alagút

An alagút is a tunnel—a passage excavated through earth, rock, or water to enable transportation, utility conveyance, or access beneath obstacles such as mountains, rivers, or urban areas. In Hungarian usage, the term generally refers to artificial tunnels built for roads, railways, or utilities, but it can also describe underwater or subterranean passages that shorten routes or protect infrastructure from surface disturbances.

Construction methods vary. Bored tunnels are created with tunnel boring machines that excavate and simultaneously line the passage. Cut-and-cover tunnels are built by excavating a trench, constructing a lining, and then replacing the earth. Immersed-tube tunnels are assembled in sections, floated to the site, and submerged underwater. Tunneling projects employ liners of reinforced concrete, steel segments, or shotcrete, and require systems for drainage, ventilation, lighting, and fire safety.

Design and operation considerations include ground conditions, groundwater control, settlement near the surface, and seismic or other dynamic loads. Safe operation relies on proper ventilation, reliable power and communication systems, emergency exits, cross-passages between tubes, and regular maintenance and monitoring of structural integrity, water ingress, and fire protection equipment.

Uses span road and rail transportation, pedestrian passages, and utility corridors for cables, pipelines, and drainage. Notable examples include major urban and cross-border tunnels, as well as iconic long-distance routes such as underwater and mountain-crossing tunnels. The development of alagút projects continues to emphasize safety, efficiency, and integration with surrounding infrastructure.