ABSTRACT
The use of tunnelling machines is becoming increasingly important for heading transport tunnels underground. Unlike when the shotcrete tunnelling method (NATM) is applied, mechanically-driven tunnels bored in soft ground are lined with reinforced concrete segments. Comparing both the shotcrete tunnelling method and the mechanical tunnel driving there are to be recognised significant differences concerning the construction period on one hand and the operation face on the other hand. While the conventional method (NATM) offers advantages concerning the adaptability with regard to geological and operational conditions it is linked with disadvantages related to safety and occupational health conditions, mechanisation, standardisation and economical aspects as long as longer tunnel drives are concerned. Specific design criteria with regard to the waterproofing technique have to be considered.
Current and future construction volumes in Germany and the neighbouring European countries certify tremendous efforts aiming at a real improvement of the traffic infrastructure. Some interesting correlations in this field are described and explained by some graphs taking Germany as an example.
