prEN ISO 22476-16
(Main)Geotechnical investigation and testing - Field testing - Part 16: Borehole shear test (ISO/DIS 22476‑16:2023)
Geotechnical investigation and testing - Field testing - Part 16: Borehole shear test (ISO/DIS 22476‑16:2023)
This standard describes the test method covering the procedure for drilling the borehole, inserting the probe, and performing the test in soils and weak rock by axial shearing of the borehole wall. It does not include high pressure testing in hard rock. The test works best in sands, silts, clays and weak rocks, which will maintain open test cavity or which can be held open with drilling fluid.
NOTE This document is intended to be used in conjunction with EN 1997-2. EN 1997-2 defines the way ground investigation has to be done to define a reliable ground model including resistance of soils and rocks.
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 16: Bohrscherversuch mit Phikometer (ISO/DIS 22476‑16:2023)
Dieser Teil von ISO 22476 ist auf den Bohrloch-Scherversuch nach dem Phikometerverfahren anwendbar, der allgemein als Phikometerversuch bezeichnet wird (die Wortherkunft ergibt sich aus phi für den Reibungswinkel, ko für Kohäsion und meter für Messgerät).
Das Prüfverfahren umfasst vier Schritte, nämlich das Bohren eines Bohrlochs, das Absenken der Sonde auf die Versuchstiefe, das Expandieren der Sonde in die Bohrlochwand und das Scheren des Bodens durch Ausübung mehrerer Schritte kontrollierten Radialdrucks und gleichzeitiges Herausziehen der Sonde mit einer konstanten Bewegungsgeschwindigkeit. Die Prüfabfolgen sind in Bild 1 dargestellt.
[Bild 1]
Der Versuch kann in natürlichen Böden, Schüttmaterial und künstlichen Böden aller Arten durchgeführt werden, die gesättigt und ungesättigt sein können.
Er ist nicht auf sehr weiche Böden, weiche Tone, sehr lockere Böden, Gestein, leicht umgewandeltes Gestein sowie natürliche und künstliche Böden, in denen Geröll mit einer Korngröße von mehr als 150 mm vorherrscht, anwendbar.
Im Allgemeinen ist der Versuch anwendbar in Böden, deren In situ-Widerstandscharakteristika größenordnungsmäßig wie folgt sind:
Grenzdruck des Ménard-Pressiometers: ungefähr 0,4 MPa < pLM < 3 5 MPa oder mehr als 4 MPa in körnigen, nicht kohäsiven Böden;
CPT-Spitzenwiderstand: ungefähr 1,5 MPa < qc < 15 MPa, je nach Art des Bodens (siehe Anhang E);
SPT N: ungefähr 8 < N < 50, je nach Art des Bodens (siehe Anhang E);
ANMERKUNG Der Versuch darf auch in Böden durchgeführt werden, deren Widerstand außerhalb dieser Anwendbarkeitsgrenzen liegt. Die Repräsentativität der Ergebnisse muss jedoch durch Analyse der PBST-Kurven (siehe 6.1) beurteilt oder validiert werden.
Dieses Dokument ist nur auf Versuche anwendbar, die in einer Tiefe von nicht mehr als 30 m durchgeführt werden.
In weichen Böden ist der Versuch bei großen Tiefen unter Umständen nicht anwendbar.
Die aus diesem Versuch abgeleiteten Parameter sind die Scherfestigkeitseigenschaften: Kohäsion und Reibungswinkel.
