Table Of ContentCivil excavations and tunnelling
– a practical guide
Ratan Tatiya
PublishedbyThomasTelfordPublishing,ThomasTelfordLtd,1HeronQuay,LondonE144JD.
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Preface
Excavation means dislodging the rock or ground from in situ and dis-
posing of it from there and, thereby, creating an opening. This opening,
when exposed to the sun and atmosphere, is known as an open cut or
surface opening, and when the same is created beneath the ground and is
notexposedtotheatmosphere,itisknownasanundergroundorsubsurface
opening. Civil excavations mean those excavations that are usually under
the purview of civil and construction engineering disciplines, in terms of
their planning, design, execution and construction.
Excavation activities began with ancient civilizations; naturally, men
must have madeexcavationsfortheirshelterusingancientandprimitive
tools.Duringthe19thand20thcenturiescivilexcavationsgainedmomen-
tum around the world. Many prominent highways, rail routes, building
constructions, hydro-electric projects and tunnelling projects have been
undertaken, and are still ongoing. This has been made possible with the
advancement in the techniques, methods and equipment required to
accomplish this task. Today, civil excavations are no more an art but the
tasks ofengineering.Tunnelling isopeningupthefuture.Itisshortening
distances by passing through the most difficult ground and hazardous
conditions. Presenttechnology canmeet this challenge.
The relationship between mining and excavation technology as applic-
able to civil and construction engineering is very close and very old.
Thisisduetothefactthatmostlythemethods,techniquesandequipment
usedinthemarecommon.Approachestodrivingthroughvaryingground
conditionssuchassoftandunstableground,waterystrataandhardrocks
are similar to a great extent. However, an important distinction between
them should be understood due to the fact that a mine’s life is limited to
theextentthatthemineraldepositisdepleted,whereasacivilexcavation’s
lifeisuntilitspurposeisserved,andcanbealmostunlimited.Itisacostly
affair but once built and created,it shouldprove trouble free.
Surface excavations include benching, trenching, channelling, pitting,
demolishing, road construction and constructions related to civil and
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Civilexcavationsandtunnelling
construction projects. Muck is material that is produced as a result of
these operations. Removing this muck from its place of generation is
known as mucking or loading. The equipment used for this purpose
is known as mucker, loader or excavator. These sets of equipment are also
known as earth-moving machinery. They are used for mucking, scraping,
digging,casting,pushing,shifting,ripping,dozing,levellinganddragging
theearthmaterial.Theiruseismultipleintermsofutilityastheymeetthe
requirement of many industriesand tasksof public utilities.
The use of underground space in urban areas is becoming most
important due to scarcity of land in the densely populated/inhabited
areas and environment concerns. During the last 50 years, the advances
in rock mechanics to evaluate ground conditions together with the
developments in ground consolidation and support techniques have
enabled us to create large underground excavations. Method, techniques
and equipment are available to excavate a large volume of rocks beneath
the surface efficiently. This is the reason that these large excavations,
which are known as caverns, are created for many purposes, such as civil
works, storage facilities, defence installations, hydro-electric power
plants, recreation facilities,etc.
Thus, the excavation activities for civil and construction industries are
vital,andgeneratebillionsofcubicmetresofearth-materialdaily,leaving
apart those generated by mining activities the world over. This is the
reason why many multinational companies are in the arena to produce
explosives and their accessories; earth-moving, rock-drilling and cutting,
and tunnelling machines.
Insummary,thebookisacomprehensivetextoncivilexcavationsatthe
surface as well as subsurface locales including tunnels, that could be created
with or without the aid of explosives using latest methods, equipment
and techniques with due consideration to safety and environment. The
ten chapters cover some of the following features:
. It covers unit operations such as: drilling and blasting (Chapter 2);
cutting and boring (Chapter 5); sinking and raising (Chapter 9); muck-
ing/loading, earth-moving, dozing, scraping, hauling (transportation)
and supporting (Chapters 3 and 4). It deals with equipment used to
carry out these operations such as rock drills, multi-boom jumbos,
excavators, loaders, earth movers, trucks, locomotives, conveyors,
tunnelborers,raiseborers,shields,roadheadersandafewothers.
