82-534: The Nyborg Tunnel is a proposed 8-kilometre (5.0 mi) long road tunnel between Åsane and Klauvaneset in the city-municipality of Bergen in Vestland county, Norway . If built, it would extend the four-lane motorway section of European route E39 (E39) from Åsane northwards to the Nordhordland Bridge . The tunnel is presumed financed with a five-year toll collection at the bridge while
164-537: A better system of training for siege operations was required. On 23 April 1812 an establishment was authorised, by Royal Warrant, to teach "Sapping, Mining, and other Military Fieldworks" to the junior officers of the Corps of Royal Engineers and the Corps of Royal Military Artificers, Sappers and Miners. The first courses at the Royal Engineers Establishment were done on an all ranks basis with
246-480: A dedicated force of military engineering specialists were the Romans, whose army contained a dedicated corps of military engineers known as architecti . This group was pre-eminent among its contemporaries. The scale of certain military engineering feats, such as the construction of a double-wall of fortifications 30 miles (48 km) long, in just 6 weeks to completely encircle the besieged city of Alesia in 52 B.C.E.,
328-483: A given volume in a short duration. Specific military engineering occupations also extend to the field of explosives and demolitions and their usage on the battlefield. Explosive devices have been used on the battlefield for several centuries, in numerous operations from combat to area clearance. Earliest known development of explosives can be traced back to 10th-century China where the Chinese are credited with engineering
410-449: A large factor in the decision making process. Civil engineers usually use project management techniques for developing a major structure. Understanding the amount of time the project requires, and the amount of labor and materials needed is a crucial part of project planning. The project duration must be identified using a work breakdown structure and critical path method . Also, the land needed for excavation and construction staging, and
492-467: A pipe jack, with the span of some box jacks in excess of 20 metres (66 ft). A cutting head is normally used at the front of the box being jacked, and spoil removal is normally by excavator from within the box. Recent developments of the Jacked Arch and Jacked deck have enabled longer and larger structures to be installed to close accuracy. There are also several approaches to underwater tunnels,
574-553: A popular spectacle for the local people by 1843, when 43,000 came to watch a field day laid on to test a method of assaulting earthworks for a report to the Inspector General of Fortifications. In 1869 the title of the Royal Engineers Establishment was changed to "The School of Military Engineering" (SME) as evidence of its status, not only as the font of engineer doctrine and training for the British Army , but also as
656-421: A specialized method called clay-kicking for digging tunnels in clay-based soils. The clay-kicker lies on a plank at a 45-degree angle away from the working face and rather than a mattock with his hands, inserts with his feet a tool with a cup-like rounded end, then turns the tool with his hands to extract a section of soil, which is then placed on the waste extract. Clay-kicking is a specialized method developed in
738-401: A technical discipline, the term civil engineering entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the older discipline. As the prevalence of civil engineering outstripped engineering in a military context and the number of disciplines expanded, the original military meaning of the word "engineering"
820-434: A tube can be sunk into a body of water, which is called an immersed tunnel. 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. There are two basic forms of cut-and-cover tunnelling: Shallow tunnels are often of the cut-and-cover type (if under water, of
902-747: A tunnel than a sufficiently strong bridge). Some water crossings are a mixture of bridges and tunnels, such as the Denmark to Sweden link and the Chesapeake Bay Bridge-Tunnel in Virginia . There are particular hazards with tunnels, especially from vehicle fires when combustion gases can asphyxiate users, as happened at the Gotthard Road Tunnel in Switzerland in 2001. One of the worst railway disasters ever,
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#1732801063351984-432: A tunnel. Bridges usually require a larger footprint on each shore than tunnels. In areas with expensive real estate, such as Manhattan and urban Hong Kong , this is a strong factor in favor of a tunnel. Boston's Big Dig project replaced elevated roadways with a tunnel system to increase traffic capacity, hide traffic, reclaim land, redecorate, and reunite the city with the waterfront. The 1934 Queensway Tunnel under
1066-406: A whole, including military engineering functions such as engineer support to force protection, counter-improvised explosive devices, environmental protection, engineer intelligence and military search. Military engineering does not encompass the activities undertaken by those 'engineers' who maintain, repair and operate vehicles, vessels, aircraft, weapon systems and equipment." Military engineering
