SIST EN ISO 22476-11:2017

SLOVENSKI STANDARD
SIST EN ISO 22476-11:2017
01-oktober-2017
1DGRPHãþD
SIST-TS CEN ISO/TS 22476-11:2008
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH3UHVNXãDQMHQDWHUHQXGHO
3ORVNRYQLGLODWRPHWUVNLSUHVNXV,62
Geotechnical investigation and testing - Field testing - Part 11: Flat dilatometer test (ISO
22476-11:2017)
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 11:
Flachdilatometerversuch (ISO 22476-11:2017)
Reconnaissance et essais géotechniques - Essais en place - Partie 11: Essai au
dilatomètre plat (ISO 22476-11:2017)
Ta slovenski standard je istoveten z: EN ISO 22476-11:2017
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 22476-11:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 22476-11:2017

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SIST EN ISO 22476-11:2017


EN ISO 22476-11
EUROPEAN STANDARD

NORME EUROPÉENNE

May 2017
EUROPÄISCHE NORM
ICS 93.020 Supersedes CEN ISO/TS 22476-11:2005
English Version

Geotechnical investigation and testing - Field testing - Part
11: Flat dilatometer test (ISO 22476-11:2017)
Reconnaissance et essais géotechniques - Essais en Geotechnische Erkundung und Untersuchung -
place - Partie 11: Essai au dilatomètre plat (ISO 22476- Felduntersuchungen - Teil 11:
11:2017) Flachdilatometerversuch (ISO 22476-11:2017)
This European Standard was approved by CEN on 20 March 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22476-11:2017 E
worldwide for CEN national Members.

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SIST EN ISO 22476-11:2017
EN ISO 22476-11:2017 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 22476-11:2017
EN ISO 22476-11:2017 (E)
European foreword
This document (EN ISO 22476-11:2017) 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 AFNOR.
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 November 2017 and conflicting national standards
shall be withdrawn at the latest by November 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes CEN ISO/TS 22476-11:2005.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 22476-11:2017 has been approved by CEN as EN ISO 22476-11:2017 without any
modification.


3

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SIST EN ISO 22476-11:2017

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SIST EN ISO 22476-11:2017
INTERNATIONAL ISO
STANDARD 22476-11
First edition
2017-04
Geotechnical investigation and
testing — Field testing —
Part 11:
Flat dilatometer test
Reconnaissance et essais géotechniques — Essais en place —
Partie 11: Essai au dilatomètre plat
Reference number
ISO 22476-11:2017(E)
©
ISO 2017

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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(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 . 4
4 Equipment . 4
4.1 Dilatometer equipment . 4
4.2 Insertion apparatus . 6
5 Test procedure . 7
5.1 Maintenance and checks . 7
5.2 Membrane calibration procedure . 8
5.3 Flat dilatometer test . 8
5.3.1 Operations before testing . 8
5.3.2 Basic test procedure . 8
5.3.3 C-pressure readings . 9
5.3.4 Operations after testing . 9
5.4 DMT dissipation test (DMTA) . 9
5.5 DMT short dissipation test (DMTA-s) . 9
5.6 Safety requirements .10
6 Test results .10
7 Report .11
7.1 General .11
7.2 Reporting of test results .11
7.2.1 General information .11
7.2.2 Location of sounding .12
7.2.3 Test equipment .12
7.2.4 Test procedure .13
7.2.5 Test results .13
7.3 Presentation of results .13
Annex A (informative) Example interpretation formulae .15
Bibliography .17
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
ISO 22476-11 was prepared by the European Committee for Standardization (CEN) Technical Committee
CEN/TC 341, Geotechnical investigating and testing, in collaboration with ISO Technical Committee
TC 182, Geotechniques, in accordance with the agreement on technical cooperation between ISO and
CEN (Vienna Agreement).
This first edition of ISO 22476-11 cancels and replaces ISO/TS 22476-11:2005, which has been
technically revised.
A list of all parts in the ISO 22476 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

