drfting tunneling works 79 tunnels 35 road tunnels 24 underground structures 22 geological survey 20 underground (transport) 18 more ... geoengineering 17 railway tunnels 17 building designing 14 galleries (mining) 14 transport constructions 13 tunnelling shields 11 concreting works 10 urban underground transport 7 motorways 6 utility nets 6 sewer networks 6 history 5 engineering geology 5 undermining 4 tunnelling machines 4 construction works 4 excavation 3 hydrogeology 3 numerical simulation 3 simulation and modelling 3 machines for underground and tunnelling works 3 concrete constructions 2 deep mining 2 less ...