1148-461: Is a stub . You can help Misplaced Pages by expanding it . This article related to Bergen , Norway is a stub . You can help Misplaced Pages by expanding it . Road 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
1230-651: Is allowed in this tunnel tube, and motorcyclists are directed to the other tube. Each level was built with a three-lane roadway, but only two lanes per level are used – the third serves as a hard shoulder within the tunnel. The A86 Duplex is Europe's longest double-deck tunnel. Military engineering Military engineering is loosely defined as the art, science, and practice of designing and building military works and maintaining lines of military transport and military communications . Military engineers are also responsible for logistics behind military tactics. Modern military engineering differs from civil engineering . In
1312-594: Is an academic subject taught in military academies or schools of military engineering . The construction and demolition tasks related to military engineering are usually performed by military engineers including soldiers trained as sappers or pioneers . In modern armies, soldiers trained to perform such tasks while well forward in battle and under fire are often called combat engineers . In some countries, military engineers may also perform non-military construction tasks in peacetime such as flood control and river navigation works, but such activities do not fall within
1394-611: Is an example. Such military engineering feats would have been completely new, and probably bewildering and demoralizing, to the Gallic defenders. Vitruvius is the best known of these Roman army engineers, due to his writings surviving. Examples of battles before the early modern period where military engineers played a decisive role include the Siege of Tyre under Alexander the Great , the Siege of Masada by Lucius Flavius Silva as well as
1476-412: Is commonly listed under the role of combat engineers who demolitions expertise also includes mine and IED detection and disposal. For more information, see Bomb disposal . Military engineers are key in all armed forces of the world, and invariably found either closely integrated into the force structure, or even into the combat units of the national troops. Brazilian Army engineers can be part of
1558-505: Is intended to carry both the Istanbul metro and a two-level highway, over a length of 6.5 km (4.0 miles). The French A86 Duplex Tunnel [ fr ] in west Paris consists of two bored tunnel tubes, the eastern one of which has two levels for light motorized vehicles, over a length of 10 km (6.2 miles). Although each level offers a physical height of 2.54 m (8.3 ft), only traffic up to 2 m (6.6 ft) tall
1640-639: Is now largely obsolete. In its place, the term "military engineering" has come to be used. In ancient times, military engineers were responsible for siege warfare and building field fortifications , temporary camps and roads. The most notable engineers of ancient times were the Romans and Chinese , who constructed huge siege-machines (catapults, battering rams and siege towers ). The Romans were responsible for constructing fortified wooden camps and paved roads for their legions . Many of these Roman roads are still in use today. The first civilization to have
1722-494: Is relatively long and narrow; the length is often much greater than twice the diameter , although similar shorter excavations can be constructed, such as cross passages between tunnels. The definition of what constitutes a tunnel can vary widely from source to source. For example, in the United Kingdom, a road tunnel is defined as "a subsurface highway structure enclosed for a length of 150 metres (490 ft) or more." In
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#17328010633511804-401: Is sometimes necessary during the excavation of a tunnel. They are usually circular and go straight down until they reach the level at which the tunnel is going to be built. A shaft normally has concrete walls and is usually built to be permanent. Once the access shafts are complete, TBMs are lowered to the bottom and excavation can start. Shafts are the main entrance in and out of the tunnel until
1886-515: Is that the open building pit is muted after tunnel construction; no roof is placed. Some tunnels are double-deck, for example, the two major segments of the San Francisco–Oakland Bay Bridge (completed in 1936) are linked by a 160-metre (540 ft) double-deck tunnel section through Yerba Buena Island , the largest-diameter bored tunnel in the world. At construction this was a combination bidirectional rail and truck pathway on
1968-698: Is the Siloam Tunnel , built in Jerusalem by the kings of Judah around the 8th century BC. Another tunnel excavated from both ends, maybe the second known, is the Tunnel of Eupalinos , which is a tunnel aqueduct 1,036 m (3,400 ft) long running through Mount Kastro in Samos , Greece. It was built in the 6th century BC to serve as an aqueduct . In Ethiopia , the Siqurto foot tunnel , hand-hewn in
