SIST EN ISO 18674-3:2018

Geotechnical investigation and testing - Geotechnical monitoring by field instrumentation - Part 3: Measurement of displacements across a line: Inclinometers (ISO 18674-3:2017)

ISO 18674-3 applies to the measurement of displacements across a measuring line by means
of inclinometers carried out for geotechnical monitoring.
ISO 18674-3 also refers to deflectometers (see Annex B) to supplement inclinometers for the
determination of horizontal displacements across horizontal measuring lines.

Geotechnische Erkundung und Untersuchung - Geotechnische Messungen - Teil 3: Verschiebungsmessungen senkrecht zu einer Linie mit Inklinometern (ISO 18674-3:2017)

Dieses Dokument legt geotechnische Verschiebungsmessungen senkrecht zu einer Messlinie mit Hilfe eines Inklinometers fest. Allgemeine Regeln für die Überwachung des Verhaltens des Baugrunds, von Bauwerken, die mit dem Baugrund in Wechselwirkung stehen, von Auffüllungen und von geotechnischen Anlagen sind in ISO 18674-1 festgelegt.
Dieses Dokument bezieht sich auch auf Deflektometer (siehe Anhang B), um Inklinometer für die Bestimmung von horizontalen Verschiebungen senkrecht zu horizontalen Messlinien zu ergänzen.
ANMERKUNG   Im Allgemeinen gibt es zwei unabhängige Verschiebungskomponenten, die senkrecht zu Messlinien wirken. Inklinometer ermöglichen die Bestimmung zweier Komponenten für vertikale Messlinien. Bei horizontalen Linien sind Inklinometer lediglich auf die Bestimmung der vertikalen Komponente beschränkt.
Wenn es zusammen mit ISO 18674 2 angewendet wird, ermöglicht dieses Dokument die Bestimmung von Verschiebungen, unabhängig davon, in welche Richtung sie wirken.
Dieses Dokument gilt für:
—   die Prüfung geotechnischer Ausführungsvorschläge im Zusammenhang mit der Beobachtungsmethode;
—   die Überwachung von geotechnischen Anlagen vor, während und nach dem Bau (z. B. von natürlichen Böschungen, Böschungseinschnitten, Aufschüttungen, Baugrubenwänden, Gründungen, Dämmen, Mülldeponien, Tunneln);
—   die Ableitung geotechnischer Schlüsselparameter (z. B. von Ergebnissen von Pfahlprobebelastungen oder Probestollen);
—   Identifikation und Beobachtung von aktiven Scherebenen im Baugrund.
ANMERKUNG   Dieses Dokument erfüllt die Anforderungen an die Überwachung des Verhaltens des Baugrunds, von Bauwerken, die mit dem Baugrund in Wechselwirkung stehen, sowie von geotechnischen Anlagen mit Hilfe eines Inklinometers als Teil der geotechnischen Erkundung und Untersuchung in Übereinstimmung mit den Literaturhinweisen [1] und [2].

Reconnaissance et essais géotechniques - Surveillance géotechnique par instrumentation in situ - Partie 3: Mesurages des déplacements perpendiculairement à une ligne par inclinomètre (ISO 18674-3:2017)

Ce document spécifie la mesure des déplacements perpendiculairement à une ligne au moyen d'inclinomètres réalisés dans un but de surveillance géotechnique. Les règles générales de surveillance des performances du terrain, des structures en interaction avec le terrain, des remblais géotechniques et des travaux géotechniques sont présentées dans l'ISO 18674‑1.
Ce document fait également référence aux déflectomètres (voir l'Annexe B) en complément des inclinomètres pour la détermination des déplacements horizontaux perpendiculairement aux lignes de mesures horizontales.
NOTE       En général, deux composantes de déplacement indépendantes agissent perpendiculairement aux lignes de mesures. Dans le cas des lignes de mesures verticales, les inclinomètres permettent de déterminer ces deux composantes. Pour les lignes horizontales, les inclinomètres sont limités à la détermination de la seule composante verticale.
Si elle est appliquée conjointement à la norme ISO 18674‑2 cette norme permet de déterminer les déplacements agissant dans toutes les directions.
Ce document s'applique:
—          au contrôle des calculs géotechniques en lien avec la méthode observationnelle;
—          à la surveillance des structures géotechniques avant, pendant et après une phase de construction (p. ex. pentes naturelles, déblais, remblais, parois d'excavation, fondations, barrages, terrils, tunnels);
—          à l'obtention des principaux paramètres géotechniques (p.ex. à partir des résultats des essais de chargement de pieu ou des essais de creusement de tunnel);
—          à l'identification et à la surveillance des plans de cisaillement actifs du terrain.
NOTE       Le présent document satisfait aux exigences relatives à la surveillance des performances du terrain, des structures en interaction avec le terrain et des ouvrages géotechniques au moyen d'inclinomètres dans le cadre des études et essais géotechniques conformément aux Références [1] et [2].

