SIST EN ISO 14688-1:2018

SLOVENSKI STANDARD
01-april-2018
1DGRPHãþD
SIST EN ISO 14688-1:2004
SIST EN ISO 14688-1:2004/A1:2013
SIST EN ISO 14688-1:2004/AC:2008
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH3UHSR]QDYDQMHLQUD]YUãþDQMH]HPOMLQ
GHO3UHSR]QDYDQMHLQRSLVRYDQMH,62
Geotechnical investigation and testing - Identification and classification of soil - Part 1:
Identification and description (ISO 14688-1:2017)
Geotechnische Erkundung und Untersuchung - Benennung, Beschreibung und
Klassifizierung von Boden - Teil 1: Benennung und Beschreibung (ISO 14688-1:2017)
Reconnaissance et essais géotechniques - Identification et classification des sols - Partie
1: Identification et description (ISO 14688-1:2017)
Ta slovenski standard je istoveten z: EN ISO 14688-1:2018
ICS:
13.080.05 Preiskava tal na splošno Examination of soils in
general
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14688-1
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2018
EUROPÄISCHE NORM
ICS 13.080.05; 93.020 Supersedes EN ISO 14688-1:2002
English Version
Geotechnical investigation and testing - Identification and
classification of soil - Part 1: Identification and description
(ISO 14688-1:2017)
Reconnaissance et essais géotechniques - Identification Geotechnische Erkundung und Untersuchung -
et classification des sols - Partie 1: Identification et Benennung, Beschreibung und Klassifizierung von
description (ISO 14688-1:2017) Boden - Teil 1: Benennung und Beschreibung (ISO
14688-1:2017)
This European Standard was approved by CEN on 23 November 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14688-1:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 14688-1:2018) has been prepared by Technical Committee ISO/TC 182
“Geotechnics” in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and
Testing” the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2018, and conflicting national standards shall
be withdrawn at the latest by August 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14688-1:2002.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 14688-1:2017 has been approved by CEN as EN ISO 14688-1:2018 without any
modification.
INTERNATIONAL ISO
STANDARD 14688-1
Second edition
2017-12
Geotechnical investigation and
testing — Identification and
classification of soil —
Part 1:
Identification and description
Reconnaissance et essais géotechniques — Identification et
classification des sols —
Partie 1: Identification et description
Reference number
ISO 14688-1:2017(E)
©
ISO 2017
ISO 14688-1:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
Contents Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  General . 3
5  Identification of soil . 4
5.1 Mineral soil . 4
5.1.1 General. 4
5.1.2 Composite soils . 8
5.1.3 Plasticity . 9
5.1.4 Organic content in mineral soils . 9
5.2 Organic soils . 9
5.3 Carbonate soils .10
5.4 Sulfide soils .10
5.5 Volcanic soils .10
5.6 Loess .10
5.7 Glacial soils .10
5.8 Anthropogenic soil . .10
5.9 Origin of deposit .11
5.9.1 General.11
5.9.2 Depositional environment .11
5.9.3 Geological unit .11
6  Description of soil .11
6.1 Description of soil properties .11
6.1.1 Particle size distribution .11
6.1.2 Particle shape .11
6.1.3 Particle strength .12
6.1.4 Mineral composition . .12
6.1.5 Fines content .12
6.1.6 Consistency .12
6.1.7 Soil colours .13
6.1.8 Organic content .14
6.1.9 Carbonate content .14
6.1.10 Degree of decomposition of peat .14
6.2 Description of different soil types .15
6.2.1 Volcanic soils .15
6.2.2 Loess .15
6.2.3 Glacial soils .15
6.2.4 Anthropogenic soil .16
7  Description of bedding and discontinuities .16
7.1 Bedding .16
7.2 Discontinuities .17
7.3 Interbedding and mixed soils .17
8  Reporting .17
Annex A (informative) Procedures for identification of the primary fraction in mineral soils .19
Bibliography .23
ISO 14688-1:2017(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 182, Geotechnics.
This second edition cancels and replaces the first edition (ISO 14688-1:2002), which has been
technically revised. It also incorporates the Amendment ISO 14688-1:2002/Amd 1:2013.