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SIST EN ISO 22476-11:2017
INTERNATIONAL STANDARD ISO 22476-11:2017(E)
Geotechnical investigation and testing — Field testing —
Part 11:
Flat dilatometer test
1 Scope
This document establishes guidelines for the equipment requirements, execution of and reporting on
flat dilatometer tests.
NOTE This document fulfils the requirements for flat dilatometer tests as part of the geotechnical
investigation and testing according to EN 1997-1 and EN 1997-2.
The basic flat dilatometer test consists of inserting vertically into the soil a blade-shaped steel probe
with a thin expandable circular steel membrane mounted flush on one face and determining two
pressures at selected depth intervals: the contact pressure exerted by the soil against the membrane
when the membrane is flush with the blade and, subsequently, the pressure exerted when the central
displacement of the membrane reaches 1,10 mm.
Results of flat dilatometer tests are used mostly to obtain information on soil stratigraphy, in situ state
of stress, deformation properties and shear strength. It is also used to detect slip surfaces in clays. The
flat dilatometer test is most applicable to clays, silts and sands, where particles are small compared to
the size of the membrane.
2 Normative references
There are no normative references in this document.
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:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1.1
dilatometer blade
dilatometer probe
blade-shaped steel probe that is inserted into the soil to perform a flat dilatometer test
3.1.2
membrane
thin circular steel diaphragm that is mounted flush on one face of the blade and is expanded by applying
a gas pressure at its back
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

3.1.3
switch mechanism
apparatus housed inside the blade, behind the membrane, capable of switching on and off an electric
contact when the membrane expands and reaches two preset deflections equal, respectively, to
0,05 mm (A-pressure (3.1.10) reading) and 1,10 mm (B-pressure (3.1.11) reading)
3.1.4
signal
activation (signal on) or disconnection (signal off) by the switch mechanism between the blade and the
membrane to detect two preset positions of the membrane equal to 0,05 mm and 1,10 mm
3.1.5
pneumatic-electric cable
cable that connects the control unit to the blade, delivers gas pressure at the back of the membrane and
provides electric continuity between the control unit and the switch mechanism
3.1.6
control and calibration unit
set of suitable devices capable of supplying gas pressure to the back of the membrane and measuring
the pressure when the switch mechanism activates and disconnects the electric contact behind the
membrane
3.1.7
earth wire
wire connecting the control unit to the earth
3.1.8
pressure source
pressurized gas tank filled with any dry non-flammable and non-corrosive gas incorporating a pressure
regulator
3.1.9
dilatometer sounding
sequence of dilatometer tests executed from the same station at ground level in a vertical direction at
closely spaced intervals with depth increments ranging from 100 mm to 300 mm
3.1.10
A-pressure
A
pressure that is applied to the back of the membrane to expand its centre 0,05 mm against the soil
3.1.11
B-pressure
B
pressure that is applied to the back of the membrane to expand its centre 1,10 mm against the soil
3.1.12
C-pressure
C
pressure that is applied to the back of the membrane when the centre of the membrane returns to the
A-pressure position during a controlled, gradual deflection following the B-pressure
3.1.13
A-membrane-calibration-pressure
ΔA
suction recorded as a positive value that is applied to the back of the membrane to retract its centre to
the 0,05 mm deflection in air
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

3.1.14
B-membrane-calibration-pressure
ΔB
pressure that is applied to the back of the membrane to expand its centre to the 1,10 mm deflection in air
3.1.15
zero gauge value
Z
M
pressure gauge deviation from zero when venting the blade to atmospheric pressure
3.1.16
soil pressure
p
0
corrected A-pressure (3.1.10)
Note 1 to entry: The term “contact pressure” is also used.
3.1.17
soil pressure
p
1
corrected B-pressure (3.1.11)
3.1.18
soil pressure
p
2
corrected C-pressure (3.1.12)
3.1.19
in situ pore water pressure
u
0
water pressure prior to blade insertion at the depth of the centre of the membrane
3.1.20
in situ effective vertical stress
σ’
vo
vertical stress prior to blade insertion at the depth of the centre of the membrane
3.1.21
dilatometer material index
I
D
index used to classify soils according to their response to the test
3.1.22
dilatometer
horizontal stress
index
K
D
index related to the in situ horizontal stress
3.1.23
dilatometer modulus
E
D
parameter related to the stiffness of the soil
3.1.24
pore pressure index
U
D
index related to the permeability of the soil
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

