102-673: The Homer Tunnel is a 1.2 km (0.75 miles) long road tunnel in the Fiordland region of the South Island of New Zealand , opened in 1953. New Zealand State Highway 94 passes through the tunnel, linking Milford Sound to Te Anau and Queenstown , by piercing the Darran Mountains at the Homer Saddle. It connects between the valley of the Hollyford River to the east and that of
204-440: A bus and a smaller vehicle to pass, meetings involving two coaches or campervans are problematic. This is alleviated by the fact that the traffic is very tidal, towards Milford Sound in the morning and toward Te Anau in the afternoon. The traffic lights operate only during the day during the peak summer season, since the avalanche risk makes it unsafe to stop and queue at the portals in winter and spring. With increasing traffic on
306-571: A great peaking of demand at the day-cruises terminal where the large tourist boats lie empty for most of the day, becoming extremely active only during the 3–4 hours around and past noon. The above difficulties in reaching this extremely popular destination have led to a number of serious proposals on how to better connect the attractions of Milford Sound to the rest of New Zealand, and how to increase tourism without reducing sustainability for this national natural treasure. In conjunction with these plans, proposals are also being considered how to upgrade
408-449: 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
510-534: A major tourist attraction, receiving numbers of visitors unprecedented for such a remote location, over 550,000 per year. This was expected to rise to 750,000 by 2012. The expected rise in numbers did not happen as a result of the recession and other unknown factors. A study has found that of all tourists travelling the South Island of New Zealand in summer, 54% travelled the Milford Road at some point. Increasing
612-461: 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,
714-440: A powerhouse in the nearby river were eventually built to pump out 40,000 litres of water per hour. Work was also interrupted by World War II (though the actual piercing of the mountain had successfully been achieved in 1940), and an avalanche in 1945 which destroyed the eastern tunnel portal. These problems delayed the tunnel's completion and opening until 1953. In 2002 a tour bus carrying tourists from Singapore caught fire inside
816-581: A remote area (estimated at NZ$ 165–275 million) and issues with constructing a new road through Fiordland National Park were noted, in addition to the new route possibly increasing congestion on the shared part of the route (from the Hollyford Valley to Milford Sound). In April 2001, a tabloid publication was circulated via daily newspapers in the South Island by backers of the plan for both the Haast-Hollyford and Karamea-Collingwood links. The publication
918-421: 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
1020-434: 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
1122-710: 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,
SECTION 10
#17328555533061224-432: 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
1326-582: Is a fjord in the southwest of the South Island of New Zealand, located in Fiordland , the most remote and least populated region of the country. Divided from more populous areas to the east by the high southern spurs of the Southern Alps , its only entry apart from a difficult mountain road is a narrow channel to the Tasman Sea , which explorer Captain Cook did not enter during his 1769/1770 journey, as he considered
1428-438: Is a long-standing proposal to link Haast , a coastal town north of Milford Sound, via the Hollyford Valley to Milford Sound and Te Anau in the South Island of New Zealand. Proposals for this road have been mooted since the 1880s. It would allow a multi-day round trip, for example from Queenstown to Te Anau to Milford Sound to Haast and back to Queenstown. However, high costs associated with building around 120 km of new road in
1530-456: Is a traffic-light controlled one-way route during peak summer periods, as it is not wide enough to allow coaches to pass each other (though passing bays are provided). Improvements to both the road and Homer Tunnel are planned by Transit New Zealand, though a widening of the tunnel is considered unlikely due to the high costs involved. In the 2010s, the road received a variable message sign (VMS) traffic information system to inform travellers on
1632-593: 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. Transport in Milford Sound#Milford Dart tunnel (rejected by NZ government 2013) Transport in Milford Sound in New Zealand
1734-419: Is based on very little research, the ground has not had the sufficient surveying to calculate an accurate cost. The cost is likely to be much higher, seeing as the tunnel is going through 5 known fault lines. The proposed tunnel faces a number of criticisms. One of the major hindrances is the location of both entrances in national parks, Fiordland National Park in the west and Mount Aspiring National Park in
1836-405: Is characterised by the remoteness of the area in which it is located. As a popular tourism destination in the South Island , Milford Sound (the fiord) and the village of the same name receive very large numbers of visitors. These tend to arrive and depart within just a few hours each day, as there is little accommodation at the village, leading to strong demand peaks for tourism services during
1938-500: 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
2040-487: 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
2142-401: 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
SECTION 20
#17328555533062244-515: 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
2346-673: 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
