File:Signalisation_routière_entrée_sud_tunnel_du_Galibier.jpg · Wikimedia Commons · See Wikimedia Commons

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tunnel

AI overview

A tunnel is an underground or enclosed passageway excavated through earth, rock, or built structures that allows people, vehicles, or utilities to pass through obstacles like mountains, water bodies, or buildings. Tunnels matter because they enable transportation networks, utility systems, and infrastructure to connect places that would otherwise be difficult or impossible to reach, making them essential for modern roads, railways, metro systems, and essential services.

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Wikidata facts

Image: Southern portal of Chirk canal tunnel - geograph.org.uk - 1293092.jpg

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Commons category: Tunnels
equivalent class: dbpedia.org/ontology/Tunnel
Commons gallery: Tunnel
exact match: purl.obolibrary.org/obo/ENVO_00000068

Sources (5)

via Wikidata · CC0

~66 min read

Article

37 sections

Contents

Etymology
History
Antiquity and early middle ages
Geotechnical investigation and design
Choice of tunnels versus bridges
Project planning and cost estimates
Construction
Cut-and-cover
Boring machines
Shafts
Sprayed concrete techniques
Pipe jacking
Box jacking
Underwater tunnels
Temporary way
Enlargement
Open building pit
Other construction methods
Variant tunnel types
Double-deck and multipurpose tunnels
Covered passageways
Underpass
Utility Tunnel
Safety and security
Examples
In history
Longest
Notable
Mining
Military use
Secret tunnels
Natural tunnels
Major accidents
See also
References
Bibliography
External links

thumb|right|Tunnel in Col du Galibier, France thumb|right|Tunnel in Fort de Mutzig, France thumb|Decorated portal to a road tunnel in Guanajuato, Mexico thumb|Utility tunnel for heating pipes between [[Rigshospitalet and Amagerværket in Copenhagen, Denmark]] thumb|Tunnel on the Taipei Metro in [[Taiwan]] thumb|Southern portal of the Chirk Tunnel|Chirk canal tunnel, Wales thumb|Victory Tunnel in [[Shimla, India was opened on 08 May 1945 after the Allied victory in World War II]] thumb|Atal Tunnel in [[Himachal Pradesh, India was opened on 4 October 2020 which connects Manali and Keylang, bypassing Rohtang Pass in high Himalayan terrain]] A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation openings at various points along the length. A pipeline differs significantly from a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods.

A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment.