ISO 11277:2020
(Main)Soil quality — Determination of particle size distribution in mineral soil material — Method by sieving and sedimentation
Soil quality — Determination of particle size distribution in mineral soil material — Method by sieving and sedimentation
This document specifies a basic method of determining the particle size distribution applicable to a wide range of mineral soil materials, including the mineral fraction of organic soils. It also offers procedures to deal with the less common soils mentioned in the introduction. This document has been developed largely for use in the field of environmental science, and its use in geotechnical investigations is something for which professional advice might be required. A major objective of this document is the determination of enough size fractions to enable the construction of a reliable particle-size-distribution curve. This document does not apply to the determination of the particle size distribution of the organic components of soil, i.e. the more or less fragile, partially decomposed, remains of plants and animals. It is also realized that the chemical pre-treatments and mechanical handling stages in this document could cause disintegration of weakly cohesive particles that, from field inspection, might be regarded as primary particles, even though such primary particles could be better described as aggregates. If such disintegration is undesirable, then this document is not used for the determination of the particle size distribution of such weakly cohesive materials.
Qualité du sol — Détermination de la répartition granulométrique de la matière minérale des sols — Méthode par tamisage et sédimentation
Le présent document spécifie une méthode de base de détermination de la répartition granulométrique des matières minérales des sols, y compris la fraction minérale des sols organiques. Il propose également des modes opératoires permettant de traiter les sols particuliers cités dans l'introduction. Le présent document a été élaboré pour être largement utilisé dans le domaine de la science de l'environnement, et son utilisation dans des recherches géotechniques est un point pour lequel un avis professionnel peut se révéler nécessaire. Un objectif majeur du présent document est la détermination d'un nombre suffisant de fractions granulométriques pour permettre la construction d'une courbe de répartition granulométrique fiable. Le présent document ne s'applique pas à la détermination de la répartition granulométrique des composants organiques du sol, à savoir les restes plus ou moins fragiles, partiellement décomposés, de plantes ou d'animaux. Il est également à noter que les traitements chimiques préalables et les étapes de manipulation mécanique dans le présent document peuvent entraîner la désintégration de particules à faible cohérence qui, du point de vue d'une inspection sur le terrain, pourraient être considérées comme des particules primaires et mieux décrites en tant qu'agrégats. Si cette désintégration n'est pas souhaitable, alors le présent document n'est pas utilisé pour la détermination de la répartition granulométrique de ces matières à faible cohérence.
Kakovost tal - Določanje porazdelitve velikosti delcev v mineralnem delu tal - Metoda s sejanjem in usedanjem
General Information
Relations
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST ISO 11277:2020
01-november-2020
Nadomešča:
SIST ISO 11277:2011
Kakovost tal - Določanje porazdelitve velikosti delcev v mineralnem delu tal -
Metoda s sejanjem in usedanjem
Soil quality - Determination of particle size distribution in mineral soil material - Method
by sieving and sedimentation
Qualité du sol - Détermination de la répartition granulométrique de la matière minérale
des sols - Méthode par tamisage et sédimentation
Ta slovenski standard je istoveten z: ISO 11277:2020
ICS:
13.080.20 Fizikalne lastnosti tal Physical properties of soils
SIST ISO 11277:2020 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 11277:2020
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SIST ISO 11277:2020
INTERNATIONAL ISO
STANDARD 11277
Third edition
2020-04
Soil quality — Determination of
particle size distribution in mineral
soil material — Method by sieving and
sedimentation
Qualité du sol — Détermination de la répartition granulométrique
de la matière minérale des sols — Méthode par tamisage et
sédimentation
Reference number
ISO 11277:2020(E)
©
ISO 2020
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SIST ISO 11277:2020
ISO 11277:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST ISO 11277:2020
ISO 11277:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Field sampling . 3
7 Sample preparation . 4
8 Dry sieving (material >2 mm) . 4
8.1 General . 4
8.2 Apparatus . 4
8.3 Procedure . 5
8.4 Calculation and expression of results. 6
9 Wet sieving and sedimentation (material <2 mm) . 6
9.1 General . 6
9.2 Apparatus . 6
9.3 Reagents.15
9.4 Calibrations .16
9.4.1 Sampling pipette (see Figure 4) .16
9.4.2 Dispersing-agent correction .16
9.5 Test sample .16
9.6 Destruction of organic matter .17
9.6.1 General.17
9.6.2 Method A .18
9.6.3 Method B .18
9.7 Removal of soluble salts and gypsum.19
9.8 Removal of carbonates .19
9.9 Removal of iron oxides .20
9.10 Dispersion .20
9.11 Wet sieving at 0,063 mm .20
9.12 Sedimentation .21
9.13 Calculation of results for fractions <2 mm .22
10 Test report .23
Annex A (normative) Determination of particle size distribution of mineral soil material
that is not dried prior to analysis .24
Annex B (normative) Determination of particle size distribution of mineral soils by a
hydrometer method following destruction of organic matter .27
Annex C (informative) Precision of the method .36
Bibliography .38
© ISO 2020 – All rights reserved iii
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SIST ISO 11277:2020
ISO 11277:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3,
Chemical and physical characterization.
This third edition cancels and replaces the second edition (ISO 11277:2009), which has been technically
revised. The main changes compared to the previous edition are as follows:
— Alternative digestion methods were added;
— A practical order of preparation steps was added;
— References were updated;
— Document has been editorially revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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SIST ISO 11277:2020
ISO 11277:2020(E)
Introduction
The physical and chemical behaviour of soils is controlled in part by the amounts of mineral particles
of different sizes in the soil. The subject of this document is the quantitative measurement of such
amounts (expressed as a proportion or percentage of the total mass of the mineral soil), within stated
size classes.
The determination of particle size distribution is affected by organic matter, soluble salts, cementing
agents (like iron compounds), relatively insoluble substances such as carbonates and sulfates, or
combinations of these. Some soils change their behaviour to such a degree, upon drying, that the
particle size distribution of the dried material bears little or no relation to that of the undried material
encountered under natural conditions. This is particularly true of soils rich in organic matter, those
developed from recent volcanic deposits, some highly weathered tropical soils, and soils often described
as “cohesive” (see Reference [4]). Other soils, such as the so-called “sub-plastic” soils of Australia, show
little or no tendency to disperse under normal laboratory treatments, despite field evidence of large
clay content.
The procedures given in this document recognize these kinds of differences between soils from different
environments, and the methodology presented is designed to deal with them in a structured manner.
Such differences in soil behaviour can be very important, but awareness of them depends usually on
local knowledge. Given that the laboratory is commonly distant from the site of the field operation,
the information supplied by field teams becomes crucial to the choice of an appropriate laboratory
procedure. This choice can be made only if the laboratory is made fully aware of this background
information.
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SIST ISO 11277:2020
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SIST ISO 11277:2020
INTERNATIONAL STANDARD ISO 11277:2020(E)
Soil quality — Determination of particle size distribution
in mineral soil material — Method by sieving and
sedimentation
WARNING — Persons using this document should be familiar with usual laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests, conducted in accordance with this document,
be carried out by suitably qualified staff.
1 Scope
This document specifies a basic method of determining the particle size distribution applicable to a
wide range of mineral soil materials, including the mineral fraction of organic soils. It also offers
procedures to deal with the less common soils mentioned in the introduction. This document has been
developed largely for use in the field of environmental science, and its use in geotechnical investigations
is something for which professional advice might be required.
A major objective of this document is the determination of enough size fractions to enable the
construction of a reliable particle-size-distribution curve.
This document does not apply to the determination of the particle size distribution of the organic
components of soil, i.e. the more or less fragile, partially decomposed, remains of plants and animals.
It is also realized that the chemical pre-treatments and mechanical handling stages in this document
could cause disintegration of weakly cohesive particles that, from field inspection, might be regarded
as primary particles, even though such primary particles could be better described as aggregates. If
such disintegration is undesirable, then this document is not used for the determination of the particle
size distribution of such weakly cohesive materials.
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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes
of openings
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal plate
ISO 11265, Soil quality — Determination of the specific electrical conductivity
ISO 11464, Soil quality — Pretreatment of samples for physico-chemical analysis
3 Terms and definitions
There are no normative references in this document.
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SIST ISO 11277:2020
ISO 11277:2020(E)
4 Symbols
The following symbols are found throughout the text and, where appropriate, units and quantities
are as given below (the SI convention is followed for common units, e.g. g = gram; m = metre; mm =
millimetre; s = second, etc.).
6
Mg megagram (10 g)
5 Principle
The particle size distribution is determined by a combination of sieving and sedimentation, starting
from air-dried soil (see Reference [4]). A method for undried soil is given in Annex A. Particles not
passing a 2 mm aperture sieve are determined by dry sieving. Particles passing such a sieve, but
retained on a 0,063 mm aperture sieve, are determined by a combination of wet and dry sieving, whilst
particles passing the latter sieve are determined by sedimentation.