2448-504: Is therefore encouraging the use of larger and less noisy aircraft. In 2007, flight restrictions were announced, limiting the number of flights in the Fiordland area and the number of operators to 2004-2005 levels via a concession system, with 23 licenses only (the number of operators in 2004-2005). Operators are also required to pay for flight monitoring, and further restrictions may be declared if more than 25% of National Park visitors consider
2550-556: 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
2652-457: The Cleddau to the west. The tunnel is straight and was originally single-lane and gravel-surfaced. The tunnel walls remain unlined granite. The east portal end is at 945 m elevation; the tunnel runs 1270 m at approximately a 1:10 gradient down to the western portal. Until it was sealed and enlarged it was the longest gravel-surfaced tunnel in the world. William H. Homer and George Barber discovered
2754-678: The Ngāi Tahu iwi , and was to cost around NZ$ 100–110 million. With 12.6 km length, the Skytrail would have become the longest such ride in the Southern Hemisphere, and was intended to transport 900 passengers per hour. With a duration of 35 minutes for a one-way trip, the gondola was to reduce the 12-hour round trip by about 3 hours. The project was shelved after the Department of Conservation refused permission based on its expected impact on
2856-464: 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
2958-797: 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
3060-466: 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
3162-665: 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
Homer Tunnel - Misplaced Pages Continue
3264-591: 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
3366-486: 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
3468-445: The $ 21.7 billion tourism industry and significantly reducing driving time to Milford Sound. Construction was estimated to cost up to $ 315 million (and annual maintenance of over $ 1 million). According to the study, the costs would be acceptable due to the local benefits and additional tourism income it would provide, though conservation groups oppose the project. In March 2010, Minister of Economic Development Gerry Brownlee met with
3570-399: The $ 240 million plan "does not stack up either economically or environmentally." Combining a new tunnel with special-purpose guided buses to avoid the southern detour to Te Anau on the route from Queenstown to Milford Sound, this proposal would provide the shortest possible route. Proposed by a group of South Island businessmen who also have an interest in some of the tourist operations in
3672-689: 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
3774-638: 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
3876-687: 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 ;
3978-427: The 608 km round trip from Queenstown (slightly less from Invercargill ). Almost 60% travelled via coach. Future increases in traffic will have to take into account the limitations of the existing road, which features various areas lacking passing lanes (especially problematic if cars are held up behind slow coaches on the steeper sections), a number of one-lane bridges and a narrow carriageway width. Homer Tunnel
4080-567: The Department of Conservation's support of the proposal was inconsistent with the values of World Heritage status associated with Fiordland National Park. In mid 2013, the application for consent for the tunnel was rejected by the Minister for the Environment, for three reasons - the need to dispose of half a million of tonnes of tunnel spoil, the impacts of new roads and tunnel portals on the park and
4182-457: The Depression, initially just starting with five men using picks and wheelbarrows. The men had to live in tents in a mountainous area where there might be no direct sunlight for half of the year. At least three were killed by avalanches over the coming decades. Progress was slow, with difficult conditions including fractures in the rock bringing water from snow melt into the tunnel. Compressors and
Homer Tunnel - Misplaced Pages Continue
4284-524: The Homer Saddle on 27 January 1889. Homer suggested that a tunnel through the saddle would provide access to the Milford area. Government workers began the tunnel in 1935 after lobbying by J. Cockburn of the Southland Progress League , and the completion of at least a rough road to the eastern portal site in the same year. The tunnel and the associated Milford Road were built by relief workers during
4386-484: The Homer tunnel entirely to reduce the journey time from Queenstown, including a Milford Dart tunnel , which was declined in 2013. 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
4488-691: 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
4590-470: The Milford Dart project, the backers, Infinity Investment Group, believed that they would have an easier time achieving consents, as the proposal does not touch upon any National Parks, and the construction and operation process was considered to be very ecologically sustainable, such as the use of comparatively small piles for the monorail which will be bored and placed from a working vehicle moving forward on
4692-579: The Milford Road have been observed as not dropping in the same degree as visitor numbers, with coaches often travelling largely empty. It has been proposed that initiatives be considered to force or entice tourism operators to pool their transport resources for greater efficiency. It has been proposed that a park & ride shuttle bus facility should be established at a location such as Te Anau, Te Anau Downs or Eglington Valley. Access to Milford Sound would be restricted to bus shuttles operating from here (and private vehicles during off-peak times). Staggering