Geotehnično preiskovanje in preskušanje - Geotehnične meritve - 3. del: Meritve pomikov pravokotno na merilno os z inklinometri (ISO 18674-3:2017)

Standard ISO 18674-3 se uporablja za merjenje pomikov pravokotno na merilno os z inklinometri za namene geotehničnih meritev. Standard ISO 18674-3 se nanaša tudi na deflektometre (glej dodatek B) za podporo inklinometrov za določanje vodoravnih pomikov pravokotno na merilne osi.

General Information

• Status: Published
• Public Enquiry End Date: 29-Jul-2016
• Publication Date: 14-Feb-2018
• ICS: 17.020 - Metrology and measurement in general
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: KON.007 - Geotechnics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-Dec-2017
• Due Date: 23-Feb-2018
• Completion Date: 15-Feb-2018
• Ref Project: EN ISO 18674-3:2017 - Geotechnical investigation and testing - Geotechnical monitoring by field instrumentation - Part 3: Measurement of displacements across a line: Inclinometers (ISO 18674-3:2017)

Relations

• Amended By: SIST EN ISO 18674-3:2018/A1:2020 - Geotechnical investigation and testing - Geotechnical monitoring by field instrumentation - Part 3: Measurement of displacements across a line: Inclinometers - Amendment 1 (ISO 18674-3:2017/Amd 1:2020)
• Effective Date: 01-Jul-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 18674-3:2018
01-marec-2018
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH*HRWHKQLþQHPHULWYHGHO0HULWYH
SRPLNRYSUDYRNRWQRQDPHULOQRRV]LQNOLQRPHWUL,62
Geotechnical investigation and testing - Geotechnical monitoring by field instrumentation
- Part 3: Measurement of displacements across a line: Inclinometers (ISO 18674-3:2017)
Geotechnische Erkundung und Untersuchung - Geotechnische Messungen - Teil 3:
Verschiebungsmessungen senkrecht zu einer Linie mit Inklinometern (ISO 18674-
3:2017)
Reconnaissance et essais géotechniques - Surveillance géotechnique par
instrumentation in situ - Partie 3: Mesurages des déplacements perpendiculairement à
une ligne par inclinomètre (ISO 18674-3:2017)
Ta slovenski standard je istoveten z: EN ISO 18674-3:2017
ICS:
17.020 Meroslovje in merjenje na Metrology and measurement
splošno in general
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 18674-3:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 18674-3:2018

---------------------- Page: 2 ----------------------

SIST EN ISO 18674-3:2018


EN ISO 18674-3
EUROPEAN STANDARD

NORME EUROPÉENNE

December 2017
EUROPÄISCHE NORM
ICS 13.080.20; 93.020
English Version

Geotechnical investigation and testing - Geotechnical
monitoring by field instrumentation - Part 3: Measurement
of displacements across a line: Inclinometers (ISO 18674-
3:2017)
Reconnaissance et essais géotechniques - Surveillance Geotechnische Erkundung und Untersuchung -
géotechnique par instrumentation in situ - Partie 3: Geotechnische Messungen - Teil 3:
Mesurages des déplacements perpendiculairement à Verschiebungsmessungen senkrecht zu einer Linie mit
une ligne par inclinomètre (ISO 18674-3:2017) Inklinometern (ISO 18674-3:2017)
This European Standard was approved by CEN on 3 September 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: Rue de la Science 23, B-1040 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18674-3:2017 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------

SIST EN ISO 18674-3:2018
EN ISO 18674-3:2017 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------

SIST EN ISO 18674-3:2018
EN ISO 18674-3:2017 (E)
European foreword
This document (EN ISO 18674-3:2017) 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 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 June 2018, and conflicting national standards shall be
withdrawn at the latest by June 2018.
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.
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 18674-3:2017 has been approved by CEN as EN ISO 18674-3:2017 without any
modification.