3.1.25
contraflexure time
t
flex
time corresponding to the inflection point of a dissipation curve
3.2 Symbols
Symbol Name Unit
E dilatometer modulus kPa
D
I dilatometer material index —
D
K dilatometer horizontal stress index —
D
U pore pressure index
D
A A-pressure kPa
B B-pressure kPa
C C-pressure kPa
p corrected A-pressure kPa
0
p corrected B-pressure kPa
1
p corrected C-pressure kPa
2
t contraflexure time s
flex
u in situ pore pressure kPa
0
Z zero gauge value kPa
M
ΔA A-membrane-calibration-pressure kPa
ΔB B-membrane-calibration-pressure kPa
σ’ in situ effective vertical stress kPa
vo
4 Equipment
4.1 Dilatometer equipment
The equipment shall comprise the following items:
a) dilatometer blade with suitable threaded adaptor to connect to push rods;
b) membrane;
c) control and calibration unit;
d) pressure source;
e) pneumatic-electrical cable;
f) earth wire;
g) calibration syringe;
h) (optional) automated data acquisition system;
i) (optional) load cell.
The dimensions of the blade, the membrane and the apex angle of the penetrating edge shall be within
the limits shown in Figure 1.
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

Dimensions in millimetres
Key
1 push rods 4 control and calibration cable unit 7 earth wire
2 blade 5 pressure tube 8 membrane
3 pneumatic electric cable 6 pressure source
Figure 1 — Dilatometer equipment and soil pressure definition
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

The control and calibration unit shall have the following features:
— a socket for earthing;
— ability to control the rate of gas flow while monitoring and measuring the gas pressure transmitted
from the control unit to the membrane;
— ability to perform controlled venting of the pneumatic circuit;
— ability to signal the instants when the electric switch changes from on to off and vice versa;
— pressure measurement devices able to determine the pressure applied to the membrane with
intervals of 10 kPa and a reproducibility of 2,5 kPa at least for pressures lower than 500 kPa;
— pressure gauges having an accuracy of at least 0,50 %.
The pressure source shall be provided with a suitable regulator, valves and pressure tubing to connect to
the control unit. The pressure regulator should not exceed the maximum allowable pressure of the gage.
The pneumatic-electrical cable shall have metal connectors with wire insulators to prevent short circuit
and washers to prevent gas leakage.
The calibration syringe is used for calibration of membrane rigidity, at the beginning and at the end of
the test.
If the equipment incorporates a system for automatic data acquisition, such system will
— register the gas pressure and the status of the electroacustical signal,
— have transducers with linearity and hysteresis error of no more than ±0,50 %,
— have an analog-to-digital conversion of at least 14 bit, and
— have an acquisition frequency of no less than 50 Hz.
4.2 Insertion apparatus
The equipment for inserting the dilatometer blade shall comprise
— a thrust machine to insert and advance the dilatometer blade into the soil;
— push rods with suitable adaptor to connect to the blade;
— hollow slotted adaptors for lateral exit of the pneumatic-electrical cable.
The thrust machine shall be capable of advancing the blade vertically with no significant horizontal or
torsional forces. Drill rigs and CPT/CPTU rigs are frequently employed for the purpose. To increase the
capacity of penetration, suitable dead loads and/or anchors may be used.
Push rods are required to transfer the thrust from the surface insertion equipment and shall be straight
and resistant against buckling. Rods are also required to carry the pneumatic-electrical cable from the
surface control unit to the dilatometer blade. It is recommended to use rods of 1 m length. Above the
ground level, the rods should be guided to avoid buckling.
Frequently, push rods are the same as those used to push CPT/CPTu (see ISO 22476-1:2012) but other
solutions are also possible.
To release the system of friction against the rods during the penetration phase, friction reducers may
be used. Friction reducers are local increases in rod diameter. They are usually located in the first rod
attached to the blade and shall be at least 200 mm above the membrane centre.
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

