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 24TUNNEL BORING MACHINE (TBM) CUTTER BOOM BACKACTER EARTH PRESSURE BALANCE (EPBM) PRESSURISED SLURRY 5 An introduction to pipe jacking and microtunnelling 1 THE PIPE JACKING TECHNIQUE Typical microtunnelling arrangement A number of types of mechanical excavation systems are available and these are similar to those employed in other forms of tunnelling. Shields, excavation and face support can be provided for a wide variety of ground conditions. Construction tolerances are comparable with other tunnelling methods, and the pipe jacking method generally requires less overbreak than segmental tunnels and provides ground support and reduces potential ground movement. The pipe jacking technique and its components have been subject to extensive and ongoing research at leading UK universities including both Oxford and Cambridge. This has included model and full scale testing of pipes and joints and the effects of lubrication and soil conditioning on the pipe jacking process.