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Tunnel construction is a subset of underground construction. There are three basic types of tunnel construction in common use: Cut-and-cover tunnel, constructed in a shallow trench and then covered over. Bored tunnel, constructed in situ, without removing the ground above. They are usually of circular or horseshoe cross-section.
Cut-and-cover construction at Saint-Michel on Paris Métro Line 4 (c. 1910) Cut-and-cover is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. [29] There are two basic forms of cut-and-cover ...
Deep level underground is construction that is 20 m (66 ft) or more below ground and not using the cut-and-cover method, especially train stations, air raid shelters and bunkers, and some tunnels and mines. Cut-and-cover is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support ...
Underground construction has a number of unique risks and challenges but shares a lot with traditional construction and mining. Underground construction workers often work under reduced light condition, in dangerous spaces, and are at a high risk of exposure to contaminants, fire, and explosions.
An alternative to digging trenches is to create a utility tunnel. Such a tunnel may be dug by boring or by using a trench for cut-and-cover construction. The advantages of utility tunnels are the reduction of maintenance manholes, one-time relocation, and less excavation and repair, compared with separate cable ducts for each service.
Cut-and-cover; D. Daylighting (tunnels) ... Tunnel hole-through This page was last edited on 24 June 2022, at 12:08 (UTC). Text is available under the Creative ...
A secret tunnel discovered last week on the U.S.-Mexico border will be sealed by Mexican authorities, an army official in Ciudad Juarez said Saturday. The tunnel, discovered on Jan. 10, connects ...
One unusual means of creating a cut is to remove the roof of a tunnel through daylighting. Material removed from cuts is ideally balanced by material needed for fills along the same route, but this is not always the case when cut material is unsuitable for use as fill. The word is also used in the same sense in mining, in particular Open-pit ...