3

---------------------- Page: 5 ----------------------

SIST EN ISO 18674-3:2018

---------------------- Page: 6 ----------------------

SIST EN ISO 18674-3:2018
INTERNATIONAL ISO
STANDARD 18674-3
First edition
2017-10
Geotechnical investigation and
testing — Geotechnical monitoring by
field instrumentation —
Part 3:
Measurement of displacements across
a line: Inclinometers
Reconnaissance et essais géotechniques — Surveillance géotechnique
par instrumentation in situ —
Partie 3: Mesurages des déplacements perpendiculairement à une
ligne par inclinomètre
Reference number
ISO 18674-3:2017(E)
©
ISO 2017

---------------------- Page: 7 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(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. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 8 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 3
5 Instruments . 4
5.1 General . 4
5.2 Probe inclinometers . 5
5.3 In-place inclinometers . 6
5.4 Inclinometer casing. 8
5.5 Measuring range, accuracy and repeatability . 9
6 Installation and measuring procedure . 9
6.1 General . 9
6.2 Installation of guide tubes at accessible surfaces and in concrete . 9
6.3 Installation of guide tubes in boreholes .10
6.3.1 Drilling of boreholes .10
6.3.2 Installation of guide tubes .10
6.3.3 Securing borehole measuring locations .12
6.4 Installation of in-place inclinometers .12
6.5 Carrying out the measurement .13
6.5.1 Instrumentation check and calibration .13
6.5.2 Measurement .13
7 Data processing and evaluation .14
8 Reporting .15
8.1 Installation report .15
8.2 Monitoring report .15
Annex A (normative) Measuring and evaluation procedure .16
Annex B (normative) Deflectometers .20
Annex C (informative) Backfill materials.24
Annex D (informative) Geo-engineering applications .26
Annex E (informative) Measuring examples .27
Bibliography .38
© ISO 2017 – All rights reserved iii

---------------------- Page: 9 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(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: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 182, Geotechnics.
A list of all parts in the ISO 18674 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

---------------------- Page: 10 ----------------------

SIST EN ISO 18674-3:2018
INTERNATIONAL STANDARD ISO 18674-3:2017(E)
Geotechnical investigation and testing — Geotechnical
monitoring by field instrumentation —
Part 3:
Measurement of displacements across a line:
Inclinometers
1 Scope
This document specifies the measurement of displacements across a line by means of inclinometers
carried out for geotechnical monitoring. General rules of performance monitoring of the ground, of
structures interacting with the ground, of geotechnical fills and of geotechnical works are presented in
ISO 18674-1.
This document also refers to deflectometers (see Annex B) to supplement inclinometers for the
determination of horizontal displacements across horizontal measuring lines.
NOTE In general, there are two independent displacement components acting across measuring lines.
Inclinometers allow the determination of the two components for vertical measuring lines. For horizontal lines,
inclinometers are limited to the determination of the vertical component only.
If applied in conjunction with ISO 18674-2, this document allows the determination of displacements
acting in any direction.
This document is applicable to:
— checking geotechnical designs in connection with the Observational Design procedure;
— monitoring of geotechnical structures prior to, during and after construction (e.g. natural slopes,
slope cuts, embankments, excavation walls, foundations, dams, refuse dumps, tunnels);
— deriving geotechnical key parameters (e.g. from results of pile load tests or trial tunnelling);
— identification and monitoring of active shear planes in the ground.
NOTE This document fulfils the requirements for the performance monitoring of the ground, of structures
interacting with the ground and of geotechnical works by the means of inclinometers as part of the geotechnical
investigation and testing in accordance with References [1] and [2].
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 18674-1:2015, Geotechnical investigation and testing — Geotechnical monitoring by field
instrumentation — Part 1: General rules
ISO 18674-2:2016, Geotechnical investigation and testing — Geotechnical monitoring by field
instrumentation — Part 2: Measurement of displacements along a line: Extensometers
ISO 22475-1:2006, Geotechnical investigation and testing — Sampling methods and groundwater
measurements — Part 1: Technical principles for execution
© ISO 2017 – All rights reserved 1

---------------------- Page: 11 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18674-1 and ISO 18674-2 and
the following 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
inclinometer
system for monitoring displacements across a measuring line by means of inclination measurements in
the field
Note 1 to entry: The system essentially consists of an instrument with one or more tilt sensors (3.2), a guide tube,
a means to measure the position of the instrument in the guide tube and a read-out device.
Note 2 to entry: Data from inclinometers require evaluation, which can be done using proprietary software or
spreadsheets.
3.2
tilt sensor
gravity-activated electric sensor for inclination measurements
3.3
probe inclinometer
system comprising a probe with one or more built-in tilt sensors (3.2) for step-by-step measurements of
the inclination on a measuring line
Note 1 to entry: Also known as a traversing inclinometer.
Note 2 to entry: Vertical probe inclinometers measure displacements in horizontal directions.
Note 3 to entry: Horizontal probe inclinometers measure displacements in vertical directions (settlements
or heave).
Note 4 to entry: An alternative to horizontal probe inclinometers is a hydrostatic probe system.
Note 5 to entry: See also Reference [3].
3.4
in-place inclinometer
IPI
inclinometer system comprising a single element, or a series of elements, with one or more built-in tilt
sensors (3.2) in each element, for measurement of the inclination at specific locations on a measuring
line without removing the instrument
Note 1 to entry: In-place inclinometers exist which can measure at all inclinations, but when in near-horizontal
position, deflections from the azimuth cannot be measured.
3.5
uniaxial inclinometer
system for inclination measurements in a single plane
Note 1 to entry: Common for horizontal measuring lines.
3.6
biaxial inclinometer
system for inclination measurements in two planes 90° to each other
Note 1 to entry: Common for vertical measuring lines.
2 © ISO 2017 – All rights reserved