A list of all parts in the ISO 14688 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
Introduction
This document gives details of the procedures to be followed in the identification and description of
soils. Clauses 4 and 5 provide the rules for soil identification which are used at all stages of ground
investigation and geotechnical design. Clauses 6 and 7 give details of the procedures to be followed
by those actually describing soils in the field or laboratory. This comprises the description of the soil
material in all aspects and the description of the soil mass characteristics in terms of the bedding and
discontinuities.
The level of detail in a description will depend on the characteristics of the soil, the size and quality of
the soil exposure or sample, and the needs of the particular project. The person carrying out the field
identification and description should be suitably qualified, skilled and experienced to make a correct
and appropriate description and experienced in the geological materials involved in the investigation.
Practice in soil identification and description varies from country to country, in part reflecting
significant differences in geological conditions. In addition, the quality of samples available for
description vary due to the investigation methods employed, as methods of investigation have been
developed in response to the ground conditions present.
Following identification and description, ISO 14688-2 gives the means by which soils can be classified
into groups of similar composition and geotechnical properties based on the results of field and
laboratory tests with respect to their suitability for geotechnical engineering purposes. Test results
provide a means of checking the accuracy of the field or laboratory descriptions.
INTERNATIONAL STANDARD ISO 14688-1:2017(E)
Geotechnical investigation and testing — Identification and
classification of soil —
Part 1:
Identification and description
1  Scope
This document specifies the rules for the identification and description of soils and is intended to
be read in conjunction with ISO 14688-2, which outlines the basis of classification of those material
characteristics most commonly used for soils for engineering purposes. The relevant characteristics
could vary and therefore, for particular projects or materials, more detailed subdivisions of the
descriptive and classification terms could be appropriate.
This document specifies procedures for the identification and description of soils based on a flexible
system for use by experienced persons, covering both material and mass characteristics by visual
and manual techniques. Details are given of the individual characteristics for identifying soils and the
descriptive terms in regular use, including those related to the results of hand tests carried out in the
field as part of the descriptive process.
This document is applicable to the description of soils for engineering purposes which can be those laid
by natural processes, those laid by man or comprise synthetic materials.
NOTE 1 The identification and description of rocks are covered by ISO 14689-1. Identification and description
of materials intermediate between soil and rocks are carried out using the procedures in this document,
ISO 14688-2 and ISO 14689-1 as appropriate.
NOTE 2 The identification and classification of soil for pedological purposes, as well as in the framework of
measurements for soil protection and for remediation of contaminated areas, is covered by ISO 25177.
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 14688-2, Geotechnical investigation and testing — Identification and classification of soil — Part 2:
Principles for a classification
ISO 14689-1, Geotechnical investigation and testing — Identification and classification of rock — Part 1:
Identification and description
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14688-2 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at www.iso.org/obp
— IEC Electropedia: available at www.electropedia.org
ISO 14688-1:2017(E)
3.1
anthropogenic soil
soil (3.17) placed by human activity which can be divided into those composed of reworked natural
soils and those composed of synthetic materials
3.2
carbonate soil
soil (3.17) with a significant proportion of calcium carbonate
3.3
description of soil
description of the type of material, the characteristics of the mineral (inorganic) and/or organic
constituents and any fabric, bedding or discontinuities
3.4
discontinuities
bedding planes, joints, fissures, faults and shear planes
3.5
fill
anthropogenic soil or rock materials placed with engineering control
3.6
geological structure
variation in composition including bedding and discontinuities (3.4)
3.7
grading
measure of the particle sizes of a soil (3.17) and their distribution
Note 1 to entry: See 3.13.
3.8
identification of soil
naming of a soil (3.17) on the basis of its mineral composition, grading (3.7) and/or plasticity (3.16)
and/or organic content
Note 1 to entry: The identification may include geological information, such as depositional environment,
geological age and geological formation.
3.9
loess
windblown (aeolian) sediment
3.10
made ground
reconstituted ground
anthropogenic soil (3.1) or rock materials placed without engineering control
3.11
mineral soil
soil (3.17) composed largely or entirely of mineral (inorganic) constituents
3.12
organic soil
soil (3.17) containing a high proportion of plant and/or animal organic materials and the conversion
products of those materials
Note 1 to entry: Organic soil has a very low density and usually a very high water content.
