oSIST prEN ISO 22476-4:2008

SLOVENSKI STANDARD
01-april-2008
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Geotechnical investigation and testing - Field testing - Part 4: Ménard pressuremeter test
(ISO/DIS 22476-4:2007)
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 4:
Pressiometerversuch nach Ménard (ISO/DIS 22476-4:2007)
Reconnaissance et essais géotechniques - Essais en place - Partie 4: Essai
pressiométrique Ménard (ISO/DIS 22476-4:2007)
Ta slovenski standard je istoveten z: prEN ISO 22476-4
ICS:
93.020
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2007
ICS
English Version
Geotechnical investigation and testing - Field testing - Part 4:
Ménard pressuremeter test (ISO/DIS 22476-4:2007)
Reconnaissance et essais géotechniques - Essais en place Geotechnische Erkundung und Untersuchung -
- Partie 4: Essai pressiométrique Ménard (ISO/DIS 22476- Felduntersuchungen - Teil 4: Pressiometerversuch nach
4:2007) Ménard (ISO/DIS 22476-4:2007)
This draft European Standard is submitted to CEN members for second parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 341.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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 Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 22476-4:2007: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
This document (prEN ISO 22476-4:2007) has been prepared by Technical Committee CEN/TC 341
"Geotechnical Investigation and Testing", the secretariat of which is held by ELOT, in collaboration with
Technical Committee ISO/TC 182 "Geotechnics".
This document is currently submitted to the second parallel Enquiry.
DRAFT INTERNATIONAL STANDARD ISO/DIS 22476-4.2
ISO/TC 182/SC 1 Secretariat: DIN
Voting begins on: Voting terminates on:
2007-12-06 2008-02-06
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Geotechnical investigation and testing — Field testing —
Part 4:
Ménard pressuremeter test
Reconnaissance et essais géotechniques — Essais en place —
Partie 4: Essai pressiométrique Ménard
ICS 93.020
ISO/CEN PARALLEL ENQUIRY
This draft International Standard is a draft standard developed within the European Committee for
Standardization (CEN) and processed under the CEN-lead mode of collaboration as defined in the
Vienna Agreement. The document has been transmitted by CEN to ISO for circulation for ISO member
body voting in parallel with CEN enquiry. Comments received from ISO member bodies, including those
from non-CEN members, will be considered by the appropriate CEN technical body. Should this DIS be
accepted, a final draft, established on the basis of comments received, will be submitted to a parallel two-
month FDIS vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED 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 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 NATIONAL REGULATIONS.
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.
©
International Organization for Standardization, 2007

ISO/DIS 22476-4.2
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ii ISO 2007 – All rights reserved

ISO/DIS 22476-4
Contents Page
Foreword .v
1 Scope.1
2 Normative references.3
3 Terms, definitions and symbols .3
3.1 Terms and definitions .3
3.2 Symbols.6
4 Equipment.9
4.1 Pressuremeter probe .11
4.2 Pressure and volume control unit (CU).14
4.3 Connecting lines.15
4.4 Injected liquid .15
4.5 Measurement and control.15
4.6 Data logger.15
5 Test procedure.16
5.1 Assembling the parts.16
5.2 Calibration and corrections (see B).16
5.3 Pressuremeter pocket and probe placing .16
5.4 Preparation for testing.17
5.5 Establishing the loading programme.17
5.6 Establishing the differential pressure.18
5.7 Expansion .19
5.8 Back-filling of the pockets.19
5.9 Safety requirements.19
6 Test results .20
6.1    Data sheet and field print-out.20
6.2 Corrected pressuremeter curve.21
6.3 Calculated results.22
7 Reporting.22
7.1 General .22
7.2 Field report.22
7.3 Test report.22
Annex A (normative) Geometrical features of pressuremeter probes .25
A.1 Geometrical specifications for probes.25
