SIST EN ISO 22476-5:2023

SLOVENSKI STANDARD
01-september-2023
Nadomešča:
SIST EN ISO 22476-5:2013
Geotehnično preiskovanje in preskušanje - Preskušanje na terenu - 5. del: Preskus
v vrtini s presiometrom (ISO 22476-5:2023)
Geotechnical investigation and testing - Field testing - Part 5: Prebored pressuremeter
test (ISO 22476-5:2023)
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 5:
Vorgebohrter Pressiometerversuch (ISO 22476-5:2023)
Reconnaissance et essais géotechniques - Essais en place - Partie 5: Essai au
pressiomètre en préforage (ISO 22476-5:2023)
Ta slovenski standard je istoveten z: EN ISO 22476-5:2023
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22476-5
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2023
EUROPÄISCHE NORM
ICS 93.020 Supersedes EN ISO 22476-5:2012
English Version
Geotechnical investigation and testing - Field testing - Part
5: Prebored pressuremeter test (ISO 22476-5:2023)
Reconnaissance et essais géotechniques - Essais en Geotechnische Erkundung und Untersuchung -
place - Partie 5: Essai au pressiomètre en préforage Felduntersuchungen - Teil 5: Vorgebohrter
(ISO 22476-5:2023) Pressiometerversuch (ISO 22476-5:2023)
This European Standard was approved by CEN on 16 March 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22476-5:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22476-5:2023) has been prepared by Technical Committee ISO/TC 182
"Geotechnics" in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and
Testing” the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2023, and conflicting national standards shall
be withdrawn at the latest by October 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 22476-5:2012.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 22476-5:2023 has been approved by CEN as EN ISO 22476-5:2023 without any
modification.
INTERNATIONAL ISO
STANDARD 22476-5
Second edition
2023-03
Geotechnical investigation and
testing — Field testing —
Part 5:
Prebored pressuremeter test
Reconnaissance et essais géotechniques — Essais en place —
Partie 5: Essai au pressiomètre en préforage
Reference number
ISO 22476-5:2023(E)
ISO 22476-5:2023(E)
© ISO 2023
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 22476-5:2023(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviations . 5
4 Equipment . 6
4.1 General . 6
4.2 Pressuremeter probe . 10
4.3 Connecting lines . 10
4.4 Control unit (CU) . 10
4.5 Measurement and control accuracy . 11
4.5.1 Time . 11
4.5.2 Pressure and expansion . . 11
4.5.3 Display of readings . 11
4.5.4 Expansion calibration cylinder . 11
5 Test procedures .11
5.1 Assembly of parts. 11
5.2 Calibration of the testing device and corrections of readings .12
5.3 Pressuremeter test pocket and probe placing .12
5.4 Test execution . .12
5.4.1 Test loading programmes .12
5.4.2 Reference loading programmes . 13
5.4.3 Readings and recordings before and during the test .13
5.5 End of test . 14
5.6 Backfilling of borehole . 14
5.7 Safety requirements . 14
6 Test results . .14
6.1 General . 14
6.2 Corrected pressure, radial displacement and volume . 15
6.3 Apparent pressuremeter moduli . 15
6.4 Results . . 16
6.4.1 Determination of moduli . 16
6.4.2 Reference loading programme A . 16
6.4.3 Reference loading programme B. 17
6.4.4 Reference loading programme C . 18
7 Reporting .19
7.1 General . 19
7.2 Contents . 19
7.3 Presentation of test results . 21
Annex A (normative) Calibration and corrections .22
Annex B (informative) Performing the test .30
Annex C (normative) Accuracy and uncertainties .36
Bibliography .37
iii
ISO 22476-5:2023(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 22476-5:2012), which has been technically
revised.
The main changes are as follows:
— the title of the part has been modified;
— a reference loading programme with cyclic loading has been added;
— calibration procedures have been developed.
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.
iv
INTERNATIONAL STANDARD ISO 22476-5:2023(E)
Geotechnical investigation and testing — Field testing —
Part 5:
Prebored pressuremeter test
1 Scope
This document is applicable to pressuremeter tests using cylindrical flexible probes placed in pre-
existent boreholes using testing procedures other than the Menard procedure.
Pressuremeter tests following the Menard procedure are provided in ISO 22476-4.
NOTE A high-pressure flexible pressuremeter probe which contains transducers for the measurement of
radial displacements is also known as flexible dilatometer probe or high-pressure dilatometer probe.