2 © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
3.13
particle size distribution
measure of the particle sizes of a soil (3.17) and their distribution
Note 1 to entry: See 3.7.
3.14
particle size fraction
size fraction
portion of a soil (3.17) defined by a range of particle sizes
3.15
plastic behaviour
propensity of fine soil (3.17) to undergo permanent deformation when kneaded by hand
Note 1 to entry: This behaviour, often referred to as the plasticity, depends on water content, mineral composition
and particle size fractions.
Note 2 to entry: Plasticity can be measured by the Atterberg limits in the laboratory (see ISO 14688-2).
3.16
plasticity
propensity to undergo permanent deformation when kneaded by hand
3.17
soil
aggregate of minerals and/or organic materials which can be disaggregated by hand in water
Note 1 to entry: The term is also applied to anthropogenic soil consisting of materials exhibiting similar behaviour
but reworked or artificially made, e.g. embankment fill, crushed rock, mine tailings.
Note 2 to entry: Soils may result from the weathering of rocks and have rock structures and/or textures, but are
of lower strength than rocks.
3.18
sulfide soil
soil (3.17) with a high iron sulfide content
3.19
till
original form of a glacigenic multi-graded material derived from ice sheets and glaciers
3.20
volcanic soil
unconsolidated pyroclastic sediment produced and formed by explosive volcanic eruption
4  General
Soils shall be identified and described in accordance with this document. The classification of soils
and the description of rocks shall be carried out in accordance with ISO 14688-2 and ISO 14689-1,
respectively.
Soils are categorized as natural soils or anthropogenic soils. Natural soils are either mineral soils
(including carbonate soils, volcanic soils, loess and till) or organic soils.
The characteristics of soils are identified in accordance with the rules given in Annex A which are
based on the particle size grading of very coarse and coarse particles, the plasticity of fine particles,
the content of organic matter (for organic soils) and the content of carbonate (for carbonate soils) all of
which play a major role in determining the engineering properties of the soil and form the basis of the
soil’s identification. The soils shall be identified in the field following the guidance given in Clause 5.
ISO 14688-1:2017(E)
This comprises decisions as to the primary soil fraction, the secondary and tertiary fractions, the
carbonate and organic contents (if present) and the origin of the deposit where possible.
NOTE Other chemical constituents such as salt, sulfate, gypsum can be described where present.
The description and identification of the soil can be reviewed subsequently, and adjusted if necessary,
by the results of grading, plasticity and/or laboratory tests to measure carbonate or organic contents.
Following identification, the description of the soil shall be made using the methods given in Clause 6
and Clause 7 to include relevant features.
The identification and description of soils shall conform to the flow chart in Figure 1.
The identification procedure for the mineral soils follows these steps:
a) categorization of soils into subcategories: very coarse soil, coarse soil and fine soil;
b) identification of primary, secondary and tertiary fractions;
c) naming of the soil according to the procedures outlined in this document;
d) identification of the origin of the deposit in terms of the depositional environment and geological age.
Mineral soils can contain some organic matter, but this organic content does not dominate the
engineering properties of the soil. Such soils are categorized as mineral soils with organic secondary
constituents.
5  Identification of soil
5.1  Mineral soil
5.1.1  General
Identification of very coarse and coarse mineral soils shall be made on the basis of the particle size
fractions. The identification of fine soil shall be made on the basis of the plasticity of the soil, despite
particle sizes also being defined for these soils. Table 1 shows the terms to be used for each size fraction,
together with the corresponding range of particle sizes.