A.2 Selecting pressuremeter probe and components .26
Annex B (normative) Calibration and corrections.28
B.1 Measuring devices .28
B.2 Pressure loss of central measuring cell membranes.28
B.3 Checking measuring devices at site .29
B.4 Reading corrections.29
Annex C (normative) Placing the pressuremeter probe in the ground.36
C.1 General considerations.36
C.2 Probe placement techniques without soil displacement .38
C.3 Probe placing with soil displacement: driven slotted tube (DST).40
Annex D (normative) Obtaining pressuremeter parameters .45
D.1 Obtaining a corrected pressuremeter curve .45
D.2 Assessing the quality of the pressuremeter test .47
D.3 Pressuremeter creep pressure .49
DRAFT 2007
ISO/DIS 22476-4
D.4 Pressuremeter limit pressure. 50
D.5 Obtaining the Ménard pressuremeter modulus. 51
D.6 Final check on pressuremeter parameters . 53
Annex E (informative) Resolution, uncertainties and effects on results. 54
E.1 Resolution of the measuring devices. 54
E.2 Uncertainties of the measurements. 54
Annex F (informative) Typical Forms . 56
Bibliography. 59

iv © ISO 2005 – All rights reserved

DRAFT 2007
ISO/DIS 22476-4
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
EN ISO 22476-4 was prepared by Technical Committee CEN/TC 341, Geotechnical investigation and testing
and by Technical Committee ISO/TC 182, Geotechnics, in collaboration.
EN ISO 22476 consists of the following parts, under the general title Geotechnical investigation and testing —
Field testing:
⎯ Part 1: Electrical cone penetration tests
⎯ Part 2: Dynamic probing
⎯ Part 3: Standard penetration test
⎯ Part 4:Menard pressuremeter test
⎯ Part 5: Flexible dilatometer test
⎯ Part 6: Self-boring pressuremeter test
⎯ Part 7: Borehole jack test
⎯ Part 8: Full displacement pressuremeter test
⎯ Part 9: Field vane test
⎯ Part 10: Weight sounding test
⎯ Part 11: Flat dilatometer test
⎯ Part 12: Mechanical cone penetration test
⎯ Part 13: Plate loading test
⎯ Part 14: Phicometer test
DRAFT 2007
ISO/DIS 22476-4
Geotechnical investigation and testing — Field testing —
Part 4:
Ménard pressuremeter test
1 Scope
This document deals with field testing using the Ménard pressuremeter test as part of geotechnical
investigation and testing according to EN 1997-1 and EN 1997-2.
The present document describes the procedure for conducting a Ménard pressuremeter test in natural soils,
treated or untreated fills and in very hard soils, or soft rocks, either on land or off-shore.
The pressuremeter sounding results of this document are well suited to a quantitative determination of soil
strength and deformation parameters. Pressuremeters sounding results can yield lithological information.
They can also be combined with direct investigation (e;g; sampling according to EN ISO 22475-1) or
compared with other in situ tests (see EN 1997-2, 2.4.1.4(2) P, 4.1 (1) P and 4.2.3(2) P).
The Ménard pressuremeter test is performed by the radial expansion of a tricell probe placed in the ground
(see Figure 1). During the injection of the liquid volume in the probe, the inflation of the three cells first brings
the outer cover of the probe into contact with the borehole walls and then presses on them resulting in a soil
displacement. Pressure applied to, and the associated volume expansion of the probe are measured and
recorded so as to obtain the stress-strain relationship of the soil as tested.
This Standard refers to a probe historically described as the 60 mm G type probe. This standard applies to
test depths limited to 50 m and test pressure limited to 5 MPa.
NOTE 1  In the following instances: Ménard pressuremeter tests carried out at pressures above 5 MPa, Ménard
pressuremeter tests at depths exceeding 50m, Ménard pressuremeter tests carried out with E type probes, Full
displacement pressuremeter tests, the test procedures and the test interpretations are not necessarily covered by
this standard.
NOTE 2 Ménard pressuremeter tests can be carried out with other diameter probes such as 44 mm and 76 mm probes.