The pipette method is preferred. As an alternative, the hydrometer method is given in Annex B. A
combination of sieving and sedimentation enables the construction of a continuous particle-size-
distribution curve.
The key points in this procedure are summarized as a flow chart in Figure 2. This document requires
that the proportions of fractions separated by sedimentation and sieving be determined from the
masses of such fractions obtained by weighing. Other methods of determining the mass of such fractions
rely on such things as the interaction of particles with electromagnetic radiation or electrical fields
(see Reference [2]). There are often considerable difficulties in relating the values obtained by these
different methods for the same sample. It is one of the intentions of this document that close adherence
to its details should help minimize interlaboratory variation in the determination of the particle size
distribution of mineral soils. Therefore, the proportions of fractions shall be determined only by
weighing. If this is not the method used, then conformance with this document cannot be claimed in the
test report (see Clause 10).
Both the pipette and hydrometer methods assume that the settling of particles in the sedimentation
cylinder is in accordance with Stokes's Law (see References [2],[4], and [7]), and the constraints that
this implies, namely:
a) the particles are rigid, smooth spheres;
b) the particles settle in laminar flow, i.e. the Reynolds Number is less than about 0,2; this constraint
sets an upper equivalent spherical particle diameter (see below) slightly greater than 0,06 mm for
Stokesian settling under gravity (Reference [2]);
c) the suspension of particles is sufficiently dilute to ensure that no particle interferes with the
settling of any other particle;
d) there is no interaction between the particle and fluid;
e) the diameter of the suspension column is large compared to the diameter of the particle, i.e. the
fluid is of “infinite extent”;
f) the particle has reached its terminal velocity;
g) the particles are of the same relative density.
Thus, the diameter of a particle is defined in terms of the diameter of a sphere whose behaviour in
suspension matches that of the particle. This is the concept of equivalent spherical diameter. It is the
principle upon which the expression of the diameter of particles, as derived from sedimentation, is
based in this document.
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SIST ISO 11277:2020
ISO 11277:2020(E)
Stokes's Law can be written, for the purposes of this document, as in Formula (1):
2
th=−18ηρ/ ()ρ gd (1)
sw p
where
t is the settling time, in seconds, of a particle of diameter d (see below);
p
η is the dynamic viscosity of water at the test temperature (see Table B.2), in millipascals
per second;
h is the sampling depth, in centimetres;
3
ρ is the mean particle density, in megagrams per cubic metre (taken as 2,65 Mg/m ; see note);
s
ρ is the density of the liquid containing the soil suspension, in megagrams per cubic metre
w
3
(taken as 1,00 Mg/m ; see note);
2
g is the acceleration due to gravity, in centimetres per second squared (taken as 981 cm/s );
d is the equivalent spherical diameter of the particle of interest, in millimetres.
p
NOTE 1 It is realized that there are considerable differences between the densities of soil particles, but for
3
the purposes of this document it is assumed that the mean particle density is that of quartz, i.e. 2,65 Mg/m
(Reference [8]), as this is the commonest mineral in a very wide range of soils. The density of water is 0,998 2 Mg/
3 3
m and 0,995 6 Mg/m at 20 °C and 30 °C, respectively (see Reference [6]). Given the effect of the addition of
3
a small amount of dispersant (see 9.3.2), the density of water is taken as 1,000 0 Mg/m over the permitted
temperature range of this document (see 9.2.2).
Furthermore, for routine use, it is recommended that the sampling times be converted to minutes and/
or hours, as appropriate, to lessen the risk of error (see Table 3).
Particles within particular size ranges or classes are commonly described as cobbles, gravel, coarse
sand, silt, etc. The meaning of such trivial names differs between countries, and in some cases there are
no exact translations of such words from one language to another; for example, the Dutch word “zavel”
has no equivalent in English. The only fraction for which there appears to be common agreement is clay,
which is defined as material of less than 0,002 mm equivalent spherical diameter (References [4]). Such
trivial names shall not be used in describing the results of particle size determination according to this
document. Phrases such as “. passing a 20 mm aperture sieve .” or “. less than 0,063 mm equivalent
spherical diameter .” shall be used instead. If trivial names shall be used, for example, to cross-reference
to another International or National Standard, then the trivial name should be defined explicitly, so as
to remove any doubt as to the meaning intended, e.g. silt (0,063 mm to 0,002 mm equivalent spherical
diameter) (see Clause 4). Furthermore, it is common to use the word “texture” to describe the results
of particle-size-distribution measurements, e.g. “the particle size of this soil is of clay texture”. This is
incorrect as the two concepts are different, and the word “texture” shall not be used in the test report
(see Clause 10) to describe the results obtained by the use of this document.
6 Field sampling
The mass of sample taken in the field shall be representative of the particle size distribution,
especially if the amount of the larger particles is to be determined reliably. Table 1 gives recommended
minimum masses.
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SIST ISO 11277:2020
ISO 11277:2020(E)
Table 1 — Mass of soil sample to be taken for sieving
Maximum size of material forming > 10 % of the soil Minimum mass of sample to be taken for sieving
(given as test sieve aperture, in mm) kg
63 50
50 35
37,5 15
28 6
20 2
14 1
10 0,5
6,3 0,5
5 0,2
2 or smaller 0,1
7 Sample preparation
Samples shall be prepared in accordance with the methods given in ISO 11464.
NOTE For many purposes, particle size distribution is determined only for the fraction of the soil passing
a 2 mm aperture sieve. In this case, the test sample (9.5) can be taken either according to the procedures in
ISO 11464 or from the material passing a 2 mm aperture sieve according to 8.2.
8 Dry sieving (material >2 mm)
8.1 General
The procedure specified in this clause applies to material retained on a 2 mm aperture sieve. Table 2
gives the maximum mass which shall be retained on sieves of different diameters and apertures. If more
than this amount of material is retained, then it shall be subdivided appropriately and sieved again.
It is common to refer to sieves as having a particular mesh-size or mesh number. These are not the same
as the sieve aperture, and the relationship between the various numbers is not immediately obvious.
The use of mesh numbers as a measurement of particle size is difficult to justify, and shall not be used in
reporting the results of this document.
8.2 Apparatus
8.2.1 Test sieves, with apertures according to ISO 565, and with well-fitting covers and receivers.
The full range of sieves appropriate to the largest particle(s) present should be used (see Table 1 and
9.2.3). The apertures chosen shall be stated in the test report (Clause 10). The accuracy of the sieves
shall be verified monthly against a set of master sieves kept for this purpose, using an accepted
method such as particle reference materials, microscopy, etc. (see Reference [2) depending on the sieve
aperture. Tolerances shall meet the requirements of ISO 3310-1 and ISO 3310-2. Sieves that do not meet
these specifications shall be discarded. A record shall be kept of such testing.
Brass sieves are particularly liable to splitting and distortion, and steel sieves are strongly recommended
for the larger apertures.
Special care shall be taken to ensure that covers and receivers do not leak. Sieves shall be inspected
weekly when in regular use, and on every occasion if used less often. A record shall be kept of such
inspections. Round-hole sieves shall not be used.
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SIST ISO 11277:2020
ISO 11277:2020(E)
8.2.2 Balance, capable of weighing to an accuracy of within ±0,5 g.
8.2.3 Mechanical sieve shaker.
It is usually impracticable to sieve mechanically at sieve apertures much greater than 20 mm, unless
very heavy-duty equipment is available. Mechanical sieve shaking is essential to sieve efficiency at
smaller apertures.
8.2.4 A sieve brush and a stiff brush.
8.2.5 Ultrasonic bath.
8.3 Procedure
Weigh the dry test sample, prepared in accordance with ISO 11464, to the nearest 0,5 g (m ). Place the
1
weighed material on the 20 mm sieve, and by brushing the material gently over the sieve apertures with
the stiff brush (to remove any adhering soil), sieve the material. Take care not to detach any fragments
from the primary particles. Sieve the retained material on the nest of sieves of selected apertures
(8.2.1) and record the amount retained on each sieve to the nearest 0,5 g. Do not overload the sieves
(see Table 1) but sieve the material in portions if necessary.
Weigh the material passing the 20 mm aperture sieve (m ), or a suitable portion of it (m ) (see Table 2)
2 3
obtained by an appropriate subsampling method (see Clause 6), and place this on a nest of sieves, the
lowermost having an aperture of 2 mm. Shake the sieves mechanically until no further material passes
any of the sieves (see Note). Record the mass of material retained on each sieve and the mass passing
the 2 mm aperture sieve.
The total mass of the fractions should be within 1 % of m or m , as appropriate. If it is not, then check
2 3
for sieve damage and discard sieves as appropriate (see 8.2.1).
NOTE For practical purposes, it is usual to choose a standard sieve shaking time which gives an
acceptable degree of sieving efficiency with a wide range of soil materials. The minimum recommended period
is 10 min.
