World's Biggest TBM Finishes Boring in Madrid 'Dulcinea', the world's biggest TBM featuring a 15.2 m diameter and a power of 22,000 kW, has completed its job in record time. Machine S-300, specially designed by Herrenknecht to dig the north tunnel of the south bypass on the M-30 in Madrid, has concluded the construction and placement of lining rings in the 3,578 tunnel in seven months. Madrid mayor Alberto Ruiz-Gallardon attended on 17th July the end of tunnelling. View video here. The machine commenced to work on 25th November, 2005 and broke through two months earlier than scheduled. Click here. It worked at a monthly pace of 500 metres, 200 metres more than the 300 metres initially planned. The machine's record advance has been 36 metres in one day. Throughout tunnelling, the machine extracted over one million cubic metres of soils or, in other words, 500 daily dumptruck loads 24 hours round the clock. Approx. 600 persons worked on the tunnel in four shifts 24 hours a day. The completed tunnel is 13.45 m wide and will carry three lanes. Visit www.herrenknecht.com This tunnel and its twin, bored southward by the second machine, dubbed 'Tizona', form part of one of the major schemes for the makeover of the M-30 i.e. the south bypass which connects the A-3 and the M-30 at Conde de Casal with Paseo de Santa Maria de la Cabeza and the tunnels along the Manzanares river. 'Tizona' could end its job before Christmas. Construction of the south bypass implies a path 1.5 km shorter than the current surface artery. It will thus be an attractive option for the 260,000 motorists who drive daily through the south loop of the M-30, one third of whom (80,000) will use the new tunnels, thereby saving 120,000 kilometres a day. The tunnel will be a real benefit to 650,000 residents in Arganzuela, Retiro, Puente de Vallecas and Usera. Vehicle emissions in the tunnel will not be released directly to the atmosphere but will be processed by a high technology ventilation and filtration system, able to withstand 80% of the gas emissions. Click here.Road safety in the new infrastructure will be ensured by CCTV cameras, AID, variable signs, loudspeakers, SOS niches, a specific control centre, tunnels for service and rescue vehicles and tunnels for pedestrians and removal of cars. Both tunnels will be cross-connected by escape tunnels, spread out every 200 metres along the alignment.One major achievement of the north tunnel on the south bypass of the M-30 is the construction planning, not only for the design and route, particularly complex, but also for the logistics to assemble the TBM, the geotechnical surveys and the installation of ground monitoring instrumentation managed by the Centre for Security and Control of Municipal Infrastructure Works (SECOIM), which installed in the area 1,911 gauges to measure surrounding buildings. Click es/104. Visit www.munimadrid.es 31-32/06.