SIST EN ISO 19901-4:2004
(Main)Petroleum and natural gas industries - Specific requirements for offshore structures - Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2003)
Petroleum and natural gas industries - Specific requirements for offshore structures - Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2003)
ISO 19901-4:2003 contains requirements and recommendations for those aspects of geoscience and foundation engineering that are applicable to a broad range of offshore structures, rather than to a particular structure type. Such aspects are site characterization, soil and rock characterization, and design and installation of foundations supported by the seabed (shallow foundations) and the identification of hazards.
Aspects of soil mechanics and foundation engineering that apply equally to offshore and onshore structures are not addressed. The user of this part of ISO 19901-4:2003 is expected to be familiar with such aspects.
Erdöl- und Erdgasindustrie - Offshore-Plattformen - Teil 4: Geotechnische und Fundament-Auslegungsmerkmale (ISO 19901-4:2003)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures en mer - Partie 4: Bases conceptuelles des fondations (ISO 19901-4:2003)
L'ISO 19901-4:2003 contient les exigences et les recommandations relatives aux aspects géotechniques et de dimensionnement des fondations qui s'appliquent à une vaste gamme de structures en mer, plutôt qu'à un type particulier de structure. Ces aspects sont la caractérisation du site, la caractérisation des sols et des roches, le dimensionnement et installation des fondations supportées par le lit océanique (fondations superficielles), et l'identification des risques.
Les aspects de mécanique des sols et de dimensionnement des fondations qui s'appliquent aussi bien aux structures en mer qu'aux structures terrestres ne sont pas couverts. L'utilisateur de l'ISO 19901-4:2003 est considéré comme familier de ces aspects.
Petroleum and natural gas industries - Specific requirements for offshore structures - Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2003)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 19901-4:2004
01-maj-2004
Petroleum and natural gas industries - Specific requirements for offshore
structures - Part 4: Geotechnical and foundation design considerations (ISO 19901
-4:2003)
Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2003)
Erdöl- und Erdgasindustrie - Offshore-Plattformen - Teil 4: Geotechnische und
Fundament-Auslegungsmerkmale (ISO 19901-4:2003)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 4: Bases conceptuelles des fondations (ISO 19901-4:2003)
Ta slovenski standard je istoveten z: EN ISO 19901-4:2003
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
SIST EN ISO 19901-4:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 19901-4:2004
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SIST EN ISO 19901-4:2004
EUROPEAN STANDARD
EN ISO 19901-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2003
ICS 75.180.10
English version
Petroleum and natural gas industries - Specific requirements for
offshore structures - Part 4: Geotechnical and foundation design
considerations (ISO 19901-4:2003)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Offshore-Plattformen - Teil 4:
spécifiques relatives aux structures en mer - Partie 4: Geotechnische und Fundament-Auslegungsmerkmale (ISO
Bases conceptuelles des fondations (ISO 19901-4:2003) 19901-4:2003)
This European Standard was approved by CEN on 10 July 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-4:2003 E
worldwide for CEN national Members.
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SIST EN ISO 19901-4:2004
EN ISO 19901-4:2003 (E)
Foreword
This document (EN ISO 19901-4:2003) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum and natural gas industries" in
collaboration with Technical Committee CEN/TC 12 "Materials, equipment and offshore
structures for petroleum 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 February 2004, and conflicting national
standards shall be withdrawn at the latest by February 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
NOTE FROM CMC The foreword is susceptible to be amended on reception of the German
language version. The confirmed or amended foreword, and when appropriate, the normative
annex ZA for the references to international publications with their relevant European
publications will be circulated with the German version.
Endorsement notice
The text of ISO 19901-4:2003 has been approved by CEN as EN ISO 19901-4:2003 without any
modifications.