2050-569: The Balvano train disaster , was caused by a train stalling in the Armi tunnel in Italy in 1944, killing 426 passengers. Designers try to reduce these risks by installing emergency ventilation systems or isolated emergency escape tunnels parallel to the main passage. Government funds are often required for the creation of tunnels. When a tunnel is being planned or constructed, economics and politics play
2132-629: The Battle of the Trench under the suggestion of Salman the Persian to dig a trench. For about 600 years after the fall of the Roman empire , the practice of military engineering barely evolved in the west. In fact, much of the classic techniques and practices of Roman military engineering were lost. Through this period, the foot soldier (who was pivotal to much of the Roman military engineering capability)
2214-522: The Brazilian Air Force is occupied by engineers professionalized by Centro de Instrução e Adaptação da Aeronáutica (CIAAR) (Air Force Instruction and Adaptation Center) and trained, or specialized, by Instituto Tecnológico de Aeronáutica (ITA) (Aeronautics Institute of Technology). The Royal School of Military Engineering is the main training establishment for the British Army 's Royal Engineers . The RSME also provides training for
2296-481: The British Army in the conduct of siege operations and bridging. During this war low-ranking Royal Engineers officers carried out large-scale operations. They had under their command working parties of two or three battalions of infantry, two or three thousand men, who knew nothing in the art of siegeworks. Royal Engineers officers had to demonstrate the simplest tasks to the soldiers, often while under enemy fire. Several officers were lost and could not be replaced, and
2378-562: The Churchill AVRE . These and other dedicated assault vehicles were organised into the specialised 79th Armoured Division and deployed during Operation Overlord – 'D-Day'. Other significant military engineering projects of World War II include Mulberry harbour and Operation Pluto . Modern military engineering still retains the Roman role of building field fortifications , road paving and breaching terrain obstacles. A notable military engineering task was, for example, breaching
2460-471: The Port Authority of New York and New Jersey was not aware of this bill and had not asked for a grant for such a project. Increased taxes to finance a large project may cause opposition. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the groundwater conditions, the length and diameter of
2542-848: The Queens-Midtown Tunnel between Manhattan and the borough of Queens on Long Island ; the Detroit-Windsor Tunnel between Michigan and Ontario ; and the Elizabeth River tunnels between Norfolk and Portsmouth, Virginia ; the 1934 River Mersey road Queensway Tunnel ; the Western Scheldt Tunnel , Zeeland, Netherlands; and the North Shore Connector tunnel in Pittsburgh, Pennsylvania . The Sydney Harbour Tunnel
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2624-472: The River Mersey at Liverpool was chosen over a massively high bridge partly for defense reasons; it was feared that aircraft could destroy a bridge in times of war, not merely impairing road traffic but blocking the river to navigation. Maintenance costs of a massive bridge to allow the world's largest ships to navigate under were considered higher than for a tunnel. Similar conclusions were reached for
2706-768: The Royal Navy , Royal Air Force , other Arms and Services of the British Army , Other Government Departments, and Foreign and Commonwealth countries as required. These skills provide vital components in the Army's operational capability, and Royal Engineers are currently deployed in Afghanistan , Iraq , Cyprus , Bosnia , Kosovo , Kenya , Brunei , Falklands , Belize , Germany and Northern Ireland . Royal Engineers also take part in exercises in Saudi Arabia , Kuwait , Italy, Egypt , Jordan , Canada, Poland and
2788-523: The Suez Canal during the Yom Kippur War . Military engineers can come from a variety of engineering programs. They may be graduates of mechanical , electrical , civil , or industrial engineering . Modern military engineering can be divided into three main tasks or fields: combat engineering, strategic support, and ancillary support. Combat engineering is associated with engineering on
2870-679: The United Kingdom of digging tunnels in strong clay-based soil structures. This method of cut and cover construction required relatively little disturbance of property during the renewal of the United Kingdom's then ancient sewerage systems. It was also used during the First World War by Royal Engineer tunnelling companies placing mines beneath German lines, because it was almost silent and so not susceptible to listening methods of detection. Tunnel boring machines (TBMs) and associated back-up systems are used to highly automate
2952-610: The canton of Glarus . The borehole has a diameter of 8.03 metres (26.3 ft). The four TBMs used for excavating the 57-kilometre (35 mi) Gotthard Base Tunnel , in Switzerland , had a diameter of about 9 metres (30 ft). A larger TBM was built to bore the Green Heart Tunnel (Dutch: Tunnel Groene Hart) as part of the HSL-Zuid in the Netherlands, with a diameter of 14.87 metres (48.8 ft). This in turn