---------------------- Page: 12 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

3.7
inclinometer casing
guide tube appropriate to the inclinometer system being used
Note 1 to entry: Commonly, the inner side of inclinometer casings have four longitudinal keyways. Commercially
available casings differ with regard to material, dimension, type of coupling, number of keyways etc. (see 5.4).
Note 2 to entry: The corners of casings with square section can be considered as keyways.
3.8
gauge length
L
distance between adjacent contact points of the instrument
Note 1 to entry: For probe inclinometers (3.3), L is commonly 0,5 m or 1,0 m.
3.9
base length
distance between adjacent measuring points used in the evaluation procedure
Note 1 to entry: For probe inclinometers (3.3), the base length is equal to the gauge length (3.8).
4 Symbols
Symbol Name Unit
A measuring plane of the probe which coincides with the plane of the guide wheels —
a lateral displacement component in Plane A m
B measuring plane of the inclinometer probe normal to Plane A —
b lateral displacement component in Plane B m
d depth, distance m
F subscript for follow-up measurement —
h height with respect to sea level m
i number of a measuring point —
L gauge length of an inclinometer or deflectometer probe m
l distance between measuring points m
n total number of measuring points along a measuring line —
R subscript for reference measurement —
t elapsed time s
t date and time of a follow-up measurement —
F
t date and time of a reference measurement —
R
u, v, w displacement component in x-, y- and z-direction, respectively m
x, y, z local coordinates of a guiding tube or borehole m
α tilt angle of the probe axis in Plane A ° (degree)
β tilt angle of the probe axis in Plane B ° (degree)
ψ angle between guide tube coordinate x and plane A of the inclinometer ° (degree)
θ, ρ auxiliary quantities ° (degree)
© ISO 2017 – All rights reserved 3

---------------------- Page: 13 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

5 Instruments
5.1 General
5.1.1 Probe and in-place inclinometers should be distinguished from each other (see Table 1 and
Figures 1, 2 and A.1).
Table 1 — Inclinometer types
Automatic data
No. Type Sub-type Principal measuring procedure
acquisition
Probe moved inside a guide tube from one
Inclinometer
Probe (see measuring point to the next (see Figures 1
1 — Vertical inclinometer Not common
5.2) and A.1). Repeated measurements within
— Horizontal inclinometer
the measuring period.
In-place inclinometer (IPI)
Instrument inserted into a guide tube and
In-place — Vertical inclinometer
2 held in measuring position throughout the Common
(see 5.3) — Horizontal inclinometer
measuring period
— Combined
NOTE A combined IPI is a series of elements in which some elements act as vertical and some act as horizontal
inclinometers.
5.1.2 Changes of tilt shall be measured by comparison of the measured values with those of the
reference measurement. Displacements of the measuring points across the measuring line shall be
deduced in accordance with Annex A.
5.1.3 The point to which the measurements are related shall be denoted the “reference point”.
5.1.4 For absolute displacement measurements, the coordinates of the reference point shall be
independently determined or assumed as fixed and verified.
NOTE If the reference point is assumed to be at the deepest measuring point, surveying of the inclinometer
head can serve as a check.
5.1.5 The sensing element shall consist of a housing with either one (uniaxial configuration) or two
(biaxial configuration) built-in tilt sensors. In the case of a biaxial configuration, the tilt sensors shall be
installed with axes perpendicular (90°) to each other.
4 © ISO 2017 – All rights reserved

---------------------- Page: 14 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

