EN ISO 19901-8:2015

SLOVENSKI STANDARD
01-november-2015
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Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 8: Marine soil investigations (ISO 19901-8:2014)
Erdöl- und Erdgasindustrie - Spezielle Anforderungen für Offshore-Anlagen - Teil 8:
Meeresbodenuntersuchungen (ISO 19901-8:2014)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 8: Investigations des sols en mer (ISO 19901-8:2014)
Ta slovenski standard je istoveten z: EN ISO 19901-8:2015
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 19901-8
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2015
ICS 75.180.10
English Version
Petroleum and natural gas industries - Specific requirements for
offshore structures - Part 8: Marine soil investigations (ISO
19901-8:2014)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Spezielle Anforderungen für
spécifiques relatives aux structures en mer - Partie 8: Offshore-Anlagen - Teil 8: Meeresbodenuntersuchungen
Investigations des sols en mer (ISO 19901-8:2014) (ISO 19901-8:2014)
This European Standard was approved by CEN on 26 August 2015.

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, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-8:2015 E
worldwide for CEN national Members.

Contents Page
Foreword .3
Foreword
The text of ISO 19901-8:2014 has been prepared by Technical Committee ISO/TC 67 “Materials, equipment
and offshore structures for petroleum, petrochemical and natural gas industries” of the International
Organization for Standardization (ISO) and has been taken over as EN ISO 19901-8:2015 by Technical
Committee CEN/TC 12 “Materials, equipment and offshore structures for petroleum, petrochemical and
natural gas industries” the secretariat of which is held by AFNOR.
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 March 2016, and conflicting national standards shall be withdrawn at
the latest by March 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 19901-8:2014 has been approved by CEN as EN ISO 19901-8:2015 without any modification.

INTERNATIONAL ISO
STANDARD 19901-8
First edition
2014-12-01
Petroleum and natural gas
industries — Specific requirements
for offshore structures —
Part 8:
Marine soil investigations
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 8: Investigations des sols en mer
Reference number
ISO 19901-8:2014(E)
©
ISO 2014
ISO 19901-8:2014(E)
© ISO 2014
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
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
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Published in Switzerland
ii © ISO 2014 – All rights reserved

ISO 19901-8:2014(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 2
4 Symbols, units and abbreviated terms . 6
4.1 Symbols . 6
4.2 Units . 7
4.3 Abbreviated terms . 7
5  Objecti  ves, planning and requirements . 9
5.1 Objectives. 9
5.2 Planning . 9
5.3 Scope of work .12
5.4 Health, safety and environmental (HSE) requirements for marine operations . .13
5.5 Other requirements .14
6  Deployment of investigation equipment .15
6.1 Deployment modes .15
6.2 Accuracy of vertical depth measurements .17
6.3 Positioning requirements .18
6.4 Interaction of investigation equipment with the seafloor .18
7 Drilling and logging .19
7.1 General .19
7.2 Project-specific drilling requirements .19
7.3 Drilling objectives and selection of drilling equipment and procedures .20
7.4 Drilling operations plan .20
7.5 Recording of drilling parameters .20
7.6 Borehole geophysical logging .21
8 In situ testing .21
8.1 General .21
8.2 General requirements for the documentation of in situ tests .22
8.3 Cone penetration test (CPT/CPTU) .22
8.4 Pore pressure dissipation test (PPDT) .26
8.5 Ball and T-bar penetration tests .28
8.6 Seismic cone penetration test (SCPT/SCPTU) .33
8.7 Field vane test (FVT) .34
8.8 Other in situ tests .38
9 Sampling .39
9.1 General .39
9.2 Purpose of sampling .39
9.3 Sampling systems .40
9.4 Selection of samplers .40
9.5 Sample recovery considerations .42
9.6 Handling, transport and storage of samples .43
10 Laboratory testing .44
10.1 General .44
10.2 Presentation of laboratory test results .46
10.3 Instrumentation, calibration and data acquisition .47
10.4 Preparation of soil specimens for testing .47
10.5 E valuation of intact sample quality .49
ISO 19901-8:2014(E)
11 Reporting .50
11.1 Definition of reporting requirements .50
11.2 Presentation of field operations and measured and derived geotechnical parameters .50
11.3 Data interpretation and evaluation of representative geotechnical parameters .51
Annex A (informative) Objectives, planning and requirements.53
Annex B (informative) Deployment of investigation equipment .59
Annex C (informative) Drilling and logging .67
Annex D (informative) In situ testing .75
Annex E (informative) Sampling .81
Annex F (informative) Laboratory testing .91
Annex G (informative) Reporting .127
Bibliography .132
iv © ISO 2014 – All rights reserved