3034-489: The water table . This pressurizes the ground ahead of the TBM cutter head to balance the water pressure. The operators work in normal air pressure behind the pressurized compartment, but may occasionally have to enter that compartment to renew or repair the cutters. This requires special precautions, such as local ground treatment or halting the TBM at a position free from water. Despite these difficulties, TBMs are now preferred over
3116-483: The 14th-century development of gunpowder , new siege engines in the form of cannons appeared. Initially military engineers were responsible for maintaining and operating these new weapons just as had been the case with previous siege engines. In England, the challenge of managing the new technology resulted in the creation of the Office of Ordnance around 1370 in order to administer the cannons, armaments and castles of
3198-689: The 16th century as a metaphor for a narrow, confined space like the inside of a cask. Some of the earliest tunnels used by humans were paleoburrows excavated by prehistoric mammals. Much of the early technology of tunneling evolved from mining and military engineering . The etymology of the terms "mining" (for mineral extraction or for siege attacks ), " military engineering ", and " civil engineering " reveals these deep historic connections. Predecessors of modern tunnels were adits that transported water for irrigation , drinking, or sewerage . The first qanats are known from before 2000 BC. The earliest tunnel known to have been excavated from both ends
3280-638: The 1960s. The main idea of this method is to use the geological stress of the surrounding rock mass to stabilize the tunnel, by allowing a measured relaxation and stress reassignment into the surrounding rock to prevent full loads becoming imposed on the supports. Based on geotechnical measurements, an optimal cross section is computed. The excavation is protected by a layer of sprayed concrete, commonly referred to as shotcrete . Other support measures can include steel arches, rock bolts, and mesh. Technological developments in sprayed concrete technology have resulted in steel and polypropylene fibers being added to
3362-716: The 1971 Kingsway Tunnel under the Mersey. In Hampton Roads, Virginia , tunnels were chosen over bridges for strategic considerations; in the event of damage, bridges might prevent US Navy vessels from leaving Naval Station Norfolk . Water-crossing tunnels built instead of bridges include the Seikan Tunnel in Japan; the Holland Tunnel and Lincoln Tunnel between New Jersey and Manhattan in New York City ;
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3444-409: The 20th and 21st centuries, military engineering also includes CBRN defense and other engineering disciplines such as mechanical and electrical engineering techniques. According to NATO , "military engineering is that engineer activity undertaken, regardless of component or service, to shape the physical operating environment. Military engineering incorporates support to maneuver and to the force as
3526-709: The Middle Ages, crosses a mountain ridge. In the Gaza Strip , the network of tunnels was used by Jewish strategists as rock-cut shelters, in first links to Judean resistance against Roman rule in the Bar Kokhba revolt during the 2nd century AD. A major tunnel project must start with a comprehensive investigation of ground conditions by collecting samples from boreholes and by other geophysical techniques. An informed choice can then be made of machinery and methods for excavation and ground support, which will reduce
3608-741: The Quadro Complementar de Oficiais da Armada and the Quadro Complementar de Oficiais Fuzileiros Navais. Officers can come from the Centro de Instrução Almirante Wandenkolk (CIAW) (Admiral Wandenkolk Instruction Center) and the Escola Naval (EN) (Naval School) which, through internal selection of the Navy, finish their graduation at the Universidade de São Paulo (USP) (University of São Paulo) . The Quadro de Oficias Engenheiros of
3690-679: The Quadro de Engenheiros Militares, with its members trained or professionalized by the traditional Instituto Militar de Engenharia (IME) (Military Institute of Engineering) , or the Arma de Engenharia, with its members trained by the Academia Militar das Agulhas Negras (AMAN) (Agulhas Negras Military Academy). In the Brazil's Navy , engineers can occupy the Corpo de Engenheiros da Marinha,
3772-599: The United States, the NFPA definition of a tunnel is "An underground structure with a design length greater than 23 m (75 ft) and a diameter greater than 1,800 millimetres (5.9 ft)." The word "tunnel" comes from the Middle English tonnelle , meaning "a net", derived from Old French tonnel , a diminutive of tonne ("cask"). The modern meaning, referring to an underground passageway, evolved in
3854-663: The United States. The prevalence of military engineering in the United States dates back to the American Revolutionary War when engineers would carry out tasks in the U.S. Army. During the war, they would map terrain to and build fortifications to protect troops from opposing forces. The first military engineering organization in the United States was the Army Corps of Engineers. Engineers were responsible for protecting military troops whether using fortifications or designing new technology and weaponry throughout
