|
Tunnel
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.Salazar, Waneta. ''Tunnels in Civil Engineering''. Delhi, India : Wh ... [...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, Modular construction, 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, Estuary, 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 Boring (earth), 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 Prefabrication, prefabricated in a manageable length, then having the ends sealed with Bulkhead (partition), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid Transit
Rapid transit or mass rapid transit (MRT) or heavy rail, commonly referred to as metro, is a type of high-capacity public transport that is generally built in urban areas. A grade separation, grade separated rapid transit line below ground surface through a tunnel can be regionally called a subway, tube, metro or underground. They are sometimes grade-separated on elevated railways, in which case some are referred to as el trains – short for "elevated" – or skytrains. Rapid transit systems are usually electric railway, electric railways, that unlike buses or trams operate on an exclusive right-of-way (transportation), right-of-way, which cannot be accessed by pedestrians or other vehicles. Modern services on rapid transit systems are provided on designated lines between metro station, stations typically using electric multiple units on railway tracks. Some systems use rubber-tyred metro, guided rubber tires, magnetic levitation (''maglev''), or monorail. The stations typica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secret Passage
Secret passages, also commonly referred to as hidden passages or secret tunnels, are hidden routes used for stealthy travel, escape, or movement of people and goods. They are sometimes inside buildings leading to secret rooms. Others allow people to enter or exit buildings without being seen. Hidden passages and secret rooms have been built in castles and houses owned by heads of state, the wealthy, criminals, and abolitionists associated with the American Underground Railroad. They have helped besieged rulers escape attackers, including Pope Alexander VI in 1494, Pope Clement VII in 1527 and Marie Antoinette in 1789. Passages and tunnels have been used by criminals, armies (notably the Viet Cong in the Vietnam War) and political organizations to smuggle goods and people or conceal their activities. Appearance and construction Entrances to some secret passages appear as architectural features, such as a fireplaces or built-in sliding bookcases. Some entrances are more elabo ... [...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 avoid t ... [...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 an ... [...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 or death 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, railroa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rail Transport
Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of land transport, next to road transport. It is used for about 8% of passenger and rail freight transport, freight transport globally, thanks to its Energy efficiency in transport, energy efficiency and potentially high-speed rail, high speed.Rolling stock on rails generally encounters lower friction, frictional resistance than rubber-tyred road vehicles, allowing rail cars to be coupled into longer trains. Power is usually provided by Diesel locomotive, diesel or Electric locomotive, electric locomotives. While railway transport is capital intensity, capital-intensive and less flexible than road transport, it can carry heavy loads of passengers and cargo with greater energy efficiency and safety. Precursors of railways driven by human or an ... [...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, the ancient Near East, ancient Rome, ancient Aztec, and ancient Inca. 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 ... [...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 Panama Can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road
A road is a thoroughfare used primarily for movement of traffic. Roads differ from streets, whose primary use is local access. They also differ from stroads, which combine the features of streets and roads. Most modern roads are paved. The words "road" and "street" are commonly considered to be interchangeable, but the distinction is important in urban design. There are many types of roads, including parkways, avenues, controlled-access highways (freeways, motorways, and expressways), tollways, interstates, highways, and local roads. The primary features of roads include lanes, sidewalks (pavement), roadways (carriageways), medians, shoulders, verges, bike paths (cycle paths), and shared-use paths. Definitions Historically, many roads were simply recognizable routes without any formal construction or some maintenance. The Organization for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroelectric
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energy, renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of Low-carbon power, low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portal (architecture)
A portal is an opening in a wall of a building, gate or fortification, especially a grand entrance to an important structure. Doors, metal gates, or portcullis in the opening can be used to control entry or exit. The surface surrounding the opening may be made of simple building materials or decorated with ornamentation. The elements of a portal can include the voussoir, tympanum, an ornamented mullion or ''trumeau'' between doors, and columns with carvings of saints in the westwork of a church. Examples File:Baroque portal in Brescia.jpg, Baroque portal of a private palace in Brescia File:Quito Iglesia de El Carmen Bajo Southwestern carved door.jpg, Baroque portal of the Church of El Carmen Bajo Monastery in Quito File:Dülmen, St.-Viktor-Kirche, Eingangsportal -- 2021 -- 4504-10.jpg, Wooden portal of the Church of St. Victor in Dülmen File:Porto - Sant Martí de Cedofeita - Façana principal.JPG, Romanesque portal of the Church of São Martinho de Cedofeita, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
