ISO 22476-1:2022
(Main)Geotechnical investigation and testing — Field testing — Part 1: Electrical cone and piezocone penetration test
Geotechnical investigation and testing — Field testing — Part 1: Electrical cone and piezocone penetration test
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.
Reconnaissance et essais géotechniques — Essais en place — Partie 1: Essais de pénétration au cône électrique et au piézocône
Le présent document établit les exigences et les recommandations en matière d’appareillage, de modes opératoires et de compte rendu pour les essais de pénétration au cône et au piézocône NOTE Le présent document traite des exigences relatives au cône et au piézocône dans le cadre de la reconnaissance et des essais géotechniques selon la série de normes EN 1997. Ce document spécifie les caractéristiques suivantes: a) type d’essai de pénétration au cône; b) classe de pointe pénétrométrique selon le Tableau 2; c) catégories d’essai selon le Tableau 3; d) longueur ou profondeur de pénétration; e) la cote altimétrique de la surface du sol ou la cote de la surface de la nappe à l’emplacement de l’essai de pénétration au cône par rapport à un repère précisé; f) l’emplacement de l’essai de pénétration au cône par rapport à un point de référence fixe reproductible; g) les essais de dissipation de la pression interstitielle. Ce document couvre les essais de pénétration au cône (CPT) en milieu terrestre et en milieu côtier. Pour les exigences relatives aux essais CPT en mer, voir l’ISO 19901-8.
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 22476-1
Second edition
2022-12
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
Reference number
ISO 22476-1:2022(E)
© ISO 2022
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ISO 22476-1:2022(E)
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© ISO 2022
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ISO 22476-1:2022(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 . 2
3.2 Symbols . 8
4 Equipment .11
4.1 General . 11
4.1.1 Tolerances . 11
4.1.2 Gaps and soil seals . 11
4.2 Cone penetrometer . 11
4.3 Surface roughness and hardness . 11
4.4 Cone .12
4.5 Friction sleeve . 13
4.6 Filter element . 14
4.6.1 General filter location . 14
4.6.2 Pore pressure u . 14
1
4.6.3 Pore pressure u . 15
2
4.6.4 Pore pressure u . 15
3
4.7 Pushrods . 15
4.8 Measuring system . 15
4.8.1 Accuracy . 15
4.8.2 Sensors for cone resistance and sleeve friction. 16
4.8.3 Sensor for pore pressure . 16
4.8.4 Sensor for inclination . 16
4.8.5 Sensor for temperature . 16
4.8.6 Measuring of penetration length . 16
4.8.7 Raw data . 16
4.9 Thrust machine . 17
5 Test procedures .17
5.1 Selection of equipment, procedures and evaluation of results . 17
5.1.1 General . 17
5.1.2 Calibration and verification requirements . 17
5.1.3 Cone penetrometer class conformity assessment . 18
5.2 Position and verticality of thrust machine . 20
5.3 Preparation of the test . 20
5.4 Pushing of the cone penetrometer . 21
5.5 Use of friction-reducing techniques. 21
5.6 Frequency of test data recording . 21
5.7 Registration of penetration length . 21
5.8 Pore pressure dissipation test (PPDT). 22
5.9 Test completion .22
5.10 Evaluation of CPT/CPTU in relation to test category . 23
5.11 Equipment checks and calibrations . 24
5.12 Safety requirements . 24
6 Test results . .24
6.1 Measured parameters . 24
6.2 Correction of parameters.25
6.3 Calculated parameters . 27
7 Reporting .27
7.1 General . 27
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ISO 22476-1:2022(E)
7.2 Reporting of test results . 27
7.2.1 General information . 27
7.2.2 Location of the test .28
7.2.3 Test equipment .28
7.2.4 Test results .29
7.3 Presentation of test results .29
Annex A (informative) Suitability of test methods .31
Annex B (normative) Maintenance, checks and calibration .34
Annex C (informative) Calibration report example .52
Annex D (normative) Calculation of penetration depth .62
Annex E (informative) Correction of sleeve friction for water pressure .63
Annex F (informative) Preparation of the piezocone .64
Annex G (informative) Friction reduction techniques .65
Bibliography .66
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ISO 22476-1:2022(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).
This second edition cancels and replaces the first edition (ISO 22476-1:2012), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 22476-1:2012/Cor 1:2013.