This document applies to tests performed in any kind of grounds, starting from soils, treated or
untreated fills, hard soils and soft rocks, up to hard and very hard rocks, either on land or offshore.
The parameters derived from this test can include stiffness, strength, initial in-situ stress state and
consolidation properties.
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.
EN 16228-1, Drilling and foundation equipment – safety – Part 1:Common requirements
EN 16228-2, Drilling and foundation equipment – safety – Part 2: Mobile drill rigs for civil and geotechnical
engineering, quarrying and mining
ISO 10012, Measurement management systems — Requirements for measurement processes and measuring
equipment
ISO 14689, Geotechnical investigation and testing — Identification, description and classification of rock
ISO 22475-1, Geotechnical investigation and testing — Sampling methods and groundwater measurements
— Part 1: Technical principles for the sampling of soil, rock and groundwater
ISO 22476-4, Geotechnical investigation and testing — Field testing — Part 4: Prebored pressuremeter test
by Ménard procedure
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 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/
ISO 22476-5:2023(E)
3.1.1
pressuremeter probe
cylindrical flexible probe which can be expanded by the application of hydraulic pressure and/or
pressurised gas
Note 1 to entry: Pressuremeter probes contains means of measurement of its radial displacements or volume.
3.1.2
flexible dilatometer probe
high-pressure dilatometer probe
high-pressure flexible pressuremeter probe which contains transducers for the measurement of radial
displacements
3.1.3
pressuremeter control unit
set of suitable devices capable of supplying fluid and/or gas pressure to the probe, to control and take
readings of the probe’s pressure, radial displacements or volume of the measuring cell
3.1.4
connecting line
cable that connects the control unit to the probe, delivers fluid and/or gas pressure in the measuring
and guard cells
3.1.5
pressuremeter test pocket
circular cylindrical cavity formed in the ground to receive a pressuremeter probe (3.1.1)
3.1.6
pressuremeter test
process of expanding the pressuremeter probe so as to pressurize the flexible membrane against the
pocket wall and so measure pressure, radial displacements or volume as a function of time during the
expansion test
Note 1 to entry: See Figure 1.
3.1.7
pressuremeter sounding
series of pressuremeter tests in a borehole
3.1.8
seating pressure
pressure during the expansion of the pressuremeter at which the pressuremeter membrane contacts
the pocket wall
3.1.9
controlling parameter
variable used to define the loading programme of the test according to a pre-determined programme
and recorded in the control unit
Note 1 to entry: This variable can be the pressure, the radius displacement or the injected volume.
3.1.10
radial displacement
change in pressuremeter probe radius/diameter or in cavity wall displacement
3.1.11
pressuremeter curve
graphical plot of pressure versus the associated cavity wall displacement or measuring cell volume
ISO 22476-5:2023(E)
3.1.12
pressuremeter shear modulus
G
PBP
shear modulus obtained from the pressuremeter curve
Note 1 to entry: See 6.3
ISO 22476-5:2023(E)
Key
1 ground surface
2 borehole wall
3 pocket
4 expanding pressuremeter probe
P applied pressure
A-A axial section
B-B cross section
Figure 1 — Example of a prebored pressuremeter test
ISO 22476-5:2023(E)
3.1.13
depth of test
distance between the ground level and the centre of the expanding length of the pressuremeter probe
measured along the borehole axis
Note 1 to entry: See Figure 2.
3.1.14
operator
qualified person who carries out the test
3.1.15
phase
section of the loading or expansion program characterized by a controlling parameter, a loading rate
and a loading direction
3.1.16
loop
sequence of the loading or expansion program including at least an unloading phase and a reloading
phase, and possibly an intermediate hold phase
3.2 Symbols and abbreviations
For the purposes of this document, the symbols in Table 1 apply.
