrected for pore pressure effects
3.1.10
dissipation test

measurement of the pore pressure change with time, during a pause in pushing while holding the cone

penetrometer stationary
3.1.11
excess pore pressure
Δu , Δu , Δu
1 2 3

pore pressure in excess of the ambient pore pressure at the level of the filter caused by the penetration

of the cone penetrometer into the ground:
Δuuu=− (1)
11 0
Δuuu=− (2)
220
Δuuu=− (3)
33 0
3.1.12
filter element

porous element in the cone penetrometer that transmits the pore pressure to the pore pressure sensor,

maintaining the geometry of the cone penetrometer

Note 1 to entry: Slotted filter may be used as the filter element for measurements of u , in certain soil conditions.

3.1.13
friction ratio

ratio of the measured sleeve friction to the measured cone resistance at the same depth

3.1.14
friction reducer
device used to reduce friction along the push rod
3.1.15
friction sleeve

section of the cone penetrometer where friction between the soil and the sleeve is developed and the

load is transferred to the sleeve load cell.
3.1.16
in situ pore pressure
original in situ pore pressure
3.1.17
inclination
angular deviation of the cone penetrometer from the vertical
3.1.18
initial pore pressure
measured pore pressure at the start of the dissipation test
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
3.1.19
measured cone resistance

quotient of the measured force on the cone, Q , and cross-sectional projected area of the cone A :

c c
qQ= /A (4)
cc c
3.1.20
measured pore pressure
u , u , u
1 2 3

pressure measured in filter element during penetration, dissipation testing and pore pressure

observation test

Note 1 to entry: The pore pressure can be measured at several locations as follows (see Figure 2):

u on the face of the cone;

u on the cylindrical section of the cone (in the gap between the cone and the sleeve;

u just behind the friction sleeve.
Key
1 friction sleeve
2 cone penetrometer
3 cone
Figure 2 — Locations of pore pressure filters
3.1.21
measured sleeve friction

division of the measured force acting on the friction sleeve, F , by the area of the sleeve, A :

s s
fF= /A (5)
ss s
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
3.1.22
measuring system

all sensors and auxiliary parts used to transfer and/or store the electrical signals generated during the

cone penetration test

Note 1 to entry: The measuring system normally includes components for measuring force (cone resistance,

sleeve friction), pressure (pore pressure), inclination, clock time and penetration length.

3.1.23
net area ratio of the cone

ratio of the cross-sectional area of the load cell or shaft, A , of the cone penetrometer above the cone at

the location of the gap where fluid pressure can act, to the nominal cross-sectional area of the base of

the cone, A
Note 1 to entry: See Figure 6.
3.1.24
net area ratio of the friction sleeve

ratio of the difference between cross-sectional area of the bottom of the sleeve friction, A , and the top

of the sleeve friction, A , to the area of friction sleeve, A .
st s
3.1.25
net cone resistance

measured cone resistance corrected for the total overburden soil pressure and pore pressure

3.1.26
net friction ratio

ratio of the sleeve friction to the net cone resistance measured at the same depth

3.1.27
normalized excess pore pressure

excess pore pressure during a dissipation test compared to the initial excess pore pressure

Note 1 to entry: See 7.4.
3.1.28
penetration depth
vertical depth of the base of the cone, relative to a fixed point
Note 1 to entry: See Figure 3.
3.1.29
penetration length

sum of the lengths of the pushrods and the cone penetrometer, reduced by the height of the conical

part, relative to a fixed horizontal plane
Note 1 to entry: See Figure 3.

Note 2 to entry: The fixed horizontal plane usually corresponds to the level of the ground surface (on shore or

offshore). This can be different from the starting point of the test.
6 © ISO 2021 – All rights reserved
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oSIST prEN ISO 22476-1:2021
ISO/DIS 22476-1:2021(E)
Key
a fixed horizontal plane
b base of conical part of cone
l penetration length
z penetration depth
Figure 3 — Penetration length and penetration depth (schematic only)
3.1.30
piezocone penetration test
CPTU

electrical cone penetration test with measurement of the pore pressures around the cone

3.1.31
pore pressure ratio

ratio of the excess pore pressure at the u filter position to the net cone resistance

3.1.32
pushrod
part of a string of rods for the transfer of forces to the cone penetrometer
3.1.33
reference reading

stable output of a measuring system reading of a sensor just before the penetrometer penetrates the

ground or just after the penetrometer leaves the ground
Note 1 to entry: With tests starting onshore from the ground surface, th
...

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