conduit

tunnel

Also known as: cut-and-cover tunnel

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Last updated

June 24, 2026

Quick Summary

A conduit is a channel or pipe used to convey water, fluids, or protect electric cables. In water systems, conduits are often covered or closed sections of aqueducts that transport water under pressure. They can be made from materials like steel, reinforced concrete, cast iron, or asbestos cement.1

A tunnel is a horizontal underground passageway created by excavation or natural processes. Tunnels serve various purposes, including mining, transportation (for vehicles, trains, and subways), and conducting water and sewage. Underground chambers, often connected by tunnels, are increasingly used for hydroelectric power plants, ore processing, storage, and military needs. Tunnels can have entrances called portals and may also be accessed via shafts or adits.2

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tunnels and underground excavations
…cut-and-cover tunnels (more correctly called conduits) are built by excavating from the surface, constructing the structure, and then covering with backfill. Tunnels underwater are now commonly built by the use of an immersed tube: long, prefabricated tube sections are floated to the site, sunk in a prepared trench, and covered…
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…cut-and-cover tunnels (more correctly called conduits) are built by excavating from the surface, constructing the structure, and then covering with backfill. Tunnels underwater are now commonly built by the use of an immersed tube: long, prefabricated tube sections are floated to the site, sunk in a prepared trench, and covered…
Read More

subway
…Railway began in 1860 by cut-and-cover methods—that is, by making trenches along the streets, giving them brick sides, providing girders or a brick arch for the roof, and then restoring the roadway on top. On January 10, 1863, the line was opened using steam locomotives that burned coke and, later,…
Read More
…Railway began in 1860 by cut-and-cover methods—that is, by making trenches along the streets, giving them brick sides, providing girders or a brick arch for the roof, and then restoring the roadway on top. On January 10, 1863, the line was opened using steam locomotives that burned coke and, later,…
Read More