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41-404: Prior to its construction, all traffic had to use the historic high-level route via the 1.8 km (1.1 mi) long Furka Summit Tunnel , which was only available seasonally due to the threat posed by heavy snowfalls. Construction commenced during 1971, taking ten years to complete. An innovative permanent support system was used, comprising rock anchors and a shotcrete coating, which included

82-537: A base tunnel had long been identified as an attractive solution, but the prospects for constructing such a tunnel were complicated by multiple factors in both its design and construction. Initial authorisation from the Federal Council for preparatory work was given in 1971. During 1976, the Parliament of Switzerland passed a comprehensive bill for the base tunnel's construction, sponsored by Roger Bonvin ;

123-654: A dry or wet mix process. However, shotcrete may also sometimes be used to distinguish wet-mix from the dry-mix method. The term shotcrete was first defined by the American Railway Engineers Association (AREA) in the early 1930s. By 1951, shotcrete had become the official generic name of the sprayed concrete process—whether it utilizes the wet or dry process. Shotcrete is commonly used to line tunnel walls, in mines, subways, and automobile tunnels. Fire-resistant shotcrete developed in Norway

164-530: A new ventilation system for the Furka tunnel, intended to supply fresh air in the event of a major fire within the latter tunnel. The construction techniques used for the Furka Base Tunnel were relatively innovative for the era. One such technique involved the application of a recently developed polyurethane -based grouting to make the rock surrounding the tunnel portals impermeable. It was reportedly

205-470: A single track throughout, its cross section varying between 26 and 42 m throughout its length. This often narrow cross section has been attributed as one reason for the tunnel's construction requiring ten years, as it hindered the movement of bulky construction equipment. During 1982, the Furka Base Tunnel was opened to traffic. During its initial year of operation, the tunnel was used to transport in excess of 75,000 passenger cars, trucks and buses. As of 2009,

246-494: Is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface. This construction technique was invented by Carl Akeley and first used in 1907. The concrete is typically reinforced by conventional steel rods, steel mesh, or fibers. The concrete or mortar is formulated to be sticky and resist flowing when at rest to allow use on walls and ceilings, but exhibit sufficient shear thinning to be easily plumbable through hoses. Shotcrete

287-468: Is 15,407 m (16,849 yd) in length, and replaced the previous track that climbed to an apex of 2,160 m (7,090 ft) above sea level, thus allowing year-round service through service on the Furka–Oberalp line. In the middle of the base tunnel, is a 5,221-metre-long (5,710 yd) access tunnel to Bedretto in the canton of Ticino (elevation 1,480 m (4,860 ft)); some proponents of

328-412: Is applied by pneumatic pressure from a gun, hence gun -ite. The term Gunite became the registered trademark of Allentown Equipment , the oldest manufacturer of gunite equipment. Other manufacturers were thus compelled to use other terminology to describe the process such as shotcrete, pneumatic concrete, guncrete, etc. Shotcrete is an all-inclusive term for spraying concrete or mortar with either

369-406: Is completed the area between its foundation and the shotcrete is backfilled and compacted. Shotcrete is also a viable means and method for placing structural concrete. Shotcrete is very useful in hard rock mining . Development of decline pathway to go underground is critical for movement of heavy machinery, miners, and material. Shotcrete helps make these paths safe from any ground fall. Also,

410-520: Is used on the Marmaray tunnel in Istanbul . Shotcrete is used to reinforce both temporary and permanent excavations. It may be employed, in concert with lagging and other forms of earth anchor , to stabilize an excavation for an underground parking structure or hi-rise buildings during construction. This provides a large waterproof enclosure in which a structure can be erected. Once the structure

451-467: Is usually an all-inclusive term for both the wet-mix and dry-mix versions invented by Akeley. In pool construction, however, shotcrete refers to wet mix and gunite to dry mix. In this context, these terms are not interchangeable. Shotcrete is placed and compacted/consolidated at the same time, due to the force with which it is ejected from the nozzle. It can be sprayed onto any type or shape of surface, including vertical or overhead areas. Shotcrete has

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492-561: The Furka Heritage Railway , which routinely put on tourist trains through the historic Furka Pass, including the Furka Summit Tunnel. During August 2018, a comprehensive modernisation of the Furka Base Tunnel's infrastructure commenced. This programme, costed at CHF 190 million, largely revolves around the refurbishment of the tunnel's structure, the wholesale replacement of the track and trackbed, as well as

533-783: The Muttbach-Belvédère halting point , in Valais . Until 1982, when the summit tunnel was replaced by the Furka Base Tunnel , the railway line passing through the summit tunnel was part of the Furka Oberalp Bahn (FO). However, that line, which, along with the summit tunnel, was closed in 1981 and reopened in 2000, is now part of the Furka Cogwheel Steam Railway , a heritage railway operating in summer only. Between 1926 and 1981,

574-416: The nozzle as it was released. In 1911, he was grantvovd a patent for his inventions: the "cement gun", the equipment used; and "gunite", the material that was produced. There is no evidence that Akeley ever used sprayable concrete in his taxidermy work, as is sometimes suggested. F. Trubee Davison covered this and other Akeley inventions in a special issue of Natural History magazine. The dry-mix process