Table 1 — Symbols
Symbol Description Unit
-1
a Corrected equipment radial displacement or volume mm.MPa
loss coefficient, taking into account calibration cylinder
or
self-deformability
3 -1
cm .MPa
-1
a Raw equipment radial displacement or volume loss mm.MPa
r
coefficient
or
3 -1
cm .MPa
-1
a Radial displacement or equivalent volume loss taking into mm.MPa
cc
account calibration cylinder self-deformability
or
3 -1
cm .MPa
d Calibration cylinder inside diameter mm
cc
d Initial external diameter of the pressuremeter probe mm
c
E A Young modulus derived from a prebored pressuremeter MPa
PBP
test
G Shear modulus MPa
G First loading pressuremeter shear modulus MPa
L1
G Pressuremeter shear modulus MPa
PBP
G A reloading pressuremeter shear modulus MPa
Ri
G Apparent shear modulus of the equipment or system during MPa
sys
unloading-reloading loops
G An unloading pressuremeter shear modulus MPa
Ui
G An unloading/reloading pressuremeter shear modulus MPa
URi
k Creep parameter in reference loading programme C mm
f
L Expanding length of the pressuremeter probe mm
FD
p Corrected pressure MPa
ISO 22476-5:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Symbol Description Unit
p Constant full relief pressure for loops in reference loading MPa
1.1
programme A
p Pressure loss associated with membrane stiffness
e
p Corrected reversal pressure before loop i MPa
i
p Average corrected pressure in reference loading programme MPa
mean
D
p Minimum corrected pressure in reference loading pro- MPa
min
gramme D
p Maximum corrected pressure in reference loading pro- MPa
max
gramme D
p Pressure as read at the measuring unit MPa
r
p Seating pressure MPa
s
r Corrected radius mm
r Corrected radius at time t in reference loading programme mm
1 1
C
r Corrected radius at time t in reference loading programme mm
2 2
C
r Radius correction mm
e
r Nominal cavity radius mm
s
t Time min
T Period in reference loading programme D min
t Time 1 in reference loading programme C min
t Time 2 in reference loading programme C min
ΔV Corrected injected volume cm
ΔV Injected volume correction cm
e
ΔV Injected volume, as read at the control unit cm
r
V Total volume cm
z Test depth m
δ Corrected radial displacement mm
δ Radial displacement correction mm
e
δ Radial displacement, as read at the control unit mm
r
δ Radial displacement corresponding to the seating pressure mm
s
Δd Increase of diameter, as read at the control unit mm
r
Δd Corrected diameter increase mm
Δp Pressure increment, as read at the control unit MPa
r
Δp Corrected pressure increment MPa
ε Cavity strain -
c
ν Poisson’s ratio -
4 Equipment
4.1 General
The test with the pressuremeter is performed by the expanding of a pressuremeter membrane placed
in the ground (see Figure 1). The pressure and the associated expansion of the probe are measured and
recorded so as to obtain a pressure-expansion relationship for the ground as tested.
ISO 22476-5:2023(E)
The equipment to carry out pressuremeter tests shall consist of the components shown in Figure 2.
The following components are mandatory:
— pressuremeter probe (no. 8 in Figure 2);
— connecting line (no. 6 in Figure 2);
— signal cable (no. 5 in Figure 2);
— displacement or volume measuring unit (no. 2 in Figure 2);
— pressure control unit (no. 3 in Figure 2);
— pressure source (no. 4 in Figure 2).
— setting rods (no.1 in Figure 2).
The following components may be added to allow orientation of the instrument if needed:
— data logger (no. 9 in Figure 2);
— sediment collection tube (no. 14 in Figure 3);
— pore pressure measuring system;
— accelerometer or geophones to perform shear wave velocity measurements.
ISO 22476-5:2023(E)
Key
1 setting rods 6 connecting line
2 displacement or volume measuring unit 7 probe rode coupling sediment collection tube
3 pressure control unit 8 pressuremeter probe
4 pressure source 9 data logger
5 signal cable z test depth
Figure 2 — Schematic diagram of pressuremeter equipment
ISO 22476-5:2023(E)
a) Tri-cellular or monocellular b) Monocellular probe with c) Monocellular probe with
probe with expansion followed displacement measured displacement measured
through the volume of central inside the membrane at the cavity wall
cell
Key
1 control unit (CU): 1a pressurization, differential pressurization (if any) and
injection devices
1b pressure and displacement or volume measuring
devices
1c acquisition, storage and printing out of the data
(required for CU type B and C)
2 connecting lines: 2a line for liquid injection
2b line for gas injection
2c signal cable
3 depth measurement system
4 setting rods
5 pressuremeter probe 5a upper guard cell
5b central measuring cell
5c lower guard cell
6 ground
7 pressuremeter test pocket
8 probe body, hollow
9 probe rod coupling
10 and 11 displacement transducers
12 metal insert at the extremities
of the displacement transducers
13 membrane clamping ring
14 sediment collection tube
15 pressure transducer (if applicable)
16 compass (if applicable)
Figure 3 — Sketch of pressuremeter probes
ISO 22476-5:2023(E)
Preparation of pressuremeter test pocket shall be performed according to ISO 22476-4. The annular
space between borehole wall and the probe, if any, shall be chosen taking into account the measuring
range of the displacement transducers if any. Drilling parameters should be recorded according to
ISO 22476-15. Borehole log should be recorded according to ISO 22475-1 and ISO 14689.
