tunneling works 249 tunnels 90 drfting 79 road tunnels 62 building designing 56 underground structures 51 transport constructions 46 more ... railway tunnels 46 geological survey 38 underground (transport) 37 geoengineering 31 concreting works 22 urban underground transport 21 history 16 tunnelling shields 16 galleries (mining) 15 machines for underground and tunnelling works 13 engineering geology 11 railway transport 11 motorways 10 real estate development 10 waterproof insulations 8 sewer networks 8 reconstruction 8 concrete constructions 7 tunnelling machines 7 iron-concrete constructions 7 undermining 6 building construction reliability 6 utility nets 5 less ...