. The text gives fair treatment to explosives, blasting accessories and
controlled blasting (Chapters 2, 3 and 4). Chipping hammers and
pneumatic breakers used by the construction industry have been
includedinChapter2.
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Preface
. Criteria to select equipment have been demonstrated through a case
study giving due consideration to factors related to environment,
safety,ergonomics,economyandtechnical(Chapter3).
. AnattempthasbeenmadeinChapter5togivecomprehensivetreatment
to modern partial-face borers, full-face tunnel borers, multi-tool miner
(MTM)attachmentsandimpacthammers.
. Chapter 7 has been devoted to describing tunnelling methods not
covered in Chapters 4 to 6. These include: new Austrian tunnelling
method (NATM); Lee’s Tunnelling Method (LTM); pre-vault method;
mechanicalpre-cuttingtunnellingmethod(MPTM),etc.
. In general, the term microtunnelling refers to driving of subsurface
small-sized openings or trenches to lay down the pipelines for water
and gas, cables for power and telecom, and sewer lines. This is also
known as trenchless technology, as described in Chapter 8. It has huge
potential.
. A network of vertical, inclined and horizontal openings (excavations)
that is required while constructing caverns for different purposes such
as repository, oil storage, power generation and recreation facilities for
the general public has been described in Chapter 9. Applications of
various techniques and unit operations that are required to execute or
undertake the excavations of various types have been tabulated at the
endofthischapter.
. While creating excavations of any kind at any locale surface or under-
ground, damage to the environment (pollution) and accidents are
unavoidable. They cannot be eliminated but efforts could be made to
minimize them. These aspects have been covered in Chapter 10 on
hazards,safetyandenvironment.
The foregoing discussion reveals that locales for the subject areas chosen
forthisbookaremany,andtheyarevital.Itistheauthor’s34yearsback-
groundofworkinginexcavation-relateddisciplines,initiallyforadecade
inthefieldandthenasuniversityprofessorandindustrialconsultant,that
inspired him to write this book. Excavation is a multi-disciplined activity
involving civil, construction and mining engineers, earth-scientists and
geologists. Hence, this book is likely to be used by the students, officials
and engineers of these disciplines.
Thisbook isintended toserve studentsof undergraduate level andthe
first year of graduate level at schools or institutes teaching any of the
above-mentioned disciplines.
In the end, this book is a result of appreciation from students and
colleagues, support from my family members and cooperation from
professional societies (SME and IOM3) and academic institutes including
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Civilexcavationsandtunnelling
Sultan Qaboos University, Oman. Companies such as: Robbins, USA;
Herrenknecht GmbH, Schwanau, Germany; Sandvik-Tamrock, Finland;
and Atlas Copco, Sweden, have encouraged me to prepare this book by
providing valuable information promptly, as and when I requested. I
wish to express my sincere gratitude to them, and to all those who
helped me directly or indirectly in this endeavour.