4794-594: The Routeburn Track, and due to the works being inconsistent with the national park management plan. The minister also noted doubts about the economic viability of the $ 170 million project. A third option, previously proposed around 2001, would have created a gondola route between the Caples Valley and the Hollyford Valley . The proposal was a cooperation between Skyline Enterprises of Queenstown and Rotorua, and
4896-634: The Sound while stopping over in New Zealand from overseas or travelling from (the relatively distant) New Zealand harbours, or alternatively on private yachts. However, few such vessels nowadays travel along the rugged southwest coastline of the Island. Numbers of tourists arrive via small planes or helicopters, or use them to overfly the Sound as part of the trip. In 2004 Milford Sound Airport had approximately 16,000 aircraft movements, most associated with flights to and from Queenstown . Around 35 aircraft can operate at
4998-618: The Sound, this scheme would make use of the fact that the Hollyford Valley , where the existing road to Milford Sound from Te Anau turns west up to Homer Tunnel, is only a few dozen kilometres away from the Routeburn Valley (of Routeburn Track fame), in turn easily reached by existing roads. The proposal would create an 11.3 km tunnel through the mountain range and link up the existing roads with short extensions, cutting travel distances from 304 km one-way to only 125 km, with travel time reduced from 5.5 hours to 2 hours. Within
5100-581: 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
5202-592: The Westland and Southland district councils and with Hagaman, saying "I'm personally supportive of [a road] but it's not something that the Government is actually considering at the present time." The Ministry of Economic Development briefly considered a new proposal for the road the same year, but did not see any net gain from an economic viewpoint. This proposal intended to combine a number of innovative transport options into one trip (hence 'Experience'), while still cutting
SECTION 50
#17328555533065304-639: The aircraft noise annoying. Some operators have already complained about the restrictions, and DOC has noted that flight numbers could conceivably be increased if noise emissions would be reduced. There exists one main track into Milford Sound from the eastern side of the main range of the Southern Alps, the Milford Track. Starting at the northernmost edge of Lake Te Anau , the 53 km track takes four days to complete and includes one mountain pass and many areas prone to flooding. Due to concerns about degrading
5406-420: The airport at any one time, though this level has not yet been reached. As flights can be spread over the day better than coach trips, only about 25 aircraft operated here during peak times of the day in 2004. The Department of Conservation has noted that aircraft noise and activity in the Sound are often remarked on by tourists as being unexpectedly substantial (even more so on the nearby Milford Track ). DOC
5508-400: 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
5610-461: The burning bus. As a result of this incident a satellite phone and fire extinguishers were installed in the tunnel. Two tourist buses were destroyed by fire outside the tunnel in January and March 2008, though the fires were not related to the tunnel. Roof lighting was fitted and traffic lights reintroduced in 2004 to reduce capacity constraints and safety issues. Although the tunnel is large enough for
5712-498: 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
5814-447: The departure would help reduce congestion both on the road and at the viewing spots. However, the proposal was considered to reduce tourism operator and tourist freedom, as well as to add transfer times to an already very long journey. Finally, it would take away the free right of access. As such, it was negatively reviewed and is unlikely to proceed. Expanding Milford Sound Airport to allow larger aircraft to fly tour groups in and out of
5916-474: The difficulties for tourism to the Sound is the location within Fiordland National Park , which prevents substantial accommodation from being built - around 90% of all tourists are therefore only on a day trip , and around 80% return in the late afternoon to Te Anau, or Queenstown , a 12-hour round trip. Due to the long trip from Queenstown, a majority of tourists arrive and depart quickly, leading to
6018-507: The east. While the proposed new road sections would be very short, they have already led to criticism from the environmental group Forest and Bird which noted that the Department of Conservations's general policy forbids the construction of new roads in National Parks. The disposal of up to 250,000 cubic metres of soil from the tunnel excavation is also considered problematic. Southland and Te Anau business interests are also concerned that
6120-409: 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
6222-469: The entry too treacherous and was unaware of the large body of water sheltered behind it. The first post office of the fjord was a tiny island. A rum barrel was hung on a tree where mail was posted and a white flag was raised to indicate unsent mail. Passing ships would then stop and browse the mails. If any were addressed to a location they were heading they would take it with them. By virtue of its great natural features, Milford Sound has long since become
SECTION 60
#17328555533066324-408: The existing road to Milford Sound. Tourists to Milford Sound arrive mainly via coach over Milford Road State Highway 94 , a high mountain road prone to avalanches in winter. The road was only opened in 1953, after Homer Tunnel was finished after almost 20 years of intermittent work. The road is one of the more dangerous public roads in New Zealand, with injury crash rates around 65% higher than
6426-441: 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
