Benoît Jones reviews the most recent addition to the Taylor and Francis series on Applied Geotechnics. Introduction to Tunnel Construction By David Chapman, Nicole Metje and Alfred Stärk This book ‘seeks to provide an introduction to tunnel construction for people who have little experience of the subject’. It is intended as a comprehensive introduction for undergraduates who are intrigued by tunnelling or recent graduates who have by luck or wit found themselves working in the tunnelling industry. The book does not skimp on useful diagrams and photographs that communicate the excitement of tunnelling and is thorough in its treatment of ground improvement techniques, tunnel lining systems and tunnel construction methods. The 390 pages are divided into eight chapters. The first (the introduction) begins with a brief foray into the philosophy of tunnelling, emphasising the fact that, unlike many other civil engineering structures, the ground is a major part of the structure, with both a supporting and a loading role. Due to the many uncertainties involved, not just theory but the use of observation and experience are required. After clarifying the scope, there is then a brief dash through the history of tunnelling and an explanation of ground and tunnel terminology. The next two chapters, ‘Site investigation’ and ‘Preliminary analyses for the tunnel’, are necessarily quite short. However, although the use of site investigation to characterise the geology is adequately covered at a basic level there is no mention of hydrogeology or the use of piezometers to determine the groundwater pressures. As this is often critical to the selection of the construction method, it should be given more prominence. ‘Preliminary analyses for the tunnel’ outlines several simple calculation methods for stability and the dimensioning of support. This chapter is not intended to be comprehensive but at times definitions are imprecise and the assumptions are not stated. However, the chapter does serve to illustrate how tunnels work as structures interacting with the ground around them. The fourth and fifth chapters form the heart of the book where the enthusiasm of the authors really shines through and I would almost recommend they be read first (particularly as there is a photo of me in Figure???). Chapter 4, ‘Ground improvement techniques and lining systems’, covers a broad range of ground improvement techniques such as ground freezing and various methods of improving the ground using grouting in both soil and rock. Then various ground mass reinforcing elements are dealt with including rock bolts, anchors, face dowels and roof pipe umbrellas before moving onto compensation grouting and the use of compressed air. The second half of the chapter describes tunnel lining systems, first outlining some of the design issues. The section on sprayed concrete refers the reader repeatedly to Alun Thomas’s book (volume 2 of the Applied Geotechnics series), which was reviewed by Barry New in the last issue of Tunnelling Journal. Segmental linings come next and a useful table provided by Mike King explains the advantages and disadvantages of segmental linings made from different materials. Waterproofing, shaft lining by underpinning and caisson-sinking, in situ concrete linings and fire resistance complete the chapter. As might be expected, the fifth chapter entitled ‘Tunnel construction techniques’ is by far the longest, weighing in at 116 pages. There are rakes of clear diagrams and well-chosen photographs, which really give a sense of the scale and variety of tunnelling projects and will certainly inspire and enthuse the target audience. Even experienced tunnel engineers, unless they have worked in every type of tunnel ever built, will learn something from this chapter. Timber headings, myriad TBMs, drill and blast, sprayed concrete, cut and cover, immersed tube, jacked box, pipe-jacking, microtunnelling and horizontal directional drilling are all covered. The section on NATM and SCL in chapter 5 is of particular interest, and the authors manage to explain the history and usage of the terms very clearly. The name ‘New Austrian Tunnelling Method’ was introduced to differentiate it from the ‘Austrian Method’, which was a timbering support method followed by late installation of a thick brick arch lining. The NATM was revolutionary in that it sought to use the early installation of anchors and a sprayed concrete lining providing intimate contact with the ground, together with early ring closure, to prevent the development of ‘loosening pressures’ arising from excessive deformation. A common misunderstanding of the NATM surrounds the concept of activating a ground arch by allowing ground deformation to occur, when by far the most important principle is that of preservation of the ground’s ability to support itself through early installation of support. Professor Rokahr (to whom this book is dedicated) explained this excellently in his seminal paper ‘Wie Sicher ist die NÖT?’ (‘How safe is the NATM?’) in 1995. Chapter 6, on ‘Health and safety, and risk management in tunnelling’ by Donald Lamont is wellwritten and concise, with well-chosen references for further reading. ‘Ground movements and monitoring’ are the subject of chapter 7. This is more akin to a state-of-theart review that engineers of all levels of experience will find useful. The authors clearly have much expertise in this area and communicate this with precision and style. A lot of space is given to the principle of the ‘stress intensity index’, a method of determining the factor of safety of a sprayed concrete lining from tunnel displacement monitoring developed at the University of Hanover. However, since textbooks of this kind are usually read uncritically by their target audience, the authors should have mentioned the potential for errors in this method, the existence of other backcalculation methods and the possibility of using strain gauges or pressure cells instead. The final chapter details three case histories of the Egge tunnel in Germany, the Piccadilly Line Extension Junction at Heathrow Terminal 5 in the UK and the Lainzer tunnel in Austria. These give a flavour of how tunnelling challenges can be overcome by good engineering; through the use of observation, experience, practical knowledge and theory. This is the theme which runs throughout the book. This book will be an excellent introduction to tunnel construction for all those new recruits who will be needed when the workload increases over the next few years.