3936-507: The ability of defenders to bring fire onto attacking enemies. Fort construction proliferated in 16th-century Europe based on the trace italienne design. By the 18th century, regiments of foot (infantry) in the British, French, Prussian and other armies included pioneer detachments. In peacetime these specialists constituted the regimental tradesmen, constructing and repairing buildings, transport wagons, etc. On active service they moved at
4018-568: The attack on Fort Eben-Emael in Belgium was conducted by Luftwaffe glider -deployed combat engineers. The need to defeat the German defensive positions of the " Atlantic wall " as part of the amphibious landings in Normandy in 1944 led to the development of specialist combat engineer vehicles. These, collectively known as Hobart's Funnies , included a specific vehicle to carry combat engineers,
4100-438: The battlefield. Combat engineers are responsible for increasing mobility on the front lines of war such as digging trenches and building temporary facilities in war zones. Strategic support is associated with providing service in communication zones such as the construction of airfields and the improvement and upgrade of ports, roads and railways communication. Ancillary support includes provision and distribution of maps as well as
4182-400: The blocky nature of rocks, the exact location of fault zones, or the stand-up times of softer ground. This may be a particular concern in large-diameter tunnels. To give more information, a pilot tunnel (or "drift tunnel") may be driven ahead of the main excavation. This smaller tunnel is less likely to collapse catastrophically should unexpected conditions be met, and it can be incorporated into
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#17328010633514264-502: The concrete mix to improve lining strength. This creates a natural load-bearing ring, which minimizes the rock's deformation . By special monitoring the NATM method is flexible, even at surprising changes of the geomechanical rock consistency during the tunneling work. The measured rock properties lead to appropriate tools for tunnel strengthening . In pipe jacking , hydraulic jacks are used to push specially made pipes through
4346-536: The director of the Establishment, was keen to confirm his teaching, and regular exercises were held as demonstrations or as experiments to improve the techniques and teaching of the Establishment. From 1833 bridging skills were demonstrated annually by the building of a pontoon bridge across the Medway which was tested by the infantry of the garrison and the cavalry from Maidstone . These demonstrations had become
4428-448: The disposal of unexploded warheads. Military engineers construct bases, airfields, roads, bridges, ports, and hospitals. During peacetime before modern warfare, military engineers took the role of civil engineers by participating in the construction of civil-works projects. Nowadays, military engineers are almost entirely engaged in war logistics and preparedness. Explosives are defined as any system that produces rapidly expanding gases in
4510-821: The end of World War I , the standoff on the Western Front caused the Imperial German Army to gather experienced and particularly skilled soldiers to form "Assault Teams" which would break through the Allied trenches. With enhanced training and special weapons (such as flamethrowers ), these squads achieved some success, but too late to change the outcome of the war. In early WWII, however, the Wehrmacht "Pioniere" battalions proved their efficiency in both attack and defense, somewhat inspiring other armies to develop their own combat engineers battalions. Notably,
4592-409: The entire tunnelling process, reducing tunnelling costs. In certain predominantly urban applications, tunnel boring is viewed as a quick and cost-effective alternative to laying surface rails and roads. Expensive compulsory purchase of buildings and land, with potentially lengthy planning inquiries, is eliminated. Disadvantages of TBMs arise from their usually large size – the difficulty of transporting
4674-441: The final tunnel or used as a backup or emergency escape passage. Alternatively, horizontal boreholes may sometimes be drilled ahead of the advancing tunnel face. Other key geotechnical factors: For water crossings, a tunnel is generally more costly to construct than a bridge. However, both navigational and traffic considerations may limit the use of high bridges or drawbridges intersecting with shipping channels, necessitating
4756-522: The greatest regard to economy. To reduce staff the NCOs and officers were responsible for instructing and examining the soldiers. If the men could not read or write they were taught to do so, and those who could read and write were taught to draw and interpret simple plans. The Royal Engineers Establishment quickly became the centre of excellence for all fieldworks and bridging. Captain Charles Pasley ,
4838-405: The ground behind a TBM or shield. This method is commonly used to create tunnels under existing structures, such as roads or railways. Tunnels constructed by pipe jacking are normally small diameter bores with a maximum size of around 3.2 metres (10 ft). Box jacking is similar to pipe jacking, but instead of jacking tubes, a box-shaped tunnel is used. Jacked boxes can be a much larger span than