6528-405: 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
6630-636: 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
6732-435: 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
6834-468: 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
6936-969: 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
7038-562: The line would allow four trains to run, at speeds of up to 90 km/h. Kiwi Burns Saddle, the highest point of the journey, is 675 m above sea level, and the higher-altitude section of the rail would be heated to prevent snow-buildup in winter. Each monorail train would seat 160 passengers, consisting of 16 articulated 2.6 m wide sections totalling 66 m in length. Only one train would be constructed initially. The proposal, which would cost up to NZ$ 132 million, would have to achieve around 220,000 two-way passengers per year to be viable. Compared to
7140-607: 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
7242-428: The natural landscape, the track can be walked on a quota system only (and only westwards, with walkers having to stop at designated huts every night). With only several dozen walkers allowed on the track every day, places in the quota system are usually booked out many months in advance from the administering New Zealand Department of Conservation. In winter, during those times that the road remains open, coach numbers on
7344-405: The noon and early afternoon period. The journey from Te Anau is rated as one of the most photographic drives of the world. To reduce this peaking and to allow further expansion without impacting the environment or reducing tourist amenity, various schemes have been proposed over the years for better links to the Sound, including a new tunnel , a monorail and a gondola lift . Milford Sound
7446-483: 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
7548-622: The opening of the road. The Council passed a motion of support for the proposed road and allocated $ 100,000 towards improving the gravelled road from Jackson Bay to the Cascade River. In 2010, Christchurch businessman Earl Hagaman commissioned a report (the Octa Report) suggesting a toll road could be built for $ 225–315 million. Hagaman, founder of the Scenic Circle Hotels chain, argued the road would be of national significance, boosting
7650-540: 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
7752-467: The pristine wilderness it was to cross. Critics such as Forest and Bird Society had, amongst other reasons, protested against the destruction of beech forest for 85 towers and 2 transfer stations, bus traffic on previously less used roads, and the despoiling of natural landscapes by gondola traffic. There was also some concern about the location of the Skytrail in an area of strong seismic and wind activity. Further options considered at some stage in
7854-510: 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
7956-485: 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,
8058-640: The proposal is inconsistent with the National Parks Act, the Conservation Act, and the Fiordland and Mt Aspiring National Park Plans and that it is also inconsistent with the General Policy for National Parks. In January 2012, Minister of Conservation Kate Wilkinson gave notice of her intention to grant a concession for the Milford Dart proposal, subject to public submissions and hearings. Southland District Council Mayor Frana Cardno submitted that
8160-562: The rail being constructed, thus making construction roads unnecessary. Originally it was hoped that the consent process would start in mid 2007, with commercial operations beginning in 2011. That, however, did not happen. In October 2013 it was reported that the New Zealand Conservation Minister was supportive of the project." On 29 May 2014, the Conservation Minister Nick Smith rejected the proposal saying
8262-414: The recent decade included a new one-way route (Queenstown-Milford Sound) via Glenorchy (northwest of Queenstown) and through a tunnel in the Darran Mountains (reducing the one-way trip to the Sound from five hours to two hours). The scheme had some similarities to the 'Milford Dart' scheme, but apparently did not go forward apparently due to the high difficulties faced with building new infrastructure in
8364-492: The rest of New Zealand's network, and a fatality crash rate of almost twice average (per vehicle kilometre travelled), making it the third most dangerous section of New Zealand's State Highway network (as of 2008). Stopping is prohibited on long stretches due to rock or snow avalanche dangers, and the road is often closed in winter, with the carrying of snow chains mandatory during snow conditions. Helicopters are used during winter to drop explosives onto snow buildup zones above
8466-482: 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
8568-630: The road in order to cause controlled avalanches, and the avalanche control programme is world-renowned. However even this does not absolutely eliminate the danger that road traffic may be hit by an uncontrolled event, especially in the area of the Homer Tunnel portals. The last known fatality from an avalanche on the road was in 1983. Drivers are encouraged to start the drive from Te Anau with full tanks of fuel, as there are very limited options to refuel thereafter. All of this does not discourage up to 50 coaches and hundreds of private cars daily from making
8670-540: The road of incidents and closures, in a more timely fashion than the old, hand-changed signs. The system received a 2012 New Zealand Engineering Excellence Award, partly due to the information system using satellite links as their primary communication system making unnecessary the much more costly laying of communications cables along the road. The message signs are powered by small hydro-power systems with battery back-ups. A small number of tourists arrive via long-distance sea travel, such as on smaller cruise ships entering