Reconnaissance et essais géotechniques - Essais en place - Partie 16: Essai de cisaillement en forage (ISO/DIS 22476‑16:2023)
Geotehnično preiskovanje in preskušanje - Preskušanje na terenu - 16. del: Strižni preskus v vrtini (ISO/DIS 22476-16:2023)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 22476-16:2023
01-junij-2023
Geotehnično preiskovanje in preskušanje - Preskušanje na terenu - 16. del: Strižni
preskus v vrtini (ISO/DIS 22476-16:2023)
Geotechnical investigation and testing - Field testing - Part 16: Borehole shear test
(ISO/DIS 22476-16:2023)
Geotechnische Erkundung und Untersuchung - Felduntersuchungen - Teil 16:
Bohrscherversuch mit Phikometer (ISO/DIS 22476-16:2023)
Reconnaissance et essais géotechniques - Essais en place - Partie 16: Essai de
cisaillement en forage (ISO/DIS 22476-16:2023)
Ta slovenski standard je istoveten z: prEN ISO 22476-16
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN ISO 22476-16:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 22476-16:2023
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oSIST prEN ISO 22476-16:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22476-16
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
2023-03-20 2023-06-12
Geotechnical investigation and testing — Field testing —
Part 16:
Borehole shear test
Reconnaissance et essais géotechniques — Essais en place —
Partie 16: Essai de cisaillement en forage
ICS: 93.020
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
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oSIST prEN ISO 22476-16:2023
ISO/DIS 22476-16:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22476-16
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
Geotechnical investigation and testing — Field testing —
Part 16:
Borehole shear test
Reconnaissance et essais géotechniques — Essais en place —
Partie 16: Essai de cisaillement en forage
ICS: 93.020
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
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© ISO 2023
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NATIONAL REGULATIONS.
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023
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oSIST prEN ISO 22476-16:2023
ISO/DIS 22476-16:2023(E)
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 and abbreviations . 7
4 Equipment . 8
4.1 General . 8
4.2 Phicometer probe . 8
4.3 Connection tube line and pulling rods . 9
4.3.1 Connection tube line . 9
4.3.2 Pulling rods . 9
4.4 Equipment at ground surface . 11
4.4.1 Pulling device . 11
4.4.2 Pressure-volume control unit (CU) . 11
4.4.3 Regulation system of the traction speed of the probe . 11
4.5 Means of measurement and control . 11
4.5.1 Time . 11
4.5.2 Pressure, volume and pulling force .12
4.5.3 Axial displacement .12
4.5.4 Display of readings .12
4.5.5 Dimensions of the shearing zone of the probe .12
5 Test procedure .12
5.1 Checks and measurements before insertion of the probe in the ground .12
5.2 Borehole drilling phase, probe placing phase and zero setting .12
5.3 Minimum spacing between tests . 13
5.4 Teeth insertion phase .15
5.5 Shearing phase . 17
5.5.1 Loading program – applied hold pressures in the probe . 17
5.5.2 Successive shearing stages under pressure holds . 17
5.5.3 End of the test . 18
6 Back-filling of the phicometer borehole .19
7 Safety requirements.19
8 Test results . .19
8.1 General . 19
8.2 Shearing curve graph – shear strength parameters φ and c . 19
i i
8.3 Associated graphs . 20
8.4 Adjustment and determination of the in situ angle of friction φ and the in situ
i
cohesion c . 20
i
8.5 Examples of adjustment and determination of the in situ angle of friction φ and
i
cohesion c . 20
i
9 Reporting .22
9.1 General .22
9.2 Field report . 22
9.3 Test report . 24
9.4 Tests log . 25
Annex A (normative) Characteristics of the phicometer probe .26
Annex B (normative) Calibration, checks and corrections .27
Annex C (normative) Execution of the PBST borehole .31
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Annex D (normative) Determination of the parameters of shearing .33
Annex E (informative) Correlations to estimate p from other soil resistance parameters
LM
q and N .35
c
Annex F (normative) Accuracy and uncertainties .36
Annex G (informative) Examples of adjustment and determination of the in situ angle of
friction φ and cohesion c .38
i i
Annex H (informative) Example of installation of the PBST equipment .43
Bibliography . 44
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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.
The determination of the shear strength of soils is of paramount importance in Geotechnical
investigation and testing of soils. The shear resistance of soils and materials, characterised by the
friction angle φ and the cohesion c, represents an important parameter for the geotechnical engineer
while studying the stability of construction works and structures in relation with soils and materials.
Usually, this resistance is measured in the laboratory using triaxial tests or direct shear tests carried
out on field samples and only if sampling, conservation and preparation make it possible to consider the
samples as non remolded and sufficiently representative of the soil in place.
Since the 1960’s, various experimental devices have been designed and developed to determine the
shear strength directly in situ from tests carried out in boreholes, in different soils at different depths.
The study of the bibliography literature shows that the majority of the existing borehole shear tests are
based on the use of probes for applying and maintaining a normal pressure on the walls of the borehole
and then to carry out a shear phase by a linear displacement of the probe on the soil against the walls of
the borehole. The procedure is then repeated through a multistage increase of the normal pressure to
obtain more values relating normal pressure and shear resistance.