4920-429: The head of marching columns with axes, shovels, and pickaxes, clearing obstacles or building bridges to enable the main body of the regiment to move through difficult terrain. The modern Royal Welch Fusiliers and French Foreign Legion still maintain pioneer sections who march at the front of ceremonial parades, carrying chromium-plated tools intended for show only. Other historic distinctions include long work aprons and
5002-640: The immersed-tube type), while deep tunnels are excavated, often using a tunnelling shield . For intermediate levels, both methods are possible. Large cut-and-cover boxes are often used for underground metro stations, such as Canary Wharf tube station in London. This construction form generally has two levels, which allows economical arrangements for ticket hall, station platforms, passenger access and emergency egress, ventilation and smoke control, staff rooms, and equipment rooms. The interior of Canary Wharf station has been likened to an underground cathedral, owing to
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#17328010633515084-435: The inevitable smoke and steam. A major disadvantage of cut-and-cover is the widespread disruption generated at the surface level during construction. This, and the availability of electric traction, brought about London Underground's switch to bored tunnels at a deeper level towards the end of the 19th century. Prior to the replacement of manual excavation by the use of boring machines, Victorian tunnel excavators developed
5166-562: The kingdom. Both military engineers and artillery formed the body of this organization and served together until the office's successor, the Board of Ordnance was disbanded in 1855. In comparison to older weapons, the cannon was significantly more effective against traditional medieval fortifications . Military engineering significantly revised the way fortifications were built in order to be better protected from enemy direct and plunging shot. The new fortifications were also intended to increase
5248-468: The large TBM to the site of tunnel construction, or (alternatively) the high cost of assembling the TBM on-site, often within the confines of the tunnel being constructed. There are a variety of TBM designs that can operate in a variety of conditions, from hard rock to soft water-bearing ground. Some TBMs, the bentonite slurry and earth-pressure balance types, have pressurized compartments at the front end, allowing them to be used in difficult conditions below
5330-606: The leading scientific military school in Europe. The dawn of the internal combustion engine marked the beginning of a significant change in military engineering. With the arrival of the automobile at the end of the 19th century and heavier than air flight at the start of the 20th century, military engineers assumed a major new role in supporting the movement and deployment of these systems in war. Military engineers gained vast knowledge and experience in explosives . They were tasked with planting bombs, landmines and dynamite . At
5412-969: 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. 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. Tunnels can be connected together in tunnel networks . A tunnel
5494-629: The lower deck with automobiles above, now converted to one-way road vehicle traffic on each deck. In Turkey, the Eurasia Tunnel under the Bosphorus , opened in 2016, has at its core a 5.4 km (3.4 miles) two-deck road tunnel with two lanes on each deck. Additionally, in 2015 the Turkish government announced that it will build three -level tunnel, also under the Bosporus. The tunnel
5576-483: The older method of tunnelling in compressed air, with an airlock/decompression chamber some way back from the TBM, which required operators to work in high pressure and go through decompression procedures at the end of their shifts, much like deep-sea divers . In February 2010, Aker Wirth delivered a TBM to Switzerland, for the expansion of the Linth–Limmern Power Stations located south of Linthal in
5658-540: The operation of empty and loaded trains at the same time. The temporary way is replaced by the permanent way at completion, thus explaining the term " Perway ". The vehicles or traffic using a tunnel can outgrow it, requiring replacement or enlargement: An open building pit consists of a horizontal and a vertical boundary that keeps groundwater and soil out of the pit. There are several potential alternatives and combinations for (horizontal and vertical) building pit boundaries. The most important difference with cut-and-cover
5740-439: The project is completed. If a tunnel is going to be long, multiple shafts at various locations may be bored so that entrance to the tunnel is closer to the unexcavated area. Once construction is complete, construction access shafts are often used as ventilation shafts , and may also be used as emergency exits. The New Austrian Tunnelling method (NATM)—also referred to as the Sequential Excavation Method (SEM) —was developed in