NOTE 3 Ménard pressuremeter tests can be carried out with a pressure exceeding 5 MPa or at a depth exceeding
50 m. However the corresponding test procedure and test interpretation are not covered by this standard.
Two alternative methods of measurement are provided as follows:
⎯ procedure A: data is recorded manually;
⎯ procedure B: data is recorded automatically.

DRAFT 2007
ISO/DIS 22476-4
Key
1 Ground surface                                                  A – A axial section
2 Ground
3 Borehole                                                         B - B cross section
4 Expanding pressuremeter probe
Figure 1 — Principle of a pressuremeter test
DRAFT 2007
ISO/DIS 22476-4
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 1997-1, Eurocode 7: Ground investigation and testing – Part 1: General rules.
EN 1997-2, Eurocode 7: Ground investigation and testing – Part 2: Design assisted by laboratory and field
testing.
ENV 13005:1999, Guide to the expression of uncertainty in measurement.
EN ISO 14688-1, Geotechnical investigation and testing – identification and classification of soil – Part 1:
identification and description.
EN ISO 14689-1, Geotechnical investigation and testing – identification and classification of rock – Part 1:
identification and description.
EN ISO 22475-1, Geotechnical investigation and testing – Sampling by drilling and excavationand ground
water measurements – Part 1: Technical principles for execution.
EN ISO 10012, Measurement management systems – Requirements for measurement processes and
measuring equipment
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1.1
pressuremeter
the whole equipment which is used to carry out a Ménard pressuremeter test, excluding the means .
necessary to place the pressuremeter probe into the ground
A pressuremeter includes a pressuremeter probe, a pressure and volume control unit, called CU, lines to
connect the probe to the CU and in the case of procedure B, a data logger which is either built into the CU or
linked to it.
3.1.2 pressuremeter test pocket
A circular cylindrical cavity formed in the soil to receive a pressuremeter probe. The primary concern shall be
the quality of the pocket wall obtained, using the methods described in Annex C.
3.1.3pressuremeter borehole
a borehole in which cylindrical pockets with circular cross sections are made in the ground, and into which the
pressuremeter probe is to be placed.
3.1.4
pressuremeter test
the process during which a cylindrical probe is inflated in the ground and the resulting cavity expansion is
measured by volume as a function of time and pressure increments according to a defined programme (see
Figure 4)
DRAFT 2007
ISO/DIS 22476-4
3.1.5
pressuremeter sounding
the whole series of sequential operations necessary to perform Ménard pressuremeter testing at a given
location: i.e. forming pressuremeter pockets and performing pressuremeter tests in them
3.1.6
pressuremeter pressure reading p
r
the pressure p as read at the CU elevation in the liquid circuit supplying the central measuring cell
r
3.1.7
pressure loss
the pressure loss is the difference between the pressure inside the probe and the pressure applied to the
pocket wall.
3.1.8
volume loss
the volume loss is the difference between the volume actually injected into the probe and the volume read on
the measuring device.
3.1.9
raw pressuremeter curve
the raw pressuremeter curve is the graphical plot of the injected volumes recorded at time 60 s, V , versus
the applied pressure at each pressure hold, p
r
3.1.10
corrected pressuremeter curve
the corrected pressuremeter curve is the graphical plot of the corrected volume V versus the corrected
pressure p (see Figure 5)
3.1.11
Ménard creep
Ménard creep is defined as the difference in volumes recorded at 60 s and at 30 s at each pressure
hold: V – V = ∆V
60 30 60/30
3.1.10
corrected Ménard creep curve
a graphical plot of the corrected Ménard creep versus the corrected applied pressure at each pressure hold
,
(see Figure 5)
3.1.11
pressuremeter log
a graphical report of the results of the pressuremeter tests performed at a succession of depths in the same
pressuremeter borehole, together with all the information gathered during the drilling (see Figure 7)
3.1.12
Ménard pressuremeter modulus E
M
E-modulus obtained from the section between (p V ) and (p V ) of the pressuremeter curve (see Figure 5
, ,
1 1 2 2
and Annex D).