ISO 19901-8:2014(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, SC 7, Offshore structures.
ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries —
Specific requirements for offshore structures:
— Part 1: Metocean design and operating considerations
— Part 2: Seismic design procedures and criteria
— Part 3: Topsides structure
— Part 4: Geotechnical and foundation design considerations
— Part 5: Weight control during engineering and construction
— Part 6: Marine operations
— Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
— Part 8: Marine soil investigations
ISO 19901-8:2014(E)
Introduction
The series of International Standards applicable to offshore structures, ISO 19900 to ISO 19906,
constitutes a common basis covering those aspects that address design requirements and assessments
of all offshore structures used by the petroleum and natural gas industries worldwide. Through their
application, the intention is to achieve reliability levels appropriate for manned and unmanned offshore
structures, whatever the nature or combination of the materials used.
It is important to recognize that structural integrity is a concept comprising models for describing
actions, structural analyses, design rules, safety elements, workmanship, quality control procedures
and national requirements, all of which are mutually dependent. The modification of one aspect of
design in isolation can disturb the balance of reliability inherent in the overall concept of structural
integrity. The implications involved in modifications, therefore, need to be considered in relation to the
overall reliability of all offshore structural systems.
This part of ISO 19901 is applicable for marine soil investigation, which is only one of many possible
marine site investigations as illustrated in Figure 1. The terminology used in Figure 1 and other
important terminology are defined and given in Clause 3.
The scope of a marine soil investigation, such as field programme, equipment to be used, laboratory
testing programme, soil parameters to be established and reporting should be defined in project
specifications based on important factors such as type of structures involved, type of soil conditions
expected, regional or site-specific investigation, preliminary or final soil investigations.
The reporting can comprise anything from field data only to reporting of soil parameters. An example
report format is given in Annex G, Table G.1, but for each project the final reporting structure can be
adjusted by deleting inapplicable sections, or by adding new sections.
This part of ISO 19901 gives requirements, recommendations and guidelines for the planning and
execution of marine soil investigations and is applicable from the planning phase to reporting of soil
parameters. It is important to use documented methods when soil parameters are established, and to
refer to these methods in the report.
In situ and laboratory testing methods included in this part of ISO 19901 are selected based on their
importance in marine soil investigation practice, availability in commercial geotechnical laboratories
and the existence of an accepted testing procedure.
Figure 1 — Marine soil investigations shown as one of many types of marine site investigations
Seabed characterization can require several types of site investigations, for example marine soil
investigations and geophysical investigations including geological and geohazard evaluations. For each
project, the types of site investigations required are usually defined in project specifications. Also of
importance for proper seabed characterization is consideration of required investigation equipment and
its deployment mode(s) and methods, in order to acquire adequate quality soil data to the target depth.
This part of ISO 19901 is applicable for marine soil investigations at any water depth and to any depth
below seafloor which can be reached with the tools used.
vi © ISO 2014 – All rights reserved