4.2 Pressuremeter probe
The probe expansion shall be monitored by radial displacement [see Figure 3 b) and c)] or volume
measurement [see Figure 3 a)].
The probe shall have a cover in a shape of monocellular or be tricellular. When small strain measurement
(as defined in EN 1997-2) is needed, local displacement measurement can be implemented in the probe.
Radial displacements shall be measured by electrical transducers on two or more points, placed in the
vicinity of the mid plane [see Figure 3 b) and c)].
NOTE The arrangement shown in Figure 3 a) and b) with measurement at the inner wall of the membrane is
primarily used in soils. The arrangement shown in Figure 3 c) with measurement on inserts that penetrate the
membrane and directly bear on the cavity walls is primarily used in rocks.
In arrangement shown in Figure 3 a) and b), because membrane compression influences the readings of
pressure and displacement, proper corrections shall be determined by corresponding calibration (see
A.3).
The slenderness of the pressuremeter probe (ratio between expanding length L and initial external
FD
diameter d ) shall at least be equal to 6.
c
If included, pore pressure may be measured in the mid plane of the probe.
4.3 Connecting lines
The pressure connecting line and signal cable connect the control unit to the probe. The pressure
connecting line conveys the fluid to the probe and may be either parallel or coaxial with the signal
cable.
The injected fluid and inner diameter of the connecting lines shall be selected so that the pressure
differential between the CU and the probe remains limited.
4.4 Control unit (CU)
The control unit shall control the probe expansion and permit the reading of liquid or gas pressure and
displacement or volume as a function of time.
The pressurizing system (3 and 4 in Figure 2) shall allow:
— reaching a pressure defined by the project;
— implementing a pressure increment of 0,5 MPa as measured on the control unit in less than 20 s;
— stopping the injection when necessary.
The control unit shall include:
— equipment to apply the controlling parameters, and so to inflate or deflate the probe, and to maintain
constant pressures as required during the test;
— equipment to maintain an appropriate pressure difference between the central measuring cell and
the guard cells if any;
— a device that allows, according to the type defined in Table 2, the reading and recording of the
parameters to be measured: time, pressure and displacement or volume.
ISO 22476-5:2023(E)
Table 2 — Types of pressuremeter control unit
Type of control unit Type of test control Type of reading Type of recording
A manual manual manual
B manual automatic automatic
C automatic automatic automatic
Some means of measuring the depth of the test with appropriate accuracy shall be provided.
4.5 Measurement and control accuracy
4.5.1 Time
The accuracy of the device used to measure time shall be in accordance with Annex C.
4.5.2 Pressure and expansion
The pressure measuring devices for the liquid or for the gas in the measuring cell shall be located:
— at least in the control unit;
— if relevant, also inside the probe, in this case at less than 1 m above the centre of the measuring cell.
The maximum uncertainty of measurement of the devices measuring pressure and probe expansion
shall be as specified in Annex C.
4.5.3 Display of readings
On site, the pressure control and probe expansion measuring units shall give a simultaneous and
instantaneous display of the following readings: time, pressure of the fluid injected into the probe and
radial displacements or injected volume.
4.5.4 Expansion calibration cylinder
The main dimensions of the steel calibration cylinder serving the calibration for membrane compression
and additional effects shall be as follows:
— a known inside diameter which closely fits the deflated instrument;
— a thickness appropriate to the maximum pressure to be applied;
— a length appropriately greater than the expanding length of the instrument.
5 Test procedures
5.1 Assembly of parts
The cover, the membrane and possibly the rigid protection or the slotted tube if required shall be
selected according to the planned loading programme and type of the ground in which the probe is to
be used.
Then the probe shall be linked to the control unit through the connecting lines and cables. The whole
system shall be filled with working fluid and purged to remove air bubbles if relevant.