3.1.13
pressuremeter limit pressure p
LM
by convention pressure at which the pressuremeter cavity has doubled its original volume, see Annex D
3.1.14
pressuremeter creep pressure p
f
a pressure derived from the creep curve, as in Annex D
DRAFT 2007
ISO/DIS 22476-4
3.1.15
operator
the qualified person who carries out the test
3.1.16
casing
lengths of tubing inserted into a borehole to prevent the hole caving in or to prevent the loss of flushing
medium to the surrounding formation
DRAFT 2007
ISO/DIS 22476-4
3.2 Symbols
For the purposes of this standard, the following symbols apply:
Table 1 — Symbols
Description Unit
Symbol
Apparatus volume loss coefficient
a
cm /MPa
d Outside diameter of the inner part of the probe with slotted tube Mm
ci
Inside diameter of the calibration cylinder used for the volume loss calibration Mm
d
i
Outside diameter of the central measuring cell, including any additional Mm
d
c
protection such as a slotted tube

Drilling tool diameter Mm
d
t
Wall thickness of the calibration cylinder used for the volume loss calibration Mm
e
Length of the calibration cylinder used for the volume loss calibration Mm
l
p
Length of each guard cell Mm
l
g
l Length of each guard cell for a short central measuring cell pressuremeter Mm
gs
probe
l Length of each guard cell for a long central measuring cell pressuremeter probe Mm
gl
Length along the tube axis of the slotted section of the slotted tube Mm
l
m
Length of the central measuring cell of the probe, measured after fitting the Mm
l
c
membrane
l Length of the short central measuring cell after fitting the membrane Mm
cs
l Length of the long central measuring cell after fitting the membrane Mm
cl
Minimum value, strictly positive, of the m slopes
m i
cm /MPa
E
Slope of the corrected pressuremeter curve between the two points with
m
cm /MPa
i
coordinates (p , V ) and (p , V ).
i-1 i-1 i i
Pressure applied to the ground after correction MPa
p
Correction for membrane stiffness usually called pressure loss of the probe MPa
p
e
Pressure at the origin of the segment exhibiting the slope m MPa
p E
E
p Ultimate pressure loss of the probe MPa
el
Pressuremeter creep pressure MPa
p
f
Gas pressure applied by the control unit indicator to the guard cells of the MPa
p
g
pressuremeter probe
Hydrostatic pressure between the control unit indicator and the central MPa
p
h
measuring cell of the pressuremeter probe
p Gas pressure in the guard cells of the pressuremeter probe MPa
k
p Ménard pressuremeter limit pressure of the ground MPa
LM
To be continued )
DRAFT 2007
ISO/DIS 22476-4
Table 1 (continued)
Description Unit
Symbol
Ménard nett pressuremeter limit pressure of the ground MPa
p *
LM
Ménard pressuremeter limit pressure as extrapolated by the hyperbolic best fit MPa
p
LMH
method
Ménard pressuremeter limit pressure as extrapolated by the double hyperbolic MPa
p
LMDH
method
p Ménard pressuremeter limit pressure as extrapolated by the reciprocal curve MPa
LMR
method
p Pressure loss of the central measuring cell membrane for a specific expansion. MPa
m
Pressure reading at the CU transducer elevation in the central measuring cell MPa
p
r
liquid circuit
Liquid pressure in the central measuring cell of the pressuremeter probe MPa
p
c
Target pressure according to loading program MPa
p
t
p Corrected pressure at the origin of the pressuremeter modulus pressure range MPa
Corrected pressure at the end of the pressuremeter modulus pressure range MPa
p
Time s
t
Time required for incrementing to the next pressure hold s
t
i
t Time the loading pressure level is held s
h
Pore water pressure in the ground at the depth of the test MPa
u
s
z Elevation, positively counted above datum m
Elevation of the pressure measuring device for the liquid injected in the m
z
c
measuring cell
z Elevation of the pressure measuring device for the gas injected in the guard m
cg
cells of the pressuremeter probe
Elevation of the ground surface at the location of the pressuremeter sounding m
z
N
Elevation of the measuring cell centre during testing m
z
s
Elevation of the ground water table (or free water surface in a marine or river m
z
w
environment)
CU Pressure and volume control unit ---
Type of pressuremeter probe where the three cells are formed by three ---
E
membranes in line
E Ménard pressuremeter modulus MPa
M
Type of pressuremeter probe where only the central measuring cell is formed ---
G
by a dedicated membrane (see Figure 2)
Coefficient of earth pressure at rest at the test depth ---
K
o
Value, after zeroing and data correction, of the volume injected in the central
V
cm
measuring cell and measured 60 s after starting a pressure hold
To be continued
DRAFT 2007
ISO/DIS 22476-4
Table 1 (continued)
Description Unit
Symbol
Original volume of the central measuring cell, including the slotted tube, if
V
cm
c
applicable
Volume obtained in the volume loss calibration test (see Figure B.2)
V
cm
p
value, after data correction, of the volume injected in the central measuring cell
V
cm
E
for pressure p .