Penetration rates in the range of 10 mm/s to 30 mm/s should be applied, wherever it is possible. Driving
may be used when advancing the blade through stiff or strongly cemented layers which cannot be
penetrated by static push.
A suitable load cell may be placed between the blade and the push rods. Such cell would measure
the thrust applied during the blade penetration. This measurement is not necessary for common
interpretations of the test result but it may facilitate interpretation when using both DMT and CPT
soundings on a site.
5 Test procedure
5.1 Maintenance and checks
All the control, connecting and measuring devices shall be periodically checked, at least once per year.
In addition, measuring devices shall be periodically calibrated against a suitable reference instrument
to ensure that they provide reliable and accurate measurements.
The parts of the instrument inside the membrane shall be kept perfectly clean to ensure proper electrical
contacts. In particular, these components shall be completely free from dirt, grains, tissue or rust.
The dilatometer blade and membrane shall be checked before penetrating in the soil. The blade shall
be mounted axially with the rods. It shall be planar and coaxial and have a sharp penetration edge. The
membrane shall be clean of soil particles, free of any deep scratches, wrinkles or dimples and expand
smoothly in air upon pressurization.
The maximum out of plane deviation of the blade, defined as the maximum clearance under a 150 mm
long straight edge placed along the blade parallel to its axis, shall not exceed 0,5 mm; the maximum
coaxiality error of the blade, defined as the deviation of the penetration edge from the axis of the rods
to which the blade is attached, shall not exceed 1,5 mm.
The blade, the control unit and the pneumatic-electrical cable shall be checked for leaks before starting
a sequence of dilatometer soundings by plugging the blade end of the pneumatic-electrical cable and
checking for any pressure drop in the system. Leakage in excess of 100 kPa/min under 400 kPa pressure
shall be considered unacceptable and shall be repaired before testing begins.
Continuity of the electrical circuit shall be checked, verifying that the off-on switch signal is sharply
detected.
With the dilatometer equipment assembled and ready for testing, the switch mechanisms should be
checked by hand pushing the membrane flush with the blade verifying that the audio and/or visual
signals on the control unit are activated.
Before the test is carried out, the linearity of the push rods should be checked by one of the following
methods:
— Holding the rod vertically and rotating it. If the rod appears to wobble, the straightness is not
acceptable.
— Rolling the rods on a plane surface. If the rod appears to wobble, the straightness is not
acceptable.
— Sliding a straight hollow tube which is slightly longer than the rod over the rod. If the rod can
pass through the tube without jamming, the straightness is acceptable.
If any indications of bending appear, the use of the rods should be suspended.
Other methods of checking rod straightness may be used if they consistently result in similar results to
those suggested above.
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SIST EN ISO 22476-11:2017
ISO 22476-11:2017(E)

5.2 Membrane calibration procedure
Membrane calibration consist of measuring the values ΔA (suction) and ΔB (pressure) that correspond
respectively to the external pressure which must be applied to the membrane, in free air, to collapse it
against its seating and to the internal pressure which, in free air, lifts the membrane centre 1,10 mm
from its seating.
Suction and pressure for membrane calibration should be imposed using the calibration syringe.
During calibration, the signal activated by the electric switch shall be identified unambiguously at the
moment of the readings.
Membrane calibration shall be performed with the dilatometer equipment assembled and ready for
testing immediately before inserting the blade into the soil and upon retrieval to the ground surface,
both when running a dilatometer sounding or even a single test.
If the values of the membrane calibration pressures ΔA and ΔB, obtained before penetrating the blade
into the soil, fall outside the limits ΔA = 5 kPa to 30 kPa and ΔB = 5 kPa to 80 kPa respectively, the
membrane shall be replaced before testing.
After a membrane has been replaced, the new one shall be exercised to improve the st
...