Table 2 — Maximum mass of material to be retained on each test sieve at the completion of
sieving
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
50 10 8,9 4,5 — —
37,5 8 7,1 3,5 — —
28 6 5,3 2,5 — —
20 4 3,6 2 — —
14 3 2,7 1,5 — —
10 2 1,8 1 — —
6,3 1,5 1,3 0,75 — —
5 1 0,9 0,5 — —
3,35 — — 0,3 0,15
2 — — 0,2 0,1
1,18 — — 0,1 0,05
0,6 — — 0,075 0,0375
© ISO 2020 – All rights reserved 5
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SIST ISO 11277:2020
ISO 11277:2020(E)
Table 2 (continued)
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
0,425 — — 0,075 0,0375
0,3 — — 0,05 0,025
0,212 — — 0,05 0,025
0,15 — — 0,04 0,02
0,063 — — 0,025 0,0125
8.4 Calculation and expression of results
For the material retained by the 20 mm and larger aperture sieves, calculate the proportion by mass
retained by each sieve as a proportion of m . For example (Formula (2)):
1
Proportionretainedonthem20 msieve= mm()20mm / (2)
[]
1
For the material passing the 20 mm sieve, multiply the mass of material p
...
INTERNATIONAL ISO
STANDARD 11277
Third edition
2020-04
Soil quality — Determination of
particle size distribution in mineral
soil material — Method by sieving and
sedimentation
Qualité du sol — Détermination de la répartition granulométrique
de la matière minérale des sols — Méthode par tamisage et
sédimentation
Reference number
ISO 11277:2020(E)
©
ISO 2020
---------------------- Page: 1 ----------------------
ISO 11277:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 11277:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Field sampling . 3
7 Sample preparation . 4
8 Dry sieving (material >2 mm) . 4
8.1 General . 4
8.2 Apparatus . 4
8.3 Procedure . 5
8.4 Calculation and expression of results. 6
9 Wet sieving and sedimentation (material <2 mm) . 6
9.1 General . 6
9.2 Apparatus . 6
9.3 Reagents.15
9.4 Calibrations .16
9.4.1 Sampling pipette (see Figure 4) .16
9.4.2 Dispersing-agent correction .16
9.5 Test sample .16
9.6 Destruction of organic matter .17
9.6.1 General.17
9.6.2 Method A .18
9.6.3 Method B .18
9.7 Removal of soluble salts and gypsum.19
9.8 Removal of carbonates .19
9.9 Removal of iron oxides .20
9.10 Dispersion .20
9.11 Wet sieving at 0,063 mm .20
9.12 Sedimentation .21
9.13 Calculation of results for fractions <2 mm .22
10 Test report .23
Annex A (normative) Determination of particle size distribution of mineral soil material
that is not dried prior to analysis .24
Annex B (normative) Determination of particle size distribution of mineral soils by a
hydrometer method following destruction of organic matter .27
Annex C (informative) Precision of the method .36
Bibliography .38
© ISO 2020 – All rights reserved iii
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ISO 11277:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3,
Chemical and physical characterization.
This third edition cancels and replaces the second edition (ISO 11277:2009), which has been technically
revised. The main changes compared to the previous edition are as follows:
— Alternative digestion methods were added;
— A practical order of preparation steps was added;
— References were updated;
— Document has been editorially revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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ISO 11277:2020(E)
Introduction
The physical and chemical behaviour of soils is controlled in part by the amounts of mineral particles
of different sizes in the soil. The subject of this document is the quantitative measurement of such
amounts (expressed as a proportion or percentage of the total mass of the mineral soil), within stated
size classes.
The determination of particle size distribution is affected by organic matter, soluble salts, cementing
agents (like iron compounds), relatively insoluble substances such as carbonates and sulfates, or
combinations of these. Some soils change their behaviour to such a degree, upon drying, that the
particle size distribution of the dried material bears little or no relation to that of the undried material
encountered under natural conditions. This is particularly true of soils rich in organic matter, those
developed from recent volcanic deposits, some highly weathered tropical soils, and soils often described
as “cohesive” (see Reference [4]). Other soils, such as the so-called “sub-plastic” soils of Australia, show
little or no tendency to disperse under normal laboratory treatments, despite field evidence of large
clay content.
The procedures given in this document recognize these kinds of differences between soils from different
environments, and the methodology presented is designed to deal with them in a structured manner.
Such differences in soil behaviour can be very important, but awareness of them depends usually on
local knowledge. Given that the laboratory is commonly distant from the site of the field operation,
the information supplied by field teams becomes crucial to the choice of an appropriate laboratory
procedure. This choice can be made only if the laboratory is made fully aware of this background
information.
© ISO 2020 – All rights reserved v
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INTERNATIONAL STANDARD ISO 11277:2020(E)
Soil quality — Determination of particle size distribution
in mineral soil material — Method by sieving and
sedimentation
WARNING — Persons using this document should be familiar with usual laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests, conducted in accordance with this document,
be carried out by suitably qualified staff.
1 Scope
This document specifies a basic method of determining the particle size distribution applicable to a
wide range of mineral soil materials, including the mineral fraction of organic soils. It also offers
procedures to deal with the less common soils mentioned in the introduction. This document has been
developed largely for use in the field of environmental science, and its use in geotechnical investigations
is something for which professional advice might be required.
A major objective of this document is the determination of enough size fractions to enable the
construction of a reliable particle-size-distribution curve.
This document does not apply to the determination of the particle size distribution of the organic
components of soil, i.e. the more or less fragile, partially decomposed, remains of plants and animals.
It is also realized that the chemical pre-treatments and mechanical handling stages in this document
could cause disintegration of weakly cohesive particles that, from field inspection, might be regarded
as primary particles, even though such primary particles could be better described as aggregates. If
such disintegration is undesirable, then this document is not used for the determination of the particle
size distribution of such weakly cohesive materials.
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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes
of openings
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal plate
ISO 11265, Soil quality — Determination of the specific electrical conductivity
ISO 11464, Soil quality — Pretreatment of samples for physico-chemical analysis
3 Terms and definitions
There are no normative references in this document.
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ISO 11277:2020(E)
4 Symbols
The following symbols are found throughout the text and, where appropriate, units and quantities
are as given below (the SI convention is followed for common units, e.g. g = gram; m = metre; mm =
millimetre; s = second, etc.).
6
Mg megagram (10 g)
5 Principle
The particle size distribution is determined by a combination of sieving and sedimentation, starting
from air-dried soil (see Reference [4]). A method for undried soil is given in Annex A. Particles not
passing a 2 mm aperture sieve are determined by dry sieving. Particles passing such a sieve, but
retained on a 0,063 mm aperture sieve, are determined by a combination of wet and dry sieving, whilst
particles passing the latter sieve are determined by sedimentation.
The pipette method is preferred. As an alternative, the hydrometer method is given in Annex B. A
combination of sieving and sedimentation enables the construction of a continuous particle-size-
distribution curve.
The key points in this procedure are summarized as a flow chart in Figure 2. This document requires
that the proportions of fractions separated by sedimentation and sieving be determined from the
masses of such fractions obtained by weighing. Other methods of determining the mass of such fractions
rely on such things as the interaction of particles with electromagnetic radiation or electrical fields
(see Reference [2]). There are often considerable difficulties in relating the values obtained by these
different methods for the same sample. It is one of the intentions of this document that close adherence
to its details should help minimize interlaboratory variation in the determination of the particle size
distribution of mineral soils. Therefore, the proportions of fractions shall be determined only by
weighing. If this is not the method used, then conformance with this document cannot be claimed in the
test report (see Clause 10).
Both the pipette and hydrometer methods assume that the settling of particles in the sedimentation
cylinder is in accordance with Stokes's Law (see References [2],[4], and [7]), and the constraints that
this implies, namely:
a) the particles are rigid, smooth spheres;
b) the particles settle in laminar flow, i.e. the Reynolds Number is less than about 0,2; this constraint
sets an upper equivalent spherical particle diameter (see below) slightly greater than 0,06 mm for
Stokesian settling under gravity (Reference [2]);
c) the suspension of particles is sufficiently dilute to ensure that no particle interferes with the
settling of any other particle;
d) there is no interaction between the particle and fluid;
e) the diameter of the suspension column is large compared to the diameter of the particle, i.e. the
fluid is of “infinite extent”;
f) the particle has reached its terminal velocity;
g) the particles are of the same relative density.
Thus, the diameter of a particle is defined in terms of the diameter of a sphere whose behaviour in
suspension matches that of the particle. This is the concept of equivalent spherical diameter. It is the
principle upon which the expression of the diameter of particles, as derived from sedimentation, is
based in this document.