E
V Value, after data correction, of the volume injected in the central measuring cell
cm
L
when the original volume of the pressuremeter cavity has doubled
V Volume injected in the probe as read on the CU, before data correction
cm
r
Volume of the central measuring cell including the slotted tube cm
V
t
Corrected volume at the origin of the pressuremeter modulus pressure range
V
cm
(see Figure 5)
V Corrected volume at the end of the pressuremeter modulus pressure range
cm
V Volume injected in the central measuring cell as read 30 s after the beginning of
cm
the pressure hold
Volume injected in the central measuring cell as read 60 s after the beginning of
V
cm
the pressure hold
Coefficient used to determine the pressuremeter modulus pressure range. ---
β
Unit weight of soil at the time of testing.
γ KN/m
Unit weight of the liquid injected in the central measuring cell
γ KN/m
i
Unit weight of water
γ
KN/m
w
-1
Rate of change of pressure head of gas at p per metre depth m
k
λ
g
ν Poisson’s ratio ---
Total vertical stress in the ground at test depth kPa
σ
vs
Total horizontal stress in the ground at test elevation kPa
σ
hs
Loading pressure increment MPa
∆p
Injected volume change from 30 s to 60 s after reaching the pressure hold - the
cm
Ménard creep
∆V
60/30
60 second injected volume change between successive pressure hold
cm
∆V
60/60
DRAFT 2007
ISO/DIS 22476-4
4 Equipment
The pressuremeter shown schematically on Figure 2 includes:
⎯ tri-cell probe;
⎯ string of rods to handle the probe;
⎯ control unit (CU);
⎯ lines connecting the control unit to the probe.
The control unit (CU) includes:
⎯ equipment to pressurize, and so to inflate 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;
⎯ device which permits the direct reading and in the case of procedure B the automatic recording of the
parameters to be measured: time, pressure and volume.
The pressure measuring devices for the liquid in the central measuring cell and for the gas in the guard cells
are located:
⎯ either above the ground surface;
⎯ or inside the probe, less than 1 m above the centre of the central measuring cell.
In the first case, it is important to provide the CU with means to check the stabilized pressure value at the
probe.
It is also necessary to have some means of measuring the depth of the test with appropriate accuracy.
DRAFT 2007
ISO/DIS 22476-4
Key
1 control unit (CU)
1a Pressurization, differential pressurization and injection devices
1b Pressure and volume measuring devices
1c Acquisition, storage and printing out of the data (required for procedure B)
2a Line for liquid injection
2b Line for gas injection
3 Depth measurement system
4 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
Figure 2 — Diagram of a Ménard pressuremeter
DRAFT 2007
ISO/DIS 22476-4
4.1 Pressuremeter probe
Two types of probes shall be used according to ground type and condition:
⎯ probe with a flexible cover;
⎯ probe with a flexible cover and either an additional more rigid protection or a slotted steel tube.