The main changes are as follows:
— dimensional tolerances of cone penetrometer have been updated;
— application class scheme has been replaced by cone penetrometer class and test category
classification scheme;
— introduction of temperature influence on measurements monitoring and requirements of internal
temperature sensor for cone penetrometer class 0;
— requirements for the calibration of cone penetrometers have been added;
— minor updates to figures and text have been made.
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 22476-1:2022(E)
Introduction
This document establishes general principles equipment requirements, the execution of and reporting
on cone and piezocone penetration tests.
The 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. Two International Standards define cone penetration tests: this
document 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 document, although “cone penetration
resistance” is a more correct description of the process.
The test results of this document are especially suited for the qualitative and/or quantitative
determination of a soil profile together with other investigations (e.g. sampling according to ISO 22475-1
and identification ISO 14688-1) or as a relative comparison with 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.
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INTERNATIONAL STANDARD ISO 22476-1:2022(E)
Geotechnical investigation and testing — Field testing —
Part 1:
Electrical cone and piezocone penetration test
1 Scope
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.
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/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
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ISO 22476-1:2022(E)
3.1 Terms and definitions
3.1.1
average surface roughness
R
a
average deviation between the real surface of the cone penetrometer (3.1.6) and a medium reference
plane placed along the surface of the cone penetrometer
3.1.2
base of the cone
cylindrical part of the cone (3.1.4) directly behind the conical part of the cone tip
3.1.3
calibration drift
difference between reference reading (3.1.34) before commencement of test and first reference reading
(3.1.34) after calibration
3.1.4
cone
conical shaped bottom part of the cone penetrometer (3.1.6) and the cylindrical extension
Note 1 to entry: When pushing the penetrometer into the ground, the cone resistance (3.1.7) is transferred
through the cone to the load sensor.
Note 2 to entry: This document 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.
3.1.5
cone penetration test
CPT
test in which a cone penetrometer (3.1.6) at the end of a series of pushrods (3.1.33) is pushed into the
ground at a constant rate of penetration and forces are measured electrically in the cone penetrometer
3.1.6
cone penetrometer
assembly containing the cone (3.1.4), friction sleeve (3.1.16), any other sensors and measuring system
(3.1.23) as well as the connection to the pushrods (3.1.33)
Note 1 to entry: An example of a cone penetrometer is shown in Figure 1; for other filter locations, see Figure 2.
3.1.7
cone resistance
cone penetration resistance
3.1.8
corrected cone resistance
total cone resistance
q
t
measured cone resistance (3.1.20), q , corrected for pore pressure effects
c
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ISO 22476-1:2022(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
6 load cell for combined axial forces acting on the cone and the friction sleeve
Figure 1 — Cross-sections of example cone penetrometers
3.1.9
corrected friction ratio
R
ft
ratio of the measured sleeve friction (3.1.22) or corrected sleeve friction (3.1.10) to the corrected cone
resistance (3.1.8) 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.
3.1.10
corrected sleeve friction
f
t
measured sleeve friction (3.1.22), f , corrected for pore pressure effects
s
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ISO 22476-1:2022(E)
3.1.11
dissipation test
measurement of the pore pressure change with time, during a pause in pushing while holding the cone
penetrometer (3.1.6) stationary
3.1.12
excess pore pressure
Δu , Δu , Δu
1 2 3
pore pressure in excess of the original in situ pore pressure (3.1.17) at the level of the filter caused by the
penetration of the cone penetrometer (3.1.6) into the ground, see Formulae (1), (2) and (3):
Δuuu=− (1)
11 0
Δuuu=− (2)
220
Δuuu=− (3)
33 0
3.1.13
filter element
porous element in the cone penetrometer (3.1.6) 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.
2
3.1.14
friction ratio
R
f
ratio of the measured sleeve friction (3.1.22) to the measured cone resistance (3.1.20) at the same depth
3.1.15
friction reducer
device used to reduce friction along the pushrod (3.1.33)
3.1.16
friction sleeve
section of the cone penetrometer (3.1.6) where friction between the soil and the sleeve is developed and
the load is transferred to the sleeve load cell
3.1.17
in situ pore pressure
u
o
original pressure of groundwater held within the soil
3.1.18
inclination
angular deviation of the cone penetrometer (3.1.6) from the vertical
3.1.19
initial pore pressure
u
i
measured pore pressure (3.1.21) at the start of the dissipation test (3.1.11)
3.1.20
measured cone resistance
q
c
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ISO 22476-1:2022(E)
quotient of the measured force on the cone, Q , and cross-sectional projected area of the cone A , see
c c
Formula (4):
qQ=/A (4)
cc c
3.1.21
measured pore pressure
u , u , u
1 2 3
pressure measured in filter element (3.1.13) during penetration, dissipation test (3.1.11) 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;
1
u on the cylindrical section of the cone (in the gap between the cone and the sleeve);
2
u just behind the friction sleeve (3.1.16).