5822-434: The proper machinery must be selected. Large infrastructure projects require millions or even billions of dollars, involving long-term financing, usually through issuance of bonds . The costs and benefits for an infrastructure such as a tunnel must be identified. Political disputes can occur, as in 2005 when the US House of Representatives approved a $ 100 million federal grant to build a tunnel under New York Harbor. However,
5904-511: The right to wear beards. In West Africa , the Ashanti army was accompanied to war by carpenters who were responsible for constructing shelters and blacksmiths who repaired weapons. By the 18th century, sappers were deployed in the Dahomeyan army during assaults against fortifications. The Peninsular War (1808–14) revealed deficiencies in the training and knowledge of officers and men of
5986-482: The risk of encountering unforeseen ground conditions. In planning the route, the horizontal and vertical alignments can be selected to make use of the best ground and water conditions. It is common practice to locate a tunnel deeper than otherwise would be required, in order to excavate through solid rock or other material that is easier to support during construction. Conventional desk and preliminary site studies may yield insufficient information to assess such factors as
6068-442: The scope of military engineering. The word engineer was initially used in the context of warfare, dating back to 1325 when engine’er (literally, one who operates an engine) referred to "a constructor of military engines". In this context, "engine" referred to a military machine, i. e., a mechanical contraption used in war (for example, a catapult ). As the design of civilian structures such as bridges and buildings developed as
6150-542: The sheer size of the excavation. This contrasts with many traditional stations on London Underground , where bored tunnels were used for stations and passenger access. Nevertheless, the original parts of the London Underground network, the Metropolitan and District Railways, were constructed using cut-and-cover. These lines pre-dated electric traction and the proximity to the surface was useful to ventilate
6232-400: The tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and the shape of the tunnel and appropriate risk management. There are three basic types of tunnel construction in common use. Cut-and-cover tunnels are constructed in a shallow trench and then covered over. Bored tunnels are constructed in situ, without removing the ground above. Finally,
6314-526: The tunnel is being built, and then with a toll on the tunnel for 15 years. It is estimated to cost 1,900 million kr . Construction is planned to start in 2014 . The tunnel would branch off the current E39 highway at Åsane, just west of the IKEA store, and it would head northwards. It would exit the tunnel just south of the Nordhordland Bridge. This Norwegian tunnel-related article
6396-428: The two most common being bored tunnels or immersed tubes , examples are Bjørvika Tunnel and Marmaray . Submerged floating tunnels are a novel approach under consideration; however, no such tunnels have been constructed to date. During construction of a tunnel it is often convenient to install a temporary railway, particularly to remove excavated spoil , often narrow gauge so that it can be double track to allow
6478-438: The world's first known explosive, black powder . Initially developed for recreational purposes, black powder later was utilized for military application in bombs and projectile propulsion in firearms. Engineers in the military who specialize in this field formulate and design many explosive devices to use in varying operating conditions. Such explosive compounds range from black powder to modern plastic explosives. This particular
6560-575: Was constructed to provide a second harbour crossing and to alleviate traffic congestion on the Sydney Harbour Bridge , without spoiling the iconic view. Other reasons for choosing a tunnel instead of a bridge include avoiding difficulties with tides, weather, and shipping during construction (as in the 51.5-kilometre or 32.0-mile Channel Tunnel ), aesthetic reasons (preserving the above-ground view, landscape, and scenery), and also for weight capacity reasons (it may be more feasible to build
6642-664: Was largely replaced by mounted soldiers. It was not until later in the Middle Ages , that military engineering saw a revival focused on siege warfare. Military engineers planned castles and fortresses. When laying siege, they planned and oversaw efforts to penetrate castle defenses. When castles served a military purpose, one of the tasks of the sappers was to weaken the bases of walls to enable them to be breached before means of thwarting these activities were devised. Broadly speaking, sappers were experts at demolishing or otherwise overcoming or bypassing fortification systems. With
6724-732: Was superseded by the Madrid M30 ringroad , Spain, and the Chong Ming tunnels in Shanghai , China. All of these machines were built at least partly by Herrenknecht . As of August 2013 , the world's largest TBM was " Big Bertha ", a 17.5-metre (57.5 ft) diameter machine built by Hitachi Zosen Corporation , which dug the Alaskan Way Viaduct replacement tunnel in Seattle, Washington (US). A temporary access shaft
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