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ISO 11277:2020(E)
Stokes's Law can be written, for the purposes of this document, as in Formula (1):
2
th=−18ηρ/ ()ρ gd (1)
sw p
where
t is the settling time, in seconds, of a particle of diameter d (see below);
p
η is the dynamic viscosity of water at the test temperature (see Table B.2), in millipascals
per second;
h is the sampling depth, in centimetres;
3
ρ is the mean particle density, in megagrams per cubic metre (taken as 2,65 Mg/m ; see note);
s
ρ is the density of the liquid containing the soil suspension, in megagrams per cubic metre
w
3
(taken as 1,00 Mg/m ; see note);
2
g is the acceleration due to gravity, in centimetres per second squared (taken as 981 cm/s );
d is the equivalent spherical diameter of the particle of interest, in millimetres.
p
NOTE 1 It is realized that there are considerable differences between the densities of soil particles, but for
3
the purposes of this document it is assumed that the mean particle density is that of quartz, i.e. 2,65 Mg/m
(Reference [8]), as this is the commonest mineral in a very wide range of soils. The density of water is 0,998 2 Mg/
3 3
m and 0,995 6 Mg/m at 20 °C and 30 °C, respectively (see Reference [6]). Given the effect of the addition of
3
a small amount of dispersant (see 9.3.2), the density of water is taken as 1,000 0 Mg/m over the permitted
temperature range of this document (see 9.2.2).
Furthermore, for routine use, it is recommended that the sampling times be converted to minutes and/
or hours, as appropriate, to lessen the risk of error (see Table 3).
Particles within particular size ranges or classes are commonly described as cobbles, gravel, coarse
sand, silt, etc. The meaning of such trivial names differs between countries, and in some cases there are
no exact translations of such words from one language to another; for example, the Dutch word “zavel”
has no equivalent in English. The only fraction for which there appears to be common agreement is clay,
which is defined as material of less than 0,002 mm equivalent spherical diameter (References [4]). Such
trivial names shall not be used in describing the results of particle size determination according to this
document. Phrases such as “. passing a 20 mm aperture sieve .” or “. less than 0,063 mm equivalent
spherical diameter .” shall be used instead. If trivial names shall be used, for example, to cross-reference
to another International or National Standard, then the trivial name should be defined explicitly, so as
to remove any doubt as to the meaning intended, e.g. silt (0,063 mm to 0,002 mm equivalent spherical
diameter) (see Clause 4). Furthermore, it is common to use the word “texture” to describe the results
of particle-size-distribution measurements, e.g. “the particle size of this soil is of clay texture”. This is
incorrect as the two concepts are different, and the word “texture” shall not be used in the test report
(see Clause 10) to describe the results obtained by the use of this document.
6 Field sampling
The mass of sample taken in the field shall be representative of the particle size distribution,
especially if the amount of the larger particles is to be determined reliably. Table 1 gives recommended
minimum masses.
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ISO 11277:2020(E)
Table 1 — Mass of soil sample to be taken for sieving
Maximum size of material forming > 10 % of the soil Minimum mass of sample to be taken for sieving
(given as test sieve aperture, in mm) kg
63 50
50 35
37,5 15
28 6
20 2
14 1
10 0,5
6,3 0,5
5 0,2
2 or smaller 0,1
7 Sample preparation
Samples shall be prepared in accordance with the methods given in ISO 11464.
NOTE For many purposes, particle size distribution is determined only for the fraction of the soil passing
a 2 mm aperture sieve. In this case, the test sample (9.5) can be taken either according to the procedures in
ISO 11464 or from the material passing a 2 mm aperture sieve according to 8.2.
8 Dry sieving (material >2 mm)
8.1 General
The procedure specified in this clause applies to material retained on a 2 mm aperture sieve. Table 2
gives the maximum mass which shall be retained on sieves of different diameters and apertures. If more
than this amount of material is retained, then it shall be subdivided appropriately and sieved again.
It is common to refer to sieves as having a particular mesh-size or mesh number. These are not the same
as the sieve aperture, and the relationship between the various numbers is not immediately obvious.
The use of mesh numbers as a measurement of particle size is difficult to justify, and shall not be used in
reporting the results of this document.
8.2 Apparatus
8.2.1 Test sieves, with apertures according to ISO 565, and with well-fitting covers and receivers.
The full range of sieves appropriate to the largest particle(s) present should be used (see Table 1 and
9.2.3). The apertures chosen shall be stated in the test report (Clause 10). The accuracy of the sieves
shall be verified monthly against a set of master sieves kept for this purpose, using an accepted
method such as particle reference materials, microscopy, etc. (see Reference [2) depending on the sieve
aperture. Tolerances shall meet the requirements of ISO 3310-1 and ISO 3310-2. Sieves that do not meet
these specifications shall be discarded. A record shall be kept of such testing.
Brass sieves are particularly liable to splitting and distortion, and steel sieves are strongly recommended
for the larger apertures.
Special care shall be taken to ensure that covers and receivers do not leak. Sieves shall be inspected
weekly when in regular use, and on every occasion if used less often. A record shall be kept of such
inspections. Round-hole sieves shall not be used.
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ISO 11277:2020(E)
8.2.2 Balance, capable of weighing to an accuracy of within ±0,5 g.
8.2.3 Mechanical sieve shaker.
It is usually impracticable to sieve mechanically at sieve apertures much greater than 20 mm, unless
very heavy-duty equipment is available. Mechanical sieve shaking is essential to sieve efficiency at
smaller apertures.
8.2.4 A sieve brush and a stiff brush.
8.2.5 Ultrasonic bath.
8.3 Procedure
Weigh the dry test sample, prepared in accordance with ISO 11464, to the nearest 0,5 g (m ). Place the
1
weighed material on the 20 mm sieve, and by brushing the material gently over the sieve apertures with
the stiff brush (to remove any adhering soil), sieve the material. Take care not to detach any fragments
from the primary particles. Sieve the retained material on the nest of sieves of selected apertures
(8.2.1) and record the amount retained on each sieve to the nearest 0,5 g. Do not overload the sieves
(see Table 1) but sieve the material in portions if necessary.
Weigh the material passing the 20 mm aperture sieve (m ), or a suitable portion of it (m ) (see Table 2)
2 3
obtained by an appropriate subsampling method (see Clause 6), and place this on a nest of sieves, the
lowermost having an aperture of 2 mm. Shake the sieves mechanically until no further material passes
any of the sieves (see Note). Record the mass of material retained on each sieve and the mass passing
the 2 mm aperture sieve.
The total mass of the fractions should be within 1 % of m or m , as appropriate. If it is not, then check
2 3
for sieve damage and discard sieves as appropriate (see 8.2.1).
NOTE For practical purposes, it is usual to choose a standard sieve shaking time which gives an
acceptable degree of sieving efficiency with a wide range of soil materials. The minimum recommended period
is 10 min.
Table 2 — Maximum mass of material to be retained on each test sieve at the completion of
sieving
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
50 10 8,9 4,5 — —
37,5 8 7,1 3,5 — —
28 6 5,3 2,5 — —
20 4 3,6 2 — —
14 3 2,7 1,5 — —
10 2 1,8 1 — —
6,3 1,5 1,3 0,75 — —
5 1 0,9 0,5 — —
3,35 — — 0,3 0,15
2 — — 0,2 0,1
1,18 — — 0,1 0,05
0,6 — — 0,075 0,0375
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ISO 11277:2020(E)
Table 2 (continued)
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
0,425 — — 0,075 0,0375
0,3 — — 0,05 0,025
0,212 — — 0,05 0,025
0,15 — — 0,04 0,02
0,063 — — 0,025 0,0125
8.4 Calculation and expression of results
For the material retained by the 20 mm and larger aperture sieves, calculate the proportion by mass
retained by each sieve as a proportion of m . For example (Formula (2)):
1
Proportionretainedonthem20 msieve= mm()20mm / (2)
[]
1
For the material passing the 20 mm sieve, multiply the mass of material passing each sieve by m /m
2 3
and calculate this as a proportion of m . For example (Formula (3)):
1
Proportionretainedonthem63,,msieve=mm()63mm //mm (3)
()
23 1
Present the results as a Table showing, to two significant figures, the proportion by mass retained
on each sieve and the proportion passing the 2 mm sieve. The data shall also be used to construct a
cumulative distribution curve (see Figure 1).
9 Wet sieving and sedimentation (material <2 mm)
9.1 General
This clause specifies the procedure (see Figure 2) for the determination of the particle size distribution
of the material passing the 2 mm aperture sieve down to <0,002 mm equivalent spherical diameter (see
note). In order to ensure that primary particles, rather than loosely bonded aggregates, are measured,
organic matter and salts are removed, especially sparingly soluble salts such as gypsum which would
otherwise prevent dispersion and/or promote flocculation of the finer soil particles in suspension (see
9.6), and a dispersing agent is added (9.3.2). These procedures are required in this document, and their
omission shall invalidate its application. So
...