2
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SIST EN ISO 19901-4:2004
INTERNATIONAL ISO
STANDARD 19901-4
First edition
2003-08-01
Petroleum and natural gas industries —
Specific requirements for offshore
structures —
Part 4:
Geotechnical and foundation design
considerations
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 4: Bases conceptuelles des fondations
Reference number
ISO 19901-4:2003(E)
©
ISO 2003
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
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ii © ISO 2003 — All rights reserved
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
Contents Page
Foreword. v
Introduction . vii
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 Symbols. 3
5 General requirements. 4
5.1 General. 4
5.2 Testing and instrumentation. 4
5.3 Conductor installation and shallow well drilling . 5
6 Geotechnical data acquisition and integrated geoscience studies. 5
6.1 Geotechnical assessment. 5
6.2 Shallow geophysical investigation . 5
6.3 Geological modelling and identification of hazards.6
6.4 Geotechnical investigation. 8
7 Stability of shallow foundations. 9
7.1 General. 9
7.2 Principles. 10
7.3 Acceptance criteria. 10
7.4 Undrained bearing capacity — constant shear strength. 12
7.5 Undrained bearing capacity — linearly increasing shear strength . 13
7.6 Drained bearing capacity . 13
7.7 Shear strength used in bearing capacity calculations. 14
7.8 Settlements and displacements . 14
7.9 Dynamic behaviour. 14
7.10 Hydraulic stability. 15
7.11 Installation and removal. 15
7.12 Shallow foundations equipped with skirts. 15
7.13 Shallow foundations without skirts . 15
7.14 Installation effects. 16
Annex A (informative) Additional information and guidance. 17
A.1 Scope. 17
A.2 Normative references. 17
A.3 Terms and definitions. 17
A.4 Symboles. 17
A.5 General requirements. 17
A.6 Geotechnical data acquisition and integrated geoscience studies. 18
A.6.1 Geotechnical assessment. 18
A.6.2 Shallow geophysical investigation . 18
A.6.3 Geological modelling and identification of hazards.18
A.6.4 Geotechnical investigation. 18
A.7 Stability of shallow foundations. 20
A.7.1 General. 20
A.7.2 Principles. 20
A.7.3 Acceptance criteria. 22
A.7.4 Undrained bearing capacity — constant shear strength. 22
A.7.5 Undrained bearing capacity — linearly increasing shear strength . 23
A.7.6 Drained bearing capacity . 25
© ISO 2003 — All rights reserved iii
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
A.7.7 Shear strength used in bearing capacity calculations.26
A.7.8 Settlements and displacements.26
A.7.9 Dynamic behaviour.26
A.7.10 Hydraulic stability.26
A.7.11 Installation and removal.26
A.7.12 Shallow foundations equipped with skirts .26
A.7.13 Shallow foundations without skirts.27
A.7.14 Installation effects.27
Annex B (informative) Carbonate soils.28
B.1 General.28
B.2 Characteristic features.28
B.3 Properties.29
B.4 Foundations.29
B.4.1 Driven piles.29
B.4.2 Other deep foundation alternatives.29
B.4.3 Shallow foundations.29
B.5 Assessment.30
Bibliography.31
iv © ISO 2003 — All rights reserved
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 19901-4 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee 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 4: Geotechnical and foundation design considerations
Part 5: Weight control during engineering and construction
The following parts of ISO 19901 are under preparation:
Part 1: Metocean design and operating considerations
Part 2: Seismic design procedures and criteria
Part 3: Topsides structure
Part 6: Marine operations
Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
ISO 19901 is one of a series of standards for offshore structures. The full series consists of the following
International Standards.
ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
ISO 19901 (all parts), Petroleum and natural gas industries — Specific 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, Petroleum and natural gas industries — Floating offshore structures
ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 1: Jack-ups
© ISO 2003 — All rights reserved v
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(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
vi © ISO 2003 — All rights reserved
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
Introduction
The offshore structures International Standards ISO 19900 to ISO 19906 constitute 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 type of structure and the
nature of the materials used.
It is important to recognize that structural integrity is an overall 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 or structural system. The
implications involved in modifications, therefore, need to be considered in relation to the overall reliability of all
offshore structural systems.
The offshore structures International Standards are intended to provide a wide latitude in the choice of
structural configurations, materials and techniques without hindering innovation. Sound engineering
judgement is therefore necessary in the use of these International Standards.
The overall concept of structural integrity is described above. For foundations, some additional considerations
apply. These include the time, frequency and rate at which actions are applied, the method of foundation
installation, the properties of the surrounding soil, the overall behaviour of the seabed, effects from adjacent
structures and the results of drilling into the seabed. All of these, and any other relevant information, need to
be considered in relation to the overall reliability of the foundation.
The design practice for the foundations of offshore structures has proved to be an innovative and evolving
process over the years since the 1950s. This evolution is expected to continue and is encouraged. Therefore,
circumstances can arise when the procedures described herein or in the other International Standards
ISO 19902 to ISO 19906 (or elsewhere) are insufficient on their own to ensure that a safe and economical
foundation design is achieved.
Seabed soils vary. Experience gained at one location is not necessarily applicable at another. The scope of
the site investigation for one structure is not necessarily adequate for another. Extra caution is necessary
when dealing with unfamiliar soils or foundation concepts. This part of ISO 19901 is intended to provide wide
latitude in the choice of site investigation techniques and foundation solutions, without hindering innovation.
Sound engineering judgement is therefore necessary in the use of this part of ISO 19901.
For an offshore structure and its foundations, the action effects at the interface between the structure's
subsystem and the foundation's subsystem(s) are internal forces, moments and deformations. When
addressing the foundation's subsystem(s) in isolation, these internal forces, moments and deformations may
be considered as actions on the foundation's subsystem(s) and this approach is followed in this part of
ISO 19901.