Table 1 — Particle size fractions
Particle size fractions  Range of particle sizes
Soil group
(symbol) mm
Large boulder (lBo) >630
Very coarse soil Boulder (Bo) >200 to ≤630
Cobble (Co) >63 to ≤200
Gravel (Gr) >2,0 to ≤63
Coarse gravel (cGr) >20 to ≤63
Medium gravel (mGr) >6,3 to ≤20
Fine gravel (fGr) >2,0 to ≤6,3
Coarse soil
Sand (Sa) >0,063 to ≤2,0
Coarse sand (cSa) >0,63 to ≤2,0
Medium sand (mSa) >0,20 to ≤0,63
Fine sand (fSa) >0,063 to ≤0,20
4 © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
Table 1 (continued)
Particle size fractions  Range of particle sizes
Soil group
(symbol) mm
Silt (Si) >0,002 to ≤0,063
Coarse silt (cSi) >0,02 to ≤0,063
Fine soil  Medium silt (mSi) >0,006 3 to ≤0,02
Fine silt (fSi) >0,002 to ≤0,006 3
Clay (Cl) ≤0,002
NOTE 1 The use of one significant figure (2 mm and 6 mm) rather than two significant figures (2,0 mm and
6,3 mm) for the boundaries is also widespread. The difference is of little significance in soil identification.
NOTE 2 Particle size ranges for silt and clay are given only as a reference for the particle size of “clay particles”
and “silt particles” and not for “clay” and “silt” as fine fractions.
ISO 14688-1:2017(E)
6 © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
ANTHROPOGENIC SOIL
ORGANIC SOIL
Does the soil comprise No
Yes
reworked natural
materials?
PEAT, TOPSOIL, GYTTJA or DY
Identify and describe
Identify as PEAT, TOPSOIL, GYTTJA or DY and
Identify and describe as
proportion, condition
describe according to 5.2
natural mineral soil and
and type of materials
Identify secondary mineral soil fractions
according to 5.8 and
present according to 5.8
according to 5.1.2.3
6.2.4
and 6.2.4
Add origin of deposit according to 5.9
Describe soil colour according to 6.1.7
Describe degree of decomposition according to 6.1.10
Distinguish between:
Fill (controlled placement)
or
Add any other relevant information
Made ground/reconstituted ground
(uncontrolled placement)
Figure 1 — Flowchart for the identification and description of soils
ISO 14688-1:2017(E)
5.1.2  Composite soils
5.1.2.1  General
Basic soils comprise a single size fraction as given in Table 1. Most soils are mixtures of particles of
different sizes (see Table 1) and consist of primary, one or more secondary and tertiary size fractions.
The soil identification shall be designated by a noun giving the primary fraction (usually given in upper
case) and by one or more adjectives (given in lower case) describing proportions of the secondary and
tertiary fractions (e.g. sandy GRAVEL, CLAY gravelly).
The word order used for the fractions should be established in each country to make it clear which are
the primary, secondary and tertiary fractions.
5.1.2.2  Primary fraction
The primary fraction in terms of mass (very coarse and/or coarse soils) or plastic behaviour (fine soils)
determines the engineering properties of the soil. The identification of soils on this basis shall follow
the procedures given in Annex A.
NOTE The fines fraction (silt and/or clay) is regarded as determining the characteristics of a composite soil
if the soil sticks together when wet and remoulds as given in Figure 1.
In very coarse and coarse soils, the primary fraction shall be identified as the relevant very coarse or
coarse size fraction predominating in terms of mass, as given in 5.1.2. The identification of soils on this
basis shall follow the procedures given in A.2. The very coarse fraction should be removed from the
sample before identifying the fine and coarse fractions.
If, in coarse soils, two soil fractions are present in approximately equal proportions, an oblique shall be
placed between the relevant terms, e.g. GRAVEL/SAND.
Composite coarse soils can include a secondary fines fraction (silt and/or clay) which will affect but not
determine the engineering properties of the soil.
In fine soils, the primary fraction shall be identified on the basis of its plasticity as given in 5.1.3 and
following the procedures given in A.3. The results of these individual field tests should be reported
together with the soil description.
In fine and composite fine soils, the soil shall be identified as either “CLAY” or “SILT”, depending on the
plasticity of the fines and not on the grading. The intermediate terms of “silty CLAY” or “clayey SILT”
should be used for material that is borderline in behaviour between CLAY and SILT. The identification
of these soil types shall be based on the guidance given in A.3.9.
5.1.2.3  Secondary fractions
Secondary fractions modify the engineering properties of the primary soil fraction.
The proportions of the secondary coarse fraction are assessed by mass of different size fractions and
the term “slightly” or “very” can precede the qualifying term. If the secondary fraction is fine, it shall be
identified as “clayey” or “silty” on the basis of its plasticity according to 5.1.3.