Ratan Tatiya
May, 2004
xii
Contents
Preface ix
Acknowledgements xiii
1 Introduction and site investigations 1
1.0 Introduction 1
1.1 Briefhistory – growth and developmentof civil
excavations 1
1.2 Site investigations – groundand rock characterization 5
1.3 Core drilling 7
1.4 Tomography 8
1.5 Lugeon test 8
1.6 Laboratory testing 9
1.7 Rock composition and ground types 11
1.8 Rock mass classification 12
1.9 Projection of geologicalmodel 14
References 18
2 Groundand rock fragmentation – drilling andblasting 21
2.0 Introduction 21
2.1 Drilling 21
2.2 Chipping hammers/pneumatic breakers 32
2.3 Explosives 34
2.4 Blasting 42
2.5 Blasting accessories 51
2.6 Properties of explosives 56
2.7 Blasting cost 59
2.8 Safety 59
2.9 Terminology 60
References 63
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3 Earth movers,excavators and open-cut excavations 65
3.0 Introduction 65
3.1 Classification– earthexcavation, loading and casting
units 66
3.2 Equipment details 66
3.3 Haulage system 86
3.4 Some developments 88
3.5 Equipment selection 89
3.6 Benching 94
3.7 Channelling/canal construction 100
3.8 Uprooting or blastingstumps 101
3.9 Excavation for foundations 101
3.10 Smoothblasting 102
3.11 Road construction and layingsewage lines 102
3.12 Landfill 103
References 103
4 Tunnelling byconventional methods 105
4.0 Introduction– functionof drives and tunnels 105
4.1 Pre-cursor or prior todriving civil tunnels 105
4.2 Tunnelling techniques 107
4.3 Drilling –drivage techniques with the aid of explosives 109
4.4 Blasting –charging and firing rounds 120
4.5 Muck handling and disposal atthe subsurface locale 123
4.6 Ventilation 131
4.7 Driving large-sizeddrives/tunnels in tough rocks 133
4.8 Tunnelling through soft ground and rocks–conventional
methods 136
4.9 Supports fortunnels 137
4.10 Past, present and futureof tunnelling technology 140
4.11 Over-break and scaling – some innovations 142
References 143
5 Mechanized tunnelling 145
5.0 Introduction 145
5.1 Classification 147
5.2 Partial-face heading machines 148
5.3 Full-face boring machines 156
5.4 Backup system 167
5.5 Boring system 168
5.6 Rock cuttingtools and their types 172
5.7 Cuttingheadconfiguration 173
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Contents
5.8 Some developments 173
References 174
6 Shield tunnelling in softground 177
6.0 Introduction 177
6.1 Function of the shield 178
6.2 Shield tunnelling –classification 178
6.3 Open shield 179
6.4 Partial-face extractionunits 181
6.5 Compressedair shields 182
6.6 Slurry shield 184
6.7 Slurry and mix-shield 187
6.8 Earth-pressure-balance (EPB) shield 189
6.9 Combined shield 191
6.10 Excavation tools 192
6.11 Excavation procedure 192
6.12 Excavation and transportation techniques 193
6.13 Supports/linings 194
6.14 Health, safety and environment(HSE) 194
6.15 Selection of the shield 195
6.16 Ground settlement/displacement 197
6.17 Terminology 199
References 200
7 Special methods 201
7.0 NewAustrian tunnelling method (NATM) 201
7.1 NATM case studies 207
7.2 Lee’s Tunnelling Method (LTM) 209
7.3 Semi-mechanized methods 212
7.4 Barrelvault method 214
7.5 Ground improvement 215
7.6 Use of shotcrete during tunnelling 216
7.7 Cutand cover tunnelling 217
7.8 Submerged (immersed) tubes/tunnels 217
References 218
8 Microtunnelling 221
8.0 Introduction 221
8.1 Pipe jacking 222
8.2 Pilot method 223
8.3 Thrust boring 223
8.4 Slurry microtunnelling machines 225
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Civilexcavationsandtunnelling
8.5 Iseki (Unclemole) 226
8.6 Herrenknecht microtunnelling system 226
8.7 Developments and challengesin microtunnelling 228
8.8 Some experienceof microtunnelling in North America 232
8.9 The future 233
8.10 Terminology 233
References 234
9 Raising, sinking andlarge subsurfaceexcavations 237
9.0 Introduction 237
9.1 Raising 238
9.2 Shaftsinking 247
9.3 Subsurface excavations 254
9.4 Equipment and servicesselection 265
References 271
10 Hazards, safety andtheenvironment 273
10.0 Introduction 273
10.1 Hazards 274
10.2 Potentialhazards 274
10.3 Mechanization and automation 281
10.4 Fires,rescueand escape 285
10.5 Occupationalhazards (healthand physique) 286
10.6 Legislation, guidance and norms 287
10.7 Safety and accidents 288
10.8 Conceptual planning, detailed design and evaluation 293
10.9 Risk analysis 294
10.10 Environment 295
10.11 Environmentmanagement 301
10.12 Sustainable development 301
10.13 Emergency measures/preparedness 305
References 305
11 Conversion tables 307
Index 311
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