ISO 22476-5:2023(E)
5.2 Calibration of the testing device and corrections of readings
Before testing, the operator shall make sure that:
— all measuring components have been calibrated according to ISO 10012;
— calibration of the whole system has been performed according to Annex A and reading corrections
are available.
Copies of the calibration documents shall be available on request.
5.3 Pressuremeter test pocket and probe placing
The test location is usually determined from design requirements. The position of the borehole into
which the probe is to be inserted shall be marked on a drawing and identified by its location details.
The pocket shall be drilled and the pressuremeter probe placed in the test location with the minimum
of disturbance to the borehole wall to be tested.
The pocket and the probe placing shall be performed, and samples shall be taken according to
ISO 22476-4, with the exception of techniques involving ground displacement (e.g. pushed probe, driven
slotted tube).
NOTE Pressuremeter testing for which placement of probes involves ground displacement is dealt by
ISO 22476-8.
If necessary, the instrument may be orientated in the pocket by rotating the setting rods.
The uncertainty on the probe depth measurement shall follow Annex C.
5.4 Test execution
5.4.1 Test loading programmes
The test loading programme shall be specified and available before the start of the test.
NOTE The test loading programme can take into account or cover the expected loading caused by the
structure, if known.
The test loading programme should include:
— the sequence of phases in the test, including any loops, if present;
— the controlling parameter that applies in each phase: pressure, displacement or volume;
— the mode of application of the controlling parameter by a continuous ramp or in steps:
— in case of a continuous ramp, its rate and interval;
— in case of steps, their magnitude and duration;
— the amplitude of any loop, if present;
— readings and recordings frequency;
— any additional stopping criteria.
The loading programme specification can be simplified by using or adapting any of the reference
loading programmes laid out in 5.4.2.
The parameters laid out in a test specification may be changed during the test if the operator has
reason to believe that the specified loading programme will jeopardize the test result or damage the
ISO 22476-5:2023(E)
instrument. Any adaptation to the test specification by the operator and the reasons for it shall be
recorded.
5.4.2 Reference loading programmes
A B
C D
Figure 4 — Reference loading programmes A, B, C and D
One of the following reference loading programmes provided in Figure 4 may be employed as templates
to specify the test. These reference loading programmes, which are fully described in Annex B, are:
— reference loading programme A: at least two loops with (almost) full unloading, and final unloading;
— reference loading programme B: at least three loops with partial unloading;
— reference loading programme C: a hold after a preliminary loading phase;
— reference loading programme D: a specified number of loops or cycles, after a preliminary loading
phase.
NOTE In Figure 4, the pressure is used as controlling parameter only for illustration purposes. The same
reference loading programme can be applied using either radial displacement δ or injected volume ΔV .
r r
5.4.3 Readings and recordings before and during the test
During the test, the operator shall record:
— the effective applied loading programme, including any deviation from the specification;
— the response of all measuring sensors during the loading programme.
A comprehensive number of data (see 7.2) shall be reported.
ISO 22476-5:2023(E)
5.4.3.1 During the test
At the end of each pressure hold or sequence:
— loading pressure or hold number in the series;
— any changes in the pressure and volume or displacement occurring during the hold or sequence.
Graphical representation of loading program (control variable according to time) and raw measurement
should be displayed to the operator.
5.4.3.2 At test completion
— date and time at completion of test;
— the uncorrected pressure-expansion curve;
— the full print-out authentication by the operator who signs and gives his full name in capital letters.
5.4.3.3 Data sheet and print out
Data sheets or, in case of the use of a data logger, print outs, shall be available.
5.5 End of test
The test shall be stopped when any of the following occur:
— the specified test loading programme has been carried out;
— the maximum admissible expansion of the pressuremeter membrane is reached;
— the measuring range of any of the transducers is exceeded;
— the operator considers there is a risk to jeopardize the test result or to damage the equipment.
5.6 Backfilling of borehole
After completion of a pressuremeter sounding, the borehole shall be backfilled and the site restored
according to the specifications given in ISO 22475-1.
5.7 Safety requirements
The user of this document should be aware of national safety regulations, for instance for:
— personnel health- and safety equipment;
— clean air if working in confined spaces;
— ensuring the safety of the equipment.
Drilling rigs shall be in accordance with EN 16228-1 and EN 16228-2.