The secondary fractions as adjectives shall be placed with the term describing the primary fraction in
the order of increasing proportion when there are two coarse soil secondary features, or coarse and
then fine if one of each, as shown in the following examples:
— sandy GRAVEL;
— coarse sandy fine GRAVEL;
— medium sandy SILT;
— fine gravelly silty coarse SAND;
8 © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
— very silty fine SAND;
— fine gravelly, coarse sandy SILT;
— slightly medium sandy CLAY.
NOTE The sequence of terms to describe the components is optional (e.g. “gravelly SAND” or “SAND,
gravelly”).
The presence of interbedded soils at any scale shall be recorded (see 7.3).
5.1.2.4  Tertiary fractions
Tertiary constituents in a soil shall be described when they are important in assisting in the
identification of the origin of the soil and thus indirectly its possible characteristics. However, they do
not affect the engineering behaviour of the soil. Examples of important tertiary constituents include
shell fragments, glauconite grains, iron sulfides, plant remains and rootlets, and calcareous or other
concretions.
5.1.3  Plasticity
Plasticity of the fines of fine soils, or of coarse soils with a fine secondary fraction, shall be assessed in
the field with the use of a series of visual/manual tests given in A.3.1 to A.3.9.
5.1.4  Organic content in mineral soils
The organic content of soils has a significant effect on their geotechnical properties. Even small
quantities of dispersed organic matter in mineral soil can affect the properties and produce a distinctive
odour and colours. The intensity of odour and colour indicates the proportion of organic matter and
shall be described as given in 6.1.8. The colour change may be described and correlated with the organic
content.
5.2  Organic soils
The identification of soils rich in organic matter is summarized in Table 2. Peats accumulate in situ
in a mire, are generally of low density and have a distinctive odour. The description of the degree of
decomposition of peat shall be made as given in 6.1.10. Humus accumulates in situ as the topsoil or
surface layer. Gyttja and dy are sediments deposited through water.
In the case of organic soils with secondary mineral constituents, these shall be described as given in
5.1.2.3, e.g. fine sandy PEAT, identifying whether the mineral constituent is disseminated throughout or
occurring as discrete inclusions.
Table 2 — Identification of organic soils
Term Type Description
Fibrous Fibrous structure, easily recognizable plant structure, retains some strength
PEAT Pseudo-fibrous Mixture of fibres and amorphous paste
Amorphous No visible plant structure, mushy consistency
TOPSOIL
Plant remains, living organisms and their excretions together with inorganic
OR
constituents
HUMUS
Sediment formed in nutrient-rich water and mainly consisting of more or less
GYTTJA
decomposed remains of plants and animals (detritus)
Sediment formed in nutrient-poor water and mainly consisting of precipitated
DY
colloidal humic substances (dy matter)
NOTE Gyttja can be an organic soil or as a secondary constituent in, for example, a “very organic clay”.
ISO 14688-1:2017(E)
5.3  Carbonate soils
Soils with a significant proportion of calcium carbonate occur extensively in and around coastal areas,
both onshore and offshore. Many carbonate soils are pale in colour and range from very loose or very
soft, fine grained materials to coarse fragments of shell and coral with varying degrees of cementation.
They are usually marine deposits but may be freshwater or aeolian deposits. The soils shall be described
as given in 5.1 with additional information of their carbonate content (see 6.1.9).
5.4  Sulfide soils
Sulfide soils have a black or greyish black colour. The organic content varies, but is usually low. Sulfide
soils have been formed in a stagnant (reducing) environment. Sulfide soils have a distinct odour and
readily oxidize.
5.5 Volcanic soils
Volcanic soils consist of particles of volcanic and other origin (for example, from the host rock). Volcanic
particles are glassy or vesicular and so the density of volcanic soils can be relatively low. The soil
possesses a characteristic colour depending on the property of their host magma or rock.
Volcanic soil shall be described as given in 5.1 taking into account the diagnostic features and particle
sizes of volcanic particles.
5.6 Loess
Loess is typically homogenous, structureless, and composed of 50 % to 90 % silt particles with
secondary sand and/or clay. After drying, these deposits are highly susceptible to wind erosion, which
causes winnowing of the silt, transportation and redeposition. The small range of grain sizes and mode
of deposition tend to give rise to an open, potentially collapsible structure when wetted or loaded, and
these soils are of low density. Loessic soils shall be described as given in 5.1.
