Heavy plate for
the urban tunnel in Madrid

For the 3,650 m long northern tunnel of the inner-city motorway M-30 in Madrid the Spanish construction companies ordered one of the biggest tunnel boring machines in the world. With a maximum excavation diameter of 15.20 m the cutting head outperformed all dimensions in mechanical tunnel heading before. The tunnel boring machine has an installed torque of 125,268 kNm. To ensure the effectivity of the machine with the biggest excavation diameter at that time in high friction ground conditions a novel cutting head concept was developed.

This concept consists of an inner and an outer cutting head with a drill diameter of 7 m and 15.2 m respectively. They are located on one level and can be activated and moved separately. The steel that was used to build the tunnel boring machine is normalized construction steel S355. Some of the built in elements of the machine that are exposed to high stresses have a thickness of up to 200 mm.