6 Test results
6.1 General
All the derived parameters shall be obtained from the corrected pressure (corresponding to the
pressure at the cavity walls), and the corrected radius or volume (corresponding to the radius or
volume of the cavity).
ISO 22476-5:2023(E)
The cavity radius and volumes shall be obtained considering the corrected radial displacement and
corrected injected volumes respectively.
Corrected pressure, corrected radial displacement and corrected injected volume shall be obtained
from measured values through the application of corrections described in 6.2.
The parameters derived from the pressuremeter test can include:
— shear moduli;
— undrained shear strength;
— at rest total horizontal stress;
— consolidation or creep parameters.
The interpretation assumptions shall be referenced explicitly.
6.2 Corrected pressure, radial displacement and volume
The corrected pressure p shall be obtained from Formula (1) or (2):
p = p (δ )–p (δ )+p (1)
r r e r h
p = p (ΔV ) – p (ΔV )+p (2)
r r e r h
where
p is the hydraulic head, due to the difference of elevation between the measurement of the pres-
h
sure in the measuring cell and the probe;
p is the pressure correction due to membrane resistance (see Clause A.2).
e
The corrected radial displacement δ or injected volume ΔV shall be obtained from Formula (3) or (4):
δ = δ – δ (p ,δ) (3)
r e r r
ΔV = ΔV – ΔV (p , ΔV) (4)
r e r r
where
δ is the radial displacement correction (see Clause A.3);
e
ΔV is the injected volume correction (see Clause A.3).
e
6.3 Apparent pressuremeter moduli
The apparent secant shear modulus of a prebored pressuremeter test, G can be obtained through
PBP
Formula (5) or (6):
1 Δp
Gr= (5)
PBPs
2 Δδ
Δp
GV= (6)
PBP s
ΔV
ISO 22476-5:2023(E)
where
r is the radius of the cavity corresponding to the seating pressure p ;
s s
V is the volume of the cavity corresponding to the seating pressure p ;
s s
Δp is either the change of pressure above the seating pressure p , the reversal pressure of a given
s
loop or the minimal pressure of a given loop;
ΔV is the change of corrected injected volume due to Δp;
Δδ is the change of corrected radial displacement due to Δp.
NOTE 1 The pressuremeter shear modulus G corresponds to the secant shear modulus considering that
PBP
the ground follows a linear elastic behaviour during the pressuremeter test, independent from strain and stress
level. If the linear elastic behaviour is not met, especially for soils, the shear modulus G will also vary with the
distance to the probe and the use of the previous formulae only yields an apparent shear modulus.
NOTE 2 Procedures to derive the shear modulus G from the pressuremeter shear modulus G obtained with
PBP
Formula (5) or (6) can be found in Reference [12].
6.4 Results
6.4.1 Determination of moduli
Pressuremeter shear moduli G should be determined from Formula (5) or (6).
PBP
In case of radial displacement measurements, pressuremeter shear moduli G shall be determined
PBP
using the average value of radial displacements. However, if the values differ much from each other
indicating anisotropy of the rock or soil mass, the pressuremeter shear moduli G should be
PBP
determined separately for each pair of opposing displacement transducers and reported accordingly.
When evaluating pressuremeter tests, Δp shall only be selected within a range of any loading or
unloading phase. Whichever is selected determines whether the modulus measured is a loading or
an unloading one. Distinction shall be made between the first loading modulus and various reloading
moduli. All shear moduli shall be derived and quoted individually. Shear moduli values should be quoted
to three significant digits.
6.4.2 Reference loading programme A
The prebored pressuremeter shear moduli G should be calculated as follows (see Table 3 and
PBP
Figure 5):
— the first loading modulus G are derived from the data after the seating pressure p and before the
L1 s
first unloading-reloading loop;
— the unloading moduli G are derived for every unload path between 30 % to 70 % of the pressure
Ui
range between reversal pressure p and minimum pressure p ;
i 1.1
— the reloading moduli G are derived for every reload path between 30 % to 70 % of the pressure
Ri
range between minimum pressure p and reversal pressure p .
1.1 i
Table 3 — Pressuremeter shear moduli for reference loading programme A
First loading Unloading Reloading
G G G
L1 U1 R1
- G G
U2 R2
- G G
U3 R3
ISO 22476-5:2023(E)
Key
δ corrected radial displacement
p corrected pressure
p seating pressure
s
δ corrected radial displacement corresponding to
...