ISO 19901-8:2014(E)
Use of this part of ISO 19901 is based on the assumptions that:
— adequate communication takes place between geotechnical personnel involved in marine soil
investigations and the personnel responsible for foundation design, for construction and for
installation of the offshore structures;
— soil parameters are collected, recorded and interpreted by qualified personnel;
— the project-specific scope of work for marine soil investigations is defined by one or more project
specifications.
Seabed soils can vary widely, and experience gained at one location is not necessarily applicable
at another. The scope of a soil investigation for one type of structure is not necessarily adequate for
another. Extra caution is therefore necessary when dealing with unconventional soils or unconventional
foundation concepts. Marine soil investigations include both offshore and nearshore soil investigations,
which can provide very different challenges.
The detailed requirements for equipment and methods given in this part of ISO 19901 are only applicable
if relevant for the scope of work defined in the project specifications.
This part of ISO 19901 is intended to provide flexibility in the choice of soil investigation techniques
without hindering innovation.
The primary objectives of this part of ISO 19901 are to provide requirements and guidance for how
the most important aspects of a marine soil investigation should be performed to obtain reliable soil
parameters based on documented methods.
In this part of ISO 19901, in accordance with the latest edition of the ISO/IEC Directives, Part 2, the
following verbal forms are used:
— ‘shall’ and ‘shall not’ are used to indicate requirements strictly to be followed in order to comply
with the document and from which no deviation is permitted;
— ‘should’ and ‘should not’ are used to indicate that among several possibilities one is recommended
as particularly suitable, without mentioning or excluding others, or that a certain course of action is
preferred but not necessarily required, or that (in the negative form) a certain possibility or course
of action is deprecated but not prohibited;
— ‘may’ and ‘need not’ are used to indicate a course of action permissible within the limits of the document;
— ‘can’ and ‘cannot’ are used for statements of possibility and capability, whether material,
physical or causal.
This part of ISO 19901 includes informative annexes. Informative annexes give additional information
intended to assist the understanding or use of the document. They do not contain requirements, except
that informative annexes may contain optional requirements (for example a test method that is optional
can contain requirements), but there is no need to comply with these requirements to claim compliance
with this part of ISO 19901.
The following International Standards are also relevant to offshore structures for the petroleum and
natural gas industries:
— ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
— ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
— ISO 19903, Petroleum and natural gas industries — Fixed concrete offshore structures
— ISO 19904-1, Petroleum and natural gas industries — Floating offshore structures — Part 1: Monohulls,
semi-submersibles and spars
— ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 1: Jack-ups
ISO 19901-8:2014(E)
— ISO/TR 19905-2, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 2: Jack-ups commentary
— ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
— ISO 13623, Pipeline transportation systems
— ISO 13628-1, Design and operation of subsea production systems — Part 1: General requirements and
recommendations
viii © ISO 2014 – All rights reserved