NORME ISO
INTERNATIONALE 11277
Troisième édition
2020-04
Qualité du sol — Détermination de
la répartition granulométrique de la
matière minérale des sols — Méthode
par tamisage et sédimentation
Soil quality — Determination of particle size distribution in mineral
soil material — Method by sieving and sedimentation
Numéro de référence
ISO 11277:2020(F)
©
ISO 2020
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ISO 11277:2020(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2020
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
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Publié en Suisse
ii © ISO 2020 – Tous droits réservés
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ISO 11277:2020(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 2
4 Symboles . 2
5 Principe . 2
6 Échantillonnage sur le terrain. 4
7 Préparation des échantillons . 4
8 Tamisage à sec (matériau > 2 mm) . 4
8.1 Généralités . 4
8.2 Appareillage. 4
8.3 Mode opératoire . 5
8.4 Calcul et expression des résultats . 6
9 Tamisage humide et sédimentation (matériau < 2 mm) . 6
9.1 Généralités . 6
9.2 Appareillage. 7
9.3 Réactifs .16
9.4 Étalonnages .17
9.4.1 Pipette de prélèvement (voir Figure 4) .17
9.4.2 Correction de la masse de dispersant .17
9.5 Échantillon pour essai .17
9.6 Destruction de la matière organique .18
9.6.1 Généralités .18
9.6.2 Méthode A .19
9.6.3 Méthode B .19
9.7 Élimination des sels solubles et du gypse .20
9.8 Élimination des carbonates.21
9.9 Élimination des oxydes de fer .21
9.10 Dispersion .22
9.11 Tamisage humide à 0,063 mm .22
9.12 Sédimentation .22
9.13 Calcul des résultats pour des fractions < 2 mm .23
10 Rapport d'essai .25
Annexe A (normative) Détermination de la répartition granulométrique de la fraction
minérale des sols non séchés avant analyse .26
Annexe B (normative) Détermination de la répartition granulométrique de la fraction
minérale des sols par la méthode du densimètre après destruction de la matière
organique .29
Annexe C (informative) Fidélité de la méthode .38
Bibliographie .40
© ISO 2020 – Tous droits réservés iii
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ISO 11277:2020(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www
.iso .org/ directives).
L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de
brevets reçues par l’ISO (voir www .iso .org/ brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l'Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant : www .iso .org/ iso/ fr/ avant -propos.
Le présent document a été élaboré par le comité technique ISO/TC 190, Qualité du sol, sous-comité SC 3,
Caractérisation chimique et physique.
Cette troisième édition annule et remplace la deuxième édition (ISO 11277:2009), qui a fait l’objet d’une
révision technique. Les principales modifications par rapport à l'édition précédente sont les suivantes:
— ajout d’autres méthodes de minéralisation;
— ajout d’un ordre pratique des étapes de préparation;
— mise à jour des références;
— révision rédactionnelle du document.
Il convient que l'utilisateur adresse tout retour d'information ou toute question concernant le présent
document à l'organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www .iso .org/ fr/ members .html.
iv © ISO 2020 – Tous droits réservés
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ISO 11277:2020(F)
Introduction
Le comportement physique et chimique des sols est contrôlé en partie par les quantités de particules
minérales de différentes tailles qui s'y trouvent. L'objet du présent document est le mesurage de ces
quantités (exprimé en proportion ou en pourcentage de la masse totale du sol minéral), au sein de
classes de tailles indiquées.
La détermination de la répartition granulométrique est affectée par la matière organique, les sels
solubles, les agents de cémentation (particulièrement les oxydes de fer), les substances relativement
insolubles comme les carbonates et les sulfates, ou les combinaisons de ceux-ci. Le comportement
de certains sols change dans une telle proportion au séchage que la répartition granulométrique de
la matière sèche a peu ou pas de rapport avec celle de la matière que l'on trouve dans des conditions
naturelles. Cela est particulièrement vrai pour les sols riches en matière organique, ceux élaborés à
partir de dépôts volcaniques récents, certains sols tropicaux altérés et les sols souvent décrits comme
«à forte cohésion» (voir Référence [4]). D'autres sols, comme les sols nommés «sub-plastic» d'Australie,
montrent peu ou pas de tendance à se disperser dans le cadre de traitements normaux de laboratoire,
en dépit d'une importante teneur en argile mise en évidence sur le terrain.
Les modes opératoires indiqués dans le présent document tiennent compte des différences entre les
sols provenant d'environnements différents, et la méthodologie présentée est conçue pour les traiter
de façon structurée. Ces différences de comportement du sol peuvent être très importantes, mais leur
perception dépend généralement de la connaissance locale. Étant donné que le laboratoire est souvent
éloigné du site de prélèvement sur le terrain, les informations fournies par l'équipe sur le terrain
deviennent cruciales pour le choix d'un mode opératoire approprié de laboratoire. Ce choix ne peut être
fait que si le laboratoire est pleinement informé de ces données de base.
© ISO 2020 – Tous droits réservés v
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NORME INTERNATIONALE ISO 11277:2020(F)
Qualité du sol — Détermination de la répartition
granulométrique de la matière minérale des sols —
Méthode par tamisage et sédimentation
AVERTISSEMENT — Il convient que l’utilisateur du présent document connaisse bien les
pratiques courantes de laboratoire. Le présent document n’a pas pour but de traiter de tous les
problèmes de sécurité qui sont, le cas échéant, liés à son utilisation. Il incombe à l’utilisateur de
la présente norme d’établir des pratiques appropriées en matière d’hygiène et de sécurité et de
s’assurer de la conformité à la réglementation nationale en vigueur.
IMPORTANT — Il est indispensable que les essais menés selon le présent document soient
effectués par un personnel adéquatement qualifié.
1 Domaine d’application
Le présent document spécifie une méthode de base de détermination de la répartition granulométrique
des matières minérales des sols, y compris la fraction minérale des sols organiques. Il propose également
des modes opératoires permettant de traiter les sols particuliers cités dans l'introduction. Le présent
document a été élaboré pour être largement utilisé dans le domaine de la science de l'environnement, et
son utilisation dans des recherches géotechniques est un point pour lequel un avis professionnel peut
se révéler nécessaire.
Un objectif majeur du présent document est la détermination d'un nombre suffisant de fractions
granulométriques pour permettre la construction d'une courbe de répartition granulométrique fiable.
Le présent document ne s'applique pas à la détermination de la répartition granulométrique des
composants organiques du sol, à savoir les restes plus ou moins fragiles, partiellement décomposés, de
plantes ou d'animaux. Il est également à noter que les traitements chimiques préalables et les étapes de
manipulation mécanique dans le présent document peuvent entraîner la désintégration de particules
à faible cohérence qui, du point de vue d'une inspection sur le terrain, pourraient être considérées
comme des particules primaires et mieux décrites en tant qu'agrégats. Si cette désintégration n'est
pas souhaitable, alors le présent document n'est pas utilisé pour la détermination de la répartition
granulométrique de ces matières à faible cohérence.
2 Références normatives
Les documents suivants cités dans le texte constituent, pour tout ou partie de leur contenu, des
exigences du présent document. Pour les références datées, seule l’édition citée s’applique. Pour les
références non datées, la dernière édition du document de référence s'applique (y compris les éventuels
amendements).
ISO 565, Tamis de contrôle — Tissus métalliques, tôles métalliques perforées et feuilles électroformées —
Dimensions nominales des ouvertures
ISO 3310-1, Tamis de contrôle — Exigences techniques et vérifications — Partie 1: Tamis de contrôle en
tissus métalliques
ISO 3310-2, Tamis de contrôle — Exigences techniques et vérifications — Partie 2: Tamis de contrôle en
tôles métalliques perforées
ISO 11265, Qualité du sol — Détermination de la conductivité électrique spécifique
ISO 11464, Qualité du sol — Prétraitement des échantillons pour analyses physico-chimiques
© ISO 2020 – Tous droits réservés 1
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ISO 11277:2020(F)
3 Termes et définitions
Le présent document ne contient aucune référence normative.
4 Symboles
Les symboles qui suivent sont utilisés dans le texte et, le cas échéant, sont accompagnés des unités
et grandeurs correspondantes (les conventions du système international SI sont respectées pour les
unités courantes, par exemple g = gramme; m = mètre; mm = millimètre; s = seconde, etc.).
6
Mg mégagramme (10 g)
5 Principe
La répartition granulométrique est déterminée par une combinaison de tamisage et de sédimentation
à partir d'un sol séché à l'air (voir Référence [4]). Une méthode pour un sol non séché est donnée à
l'Annexe A. Les particules ne traversant pas un tamis à ouverture de 2 mm sont déterminées par
tamisage à sec. Les particules traversant un tel tamis, mais retenues sur un tamis à ouverture
de 0,063 mm sont déterminées par une combinaison de tamisage par voie humide et par voie sèche,
alors que les particules traversant le dernier tamis sont déterminées par sédimentation.
Le prélèvement à la pipette constitue la méthode recommandée. Une méthode au densimètre est
également donnée à l’Annexe B. La combinaison du tamisage et de la sédimentation permet l'élaboration
d'une courbe de répartition granulométrique continue.