These probes are respectively described in Figures 3a and 3b and their geometrical features are given in
Table A.1.
3 3
The probe shall be capable of a volumetric expansion of at least 700 cm (550 cm for a probe with a short
central measuring cell within a slotted tube).
4.1.1 Probe with flexible cover
The probe is made up of three cylindrical cells of circular cross-section along the same axis (see figure A.1).
During a test these cells act simultaneously on the pocket wall. The probe includes:
⎯ one central measuring cell, with an outside diameter d and a length l (or l for short probe), which
c cs
c
expands radially in a pocket and applies a uniform stress to the pocket wall. This cell is inflated by
injecting a liquid which is assumed to be incompressible;
⎯ two guard cells with an outside diameter d and a length l , located above and below the central
g g
measuring cell. These cells are designed to apply to the pocket wall a stress close to but not greater than
the stress induced by the central measuring cell. These cells are inflated by gas pressure.
The probe consists of a hollow steel core with passages to inject the proper fluids to inflate the cells. The
probe is fitted with a central measuring cell membrane and a flexible cover sleeve. The steel core, on its
outside curved surface, usually bears a network of grooves which uniformly distribute the liquid in the central
measuring cell under the membrane. To this core are fixed the membrane and the flexible cover. The top of
the core is threaded and couples to the string of rods handling the probe from ground level; The central
measuring cell membrane isolates the fluid in the central measuring cell from the gas of the guard cellsThe
flexible cover which overlies the central measuring cell membrane also gives form to the guard cellsA flexible
protection made of thin steel strips usually 17mm wide either overlapping (up to half-way) or isolated, running
between fixing rings (see Figure A.1) may be added over the cover. fFluid lines connect the probe cells to the
pressure and volume control unit (CU). The drain tap of the measuring cell protrudes from the bottom of the
steel core.
NOTE 1 The flexible protection may be added to reduce damage to the cover from sharp fragments protruding
from the pocket wall.
When the probe is used in the full soil displacement procedure it is fitted with a point. In such a case the
probe body must be designed to withstand driving.
DRAFT 2007
ISO/DIS 22476-4
Key
DRAFT 2007
ISO/DIS 22476-4
1 Hollow probe body
2 measuring cell membrane
3 external sleeve or flexible cover
4 water inlet to the measuring cell
5 gas inlet to the guard cells
6 measuring cell drain outlet
7 slotted tube
8 rods
9 probe/rod coupling
3a) pressuremeter probe with flexible cover 3b) pressuremeter probe with slotted tube
Figure 3 — Pressuremeter probe (diagrammatic)
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ISO/DIS 22476-4
4.1.2 Probe with slotted tube
This probe consist of two parts: an inner part which is an assembly of three cylindrical cells of circular cross-
section along the same axis and an outer part made of a slotted steel tube (see figure A.1). During a test
these cells act simultaneously on the inside wall of the slotted tube which transfers the stresses to the pocket
wall. The probe includes:
⎯ one central measuring cell which expands radially in a pocket and applies a uniform stress to the pocket
wall. This cell is inflated by injecting a liquid which is assumed to be incompressible;
⎯ two guard cells with an outside diameter d and a length l , located above and below the central
g
g
measuring cell and designed to apply to the pocket wall a stress close to but not greater than the stress
induced by the central measuring cell. These cells are inflated by gas pressure.
This tube carries at least 6 axial or helical slots evenly distributed round the circumference (Figure 3b).The
slotted length l is measured along the tube axis. This length shall be the greater of:
m
1,3 (I + 2 l ) or 800 mm
c g
Before and after expansion, the opening of each slot of the tube shall be less than or equal to 0,4 mm. After
expansion the slotted tube and the slots must recover their original shape and size.
The assembly within the slotted tube is located by flexible spacers so as to allow the probe to expand radially
with a minimum of resistance.
4.2 Pressure and volume control unit (CU)
The control unit (CU) is built around a cylindrical volumeter fitted with a pressurizing device and a set of
measuring devices. The CU controls the probe cell expansion and permits the simultaneous reading of liquid
and gas pressures and injected liquid volume as a function of time.