INTERNATIONAL STANDARD ISO 19901-8:2014(E)
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 8:
Marine soil investigations
1 Scope
This part of ISO 19901 specifies requirements, and provides recommendations and guidelines for marine
soil investigations regarding:
a) objectives, planning and execution of marine soil investigations;
b) deployment of investigation equipment;
c) drilling and logging;
d) in situ testing;
e) sampling;
f) laboratory testing; and
g) reporting.
Rock materials are only covered by this part of ISO 19901 to the extent that ordinary marine soil
investigation tools can be used, e.g. for chalk, calcareous soils, cemented soils or similar soft rock.
Hard rock investigations are not covered by this part of ISO 19901; see F.13 for further guidance.
Foundation design is not covered by this part of ISO 19901, but by ISO 19901-4 and the respective design
standards for the specific types of offshore structures as listed in the Foreword and Introduction.
Planning, execution and interpretation of geophysical investigations are not covered by this part of
ISO 19901. However, the results from geophysical investigations should, where appropriate, be used for
planning, optimization and interpretation of marine soil investigations.
This part of ISO 19901 does not cover the planning and scope of geohazard assessment studies, only the
corresponding marine soil investigations aspects thereof.
Soil investigations from ice in Arctic regions are not covered by this part of ISO 19901.
This part of ISO 19901 is intended for clients, soil investigation contractors, designers, installation
contractors, geotechnical laboratories and public and regulatory authorities concerned with marine
soil investigations for any type of offshore and nearshore structures, or geohazard assessment studies,
for petroleum and natural gas industries.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 22476-1:2012, Geotechnical investigation and testing — Field testing — Part 1: Electrical cone and
piezocone penetration test
ISO 19901-8:2014(E)
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
accuracy
exactness of a measurement compared to the true value of the quantity being measured
3.2
application class
classification of equipment based on achievable level of accuracy or classification of soil samples which
can be used to determine various soil properties
Note 1 to entry: Application classes have been developed to provide guidance on equipment selection centred on
the accuracy required when using the results.
Note 2 to entry: The term ‘application class’ in this part of ISO 19901 is called ‘quality class’ in 3.4.1 of EN 1997–
2:2007 where the term ‘application class’ is not used. For the definition of ‘quality class’, see 3.24.
3.3
borehole geophysical logging
measurement of physical properties of a borehole and/or the surrounding soil, obtained by one or more
logging probes deployed in the borehole
3.4
characteristic value
value assigned to a basic variable associated with a prescribed probability of not being violated by
unfavourable values during some reference period
Note 1 to entry: The characteristic value is the main representative value. In some design situations a variable can
have two characteristic values, an upper and a lower value.
[SOURCE: ISO 19900:2013, definition 3.10]
3.5
characterization
description, evaluation and/or determination of the most typical characteristics based on all types of
site investigations and other available data
3.6
client
party or person with overall responsibility for the marine soil investigation, including preparation of
project specifications
3.7
contractor
party or person responsible for an assigned scope of work described in project specifications
3.8
derived value
value of a geotechnical parameter obtained from test results by theory, correlation or empiricism
3.9
design value
value derived from the representative value for use in the design verification procedure
[SOURCE: ISO 19900:2013, definition 3.18]
3.10
disturbed sample
sample whose soil structure, water content and/or constituents have changed as a result of sampling
and handling
2 © ISO 2014 – All rights reserved

ISO 19901-8:2014(E)
3.11
drained condition
condition whereby the applied stresses and stress changes are supported by the soil skeleton and do not
cause a change in pore pressure
3.12
drilling mud
drilling fluid
fluid pumped down a rotary drilled borehole to facilitate the drilling process
Note 1 to entry: The hardware associated with handling drilling fluids is commonly prefixed ‘mud’ (e.g. mud tank,
mud pump, mud valve). Drilling parameters associated with drilling fluids are similarly prefixed (mud pressure,
mud flow, etc.).
3.13
geohazard
geological state and process that can cause material and environmental damage as well as loss of life
3.14
geophysical investigation
marine site investigation of seafloor or seabed by the use of non-destructive methods requiring marine
deployment of geophysical tools
Note 1 to entry: See Figure 1 in Introduction.
3.15
ground truthing
process of using soil investigation data to characterize the various geological formations defined from
geophysical investigations
3.16
in-pipe logging
logging in a section of the borehole or drill pipe between the tool and the borehole wall
Note 1 to entry: The number of parameters that can be usefully measured in these circumstances is restricted.
3.17
intact sample
sample that was collected with intention to preserve its in situ characteristics
3.18
marine site investigation
any type of investigation at an offshore or nearshore site
EXAMPLE Marine soil investigation, geophysical investigation, marine environmental investigation,
metocean investigation. See Figure 1.
3.19
marine soil investigation
type of marine site investigation whose primary objective is to obtain reliable and representative soil
data for characterization of the seabed soil conditions to facilitate the design of offshore structures
and/or for geohazard evaluation
Note 1 to entry: See Figure 1 in Introduction.
Note 2 to entry: The scope of work and extent of a marine soil investigation varies from one project to another, but
usually includes one or more of the items listed in Clause 1.
3.20
measured value
value that is measured in a test
ISO 19901-8:2014(E)
3.21
nominal value
value assigned to a basic variable determined on a non-statistical basis, typically from acquired
experience or physical conditions
3.22
open-hole logging
logging in a section of the borehole without, for example, casing or drill pipe, allowing a direct
measurement of the soil properties outside the borehole wall to be made
3.23
project specification
scope of work for marine soil investigations assigned by the client to a contractor
3.24
quality class
classification of sample quality for low to medium OCR clays, where the sample quality is based on
measured volume change from laboratory consolidation tests
Note 1 to entry: Exact definitions of the various sample quality classes are given in 10.5, Table 6.
Note 2 to entry: The definition of ‘quality class’ given in this part of ISO 19901 differs from the definition of ‘quality
class’ given in 3.4.1 of EN 1997–2:2007. What is called ‘quality class’ in EN 1997–2:2007 is called ‘application class’
in this part of ISO 19901, see 3.2. The term ‘application class’ is not used in EN 1997–2:2007.
3.25
rat hole
additional depth drilled at the end of the borehole (beyond the last zone of interest) to ensure that the
zone of interest can be fully evaluated
Note 1 to entry: The rat hole allows tools at the top of the logging string to reach and measure the deepest
zone of interest.
3.26
reconstituted specimen
laboratory specimen prepared by mixing a soil sample to specified state using a specified procedure
Note 1 to entry: For fine-grained soils, the specimen is prepared as a slurry (at or above the liquid limit) and
then consolidated. For coarse-grained soils, it is either poured or pluviated in dry (dried) or wet conditions and
compacted, or consolidated.
3.27
remoulded sample
remoulded specimen
laboratory specimen which is thoroughly reworked mechanically at a constant water content
3.28
remoulded shear strength
shear strength measured on a remoulded specimen
3.29
representative value
value assigned to a basic variable for verification of a limit state
[SOURCE: ISO 19900:2013, definition 3.38]
3.30
residual shear strength
shear strength at large strains where measured shear stress versus strain levels off to a constant value
4 © ISO 2014 – All rights reserved

