Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 2418 An introduction to pipe jacking and microtunnelling 4 DESIGN AND CONSTRUCTION METHODS 4c) Indicative jacking lengths achievable between shafts for mechanised drives The information contained in this table is based on PJA members’ experience and lengths being achieved internationally for both straight and curved drives. The lengths listed should only be undertaken following extensive risk analysis on individual projects and subject to technical limitations. NOMINAL INTERNAL DIAMETER OF TUNNEL LINING IN METRES Pipe diameter