The pressurizing device shall allow:
⎯ reaching the pressuremeter limit pressure or a pressure p at least equal to 5 MPa;
r
⎯ holding constant each loading pressure level in the measuring cell and in the guard cells during the set
time;
⎯ implementing a pressure increment of 0,5 MPa in less than 20 s as measured on the CU;
⎯ controlling the pressure difference between the measuring cell and the guard cells;
⎯ injecting a volume of liquid in the measuring cell larger than 700 cm .
Further, in the control unit a valve between the volumeter and the pressure measuring device allows stopping
the injection.
DRAFT 2007
ISO/DIS 22476-4
4.3 Connecting lines
The flexible lines connect the pressure and volume control unit (CU) to the probe. They convey the liquid to
the measuring cell and the gas to the guard cells and may be parallel or coaxial. When the lines are coaxial
the central line conveys the liquid and the outer line conveys the gas.
4.4 Injected liquid
The liquid injected into the measuring cell is either water or a liquid of similar viscosity and must not freeze
under the conditions of use.
4.5 Measurement and control
4.5.1 Time
The accuracy of the device used to measure time shall comply with the specification given in Annex E.
4.5.2 Pressure and volume
The resolution of measurement of the devices measuring pressure and volume shall be as specified in Annex
E.
4.5.3 Display of readings
At the site the pressure and volume control unit (CU) must give a simultaneous and instantaneous display of
the following readings: time, pressure of the liquid injected into the measuring cell, volume of the liquid
injected and pressure of the gas in the guard cell circuit.
4.5.4 Volume loss calibration cylinder
The main features of this steel cylinder shall be as follows:
⎯ measured inside diameter d not more than 66 mm;
i
⎯ wall thickness e not less than 8 mm;
⎯ length I more than 1 m or the slot length I , whichever is greater.
p m
4.6 Data logger
The data logger, the device to acquire and record the data under procedure B, shall be fitted with:
⎯ internal clock;
⎯ printer;
⎯ memory devicereadable by a computer.
The data logger shall be designed to record the raw data from the transducers, the zeros, calibration
coefficients and identification of each and the resulting calibrated data of pressure and volume.
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ISO/DIS 22476-4
The data logger shall not interfere with the conduct of a test as specified in section 5.5 and it shall not obscure
any other measuring devices. It shall be designed so as automatically to:
⎯ record its own identification parameters: date, hour, minute, second, CU number, data logger number,
memory device number;
⎯ require the input of the information necessary to identify the test, as described in section 5.2;
⎯ prevent the input of pressure and volume data or other information not obtained during the testing
process.
The data logger shall include an alarm device or a special display for the following events:
⎯ no memory device in place;
⎯ no test identification parameters recorded according to section 5.2;
⎯ no electric power.
5 Test procedure
5.1 Assembling the parts
The cover, the membrane and possibly the slotted tube if required are selected according to the expected
stress-strain parameters of the ground in which the probe is to be used. They shall each fulfil the
specifications given in A. Then the probe is linked to the control unit through the connecting lines.
The whole system is filled with water and purged to remove air bubbles.
5.2 Calibration and corrections (see B)
Calibration and correction shall be performed according to B. Copies of the calibration results are to be available at the
testing location.
5.3 Pressuremeter pocket and probe placing
In Pressuremeter testing, the quality of the pocket wall is paramount. Annex C describes the requirements.
The preparation of satisfactory pockets shall be the most important step in obtaining acceptable
pressuremeter test results.
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ISO/DIS 22476-4
Three conditions are necessary to obtain a satisfactory test pocket:
⎯ the equipment and method used to prepare the test pocket shall cause the least possible disturbance to
the soil at the cavity wall (see C.1);
⎯ the diameter of the cutting tool shall meet the specified tolerances (see C.2.1);
the pressuremeter test shall be performed immediately after the pocket is
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