8772-468: The road). Arriving at the Kiwi Burn swing bridge terminal, tourists will continue on a mechanical (as opposed to maglev) monorail travelling 35 minutes through high country and native bush for a distance of 41 km, which would be the longest monorail connection in the world, before joining up with a bus park and ride facility on the existing road to Milford Sound north of Te Anau. Three passing loops along
8874-418: The road, it is expected that the risk to vehicles waiting at the portal will also increase. A widening of the tunnel, to allow for true two-laning, has been discussed many times. While this would make it unnecessary to force cars to wait in the avalanche areas, the high costs make this unlikely, especially for a road which (in national-level terms) carries little traffic—even if it is of very high importance for
8976-528: 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
9078-565: The sound was also considered, but considered problematic for tourist amenity in the Sound, and for reasons of high travel cost. Other options considered were the limitation of access to certified/compliant users (i.e. bus companies, similar to the 'mandatory park & ride' option), introducing a booking system for 'road slots', or the placing of tolls along the Milford Road. All these methods share problems of restricting access, therefore making visits to Milford Sound more complicated and costly. The Haast-Hollyford road or Haast-Hollyford Highway
9180-588: The suggestion of the Haast–Hollyford road needed to be revived. In 2005, the Department of Conservation called for submissions on a new conservation plan. The old plan had said a road through the Hollyford Valley was "unlikely". Over 800 submissions were put received on many issues, but a large proportion (over 500) were in support of a link road. Submissions to the Westland District Council 2009-2019 Long Term Council Community Plan in 2009 supported
9282-408: The tourism industry. Avalanche warning systems in the area are also considered to meet typical worldwide standards. In addition, Transit New Zealand (as of 2005) had the realignment of the Homer east portal avalanche shed as one of the 'large activity priorities' on its planning list. The project would have cost around NZ$ 14–15 million and was unlikely to start before the end of that decade. In 2010 it
9384-466: The travelling time to the Sound by about one hour each way (previous hopes of longer savings seem unlikely to be realised). In Queenstown travellers would have boarded 25-m catamarans capable of carrying up to 240 people. These would cross Lake Wakatipu to the south-western shore, 20 km away. There, passengers would travel up the mountain on an existing back-country road, using specially constructed all-terrain coaches on balloon tyres (to reduce impact on
9486-400: 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,
9588-863: The tunnel proposal will cause tourism to bypass Te Anau and overwhelm Glenorchy. In December 2007, the New Zealand Conservation Authority decided not to approve an amendment to the Mount Aspiring National Park Management Plan that would have allowed the tunnel to be built in the Mount Aspiring National Park. The plan amendment had been supported by the Otago Conservation Board and the Director-General of Conservation. The Royal Forest and Bird Protection Society of New Zealand said that
9690-431: The tunnel, buses would make use of guidance technology (side-facing wheels) to allow them to travel in a tunnel with much smaller diameter than usual, thus reducing construction costs. Speeds within the tunnel are expected to be up to 80 km/h at up to 2.5-minute frequency. The tunnel is expected to have to take at least 200,000 passengers per year to be commercially viable, and would cost around NZ$ 150 million. This cost
9792-422: The tunnel, halting 150m from the eastern portal. The passengers and the bus driver had to walk through the pitch-dark and smoke-filled tunnel to safety with the help of high beams from vehicular traffic at the entrance of the eastern portal. However, two passengers got separated and made their way to the Milford end. Three people were flown to Southland Hospital and observed for about an hour after inhaling smoke from
9894-428: 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
9996-498: Was again reported that the tunnel may be widened. In 2020 widening was not in scope when the New Zealand Government announced $ 25 million in funding for tunnel safety improvements through its rejuvenation package and the works were commenced, expecting to be completed by 2023. However in 2021 it was reported that budget constraints meant that the upgrades would need to be scaled back. Other proposals have been made to bypass
10098-566: 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
10200-460: Was first mooted, progress has been stymied by people purporting to care about the social, economic, and ecological effects of building a road through a National Park. And all the while, problems associated with congestion at, and on the road to Milford have been escalating." The re-elected Mayor for Southland District, Frana Cardno , said in an editorial to the Southland Times on 9 October that
10302-701: 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
10404-739: Was widely criticised by environmentalist groups, including Fish and Game New Zealand, the Royal Forest and Bird Protection Society of New Zealand and the Green Party. Prior to the 2002 general election, the Leader of the National Party Don Brash and others were given a reconnaissance helicopter flight over the full length of the route; all were very receptive to the concept and proposal. In 2004, Ted Loose, Chairman of Environment Southland, said in an editorial that "since [a Haast-Hollyford road]
#305694