Table of Contents

The authors

Foreword to the 2nd Edition

1 Introduction

1.1 Basic principles and terms

1.2 Types of tunnel boring machine according to DAUB

1.3 Origins and historical developments

2 Support of the cavity and settlement

2.1 Support of the face

2.2 Support of the cavity at the shield

2.3 Support of the cavity behind the shield

2.4 Settlement and damage classifications

2.5 Heave and compaction

3 Design and calculation methods

3.1 Constructional parts of the shield

3.2 Loading on the shield

3.3 Calculation of the necessary thrust force

3.4 Empirical values for the dimensioning of the shield and the thrust cylinders

3.5 Calculation and dimensioning basics

3.6 Regulations and recommendations for the design of shields

4 Excavation tools and excavation process

4.1 Excavation tools

4.2 Excavation process

5 Muck removal

5.1 Preparation for transport

5.2 Removal from the face

5.3 Transport along the tunnel and up shafts

5.4 Quantity determination and measuring equipment

5.5 Separation

5.6 Suitability of the muck for landfill

6 The tunnel lining

6.1 General

6.2 Construction principles for the tunnel lining

6.3 Segmental lining

6.4 In-situ concrete lining

6.5 Injected concrete, Extruded concrete

6.6 Shotcrete layers as the final lining

6.7 Structural calculations

7 Shield tail sealing, grouting works

7.1 Shield tail seals

7.2 Grouting process

7.3 Grouting for ground improvement

8 Open shields

8.1 Shield construction

8.2 Projects

8.3 Double shields [203]

9 Compressed air shields

9.1 Functional principle

9.2 Compressed air facilities

9.3 Air requirement

9.4 Further developments

9.5 The use of compressed air with other types of shield

9.6 Examples

10 Slurry shields

10.1 Development history

10.2 Functional principle

10.3 Scope of application

10.4 Machine types

10.5 Machine and process technology

10.6 Examples

11 Earth pressure balance shields

11.1 Development history

11.2 Functional principle

11.3 Areas of application

11.4 Operating modes and muck transport

11.5 Components

11.6 Examples

12 Convertible shields or multi mode machines

12.1 Development strategies

12.2 Machine concepts

12.3 Examples

13 Special shields and special processes

13.1 Blade shields

13.2 Multi-face shields

13.3 Enlargement of shield tunnels

13.4 Pipe jacking

13.5 New concepts in mechanised shield tunnelling

14 Guided microtunnelling processes

14.1 Pilot tube process

14.2 Auger microtunnelling

14.3 Shield microtunnelling

14.4 English Mini Tunnel system

14.5 New developments

15 Surveying and steering

15.1 Surveying

15.2 Ring design and calculation of the ring installation sequence

15.3 Ring convergence measurement

15.4 Steering

15.5 Further surveying and data logging tasks

16 Workplace safety

16.1 General safety requirements

16.2 Control stations

16.3 Electrical cut-out and safety devices

16.4 Control devices and control systems

16.5 Towing connections

16.6 Laser guidance

16.7 Ventilation and the control of dust and gas

16.8 Fire protection

16.9 Storage of safety equipment for the personnel

16.10 Maintenance

16.11 Content of handbook

16.12 Evaluation of risk in mechanised tunnelling [26]

17 Partnering contract models and construction

17.1 Introduction

17.2 Requirements for the contract model

17.3 Contract model according to VOB

17.4 Time and cost drivers

17.5 Under-pricing as a performance killer

17.6 Chances and risks of partnering

17.7 Partnering – contractual implementation

17.8 Partnering – mutual process optimisation

18 Process controlling and data management

18.1 Introduction

18.2 Procedure

18.3 Data management

18.4 Target-actual comparison

18.5 Target process structure

18.6 Analysis of the actual process

19 DAUB recommendations for the selection of tunnelling machines

19.1 Preliminary notes

19.2 Regulatory works

19.3 Definitions and abbreviations

19.4 Application and structure of the recommendations

19.5 Categorisation of tunnelling machines

19.6 Ground and system behaviour

19.7 Environmental aspects

19.8 Other project conditions

19.9 Scope of application and selection criteria

19.10 Appendices

Bibliography

Index

Prof. Dr.-Ing. Bernhard Maidl
mtc – Maidl Tunnelconsultants GmbH & Co. KG
Fuldastr. 11
47051 Duisburg

Dr.-Ing. E.h. Martin Herrenknecht
Herrenknecht AG
Schlehenweg 2
77963 Schwanau

Dr.-Ing. Ulrich Maidl
mtc – Maidl Tunnelconsultants GmbH & Co. KG
Fuldastr. 11
47051 Duisburg

Dr.-Ing. Gerhard Wehrmeyer
Herrenknecht AG
Schlehenweg 2
77963 Schwanau

Translated by David Sturge, Kirchbach, Germany

Cover:
Herrenknecht-EPB-Shield S-300 Madrid M-30
By-Pass Sue Túnel Norte, Madrid, Spain

Photo:
Herrenknecht AG

Library of Congress Card No.:
applied for

British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.

