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Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not 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. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immersed Tube
An immersed tube (or immersed tunnel) is a kind of undersea tunnel composed of segments, constructed elsewhere and floated to the tunnel site to be sunk into place and then linked together. They are commonly used for road and rail crossings of rivers, estuaries and sea channels/harbours. Immersed tubes are often used in conjunction with other forms of tunnel at their end, such as a cut and cover or bored tunnel, which is usually necessary to continue the tunnel from near the water's edge to the entrance (portal) at the land surface. Construction The tunnel is made up of separate elements, each prefabricated in a manageable length, then having the ends sealed with bulkheads so they can be floated. At the same time, the corresponding parts of the path of the tunnel are prepared, with a trench on the bottom of the channel being dredged and graded to fine tolerances to support the elements. The next stage is to place the elements into place, each towed to the final location, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Tunnel
A utility tunnel, utility corridor, or utilidor is a passage built underground or above ground to carry utility lines such as electricity, steam, water supply pipes, and sewer pipes. Communications utilities like fiber optics, cable television, and telephone cables are also sometimes carried. One may also be referred to as a services tunnel, services trench, services vault, or cable vault. Smaller cable containment is often referred to as a cable duct or underground conduit. Direct-buried cable is a major alternative to ducts or tunnels. Usage Utility tunnels are common in very cold climates where direct burial below the frost line is not feasible (such as in Alaska, where the frost line is often more than below the surface, which is frozen year round). They are also built in places where the water table is too high to bury water and sewer mains, and where utility poles would be too unsightly or pose a danger (like in earthquake prone Tokyo). Tunnels are also built to av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid Transit
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be called a subway, tube, or underground. Unlike buses or trams, rapid transit systems are railways (usually electric) that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles, and which is often grade-separated in tunnels or on elevated railways. Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on rail tracks, although some systems use guided rubber tires, magnetic levitation ('' maglev''), or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train and platform. They are typically integrated with other publi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Network
In transport, tunnels can be connected together to form a tunnel network. These can be used in mining to reach ore below ground, in cities for underground rapid transit systems, in sewer systems, in warfare to avoid enemy detection or attacks, as maintenance access routes beneath sites with high ground-traffic such as airports and amusement parks, or to extend public living areas or commercial access while avoiding outdoor weather. In warfare Sieges Tunnel networks were sometimes developed during siege warfare, even dating back to classical antiquity. Starting with a single tunnel being dug to undermine a wall that might be detected by the defenders and met with counter-tunnels, leading to tunnel warfare. Defenders might first create a series of underground listing posts to preempt such mining attacks. Trench systems Any time the use of trenches becomes extensive, this naturally leads to connecting them with tunnel networks for safe passage both along the trench lines and with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Underground
The London Underground (also known simply as the Underground or by its nickname the Tube) is a rapid transit system serving Greater London and some parts of the adjacent counties of Buckinghamshire, Essex and Hertfordshire in England. The Underground has its origins in the Metropolitan Railway, the world's first underground passenger railway. Opened on 10 January 1863, it is now part of the Circle, District, Hammersmith & City and Metropolitan lines. The first line to operate underground electric traction trains, the City & South London Railway in 1890, is now part of the Northern line. The network has expanded to 11 lines, and in 2020/21 was used for 296 million passenger journeys, making it one of the world's busiest metro systems. The 11 lines collectively handle up to 5 million passenger journeys a day and serve 272 stations. The system's first tunnels were built just below the ground, using the cut-and-cover method; later, smaller, roughly circular tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glasgow Subway
The Glasgow Subway is an underground light metro system in Glasgow, Scotland. Opened on 14 December 1896, it is the fourth-oldest underground rail transit system in Europe after the London Underground, Liverpool's Mersey Railway and the Budapest Metro. It is also one of the very few railways in the world with a track running gauge of wide. Originally a cable railway, the subway was later electrified, but the double-track circular line was never expanded. The line was originally known as the Glasgow District Subway, and was later renamed Glasgow Subway Railway. In 1936 it was renamed the Glasgow Underground. Despite this rebranding, many Glaswegians continued to refer to the network as "the Subway". In 2003, the name "Subway" was officially readopted by its operator, the Strathclyde Partnership for Transport (SPT). A £40,000 study examining the feasibility of an expansion into the city's south side was conducted in 2005 while a further commitment from Labour in 2007 to exten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wildlife Crossing
Wildlife crossings are structures that allow animals to cross human-made barriers safely. Wildlife crossings may include underpass tunnels or wildlife tunnels, viaducts, and overpasses or green bridges (mainly for large or herd-type animals); amphibian tunnels; fish ladders; canopy bridges (especially for monkeys and squirrels); tunnels and culverts (for small mammals such as otters, hedgehogs, and badgers); and green roofs (for butterflies and birds). Wildlife crossings are a practice in habitat conservation, allowing connections or reconnections between habitats, combating habitat fragmentation. They also assist in avoiding collisions between vehicles and animals, which in addition to killing or injuring wildlife may cause injury to humans and property damage. Similar structures can be used for domesticated animals, such as cattle creeps. Roads and habitat fragmentation Habitat fragmentation occurs when human-made barriers such as roads, railroads, canals, electric pow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subway (underpass)
A subway, also known as an underpass, is a grade-separated pedestrian crossing which crosses underneath a road or railway in order to entirely separate pedestrians and cyclists from motor traffic or trains respectively. Terminology In the United States, as used by the California Department of Transportation and in parts of Pennsylvania such as Harrisburg, Duncannon and Wyoming County, subway refers to a depressed road undercrossing. Where they are built elsewhere in the country, the term 'pedestrian underpass' is more likely to be used, because "subway" in North America refers to rapid transit systems such as the New York City Subway or the Toronto Subway. This usage also occurs in Scotland, where the underground railway in Glasgow is referred to as the Glasgow Subway. Effects Pedestrian underpasses allow for the uninterrupted flow of both pedestrians and vehicle traffic. However, they are normally considered a last resort by modern urban planners as they can be expensive a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rail Transport
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on sleepers (ties) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as "slab track", in which the rails are fastened to a concrete foundation resting on a prepared subsurface. Rolling stock in a rail transport system generally encounters lower frictional resistance than rubber-tyred road vehicles, so passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer faci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueduct (watercourse)
An aqueduct is a watercourse constructed to carry water from a source to a distribution point far away. In modern engineering, the term ''aqueduct'' is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose. The term ''aqueduct'' also often refers specifically to a bridge carrying an artificial watercourse. Aqueducts were used in ancient Greece, ancient Egypt, and ancient Rome. The simplest aqueducts are small ditches cut into the earth. Much larger channels may be used in modern aqueducts. Aqueducts sometimes run for some or all of their path through tunnels constructed underground. Modern aqueducts may also use pipelines. Historically, agricultural societies have constructed aqueducts to irrigate crops and supply large cities with drinking water. Etymology The word ''aqueduct'' is derived from the Latin words (''water'') and (''led'' or ''guided''). Ancient aqueducts Although particularly associated with the Romans, aqueducts we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands within the British Isles. Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between the Kingdom of England (which included Wales, annexed in 1542) and the Kingdom of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow under atmospheric pressure, and can be thought of as artificial rivers. In most cases, a canal has a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as ''slack water levels'', often just called ''levels''. A canal can be called a ''navigation canal'' when it parallels a natural river and shares part of the latter's discharges and drainage basin, and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its valley. A canal can cut across a drainage divide atop a ridge, generally requiring an external water source above the highest elevation. The best-known example of such a canal is the Panam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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