The test equipment and apparatuses differ from each other by the geometry and size of the probes and
by the shape of the friction part of these probes and by the procedure for applying normal pressure
stages and shear phases.
One of the first devices of this kind is the Iowa Borehole Shear Tester (BST) developed in the USA
(Handy & al 1967). The test is performed by placing a bilateral expandable probe, equipped with two
diametrically opposed shear plates in a predrilled borehole, expanding the probe against the wall of
the borehole and causing a shear failure in the soil by pulling the probe axially along the borehole. The
2
size of the shear plates is relatively small (32,3 cm ) and does not allow testing of soils with coarse
elements, which may somewhat limit its field of application.
In the early 1970s, H. MORI, in Japan, developed an in situ shearing device called the IST which was used
in many projects. The principle of the test is carried out by generating a shearing force while pulling
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upwards a cylindrical expandable probe provided with teeth driven into the wall of the borehole. but it
is not reported whether the IST test continues to be performed currently.
Later on a self-boring in situ friction test (SBIFT), also developed in Japan (Yoshido Maeda & al. - 1998)
allows the evaluation of soil characteristics as the initial horizontal at rest pressure, and deformation
modulus and strength characteristics (cohesion and internal friction angle) of the soil. The SBIFT
possesses a self-boring drilling functionality that can reduce the disturbance of the tested soil. However,
very few data and results are available to currently validate this device and the characteristics of the
soil it provides.
The same way as the SBIFT, a self-boring in situ shear pressuremeter (SBISP), was recently developed
in China (Kunpeng Wang & al. - 2018), that allows the evaluation of pressuremetric characteristics
as the initial horizontal at rest pressure, deformation yield pressure and modulus and also strength
characteristics (cohesion and internal friction angle) of the soil. The SBISP possesses a self-boring
drilling functionality that can greatly reduce the disturbance of the tested soil. However, very few data
and results are available to currently validate this device and the characteristics of the soil it provides.
This standard ISO 22476-16 applies to the borehole shear test using the Phicometer procedure,
commonly named the Phicometer Borehole shear test (PBST). This test has been invented and developed
by Gérard PHILIPPONNAT in the 1980’s (G. Philipponnat, 1986).
This test has been the subject, between 1986 and 1992, of several applied research programs to design
the apparatus and its components and to develop and optimize a common test procedure that can be
used in a majority of soils. Various articles have been published as a result of these researches and
since then PBST tests continue to be carried out currently, for the determination of the shear strength
parameters from the test and to derive values for the undrained shear strength and an estimation of
[3]
the drained effective shear resistance parameters (see bibliography : Philipponnat G, Zerhouni M.I.,
1993). The test has been standardized in France since 1997 (Afnor, XP P94-120 standard).
This standard ISO 22476-16 applies to the borehole shear test using the Phicometer procedure, named
the phicometer borehole shear test (PBST).
A list of all parts in the ISO 22476 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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oSIST prEN ISO 22476-16:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 22476-16:2023(E)
Geotechnical investigation and testing — Field testing —
Part 16:
Borehole shear test
1 Scope
This Part of ISO 22476 is applicable to the borehole shear test using the Phicometer procedure,
commonly named the phicometer test (etymologically derived from phi for friction angle, co for cohesion
and meter for measurement).
The test method covers a 4 steps procedure consisting of drilling a borehole, lowering the probe to
the test depth, inflating it into the borehole wall and shearing the soil by applying a series of steps of
controlled radial pressure and simultaneously pulling out the probe with a constant displacement rate.
The test sequences are shown in figure 1.
1
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ISO/DIS 22476-16:2023(E)
Key
1 ground surface 4 casing (if necessary) 7 probe (inflated state)
2 ground 5 string of rods 8 radial pressure
3 borehole 6 probe (deflated state) 9 pulling force
S shear plane
Figure 1 — General arrangement and sequences of the phicometer procedure borehole shear
test
The test can be performed in all types of natural soils, fills and artificial soils, which can be saturated
or not.
It does not apply to very soft soils, soft clays, very loose soils, rocks, slightly altered rocks and natural or
artificial soils with a predominance of cobbles having a particle diameter greater than 150 mm.