ISO 19901-8:2014(E)
3.31
sample
portion of soil or rock recovered from the seabed soil by sampling techniques
3.32
seabed
materials below the seafloor
3.33
seafloor
interface between the sea and the seabed
3.34
settlement
permanent downward movement of a structure as a result of its own weight and other actions
3.35
site
defined investigation area
3.36
soil [geotechnical] parameter
measured, derived or representative soil [geotechnical] parameter
Note 1 to entry: The term ‘geotechnical’ includes both soil and rock.
3.37
specimen
part of a sample used for a laboratory test
3.38
strength index test
test that yields an indication of the shear strength
3.39
swelling
expansion due to reduction of effective stress, resulting from either reduction of total stress or absorption
of (in general) water at constant total stress
Note 1 to entry: Swelling includes the reverse of both compression and consolidation.
Note 2 to entry: Exsolution of dissolved gas due to stress relief during sampling can cause significant swelling in
samples.
3.40
uncertainty
reliability of the measurement results due to sources of systematic and random errors
3.41
undisturbed sample
sample in which no change of practical significance has occurred in the soil characteristics
3.42
undrained condition
condition whereby the applied stresses and stress changes are supported by both the soil skeleton and
the pore fluid and do not cause a change in volume
3.43
undrained shear strength
maximum shear stress at yielding or at a specified maximum strain in an undrained condition
Note 1 to entry: Yielding is the condition of a material in which a large plastic strain occurs at little or no stress increase.
ISO 19901-8:2014(E)
Note 2 to entry: Strain softening is also to be considered.
4 Symbols, units and abbreviated terms
4.1 Symbols
a net area ratio of a cone penetrometer
c coefficient of consolidation
v
C swelling index (for consolidation tests)
s
h height of reference point above seafloor
sf
f sleeve friction
s
G specific gravity of solid particles
G initial (small strain) shear modulus
max
I liquidity index
L
I plasticity index
P
i inclination
K coefficient of earth pressure at rest (= σ’ /σ’ )
0 h0 v0
m coefficient of compressibility
v
p ’ in situ vertical effective stress (=σ’ )
0 v0
q cone resistance
c
q cone resistance corrected for pore water pressure effects
t
s vane blade thickness
s = c undrained (undisturbed) shear strength of soil
u u
s static triaxial compression undrained shear strength
uC
s static DSS undrained shear strength
uD
s static triaxial extension undrained shear strength
uE
s shear strength by field vane testing
ufv
s remoulded shear strength by field vane testing
ufv,rem
s residual shear strength by field vane testing
ufv,res
S soil sensitivity
t
u pore pressure measured through a filter location in the cylindrical cone part just above conical
part
v compression wave velocity
p
v shear wave velocity
s
v vertically (v) propagated, horizontally (h) polarized shear wave velocity
vh
6 © ISO 2014 – All rights reserved

