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  1. Tunnel - Wikipedia

    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 …

  2. Tunnels and underground excavations | History, Methods, Uses, …

    Dec 19, 2025 · tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by nature’s action in dissolving a soluble rock, such as …

  3. TUNNEL Definition & Meaning - Merriam-Webster

    The meaning of TUNNEL is a covered passageway; specifically : a horizontal passageway through or under an obstruction. How to use tunnel in a sentence.

  4. How Tunnels Work - HowStuffWorks

    Constructing a tunnel is one of the most complex challenges in the field of civil engineering. Learn about the basics behind tunnels.

  5. TUNNEL | definition in the Cambridge English Dictionary

    TUNNEL meaning: 1. a long passage under or through the ground, especially one made by people: 2. the long passage…. Learn more.

  6. Tunnel construction - Wikipedia

    Tunnels are dug in types of materials varying from soft clay to hard rock.

  7. Tunnels and underground excavations - Tunneling techniques

    Dec 19, 2025 · Tunnels are generally grouped in four broad categories, depending on the material through which they pass: soft ground, consisting of soil and very weak rock; hard rock; soft …

  8. Nada Tunnel - Wikipedia

    There is a local legend that the Nada Tunnel is haunted by a ghost of a former tunnel construction worker who perished when a stick of dynamite exploded when being thawed at a nearby fire.

  9. TUNNEL | English meaning - Cambridge Dictionary

    TUNNEL definition: 1. a long passage under or through the ground, especially one made by people: 2. the long passage…. Learn more.

  10. tunnel summary | Britannica

    tunnel, Horizontal or nearly horizontal underground or underwater passageway. Tunnels are used for mining, as passageways for trains and motor vehicles, for diverting rivers around damsites, …