Generally the test is applicable in soils with an order of magnitude of their in situ resistance
characteristics as follows:
— Ménard pressuremeter limit pressure: 0,4 MPa < p < 3 5 MPa approximately or more than 4 MPa
LM
in granular non cohesive soils;
— CPT Cone resistance: 1,5 MPa
annex E);
— SPT N: 8
NOTE The test may also be carried out in soils having a resistance outside these application limits. However,
the representativeness of the results must be assessed or validated by the analysis of the PBST graphs (see
paragraph 6.1).
2
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oSIST prEN ISO 22476-16:2023
ISO/DIS 22476-16:2023(E)
This document applies only to tests carried out at a depth less than or equal to 30 m.
In soft soils at great depths, the test may not be applicable.
The parameters derived from this test are the shear strength properties: cohesion and friction angle.
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 amendments) applies.
ISO 10012, Measurement management systems — Requirements for measurement processes and measuring
equipment
ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:
Identification and description
ISO 14688-2, Geotechnical investigation and testing — Identification and classification of soil — Part 2:
Principles for a classification
ISO 14689-1, Geotechnical investigation and testing – Identification and classification of rock - Part 1:
Identification and description
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.
3.1.1
Borehole shear test
The process during which a special shearing probe is installed in a borehole (see 3.1.4) at a defined
depth and inflated against the borehole wall and pulled to determine the resulting shear force of the
soil. This process is repeated with a succession of increased maintained normal pressure steps so as to
obtain a pressure versus shear stress relation of the soil.
3.1.2
Phicometer borehole shear test (PBST)
The shear test performed in a borehole (see 3.1.1) with the Phicometer probe (see 3.1.3) and the
Phicometer test procedure (see 5).
3.1.3
PBST device or Phicometer device
The whole equipment which is used to carry out a phicometer borehole shear test is called the
phicometer. It consists of the following parts:
— a phicometer probe
— a pressure and volume Control Unit (CU)
— a line to connect the probe to the CU
— a pulling device placed on a reaction base on the ground surface and linked to the probe with rods
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— a device to measure the pulling force
— a device to control the shearing displacement rate and to measure the displacement during the test
The equipment may also include a data logger.
A Phicometer Borehole Shear Test (PBST) device assembly is shown in figure 2:
An example of installation of the PBST equipment is shown in annex H.
4
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oSIST prEN ISO 22476-16:2023
ISO/DIS 22476-16:2023(E)
Key
1 borehole 3 string of rods 5 borehole casing (if necessary)
2 phicometer probe 4 connecting line 6 reaction base
Detail of the Phicometer probe : 2a expansible slotted tube 2c shearing zone by the probe
teeth
2b annular teeth 2d inflatable measuring cell
A data logger (optional) B2 volume measurement C2 pulling device with timer
B pressure-Volume control Unit (CU) B3 display of readings D axial displacement control
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B1 pressure regulator & injection C1 measurement of pulling force
device
Figure 2 — Diagram of the PBST test device assembly and its components
3.1.4
Phicometer borehole
The part of a borehole in which the test pocket will be set up. Its characteristics must meet the criteria
given in 5.2 and the drilling must be carried out in accordance with the specifications and requirements
of the annex C.
The drilling above the phicometer borehole can be carried out in a diameter greater or equal to the phico-
meter borehole diameter, without necessarily respecting the requirements of the phicometer borehole.
The distance between the top of the phicometer borehole and the centre of the test pocket (i.e: center of
the shearing zone of the phicometer probe) shall not be less than 1,0 m.
In most cases, it is necessary to support the walls of the borehole, by using drilling mud and/or by placing
a casing above the test pocket.
The choice between the different drilling techniques and tools is made according to the soil type, in order
to achieve a cylindrical test zone on the borehole wall with minimum disturbance (see annex C) and create
the test pocket. The direct driving of the probe into the soil is not allowed.
3.1.5
phicometer test pocket
The cylindrical cavity with a circular section made in a borehole and in which the probe of the
phicometer is placed, brought into contact and pulled upwards during the test phases.
3.1.6
phicometer probe
(see 4.2 and figure 3)
3.1.7
phicometer test diagram
The set of plots resulting from the PBST test and allowing the determination of the shearing
characteristics of the soil (see figure 6 and § 8)
3.1.8
phicometer cohesion
The in situ cohesion c obtained from the phicometer test diagram, see example in Figure 6.
i
3.1.9
phicometer angle of friction
The in situ angle of friction φ obtained from the phico
...
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