615-586: The FO allocated three schedule periods to the line passing through the summit tunnel. The summer schedule corresponded with the then European summer timetable. The other seasons, covered by the then European winter timetable, were divided by the FO into autumn and winter periods, because traffic over the Furka Pass could be operated only until mid October. As soon as snow started falling, the FO had to be ready to place individual items of rolling stock on either side of

656-635: The Furka Base Tunnel. In 1982, the original portion of the FO between Oberwald in Valais and Realp in Uri, including the summit tunnel, was replaced by an FO line passing through the then new Furka Base Tunnel. The superseded portion of the FO line was abandoned. However, strong public protests against the removal of the abandoned tracks led to the foundation 2 years later of the Furka Cogwheel Steam Railway (DFB), to preserve and operate

697-417: The Furka, according to demand. Then, during the years commencing with electrification of the line in 1942, the electrical contact wire had to be dismantled over a nearly 15 kilometres (9.3 mi) long section of line, and the line made "avalanche ready". Everything more than 1 metre (3 ft 3 in) above ground level had to be removed, necessitating a huge annual expenditure. The Steffenbach bridge, on

738-492: The Uri side of the summit tunnel, was built initially as a viaduct. However, as early as the first year following its construction, it became the victim of an avalanche. A folding bridge was then installed in its place. To this day, the 30 tonne folding bridge, which can carry a payload of up to 200 tonnes (200 long tons; 220 short tons), is made safe each autumn by drawing it back to its abutments, in three pieces. Originally it took 20 men 8 hours to set it up or withdraw it but with

779-599: The abandoned line. Since 11 July 1992  ( 1992-07-11 ) , the abandoned line has been progressively reopened from Realp, as a heritage railway operated by the DFB. On 14 July 2000  ( 2000-07-14 ) , the DFB was extended from its then temporary terminus at Furka to Gletsch , via the Summit Tunnel, which was simultaneously reopened, and Muttbach-Belvédère. Shotcrete Shotcrete , gunite ( / ˈ ɡ ʌ n aɪ t / ), or sprayed concrete

820-445: The additional requirement of delivering a concrete flow that is as constant as possible, and therefore continuous, to guarantee homogeneous spray application. Depending on the fineness of the filler, mortar shotcrete (fraction size up to 2.5 mm) is distinguished from shotcrete (up to 10 mm), and syringe concrete, or sprayed concrete (up to 25 mm). Gunite was originally a trademarked name that specifically referred to

861-415: The bare rock. It was used during the Furka Base Tunnel's construction for the removal of excavating spoil as well as to convey supplies into the construction site. The Bedretto tunnel was abandoned for a time following the completion of the Furka tunnel, being used neither for emergency access nor for maintenance purposes, in part due to three separate collapses. During the 2010s, it was restored to accommodate

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902-431: The base tunnel serves both an hourly regional train and ten daily Glacier Express trains between Zermatt and the ski resort town of St. Moritz . During the winter skiing season, traffic in the tunnel has consistently approached its maximum capacity. While the older high level route was initially closed following the diversion of all regular services through the new Furka Base Tunnel, this line has since been reopened by

943-626: The characteristics of high compressive strength, good durability, water tightness and frost resistance. Shotcrete, then known as gunite, was invented in 1907 by American taxidermist Carl Akeley to repair the crumbling façade of the Field Columbian Museum in Chicago (the old Palace of Fine Arts from the World's Columbian Exposition ). He used the method of blowing dry material out of a hose with compressed air , injecting water at

984-401: The dry ingredients into a hopper and then conveying them pneumatically through a hose to the nozzle. The nozzle operator controls the addition of water at the nozzle. The water and the dry mixture is not completely mixed, but is completed as the mixture hits the receiving surface. This requires a skilled nozzle operator, especially in the case of thick or heavily reinforced sections. Advantages of

1025-459: The dry mix process are that the water content can be adjusted instantaneously by the nozzle operator, allowing more effective placement in overhead and vertical applications without using accelerators. The dry mix process is useful in repair applications when it is necessary to stop frequently, as the dry material is easily discharged from the hose. Wet-mix shotcrete involves pumping of a previously prepared concrete, typically ready-mixed concrete, to

1066-491: The dry process concrete. Shotcrete machines are available which control the complete process and make it very fast and easy. Manual and mechanical methods are used for the wet spraying process but wet sprayed concrete is traditionally applied by machine. The high spray outputs and large cross-sections require the work to be mechanised. Concrete spraying systems with duplex pumps are mainly used for working with wet mixes. Unlike conventional concrete pumps, these systems have to meet

1107-470: The dry-mix pneumatic cement application process. In the dry-mix process, the dry sand and cement mixture is blown through a hose using compressed air, with water being injected at the nozzle to hydrate the mixture, immediately before it is discharged onto the receiving surface. Gunite was the original term coined by Akeley , trademarked in 1909 and patented in North Carolina . The concrete mixture