To meet certain needs of industry for linking software to specific elements in this part of ISO 19901, a special
numbering system has been permitted for figures, tables and equations.
Some background to and guidance on the use of this part of ISO 19901 is provided for information in Annex A.
Guidance on foundations in carbonate soils is provided for information in Annex B. There is, as yet, insufficient
knowledge and understanding of such soils to produce normative requirements.
© ISO 2003 — All rights reserved vii
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SIST EN ISO 19901-4:2004
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SIST EN ISO 19901-4:2004
INTERNATIONAL STANDARD ISO 19901-4:2003(E)
Petroleum and natural gas industries — Specific requirements
for offshore structures —
Part 4:
Geotechnical and foundation design considerations
1 Scope
This part of ISO 19901 contains requirements and recommendations for those aspects of geoscience and
foundation engineering that are applicable to a broad range of offshore structures, rather than to a particular
structure type. Such aspects are
site characterization,
soil and rock characterization,
design and installation of foundations supported by the seabed (shallow foundations), and
identification of hazards.
Aspects of soil mechanics and foundation engineering that apply equally to offshore and onshore structures
are not addressed. The user of this part of ISO 19901 is expected to be familiar with such aspects.
NOTE 1 Particular requirements for the design of piled foundations, which have a traditional association with fixed steel
structures, are given in ISO 19902.
NOTE 2 Particular requirements for the design of shallow gravity foundations, which have a traditional association with
fixed concrete structures, are detailed in ISO 19903.
NOTE 3 Particular requirements for the anchor points of mooring systems of floating structures are detailed in
[65]
ISO 19901-7 .
NOTE 4 Particular requirements for the design of spud can foundations, which have a traditional association with jack-
up mobile offshore units (MOUs), are detailed in ISO 19905 (all parts).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
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 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore units —
Part 1: Jack-ups
ISO/TR 19905-2, Petroleum and natural gas industries — Site-specific assessment of mobile offshore units —
Part 2: Jack-ups commentary
© ISO 2003 — All rights reserved 1
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19900 and the following apply.
3.1
design actions
combination of representative actions and partial safety factors representing a design situation for use in
checking the acceptability of a design
3.2
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
3.3
effective foundation area
reduced foundation area having its geometric centre at the point where the resultant action vector intersects
the foundation base level
3.4
material factor
partial safety factor applied to the strength of the soil
3.5
sea floor
interface between the sea and the seabed
3.6
seabed
materials below the sea in which a structure is founded, whether of soils such as sand, silt or clay, cemented
materials or of rock
NOTE 1 The seabed can be considered as the half-space below the sea floor.
NOTE 2 Offshore foundations are most commonly installed in soils, and the terminology in this part of ISO 19901
reflects this. However, the requirements equally apply to cemented seabed materials and rocks. Thus, the term “soil” does
not exclude any other material at or below the sea floor.
NOTE 3 As yet there are no universally accepted definitions of the various types of soil and rock, see A.6.4.3.
3.7
settlement
permanent downward movement of a structure as a result of its own weight and other actions
3.8
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
3.9
undrained shear strength
maximum shear stress at yielding or at a specified maximum strain in an undrained condition
NOTE Yielding is the condition of a material in which a large plastic strain occurs at little or no stress increase.
2 © ISO 2003 — All rights reserved
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SIST EN ISO 19901-4:2004
ISO 19901-4:2003(E)
4 Symbols
Commonly used symbols are listed below, other symbols are defined in the text following the applicable
formula. It should be noted that symbols can have different meanings between formulae.
A total foundation area
A′ effective foundation area
A embedded vertical cross-sectional area of foundation
h
a soil attraction
B′ effective width of foundation
c undrained shear strength of clay
u
c average undrained shear strength between sea floor and base level for linearly increasing isotropic
u,ave
undrained shear strength with depth
c undrained shear strength at base level
u,0
D depth to base level
b
H factored horizontal total action on base area
b
K correction factor, which accounts for inclined actions, foundation shape, and depth of embedment
c
K drained horizontal soil reaction coefficient
rd
K undrained horizontal soil reaction coefficient
ru
L effective length of foundation area
′
p effective overburden stress at base level (skirt tip level when skirts are used)
0
Q design sliding resistance
d,h
Q design bearing capacity in the absence of horizontal actions
d,v
q design unit bearing capacity in the absence of horizontal actions
d,v
V factored vertical total action on base area
b
γ material factor
m
γ ′ submerged unit weight of soil
κ rate of increase of undrained shear strength with depth
φ ′ effective angle of internal friction
© ISO 2003 — All rights reserved 3
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