Les points clés de ce mode opératoire sont résumés sous forme de diagramme à la Figure 2. Le présent
document exige que les proportions des fractions séparées par sédimentation et tamisage soient
déterminées à partir des masses obtenues par pesée. D'autres méthodes de détermination de la masse
des fractions reposent sur des principes tels que l'interaction des particules avec un rayonnement
électromagnétique ou des champs électriques (voir Référence [2]). Il est souvent extrêmement difficile
de corréler les valeurs obtenues par ces différentes méthodes pour un même échantillon. Un des buts
visés par le présent document est donc d'aider, par un respect strict des détails indiqués, à minimiser
la variation dans la détermination de la répartition granulométrique des sols minéraux par différents
laboratoires. Les proportions des différentes fractions ne doivent donc être déterminées que par pesage.
La conformité au présent document ne peut être revendiquée dans le rapport d'essai (voir Article 10) si
cette méthode n'est pas utilisée.
Les méthodes de la pipette et du densimètre supposent que la décantation des particules dans
le cylindre de sédimentation est conforme à la loi de Stokes (voir Références [2], [4] et [7]) avec les
contraintes que cela implique, à savoir:
a) les particules sont des sphères lisses et rigides;
b) la décantation des particules s'effectue en écoulement laminaire, c'est-à-dire un écoulement dont
le nombre de Reynolds est inférieur à 0,2. Cette contrainte fixe un diamètre sphérique équivalent
maximal de particule (voir ci-dessous) légèrement supérieur à 0,06 mm pour que la décantation se
fasse par gravité selon la loi de Stokes (Référence [2]);
c) la suspension des particules est suffisamment diluée pour garantir qu'aucune particule n'affecte la
décantation d'autres particules;
d) il n'y a pas d'interaction entre la particule et le fluide;
e) le diamètre de la colonne de suspension est grand par rapport au diamètre de la particule, c'est-à-
dire que le fluide est à étendue infinie;
f) la particule a atteint sa vitesse limite;
g) les particules ont la même densité.
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ISO 11277:2020(F)
Ainsi, le diamètre d'une particule est défini en termes de diamètre d'une sphère dont le comportement
en suspension correspond à celui de la particule. Cela correspond au concept de diamètre sphérique
équivalent. C'est le principe sur lequel se fonde, dans le présent document, l'expression du diamètre des
particules dérivant de la sédimentation.
La loi de Stokes peut, pour les besoins du présent document, être écrite comme dans la Formule (1):
2
th=−18ηρ/ ρ gd (1)
()
s wp
où
t est le temps, en secondes, de décantation d'une particule de diamètre d (voir ci-dessous);
p
η est la viscosité dynamique de l'eau à la température d'essai (voir Tableau B.2), en millipas-
cals par seconde;
h est la profondeur de prélèvement, en centimètres;
ρ est la masse volumique moyenne des particules, en mégagrammes par mètre cube (c'est-à-
s
3
dire 2,65 Mg/m , voir Note);
ρ est la masse volumique du liquide contenant la suspension de sol, en mégagrammes par
w
3
mètre cube (c'est-à-dire 1,00 Mg/m , voir Note);
g est l'accélération due à la pesanteur, en centimètres par seconde carrée (c'est-à-dire
2
981 cm/s );
d est le diamètre sphérique équivalent de la particule concernée, en millimètres.
p
NOTE 1 Il est reconnu qu'il existe des différences considérables entre les masses volumiques des particules
du sol, mais dans le cadre du présent document, il est supposé que la masse volumique moyenne des particules
3
est celle du quartz, c'est-à-dire 2,65 Mg/m (Référence [8]), car c'est le minéral le plus commun dans une très
3 3
large gamme de sols. La masse volumique de l'eau est de 0,998 2 Mg/m et de 0,995 6 Mg/m à 20 °C et 30 °C
respectivement (voir Référence [6]. Étant donné l'effet de l'ajout d'une petite quantité de dispersant (voir 9.3.2),
3
la masse volumique de l'eau est prise égale à 1,000 0 Mg/m pour la gamme de température autorisée du présent
document (9.2.2).
En outre, pour l'usage courant, il est recommandé que les temps d'échantillonnage soient convertis en
minutes et/ou heures, de manière appropriée, afin de réduire le risque d'erreur (voir Tableau 3).
Les particules appartenant à des gammes ou à des classes de tailles particulières sont généralement
décrites comme des galets, des graviers, du sable grossier, des limons, etc. La signification de ces
appellations consacrées par l'usage diffère selon les pays et dans certains cas il n'existe pas de
traduction exacte de ces mots d'une langue à l'autre; par exemple le mot néerlandais «zavel» n'a pas
d'équivalent en anglais. La seule fraction pour laquelle il semble y avoir un accord est l'argile qui est
[4]
définie comme une matière de moins de 0,002 mm de diamètre sphérique équivalent (Référence ). Ces
appellations traditionnelles ne doivent pas être utilisées pour décrire les résultats de la détermination
granulométrique conformément au présent document. Des expressions comme «. traversant un
tamis à ouverture de 20 mm .» ou «. inférieur à un diamètre sphérique équivalent de 0,063 mm .»
doivent être utilisées à la place. Si les appellations traditionnelles doivent être utilisées, par exemple en
référence croisée avec une autre Norme internationale ou nationale, il convient que le nom populaire
soit explicitement défini, de façon à éliminer tout doute sur la signification voulue, par exemple limon
(diamètre sphérique équivalent de 0,063 mm à 0,002 mm) (voir Article 4). En outre, il est courant
d'utiliser le mot «texture» pour décrire les résultats de mesurage de répartition granulométrique,
par exemple «la taille de particule de ce sol est une texture argileuse». Cela est incorrect car les deux
concepts sont différents, et le mot «texture» ne doit pas être utilisé dans le rapport d'essai (voir
Article 10) pour décrire les résultats obtenus en utilisant le présent document.
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ISO 11277:2020(F)
6 Échantillonnage sur le terrain
La masse d'échantillon prélevée sur le terrain doit être représentative de la répartition granulométrique,
particulièrement si la quantité des particules les plus volumineuses doit être déterminée de façon fiable.
Le Tableau 1 donne les masses minimales recommandées.
Tableau 1 — Masse d'échantillon de sol à prélever pour le tamisage
Dimension maximale des particules constituant Masse minimale d’échantillon à prélever pour le
plus de 10 % du sol tamisage
(donnée comme ouverture du tamis de contrôle, en mm) kg
63 50
50 35
37,5 15
28 6
20 2
14 1
10 0,5
6,3 0,5
5 0,2
2 ou moins 0,1
7 Préparation des échantillons
Les échantillons doivent être préparés conformément aux méthodes données dans l'ISO 11464.
NOTE Pour de nombreuses applications, la répartition granulométrique n'est déterminée que pour la
fraction de sol traversant un tamis de 2 mm d'ouverture de mailles. Dans ce cas, l'échantillon pour essai (9.5)
peut être prélevé conformément aux modes opératoires de l'ISO 11464 ou bien à partir de la matière traversant
un tamis de 2 mm d'ouverture de mailles conformément à 8.2.
8 Tamisage à sec (matériau > 2 mm)
8.1 Généralités
Le mode opératoire spécifié dans le présent article s'applique à la matière retenue sur un tamis de 2 mm
d'ouverture de mailles. Le Tableau 2 donne la masse maximale qui doit être retenue sur des tamis de
différents diamètres et de différentes ouvertures. Si la quantité de matériau retenue est supérieure, elle
doit être subdivisée de façon appropriée et de nouveau tamisée.
Il est courant de désigner les tamis par la taille de leur maille ou par un numéro de maillage. Ces termes
ne sont pas équivalents au terme ouverture et les rapports entre les différents numéros ne sont pas
immédiatement évidents. Il est difficile de justifier l'utilisation des numéros de maillage comme mesure
de la taille de particules et il ne faut donc pas les indiquer dans le rapport donnant les résultats du
présent document.
8.2 Appareillage
8.2.1 Tamis de contrôle, dont les ouvertures de mailles sont conformes à l'ISO 565, avec des couvercles
et des réceptacles appropriés.
Il convient d'utiliser toute la gamme des tamis correspondant à la taille maximale de particules
présentes (voir Tableau 1 et 9.2.3). Les ouvertures choisies doivent être indiquées dans le rapport d'essai
(Article 10). La précision des tamis doit être contrôlée mensuellement par rapport à un jeu de tamis
4 © ISO 2020 – Tous droits réservés
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ISO 11277:2020(F)
étalons conservés à cet effet et à l'aide d'une méthode reconnue, comme par exemple la comparaison
avec des matériaux de référence, l'analyse au microscope, etc. (voir Référence [2]) en fonction de
l'ouverture de mailles du tamis. Les tolérances doivent respecter les exigences de l'ISO 3310-1 et de
l'ISO 3310-2. Les tamis ne respectant pas ces spécifications doivent être mis au rebut. Un enregistrement
des résultats d'essai doit être conservé.
Les tamis en laiton sont particulièrement sujets aux détériorations et aux déformations. Les tamis en
acier sont vivement recommandés pour les ouvertures importantes.
On doit s'assurer que les couvercles et réceptacles ne fuient pas. Les tamis doivent être inspectés chaque
semaine lorsqu'ils sont utilisés régulièrement, et à chaque utilisation s'ils sont sollicités moins souvent.