1148-523: The end of the project; Bonvin died just prior to its opening in 1982. A plaque commemorating Roger Bonvin is installed as the base tunnel's entrance in Oberwald. During 1971, work commenced on the boring of the Bedretto tunnel, which functioned as an annex tunnel for the Furka Base Tunnel. Excavated by conventional techniques, including both drilling and blasting, it was a relatively narrow tunnel through

1189-426: The first use of polyurethane -based grouting within a railway tunnel. The tunnel has a relatively narrow cross section, which has been attributed with slowing the construction effort somewhat. The interconnecting Bedretto tunnel was used during the Furka Base Tunnel's construction for the removal of excavating spoil as well as to moving supplies inwards; it has since been reused for ventilation. The Furka Base Tunnel

1230-516: The first use of such material within a railway tunnel. The permanent support for the tunnel consisted only of rock anchors and a shotcrete lining along the majority of its length. Areas of particularly high rock pressure were addressed via the excavation of an elliptical or circular profile and the application of steel ribs. Engineers were guided in the use of support measures by a series of geological studies, along with construction experience, to predict and monitor systematic deformation. In spite of

1271-406: The incorporation of various safety measures. The tunnel is typically kept operational throughout the process by performing the majority of the work at night. Particular attention has been paid to the tunnel ventilation, intended to control threats such as fires. However, the study of several operational scenarios points out the weaknesses of the existing ventilation system and difficulties to dissipate

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1312-583: The installation of hydraulic winches after the restoration of the railway it takes 10 men six hours. Some early onsets of winter brought distress to the FO. On those occasions, staff members had to clear the track. For that work, steam locomotives of type HG 3/4 were used until 1968. They were then replaced with modern diesel electric locomotives of class HGm 4/4 . In the years when winter came early, locomotives and railcars sometimes had to be loaded onto standard gauge vehicles, to be transported from either Göschenen or Chur to Brig or vice versa, on

1353-401: The line was particularly challenging to operate, its closure being necessary during the winter months due to the risks associated with heavy snowfalls. These seasonal cycles of closures and reopenings required civil engineering works each time, as large sections of the railway's overhead electrical lines had to be dismantled and reinstated as well. The replacement of the Furka Summit Tunnel with

1394-420: The nozzle. Compressed air is introduced at the nozzle to impel the mixture onto the receiving surface. The wet-process procedure generally produces less rebound, waste (when material falls to the floor), and dust compared to the dry-mix process. The greatest advantage of the wet-mix process is all the ingredients are mixed with the water and additives required, and also larger volumes can be placed in less time than

1435-414: The places where they were required. By these means, the line could be reopened two weeks earlier, but at a high price. In 1963, the FO endured the most difficult of all its reopenings of the line. A team working with a steam locomotive on the snow front was hit and swept away by an avalanche. The incident cost several lives, including that of a journalist who had been along, which spurred the construction of

1476-460: The presence of multiple complex geological features along the bore, work typically proceeded at a steady pace. Typically 400 metres of the tunnel were lined each month, this rate being supported via five individual shotcrete machines that were operated simultaneously. By the end of its construction, roughly 70,000 m of dry aggregate and cement mixture had been used, while 115,000 rock bolts have been applied. The completed Furka Base Tunnel accommodates

1517-485: The project hoped to eventually build a Y-shaped tunnel connecting all three locations. The Furka Base Tunnel is completed by a bypass tunnel around Oberwald. Prior to the opening of the Furka Base Tunnel, all railway traffic on the Furka–Oberalp line traversed the challenging terrain between Valais and Uri via the historic high-level route using the 1.8 km (1.1 mi) long Furka Summit Tunnel . This section of

1558-466: The side of the pass where they were needed. At the start of June each year, the line could be reopened. Snow ploughs and blowers needed to be used for that purpose. On many occasions, the snow depths in the narrow alpine valleys were so great that the snow had to be removed by hand over many shifts, and with heavy construction equipment, until the FO's snow removal vehicles could be used. The construction equipment had to be transported on open rail wagons to

1599-522: The smokes without modifying the ventilation system. Furka Summit Tunnel The Furka Summit Tunnel ( German : Furka-Scheiteltunnel ) is a 1.86 kilometres (1.16 mi) long railway tunnel in southern Switzerland . It lies at an altitude of 2,160 metres (7,090 ft). The summit tunnel was completed in 1925, and first opened on 3 July 1926. It links the Furka railway station , in Uri , with

1640-432: The total cost of its construction had been initially estimated to be 76 million francs . However, these estimates proved to be drastically inadequate as the project proceeded, with figures in excess of 300 million francs being reached prior to the base tunnel's completion. There was substantial political tensions surrounding these cost overruns , which have been said to have contributed to Bonvin's ill health toward

1681-399: Was used until the wet-mix process was devised in the 1950s. In the 1960s, an alternative method for gunning dry material with a rotary gun appeared, using a continuously fed open hopper. The nozzle is controlled by hand on small jobs, such as a modest swimming pool. On larger work it is attached to mechanical arms and operated by hand-held remote control. The dry mix method involves placing

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