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Goin’ Underground lutionized the design and construction of sprayed concrete linings. There is a growing acceptance of the use of sprayed concrete as permanent works, Andrew Pickett, C.Eng, MICE as well as spray-applied waterproofing membranes. Senior Engineer, has been a In turn, this has generated a body of experience on Design and Project Engineer real projects which has been fed back into the for Mott MacDonald since design methods and technology. While composite 1998. Pickett has worked on permanent sprayed concrete linings may not be major UK and International suitable for all cases, there are many where this tunnel projects, and is currently approach is very effective. Table 2 illustrates how Senior Engineer on the Cross- the lining thickness could be reduced by using rail project responsible for the Bond Street and spray-on membranes and the composite action of Tottenham Court Road Station tunnel designs. all parts of the lining. As noted before, some key Contact him at andrew.pickett@mottmac.com. design assumptions limit the savings in materials for CSLs, although there are still significant sav- Dr. Alun Thomas, P.Eng, is ings in the costs of formwork and the time to install. Head of Tunnels Department, The biggest savings are offered by using the SSL Mott MacDonald, Ramboll, option. Some design issues remain and Mott Mac- Denmark. Thomas has a broad Donald is involved in ongoing research in the field experience of many types of tun- of fully composite linings. neling methods from immersed tubes to segmental linings, from Acknowledgments closed face TBMs to hand exca- The authors would like to acknowledge the vation under compressed air. He has a specialty in contributions of many colleagues at Mott Mac- sprayed concrete lined (SCL/NATM) tunnels and Donald in the development of the design numerical modeling. Thomas has been involved in approaches. The authors would also like to thank promoting the use of permanent sprayed concrete, BASF (especially Karl Gunnar Holter, Richard fiber reinforcement, and spray-applied waterproof Foord, Kevin Stubberfield, and Thomas Kothe) and membranes. Over the last 19 years, he has been Ross Dimmock at TAM International for their involved in many of the recent major UK tunneling contributions in developing some of these concepts. projects, such as the Jubilee Line Extension, Heathrow Express, Terminal 5 and Crossrail, as references well as working on design and construction of tun- 1. Thomas, A.H.: Advances in Sprayed Concrete Tunnel- nels internationally. Notably, Thomas has worked ling. Tunnelling Journal, Apr/May 2010, pp. 40-44. in Denmark, Russia, the United States, Iceland, 2. Thomas, A H.; Pickett, A P.: The design of composite Hungary, Singapore, India and Hong Kong. Recent sprayed linings. Modern use of wet mix sprayed concrete for projects include Cityringen Branch off to Nordhavn underground support, Tromsö, Norway 2011. in Copenhagen and the Chennai metro. 3. Reynolds, P.: Hindhead Hit. T&TI, October 2008, pp. 16-18. Since starting as a fresh graduate, he has moved 4. Darby, A.; Leggett, M.: Use of shotcrete as the perma- on to lead design teams, supervise construction, and nent lining of tunnels in soft ground. Mott MacDonald Milne manage projects with a construction value of hun- Award submission (unpublished). dreds of millions of euros. On the way he has gained 5. Hilar, M.; Thomas, A.; Falkner, L.: The Latest Innova- hands-on experience of many forms of tunnel tion in Sprayed Concrete Lining - the LaserShell Method. construction, been involved in research projects, and Tunel – Magazine of the Czech Tunnelling Committee and the Slovak Tunnelling Committee ITA/AITES, V. 4, participated in all stages of design development. pp. 11-19, 2005. Thomas has given lectures at the British Tunnel- 6. EN 14487 (2005) Sprayed concrete. British Standards ling Society course, the Budapest Technical Univer- Institution, London. sity, and the Danish Technical University. A regular 7. Eurocode 2 (2004) EN 1992-1-1:2004 Design of con- contributor to magazines and conferences, with more crete structures — Part 1-1: General rules and rules for build- ings. British Standards Institution, London. than 50 publications, he has written articles on 8. RILEM TC 162-TDF (2003) Test and design methods subjects ranging from sustainability to user-friendly for steel fibre reinforced concrete. Materials and Structures, contracts. A Chinese version of his book, Sprayed V. 36, pp. 560 - 567. Concrete Lined Tunnels, is under production and 9. Thomas, A.H.: Advances in Sprayed Concrete Tunnel- an update of the English version is planned. Thomas ling. Tunnelling Journal, Apr/May 2010, pp. 40-44. is a member of the ITA’s Working Group 12 on 10. Yilmaz, H.: Comparison of mechanical properties of shotcrete and Thin Spray-on Liner (TSL). ITA, SAIMM and Sprayed Concrete and he has just joined ITAtech’s SANCOT: Shotcrete for Africa, 2009. design group. Shotcrete • Fall 2013 53


2013FallShotcreteEMag
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