5.1.6 The installation planes of the tilt sensors shall be denoted as the instrument Planes A and B,
whereby Plane A shall coincide with the plane of the guide wheel assemblies (see 5.2.5). The planes shall
+
be durably marked onto the inclinometer housing, e.g. by the mark “A ” showing the positive A direction.
Key
1 undeformed inclinometer casing I top view of inclinometer casing
2 deformed inclinometer casing II side view
3 inclination measuring element III detail of inclinometer element in R- and F- positions
+
4 area of the ground subject to displacements A A direction
+
5 undeformed deeper ground for base fixity B B direction
6 reference point (here, the axis of the bottom wheel L gauge length
is set at the lowest measuring position)
7 depth measuring device R initial position of inclinometer casing at the reference
measurement
Δα change of inclination F position of inclinometer casing at a value change
measurement
Figure 1 — Measuring concept for inclinometers (schematic)
5.2 Probe inclinometers
5.2.1 Inclinometer probes shall be moved incrementally along the measuring line, whereby each
increment shall not exceed the gauge length L of the probe.
5.2.2 The depth measuring device shall have permanent and wear-resistant depth measuring marks.
The spacing of the marks should be equal to the gauge length L of the probe.
5.2.3 The length of the depth measuring device and the spacing between the marks shall be checked
throughout the measuring project. Changes shall be recorded.
© ISO 2017 – All rights reserved 5

---------------------- Page: 15 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

NOTE 1 Monitoring displacements by probe inclinometers requires good repeatability of the probe’s
positioning at the respective measuring points (see 6.5.2.3 and 7.4).
NOTE 2 The use of a cable gate or a suspension pulley can help to ensure good positioning.
5.2.4 Inclinometer casing shall be used as guide tubes (see 5.4).
5.2.5 The inclinometer probe shall be equipped with two spring-loaded guide wheel assemblies. The
width of the guide wheels shall fit the keyways of the inclinometer casings. The force of the springs
should ensure a central positioning of the probe in the casing, even for extended monitoring periods with
repeated measuring runs.
5.3 In-place inclinometers
5.3.1 The principal setup of in-place inclinometers should be as in Figure 2.
6 © ISO 2017 – All rights reserved

---------------------- Page: 16 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

a) IPI with wheel assembly b) IPI with wheel assembly c) IPI without wheel assembly
and continuous string of and discontinuous string of and discontinuous string of
sensors sensors sensors
Key
1 top suspension 7 gauge length, L
2 wheel assembly 8 base length
3 universal joint 9 intermediate suspension
4 guide tube 10 expanding joint or skid
5 connecting element 11 embedment material
6 sensor
Figure 2 — Principal setup and components of in-place inclinometers (IPIs)
5.3.2 It shall be ensured that the lengths of the connecting elements remain constant throughout the
measuring project (no elongation, no shrinkage).
5.3.3 For a continuous string of measuring elements [see Figure 2 a)], the flexibility of the measuring
elements shall be negligible.
NOTE This requirement applies in particular to horizontal strings (see Reference [4]).
© ISO 2017 – All rights reserved 7

---------------------- Page: 17 ----------------------

SIST EN ISO 18674-3:2018
ISO 18674-3:2017(E)

5.3.4 For a discontinuous string of measuring elements [see Figure 2 b) and c)], engineering judgement
shall be used to integrate angular changes into displacements.
5.3.5 Gauge lengths should not exceed 2 m. Within an installation, they can be varied to adjust to local
conditions.
NOTE Shorter lengths will commonly lead to better results.
5.3.6 The long-term reliability of the sensor signals should be considered. Intermittent removal of
the instrument for re-calibration should be avoided and is only permissible if especially justified and
documented.
NOTE An approach to checking the long-term reliability is to make measurements in two adjacent guide tubes;
one for the IPI and one for a probe inclinometer (“diversification”; in accordance with ISO 18674-1:2015, 5.4).
5.4 Inclinometer casing
5.4.1 The section of the casing shall be selected against the background of the specific measurement
requirements and the expected ground movements across the measuring line (see also 6.3.1.1).
5.4.2 The material of the casing shall fulfil the following requirements:
— be neutral to groundwater and other soil components;
— be durable during complete measuring period;
— be robust for installation;
— be flexible for bending.
NOTE 1 Acrylonitrile butadiene styrene (ABS) is a common inclinometer casing material.
NOTE 2 Metal casings, especially aluminium casings, can corrode, for example, by short-circuiting between
ground layers with different electric potentials or by aggressive groundwater.
5.4.3 If the inclinometer casing has internal keyways, the spiralling of the keyways shall be less than
0,25°/m. The string of casings should be assembled so that the keyways are continued over the joints.
5.4.4 When selecting the casing, the flexibility of the assembled string, including the backfill material
(see 6.3.2.5 and Annex C), should be considered with respect to the site conditions.
5.4.5 If using telescopic couplings, the design of the couplings, their telescopic travel and the method
of fixing should be such as to allow the string of casings to readily compress or extend in the direction of
the measuring line by an amount equal to the ground com
...