ISO 19901-8:2014(E)
ξ material damping ratio
z height above seafloor for drilling mode in situ probe zero reference readings
γ ‘ submerged unit weight of soil
ν Poisson’s ratio
σ stress
σ’ in situ vertical effective stress (= p ’)
v0 0
σ’ in situ horizontal effective stress
h0
σ’ preconsolidation stress
p
Δσ’ change in effective vertical stress
v
ϕ’ effective angle of internal friction
4.2 Units
Units to be used can vary somewhat from one clause to another based on historical use. For example, a
CPT cone cross-sectional area should be given in units of square millimetres (mm ) as used today, and
not in square metres (m ). If there are no special historical reasons for deviating from the units listed
below, then the units to be used are:
force kN
moment kN·m
density kg/m
unit weight kN/m
stress, pressure, strength and stiffness kPa
coefficient of permeability m/s
coefficient of consolidation m /s
4.3 Abbreviated terms
BHA bottom hole assembly
CCV consolidated constant volume
CD consolidated drained
CPT cone penetration test
CPTU electrical CPT with measurement of the pore pressures around the cone
CRS controlled rate of strain
CT computerized tomography
CU consolidated undrained
DGPS differential global positioning system
DS direct shear
ISO 19901-8:2014(E)
DSS direct simple shear
ERP emergency response plan
FVT field vane test
GIS geographical information system
GNSS global navigation satellite system
HAZID hazard identification
HAZOP hazard and operability
HSE health, safety and environment
HVAC heating, ventilation and air conditioning
IL incremental loading
JSA job safety analysis
LAT lowest astronomical tide
LBL long baseline
MSCL multi-sensor core logging
MSL mean sea level
OCR overconsolidation ratio
PEP project execution plan
PPE personal protective equipment
QA quality assurance
QC quality control
RFID radio-frequency identification
ROP rate of penetration
ROV remotely operated vehicle
RS ring shear
SCPT seismic CPT
SH shear wave
SHANSEP stress history and normalized soil engineering parameters
SIMOPS simultaneous operations
SOW scope of work
SRB sulfate-reducing bacteria
SWL safe working load
TC triaxial compression
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ISO 19901-8:2014(E)
TE triaxial extension
TOC total organic content
UCT unconfined compression test
USBL ultra-short baseline
UU unconsolidated-undrained
VSP vertical seismic profiling
WGS world geographic system
YSR yield stress ratio
5  Ob  jectives, planning and requirements
5.1 Objectives
The objectives of marine site investigations are to make relevant and adequate soil data available at
the various project phases. In particular, the acquired data are usually required to enable assessment
of the site suitability with respect to the offshore structure and the level of risks for the foundation and
integrity of that structure.
NOTE ISO 31000 provides guidance on risk management principles.
The general objectives of a marine soil investigation are to establish the characteristics and mechanical
properties of the seabed soils by acquisition, evaluation and presentation of geotechnical information
derived from methods relying on tools penetrating into the seabed. Specific objectives of a marine soil
investigation may be given in project specifications.
5.2 Planning
Marine site investigations commonly consist of the following activities, often performed in the
sequence listed:
a) Desk study, including the evaluation of information a
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