Un enregistrement de ces inspections doit être conservé. Les tamis à trous ronds ne doivent pas être
utilisés.
8.2.2 Balance, précise à ± 0,5 g près.
8.2.3 Tamiseur mécanique
Il est généralement peu pratique de tamiser mécaniquement à des ouvertures de tamis supérieures
à 20 mm, sauf si un équipement à haute capacité est disponible. Le tamiseur de tamis mécanique est
essentiel pour tamiser efficacement à des ouvertures plus petites.
8.2.4 Brosse pour tamis et brosse à poil dur
8.2.5 Bain à ultrasons
8.3 Mode opératoire
Peser l'échantillon pour essai sec, préparé conformément à l'ISO 11464, à 0,5 g près (m ). Placer le
1
matériau pesé sur le tamis de 20 mm et, en brossant doucement la matière au-dessus des mailles du
tamis avec la brosse à poil dur (pour retirer le sol qui adhère), tamiser l'échantillon. Veiller à ne pas
détacher de fragments des particules primaires. Tamiser le refus sur une colonne de tamis d'ouvertures
choisies (8.2.1), et enregistrer la quantité retenue sur chaque tamis à 0,5 g près. Ne pas surcharger les
tamis (voir Tableau 1), mais tamiser par portions, si nécessaire.
Peser la matière traversant le tamis à ouverture de 20 mm (m ), ou une partie convenable de celle-ci
2
(m ) (voir Tableau 2) obtenue par une méthode appropriée de sous-échantillonnage (voir Article 6), et
3
la placer sur une colonne de tamis dont le
...
SLOVENSKI STANDARD
oSIST ISO 11277:2020
01-september-2020
Kakovost tal - Določevanje porazdelitve velikosti delcev v mineralnem delu tal -
Metoda s sejanjem in usedanjem
Soil quality - Determination of particle size distribution in mineral soil material - Method
by sieving and sedimentation
Qualité du sol - Détermination de la répartition granulométrique de la matière minérale
des sols - Méthode par tamisage et sédimentation
Ta slovenski standard je istoveten z: ISO 11277:2020
ICS:
13.080.20 Fizikalne lastnosti tal Physical properties of soils
oSIST ISO 11277:2020 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST ISO 11277:2020
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oSIST ISO 11277:2020
INTERNATIONAL ISO
STANDARD 11277
Third edition
2020-04
Soil quality — Determination of
particle size distribution in mineral
soil material — Method by sieving and
sedimentation
Qualité du sol — Détermination de la répartition granulométrique
de la matière minérale des sols — Méthode par tamisage et
sédimentation
Reference number
ISO 11277:2020(E)
©
ISO 2020
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oSIST ISO 11277:2020
ISO 11277:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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oSIST ISO 11277:2020
ISO 11277:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Field sampling . 3
7 Sample preparation . 4
8 Dry sieving (material >2 mm) . 4
8.1 General . 4
8.2 Apparatus . 4
8.3 Procedure . 5
8.4 Calculation and expression of results. 6
9 Wet sieving and sedimentation (material <2 mm) . 6
9.1 General . 6
9.2 Apparatus . 6
9.3 Reagents.15
9.4 Calibrations .16
9.4.1 Sampling pipette (see Figure 4) .16
9.4.2 Dispersing-agent correction .16
9.5 Test sample .16
9.6 Destruction of organic matter .17
9.6.1 General.17
9.6.2 Method A .18
9.6.3 Method B .18
9.7 Removal of soluble salts and gypsum.19
9.8 Removal of carbonates .19
9.9 Removal of iron oxides .20
9.10 Dispersion .20
9.11 Wet sieving at 0,063 mm .20
9.12 Sedimentation .21
9.13 Calculation of results for fractions <2 mm .22
10 Test report .23
Annex A (normative) Determination of particle size distribution of mineral soil material
that is not dried prior to analysis .24
Annex B (normative) Determination of particle size distribution of mineral soils by a
hydrometer method following destruction of organic matter .27
Annex C (informative) Precision of the method .36
Bibliography .38
© ISO 2020 – All rights reserved iii
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oSIST ISO 11277:2020
ISO 11277:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3,
Chemical and physical characterization.
This third edition cancels and replaces the second edition (ISO 11277:2009), which has been technically
revised. The main changes compared to the previous edition are as follows:
— Alternative digestion methods were added;
— A practical order of preparation steps was added;
— References were updated;
— Document has been editorially revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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oSIST ISO 11277:2020
ISO 11277:2020(E)
Introduction
The physical and chemical behaviour of soils is controlled in part by the amounts of mineral particles
of different sizes in the soil. The subject of this document is the quantitative measurement of such
amounts (expressed as a proportion or percentage of the total mass of the mineral soil), within stated
size classes.
The determination of particle size distribution is affected by organic matter, soluble salts, cementing
agents (like iron compounds), relatively insoluble substances such as carbonates and sulfates, or
combinations of these. Some soils change their behaviour to such a degree, upon drying, that the
particle size distribution of the dried material bears little or no relation to that of the undried material
encountered under natural conditions. This is particularly true of soils rich in organic matter, those
developed from recent volcanic deposits, some highly weathered tropical soils, and soils often described
as “cohesive” (see Reference [4]). Other soils, such as the so-called “sub-plastic” soils of Australia, show
little or no tendency to disperse under normal laboratory treatments, despite field evidence of large
clay content.
The procedures given in this document recognize these kinds of differences between soils from different
environments, and the methodology presented is designed to deal with them in a structured manner.
Such differences in soil behaviour can be very important, but awareness of them depends usually on
local knowledge. Given that the laboratory is commonly distant from the site of the field operation,
the information supplied by field teams becomes crucial to the choice of an appropriate laboratory
procedure. This choice can be made only if the laboratory is made fully aware of this background
information.
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oSIST ISO 11277:2020
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oSIST ISO 11277:2020
INTERNATIONAL STANDARD ISO 11277:2020(E)
Soil quality — Determination of particle size distribution
in mineral soil material — Method by sieving and
sedimentation
WARNING — Persons using this document should be familiar with usual laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests, conducted in accordance with this document,
be carried out by suitably qualified staff.
1 Scope
This document specifies a basic method of determining the particle size distribution applicable to a
wide range of mineral soil materials, including the mineral fraction of organic soils. It also offers
procedures to deal with the less common soils mentioned in the introduction. This document has been
developed largely for use in the field of environmental science, and its use in geotechnical investigations
is something for which professional advice might be required.
A major objective of this document is the determination of enough size fractions to enable the
construction of a reliable particle-size-distribution curve.
This document does not apply to the determination of the particle size distribution of the organic
components of soil, i.e. the more or less fragile, partially decomposed, remains of plants and animals.
It is also realized that the chemical pre-treatments and mechanical handling stages in this document
could cause disintegration of weakly cohesive particles that, from field inspection, might be regarded
as primary particles, even though such primary particles could be better described as aggregates. If
such disintegration is undesirable, then this document is not used for the determination of the particle
size distribution of such weakly cohesive materials.
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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes
of openings
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal plate
ISO 11265, Soil quality — Determination of the specific electrical conductivity
ISO 11464, Soil quality — Pretreatment of samples for physico-chemical analysis
3 Terms and definitions
There are no normative references in this document.
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oSIST ISO 11277:2020
ISO 11277:2020(E)
4 Symbols
The following symbols are found throughout the text and, where appropriate, units and quantities
are as given below (the SI convention is followed for common units, e.g. g = gram; m = metre; mm =
millimetre; s = second, etc.).
6
Mg megagram (10 g)
5 Principle
The particle size distribution is determined by a combination of sieving and sedimentation, starting
from air-dried soil (see Reference [4]). A method for undried soil is given in Annex A. Particles not
passing a 2 mm aperture sieve are determined by dry sieving. Particles passing such a sieve, but
retained on a 0,063 mm aperture sieve, are determined by a combination of wet and dry sieving, whilst
particles passing the latter sieve are determined by sedimentation.
The pipette method is preferred. As an alternative, the hydrometer method is given in Annex B. A
combination of sieving and sedimentation enables the construction of a continuous particle-size-
distribution curve.
The key points in this procedure are summarized as a flow chart in Figure 2. This document requires
that the proportions of fractions separated by sedimentation and sieving be determined from the
masses of such fractions obtained by weighing. Other methods of determining the mass of such fractions
rely on such things as the interaction of particles with electromagnetic radiation or electrical fields
(see Reference [2]). There are often considerable difficulties in relating the values obtained by these
different methods for the same sample. It is one of the intentions of this document that close adherence
to its details should help minimize interlaboratory variation in the determination of the particle size
distribution of mineral soils. Therefore, the proportions of fractions shall be determined only by
weighing. If this is not the method used, then conformance with this document cannot be claimed in the
test report (see Clause 10).