Bibliographic information published by
the Deutsche Nationalbibliothek
The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2012 Wilhelm Ernst & Sohn, Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Rotherstr. 21, 10245 Berlin, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Coverdesign: Sonja Frank, Berlin, Germany
Produktion management: pp030 – Produktionsbüro Heike Praetor, Berlin
Typesetting: Reemers Publishing Services GmbH, Krefeld

2nd Edition
Print ISBN: 978-3-433-02995-4
ePDF ISBN: 978-3-433-60150-1
ePub ISBN: 978-3-433-60149-5
mobi ISBN: 978-3-433-60148-8
o-Book ISBN: 978-3-433-60105-1

„A plan whatever it may be must be made for the bad ground, it must be calculated to meet all exigencies, all disasters and to overcome them after they have occured.“

Marc Isambard Brunel on suggested improvements after the flooding of the Thames Tunnel in 1831.

The authors

1
Introduction
B. Maidl

2
Support of the cavity and settlement
U. Maidl

3
Construction and design methods
G. Wehrmeyer

4
Excavation tool and excavation process
M. Herrenknecht
G. Wehrmeyer

5
Muck removal
M. Herrenknecht
G. Wehrmeyer

6
The tunnel lining
B. Maidl

7
Shield tail sealing, grouting works
G. Wehrmeyer

8
Open shields
B. Maidl

9
Compressed air shields
B. Maidl

10
Slurry shields
U. Maidl

11
Earth pressure shields
U. Maidl

12
Convertible shields
B. Maidl

13
Special shields and special processes
B. Maidl

14
Guided microtunnelling processes
B. Maidl

15
Surveying and steering
M. Herrenknecht
G. Wehrmeyer

16
Workplace safety
B. Maidl

17
Partnering contract models and construction
U. Maidl

18
Process controlling and management
U. Maidl

19
DAUB recommendations for the selection of tunnelling machines
U. Maidl

Foreword to the 2nd Edition

The rapid progress of mechanised tunnelling to market leadership has continued – even exceeded predictions; the general worldwide trend in construction towards mechanisation and automation clearly demanded a similar development in tunnelling. It is significant that even in Austria, the traditional home of the New Austrian Tunnelling Method (NATM), mechanised tunnelling has also established its position in the last decade. Occupational health and safety, faster advance rates, improved cost security and labour-saving opened opportunities for mechanised tunnelling on a few major projects – normally in competition with conventional construction methods.

So it is appropriate that this book should now be revised, 20 years after its first publication. The extent of innovations and practical experience led to a complete reworking. Incidentally, the book “Hardock Tunnel Boring Machines”, which appeared in 2008, already offered access to the newest technology in the area of tunnel support. The team of authors has adapted the content to the latest technology and has been supplemented to provide the necessary specialist knowledge.

The original authors B. Maidl and M. Herrenknecht also worked on this edition. We have gained my son Dr.-Ing. U. Maidl and my former doctoral candidate Dr.-Ing. G. Wehrmeyer, who have particularly devoted themselves to new developments.

I am very thankful that I could still rely on the help of my former employees Herr H. Schmidt and Herr G. Kaufhold for the new revision. I would like to thank Herr Dipl-Ing. M. Griese from MTC, who helped a great deal with the detailed work and overall coordination. I would also like to thank my grandson Max Maidl for his assistance. A thank-you to all, especially the author colleagues and the publisher.

Bochum, January 2011

Bernhard Maidl

1

Introduction

The mined construction of underground infrastructure has made steady progress over recent years. It is now possible to construct underground works with very little impairment of buildings or traffic flow at ground level. Particularly in inner-city areas, with sensitive infrastructure and high population density, there is an enormous demand for underground structures.

