Discussion. Victoria Line: Experimentation, Design, Programming, and Early Progress.

Tunnelling

“…Furthermore this interdependence adds weight to the deliberate step-bystep approach through the planning and design of the project (Chapters 2, 3, 4 and 5) to guide the studies. Benefits derived from innovation in method or from the need to reduce uncertainty in an unfamiliar locality may well justify the use of test galleries or experimental tunnels prior to decisions on the scheme of working, for which an allowance of time must suffice to permit the results to contribute to the optimal solution, recognising the period needed for observation and for possible modification of tunnelling techniques, as for the Keilder Tunnel (Ward 1978 andCoats et al 1982), the Orange-Fish Tunnel (Kidd 1976) and the Victoria Line tunnels (Dunton et al 1965). A more general account of the benefits is given by Lane (1975).…”

“…6 ft (1.8 m), a more complex procedure was required, adopting ( 1) and ( 2) above supplemented by the threading of longitudinal Lee-McCall prestressing bars to avoid risk of spreading of the 'lintel' and 'sill' above and beneath the opening. Several means of expanding the ring were tested in an experimental tunnel for the Victoria Line of London's Underground in 1960-61 (Dunton et al 1965), including the use of internal jacks with the insertion of folding wedges and the use of a wedge segment in the crown. For the Victoria Line (Follenfant et al 1969, Clark et al 1969, jacks were used at 'knee joints' with precast blocks inserted in the space.…”

“…The procedure may positively, with advantage and familiarisation of all concerned, lead to a greater extent of demonstration trials where a particular promising innovation undergoes a full-scale trial prior to its adoption. The Victoria Line in London (Dunton et al 1965) provides one of many examples (Lane 1975) of the benefit of such a practice. The penetrating observation of a previous Director General of the Health and Safety Executive (Rimington 1993) needs to be borne constantly in mind: 'to pay too much attention to avert any harm is likely to increase harm in the long run.'…”

Development over London Underground tunnels: No. 1 Grafton Street

“…The section from Warren Street to Victoria, which is relevant to this development, was opened on 7 March 1969 (Clark et al, 1969;Follenfant, 1969). The lengths of tunnel at this location were constructed using what was at the time a new and experimental tunnel lining system, which was largely bolt free and referred to as a 'flexible cast iron lining' (Dunton et al, 1963;Morgan and Bartlett, 1969).…”