5.7 Glacial soils
Soils associated with glaciation are deposited in a range of environments, including glacial, fluvio-glacial
and lacustrine, and can be coarse or fine grained. A commonly occurring example is till, sometimes
referred to as a diamicton, comprising a wide range of grain sizes. The mode of deposition tends to give
rise to a well-packed structure, and these soils are generally of high density. Due to the composition and
origin, tills are often stiffer than post-glacially deposited soils. Till soils shall be described as given in 5.1.
5.8  Anthropogenic soil
The identification of an anthropogenic soil might rely on information about its origin, the soil fabric
and/or the presence of artefacts as primary, secondary or tertiary constituents; these should be clearly
identified in the description.
Anthropogenic soils shall be described as given in 5.1 with special attention given to the description
of fabric and artefacts. Examples of anthropogenic constituents can include plastic, paper, metal, glass,
brick, tile or slag. In anthropogenic soils, a distinction should be made, if possible, between material
placed with engineering control (fill) or without engineering control (made ground or reconstituted
ground). Engineering control in this context is placement in regular thin layers followed by some degree
of compaction.
10 © ISO 2017 – All rights reserved

ISO 14688-1:2017(E)
5.9  Origin of deposit
5.9.1  General
The lithostratigraphical or stratigraphical name of the geological unit, if possible, should be given as
required by the project.
The geological unit is usually recorded after the identification of the soil, in parenthesis, with capitals.
This also indicates some properties and mineral composition before test results become available.
5.9.2  Depositional environment
The depositional environment should be given as accurately as possible. Knowledge of the depositional
environment often provides useful information about the soil strata and in the interpolation between
the boreholes. The grain size, the grading, colour, sedimentary structures, content of fossils and
diagnostic minerals are all important observations in determining the depositional environment.
Knowledge of the general geology and stratigraphy gives a useful overview of the relevant depositional
environment. The fossils or microfossils present can give important information about the depositional
environment
5.9.3  Geological unit
In order to place a soil type stratigraphically and to understand the general geology, the geological
unit as identified by mapping should be given, if possible. Knowledge of the geological unit can provide
important information about the geotechnical properties, e.g. stiffness and density. This is particularly
useful in areas which have repeatedly been glaciated or tectonised. If there is a specific requirement for
a more refined unit name, as required by the project, then experts might be appointed to carry out this
determination, for instance, by microfloral or microfaunal analysis or thermoluminescence.
6  Description of soil
6.1  Description of soil properties
6.1.1  Particle size distribution
To assess the grading, the soil sample should be spread out such as on a flat surface or on the palm
of the hand. The particle sizes and their proportions shall be described, noting in particular any gaps
between the fractions present. The particle sizes of the sample should be compared with those of a
grading standard comprising sections containing material of different particle size ranges according to
Table 1.
As the individual particles of silt and clay are not visible to the naked eye, the methods given in Annex A
should be used in determining the characteristics of such soil.
NOTE The minimum size of soil sample required for accurate identification increases with maximum
particle size and is difficult to achieve in practice when there are very coarse fractions present.
6.1.2  Particle shape
In the case of gravel, cobbles and boulders, the particle shape should be described by reference to the
angularity of the particles (which indicates the degree of rounding at edges and corners), their general
form and their surface characteristics. Terms to be used for these aspects are given in Table 3. It is
usual practice to estimate the modal angularity or roundness using a standard set of charts.
ISO 14688-1:2017(E)
Table 3 — Terms for the designation of particle shape
Parameter Particle shape
Very angular
Angular
Subangular
Angularity/roundness
Subrounded
Rounded
Well rounded
Cubic
Form Flat
Elongate
Rough
Surface texture
Smooth
6.1.3  Particle strength
Where possible, the strength of very coarse particles should be described in accordance with
ISO 14689-1.
6.1.4  Mineral composition
The mineral composition of the individual particles of a soil should be identified according to geological
science. Where relevant, the names of the minerals present, together with any coatings, should be
included in the description of the soil. When making a field examination o
...