The cavities created in this way have until now mostly been for underground transport routes, although there are also other possible uses such as energy extraction, storage and refuge spaces, utility tunnels and, not least, underground urban development. This has led to extensive schemes and projects, particularly in Japan due to the very restricted space availability (Figure 1-1).

Particularly in the field of shield tunnelling, the prominent role of Japan has been unmistakeable. But the development of this construction method is also at a high and internationally respected level in Germany and other parts of Europe. The shield construction process enables the production of elongated underground structures, even at shallow depths, in soil with poor load-bearing capacity or under the groundwater table, without causing any disturbance or significant settlement on the ground surface. Ground conditions with loose spherical material can be mastered, as can soft plastic or flowing soils. But the use of these machines is also practicable in temporarily stable ground, where the shield only acts as head protection. All in all, shield machines have a wide scope of application.

Figure 1-1 Japanese scheme for the exploitation of underground space in an inner-city area [155]

The shield construction process could but should not generally replace other methods of tunnelling. It can, however, offer a technically feasible and also economic alternative to other methods of tunnelling in unfavourable geological conditions, for long contract sections, high advance rate requirement or where stringent surface settlement limits apply. The essential advantages and disadvantages are summarised below.

Advantages:

– the possibility of mechanisation and high advance rate,

– precision of profile,

– minimisation of the effect on buildings on the surface,

– improved safety for the miners,

– environmentally friendly construction method,

– raising of the groundwater table,

– little noise,

– enables a high-quality and economic lining.

Disadvantages:

– long lead time for the design, production and assembly of the shield machine,

– long familiarisation time,

– elaborate and expensive site facilities (a separating plant may be required); tenders may only be competitive for longer tunnels,

– performance risk in changeable ground,

– the cross-section normally has to be round with little possibility of variation,

– high cost of altering the excavated geometry, e.g. for wider sections,

– the lining normally has to be specially designed to resist the thrust forces.

Application is therefore practicable where the advantages can be sensibly exploited and the disadvantages are taken into account as far as possible in the design and construction planning. Experience shows that a shield in the smaller diameter range can generally compete with other tunnelling methods for tunnel drives up to 2,000 m. For longer tunnels, economic applications of shield machines are possible and even cheaper than using open machines or conventional methods.

The successful use of a shield always requires meticulous design and planning of the machine, the lining and the logistics. Experience and know-how are essential for a practicable and economic scheme. According to [235], too many clients have chosen the wrong machine or construction concept for the ground conditions and have later been faced with unacceptable settlement on the surface, unexpectedly slow advance rates, spalling or failure of the lining, water ingress or other defects. For the client, only a tunnel constructed on schedule, of good quality and at reasonable cost, and with as little impact on the environment as possible is of interest. The designers of shield equipment need to take these natural concerns into consideration. Mechanical engineering issues have to be effectively linked to those of the tunnel itself. Constant exchange of experience between mechanical and civil engineers is essential, with the appropriate evaluation of experience from completed projects.

1.1 Basic principles and terms

The basic principle of a shield is that a generally cylindrical steel construction is driven along the tunnel axis while the ground is excavated. The steel construction supports the excavated cavity until temporary support or the final lining has been installed. The shield therefore has to resist the pressure of the surrounding ground and hold back any groundwater.

While the cavity along the sides of the tunnel is supported by the shield skin itself, additional support measures will be required to support the face, depending on the ground and groundwater conditions encountered. Figure 1-2 shows five different methods of stabilising the face, which are described in detail in Chapter 2. These are:

– natural support,

– mechanical support,

– compressed air support,

– slurry support,

– earth pressure balance support.

These methods of supporting the face represent the great advantage of the shield tunnelling process. In contrast to other methods of tunnelling, it is possible to provide immediate support of the ground as soon as it is disturbed.

In addition to the type of face support, the method of excavation is an important characteristic of shields. The most simple process is manual digging in hand shields, and this is still used today in exceptional cases, for example for short sections and under certain geological conditions. Mechanical excavation is, however, more usual. This can be differentiated into mechanical partial- and full-face excavation. In partial-face excavation, the face is worked in sections using machinery such as hydraulic excavators or roadheaders, which are operated and controlled either by operators or automatically. The full face can be excavated, according to the ground conditions encountered, by open-mode wheels, rim wheels (in some cases with shutters) or closed cutter heads. Further methods are hydraulic excavation using pressurised jets of fluid and extrusion excavation, where the action of the thrust cylinders on highly plastic soil forces it through closable openings in the front wall of the shield. Excavation processes are described in more detail in Chapter 4.

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