3
Key
1 friction sleeve
2 cone penetrometer
3 cone
Figure 2 — Locations of pore pressure filters
3.1.22
measured sleeve friction
f
s
division of the measured force acting on the friction sleeve (3.1.16), F , by the area of the sleeve, A , see
s s
Formula (5):
fF= /A (5)
ss s
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ISO 22476-1:2022(E)
3.1.23
measuring system
all sensors and auxiliary parts used to transfer and/or store the electrical signals generated during the
cone penetration test (3.1.6)
Note 1 to entry: The measuring system normally includes components for measuring force (cone resistance and
sleeve friction), pressure (pore pressure), inclination (3.1.18), clock time and penetration length (3.1.30).
3.1.24
net area ratio of the cone
a
ratio of the cross-sectional area of shaft, A , of the cone penetrometer (3.1.6) above the cone at the
n
location of the gap where fluid pressure can act, to the nominal cross-sectional area of the base of the
cone (3.1.2), A
c
Note 1 to entry: See Figure 6.
3.1.25
net area ratio of the friction sleeve
b
ratio of the difference between cross-sectional area of the bottom of the sleeve friction, A , and the top
sb
of the sleeve friction, A , to the area of friction sleeve (3.1.16), A
st s
3.1.26
net cone resistance
q
n
measured cone resistance (3.1.20) corrected for the total overburden soil pressure and pore pressure
3.1.27
net friction ratio
R
fn
ratio of the sleeve friction to the net cone resistance (3.1.26) measured at the same depth
3.1.28
normalized excess pore pressure
U
excess pore pressure (3.1.12) during a dissipation test (3.1.11) compared to the initial excess pore
pressure
Note 1 to entry: See 7.3.
3.1.29
penetration depth
z
vertical depth of the base of the cone (3.1.2), relative to a fixed point
Note 1 to entry: See Figure 3.
3.1.30
penetration length
l
sum of the lengths of the pushrods (3.1.33) and the cone penetrometer (3.1.6), 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
nearshore). This can be different from the starting point of the test.
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ISO 22476-1:2022(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)
3.1.31
piezocone penetration test
CPTU
cone penetration test (3.1.5) with measurement of the pore pressures around the cone
3.1.32
pore pressure ratio
B
q
ratio of the excess pore pressure (3.1.12) at the u filter position to the net cone resistance (3.1.26)
2
3.1.33
pushrod
part of a string of rods for the transfer of forces to the cone penetrometer (3.1.6)
3.1.34
reference reading
stable output of a measuring system (3.1.23) 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, the reference reading equals the zero
reading.
3.1.35
thrust machine
equipment that pushes the cone penetrometer (3.1.6) and pushrods (3.1.33) into the ground at a constant
rate of penetration
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ISO 22476-1:2022(E)
3.1.36
total overburden stress
σ
vo
stress due to the total weight of the soil layers at the depth of the base of the cone (3.1.2)
3.1.37
zero drift
absolute difference between the reference readings (3.1.34) of a measuring system (3.1.23) at the start
and after completion of the cone penetration test (3.1.5)
3.2 Symbols
Symbol Name Unit
2
A cross-sectional projected area of the cone mm
c
2
A cross-sectional area of the load cell or shaft mm
n
2
A surface area of the friction sleeve mm
s
2
A cross-sectional area of the bottom of the friction sleeve mm
sb
2
A cross-sectional area of the top of the friction sleeve mm
st
a net area ratio of cone
b net area ratio of sleeve
b’ repeatability error without rotation
B pore pressure ratio
q
C correction factor for the effect of the inclination of the cone penetrometer relative to the
inc
vertical axis
d diameter of the cone at a specified height mm
cone
d diameter of the cylindrical part of the cone mm
c
d diameter of the filter mm
fil
d diameter of
...
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