Introduction to Soft Soil Geotechnique: Content, Context and Application

365 Pages·2011·7.64 MB·English

by  F.B.J. Barends

I S S
NTRODUCTION TO OFT OIL
G T
EO ECHNIQUE

Content, Context and Application
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I S S
NTRODUCTION TO OFT OIL
G T
EO ECHNIQUE

Content, Context and Application

Frans B. J. Barends
Technical University Delft / Deltares
May 2011

IOS Press
Deltares provided financial sponsorship for this publication

© 2011 The author and IOS Press. All rights reserved

ISBN 978-1-60750-788-8 (print)
ISBN 987-1-60750-789-5 (online)
Publisher
IOS Press BV
Nieuwe Hemweg 6b
1013 BG Amsterdam
The Netherlands
Tel: [phone]
Fax: [phone]
Email: [email protected]
www.iospress.nl

LEGAL NOTE
The author and the publisher are not responsible for the use that might be made of
the information in this book.

PRINTED IN THE NETHERLANDS
FOREWORD
All over the world, habitable space in deltas and river basins is under increasing
pressure from economic expansion, growing populations, subsidence and the
impacts of climate change. It is expected that, within 40 years from now, about 80
percent of all people will live in deltaic regions. The Netherlands is a typical
example of such an area. The geological stratification consists of typical soft to
very soft soils, especially in the western part of the country. More than half of the
country is located below sea level, the surface of the land is flat, and the
groundwater table is extremely high. In these areas particularly it is important to
understand the complex behaviour of the subsoil, consisting of soft soils, like
organic clays, loose sand deposits and peat. Keeping the water separated from the
land is a continuous challenge. It is important to search for solutions that draw on
the potential of the coastal system, that enhance safety in densely populated coastal
areas, and that minimise the ecological impact. Building and maintaining
infrastructure in these areas is quite challenging. Expert knowledge of soil
mechanics and geotechnical engineering is essential to reduce the risks inherent to
construction on and in deltaic areas.

Soil mechanics and geotechnical engineering. Theory and practice. Both are
equally important in order to create a safe and sustainable living environment for
us and our (grand)children. Both theory and practice can be found in this
publication. In the first part, starting from the fundamental side, the ins and outs of
the complicated multi-phase material which we call soil, are explained and
summarised. In the second and third part this theoretical knowledge is further
developed and used to analyse a large number of specific soil-related problems,
like slope stability, earth retaining structures, foundations, ground improvement,
environmental impact, underground construction, coastal engineering, dike
technology and so on.

The author has been active in this field for the past 40 years, well connected on
the one hand to the scientific world of soil mechanics and on the other hand to the
(geotechnical) engineering practice. With this book, the author has left a legacy of
his wide knowledge and expertise to the younger professionals. It is particularly
valuable for the geotechnical engineer of the 21st century, living and working in
deltaic areas.

Peter van den Berg
Deltares, Director Geo-Engineering
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CONTENTS
CONTENTS PAGE
Introduction 1
PART I FUNDAMENTALS AND CONCEPTS
1 A history of geotechnical achievements 5
2 Characteristics of soils
a Geological data 25
b Gravimetric-volumetric data 26
c Atterberg limits 28
d Structure of granular soils 30
e Strength and stiffness aspects 32
Applications 32
3 Soil investigation
a Site investigation 37
b Laboratory testing 42
c Physical model testing strategy 46
Applications 50
4 Soil and groundwater
a Vertical soil stress 51
b Groundwater flow 52
c Boiling, heave and piping 59
Applications 62
5 Uniaxial stress and strain
a Stress and strain 69
b Strain concept 70
c Uniaxial compressibility 72
Applications 73
6 Creep and consolidation
a Time-dependency 77
b Creep 78
c One-dimensional consolidation 80
d Multi-dimensional consolidation 84
e Method of the transient leakage factor 86
Applications 88
7 Triaxial stress and strain
a Continuum mechanics 93
b Mohr-Coulomb model 96
c Coefficient of earth pressure 97
d Triaxial cell 99
e Undrained strength 101
f The A and B factor 102
Applications 104
VII
CONTENTS

PART II METHODOLOGY AND TOOLS
8 Uncertainty and reliability
a Uncertainty in geotechnical engineering 109
b Partial safety factors 116
c Eurocode 7 and the observational method 119
d Risk approach and visualising the unseen 121
e Risk management process: GeoQ 124
f Expertise and experience: GeoBrain 126
Applications 129
9 Observation and prediction
a Physical simulation 133
b Constitutive models 135
c Aspects of numerical simulation 143
d A visco-plastic analytical element method 149
Applications 157
PART III DESIGN AND CONSTRUCTION
10 Stability of slopes
a Limit analysis 163
b Slide on long slopes (micro-stability) 164
c Slide on short slopes (macro-stability) 167
Applications 171
11 Stability of earth-retaining structures
a Gravity walls 176
b Embedded walls 179
c Slurry walls 182
d Reinforced walls 183
Applications 184
12 Footings and pile foundations
a Bearing capacity of footings 189
b Bearing capacity of pile foundations 193
c Deformation of foundations 199
d Dynamic soil response 201
Applications 207
13 Methods of ground improvement
a Gravity displacement methods 211
b Replacement methods 212
c Mass improvement 213
d Stiff inclusions 218
e Bio-chemical treatment 223
Applications 224
VIII
CONTENTS

14 Environmental engineering
a Physical-chemical characteristics of soil 227
b Physical-chemical processes in soil 230
c Bio-chemical processes in soil 233
d Heat / cold transport in soil 234
e Land subsidence 239
Applications 247
15 Underground engineering
a Deep building pits 249
b Soft ground tunnel-boring techniques 252
c A cylindrical cavity in a uniform infinite soil 254
d A horizontal cylindrical cavity in a uniform semi-infinite soil 258
e Tunnel boring design and construction 260
f Unseen leakage 263
Applications 264
16 Coastal engineering
a Hydro-geodynamics 267
b Waves on seabed 271
c Waves on breakwaters 281
d A liquefaction model 286
e Squeezing 290
Applications 290
17 Dike engineering
a Deltas in the world 295
b History of Dutch dike engineering 297
c Philosophy of water defence 301
d State of the art 309
e Latest developments 312
ANNEX
I Answers to the applications 321
II Recommended literature 337
III About the author 339
IV Symbols, standards, units, keywords 345
V Name index 347
VI Subject index 351

IX