Both the pipette and hydrometer methods assume that the settling of particles in the sedimentation
cylinder is in accordance with Stokes's Law (see References [2],[4], and [7]), and the constraints that
this implies, namely:
a) the particles are rigid, smooth spheres;
b) the particles settle in laminar flow, i.e. the Reynolds Number is less than about 0,2; this constraint
sets an upper equivalent spherical particle diameter (see below) slightly greater than 0,06 mm for
Stokesian settling under gravity (Reference [2]);
c) the suspension of particles is sufficiently dilute to ensure that no particle interferes with the
settling of any other particle;
d) there is no interaction between the particle and fluid;
e) the diameter of the suspension column is large compared to the diameter of the particle, i.e. the
fluid is of “infinite extent”;
f) the particle has reached its terminal velocity;
g) the particles are of the same relative density.
Thus, the diameter of a particle is defined in terms of the diameter of a sphere whose behaviour in
suspension matches that of the particle. This is the concept of equivalent spherical diameter. It is the
principle upon which the expression of the diameter of particles, as derived from sedimentation, is
based in this document.
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oSIST ISO 11277:2020
ISO 11277:2020(E)
Stokes's Law can be written, for the purposes of this document, as in Formula (1):
2
th=−18ηρ/ ()ρ gd (1)
sw p
where
t is the settling time, in seconds, of a particle of diameter d (see below);
p
η is the dynamic viscosity of water at the test temperature (see Table B.2), in millipascals
per second;
h is the sampling depth, in centimetres;
3
ρ is the mean particle density, in megagrams per cubic metre (taken as 2,65 Mg/m ; see note);
s
ρ is the density of the liquid containing the soil suspension, in megagrams per cubic metre
w
3
(taken as 1,00 Mg/m ; see note);
2
g is the acceleration due to gravity, in centimetres per second squared (taken as 981 cm/s );
d is the equivalent spherical diameter of the particle of interest, in millimetres.
p
NOTE 1 It is realized that there are considerable differences between the densities of soil particles, but for
3
the purposes of this document it is assumed that the mean particle density is that of quartz, i.e. 2,65 Mg/m
(Reference [8]), as this is the commonest mineral in a very wide range of soils. The density of water is 0,998 2 Mg/
3 3
m and 0,995 6 Mg/m at 20 °C and 30 °C, respectively (see Reference [6]). Given the effect of the addition of
3
a small amount of dispersant (see 9.3.2), the density of water is taken as 1,000 0 Mg/m over the permitted
temperature range of this document (see 9.2.2).
Furthermore, for routine use, it is recommended that the sampling times be converted to minutes and/
or hours, as appropriate, to lessen the risk of error (see Table 3).
Particles within particular size ranges or classes are commonly described as cobbles, gravel, coarse
sand, silt, etc. The meaning of such trivial names differs between countries, and in some cases there are
no exact translations of such words from one language to another; for example, the Dutch word “zavel”
has no equivalent in English. The only fraction for which there appears to be common agreement is clay,
which is defined as material of less than 0,002 mm equivalent spherical diameter (References [4]). Such
trivial names shall not be used in describing the results of particle size determination according to this
document. Phrases such as “. passing a 20 mm aperture sieve .” or “. less than 0,063 mm equivalent
spherical diameter .” shall be used instead. If trivial names shall be used, for example, to cross-reference
to another International or National Standard, then the trivial name should be defined explicitly, so as
to remove any doubt as to the meaning intended, e.g. silt (0,063 mm to 0,002 mm equivalent spherical
diameter) (see Clause 4). Furthermore, it is common to use the word “texture” to describe the results
of particle-size-distribution measurements, e.g. “the particle size of this soil is of clay texture”. This is
incorrect as the two concepts are different, and the word “texture” shall not be used in the test report
(see Clause 10) to describe the results obtained by the use of this document.
6 Field sampling
The mass of sample taken in the field shall be representative of the particle size distribution,
especially if the amount of the larger particles is to be determined reliably. Table 1 gives recommended
minimum masses.
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ISO 11277:2020(E)
Table 1 — Mass of soil sample to be taken for sieving
Maximum size of material forming > 10 % of the soil Minimum mass of sample to be taken for sieving
(given as test sieve aperture, in mm) kg
63 50
50 35
37,5 15
28 6
20 2
14 1
10 0,5
6,3 0,5
5 0,2
2 or smaller 0,1
7 Sample preparation
Samples shall be prepared in accordance with the methods given in ISO 11464.
NOTE For many purposes, particle size distribution is determined only for the fraction of the soil passing
a 2 mm aperture sieve. In this case, the test sample (9.5) can be taken either according to the procedures in
ISO 11464 or from the material passing a 2 mm aperture sieve according to 8.2.
8 Dry sieving (material >2 mm)
8.1 General
The procedure specified in this clause applies to material retained on a 2 mm aperture sieve. Table 2
gives the maximum mass which shall be retained on sieves of different diameters and apertures. If more
than this amount of material is retained, then it shall be subdivided appropriately and sieved again.
It is common to refer to sieves as having a particular mesh-size or mesh number. These are not the same
as the sieve aperture, and the relationship between the various numbers is not immediately obvious.
The use of mesh numbers as a measurement of particle size is difficult to justify, and shall not be used in
reporting the results of this document.
8.2 Apparatus
8.2.1 Test sieves, with apertures according to ISO 565, and with well-fitting covers and receivers.
The full range of sieves appropriate to the largest particle(s) present should be used (see Table 1 and
9.2.3). The apertures chosen shall be stated in the test report (Clause 10). The accuracy of the sieves
shall be verified monthly against a set of master sieves kept for this purpose, using an accepted
method such as particle reference materials, microscopy, etc. (see Reference [2) depending on the sieve
aperture. Tolerances shall meet the requirements of ISO 3310-1 and ISO 3310-2. Sieves that do not meet
these specifications shall be discarded. A record shall be kept of such testing.
Brass sieves are particularly liable to splitting and distortion, and steel sieves are strongly recommended
for the larger apertures.
Special care shall be taken to ensure that covers and receivers do not leak. Sieves shall be inspected
weekly when in regular use, and on every occasion if used less often. A record shall be kept of such
inspections. Round-hole sieves shall not be used.
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8.2.2 Balance, capable of weighing to an accuracy of within ±0,5 g.
8.2.3 Mechanical sieve shaker.
It is usually impracticable to sieve mechanically at sieve apertures much greater than 20 mm, unless
very heavy-duty equipment is available. Mechanical sieve shaking is essential to sieve efficiency at
smaller apertures.
8.2.4 A sieve brush and a stiff brush.
8.2.5 Ultrasonic bath.
8.3 Procedure
Weigh the dry test sample, prepared in accordance with ISO 11464, to the nearest 0,5 g (m ). Place the
1
weighed material on the 20 mm sieve, and by brushing the material gently over the sieve apertures with
the stiff brush (to remove any adhering soil), sieve the material. Take care not to detach any fragments
from the primary particles. Sieve the retained material on the nest of sieves of selected apertures
(8.2.1) and record the amount retained on each sieve to the nearest 0,5 g. Do not overload the sieves
(see Table 1) but sieve the material in portions if necessary.
Weigh the material passing the 20 mm aperture sieve (m ), or a suitable portion of it (m ) (see Table 2)
2 3
obtained by an appropriate subsampling method (see Clause 6), and place this on a nest of sieves, the
lowermost having an aperture of 2 mm. Shake the sieves mechanically until no further material passes
any of the sieves (see Note). Record the mass of material retained on each sieve and the mass passing
the 2 mm aperture sieve.
The total mass of the fractions should be within 1 % of m or m , as appropriate. If it is not, then check
2 3
for sieve damage and discard sieves as appropriate (see 8.2.1).
NOTE For practical purposes, it is usual to choose a standard sieve shaking time which gives an
acceptable degree of sieving efficiency with a wide range of soil materials. The minimum recommended period
is 10 min.
Table 2 — Maximum mass of material to be retained on each test sieve at the completion of
sieving
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
50 10 8,9 4,5 — —
37,5 8 7,1 3,5 — —
28 6 5,3 2,5 — —
20 4 3,6 2 — —
14 3 2,7 1,5 — —
10 2 1,8 1 — —
6,3 1,5 1,3 0,75 — —
5 1 0,9 0,5 — —
3,35 — — 0,3 0,15
2 — — 0,2 0,1
1,18 — — 0,1 0,05
0,6 — — 0,075 0,0375
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Table 2 (continued)
Test sieve Maximum mass
aperture
kg
Sieve diameter
mm
mm 450 400 300 200 100
0,425 — — 0,075 0,0375
0,3 — — 0,05 0,025
0,212 — — 0,05 0,025
0,15 — — 0,04 0,02
0,063 — — 0,025 0,0125
8.4 Calculation and expression of results
For the material retained by the 20 mm and larger aperture sieves, calculate the proportion by mass
retained by each sieve as a proportion of m . For example (Formula (2)):
1
Proportionretainedonthem20 msieve= mm()20mm / (2)
[]
1
For the material passing the 20 mm sieve, multiply the mass of material passing each s
...
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