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Earth Pressure Balance
Earth pressure balance, or EPB, is a mechanised tunneling method in which the excavated material is used to support the tunnel face whilst it is being plasticised using foams/slurry & other additives to make it transportable and impermeable. The spoil is admitted into the tunnel boring machine (TBM) via a screw conveyor (cochlea) arrangement which allows the pressure at the face of the TBM to remain balanced without the use of slurry. This has allowed soft, wet, or unstable ground to be tunneled with a speed and safety not previously possible. The Channel Tunnel, the Thames Water Ring Main, sections of the London Underground, and most new metro tunnels completed in the last 20 years worldwide were excavated using this method. EPB has historically "competed" with the slurry balance method of mechanised tunneling where the slurry is used to stabilise the tunnel face and transport spoil to the surface. See also * Tunnel boring machine * Tunnel A tunnel is an underground ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spoil (archaeology)
In archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ..., spoil is the term used for the soil, dirt and rubble that results from an excavation, and discarded off site on spoil heaps. These heaps are commonly accessed by barrow runs. Spoil management Effective management of spoil is necessary because its volume is in general three times that which it was before excavation. Best practice involves removing the spoil away from the excavation site by mechanical earth moving equipment, or the creation of barrow run fed spoil heaps. In the barrow run method, a ramp is built using spoil transported in barrows along the barrow runs. The spoil heap is progressively enlarged by tipping off the vertical end face of the barrow-run. This method is efficient in storing the maximum amount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Boring Machine
A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore through hard rock, wet or dry soil, or sand. Tunnel diameters can range from (micro-TBMs) to to date. Tunnels of less than a metre or so in diameter are typically done using trenchless construction methods or horizontal directional drilling rather than TBMs. TBMs can be designed to excavate non-circular tunnels, including u-shaped, horseshoe, square or rectangular tunnels. Tunnel boring machines are used as an alternative to drilling and blasting (D&B) methods in rock and conventional "hand mining" in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in urban areas. The major disadvan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw Conveyor
A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw blade, called a "''flighting''", usually within a tube, to move liquid or granular materials. They are used in many bulk handling industries. Screw conveyors in modern industry are often used horizontally or at a slight incline as an efficient way to move semi-solid materials, including food waste, wood chips, aggregates, cereal grains, animal feed, boiler ash, meat, and bone meal, municipal solid waste, and many others. The first type of screw conveyor was the Archimedes' screw, used since ancient times to pump irrigation water. They usually consist of a trough or tube containing either a spiral blade coiled around a shaft, driven at one end and held at the other, or a "''shaftless spiral''", driven at one end and free at the other. The rate of volume transfer is proportional to the rotation rate of the shaft. In industrial control applications, the device is often used as a variable rate f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slurry
A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pump. The size of solid particles may vary from 1 micrometre up to hundreds of millimetres. The particles may settle below a certain transport velocity and the mixture can behave like a Newtonian or non-Newtonian fluid. Depending on the mixture, the slurry may be abrasive and/or corrosive. Examples Examples of slurries include: *Cement slurry, a mixture of cement, water, and assorted dry and liquid additives used in the petroleum and other industries *Soil/cement slurry, also called Controlled Low-Strength Material (CLSM), flowable fill, controlled density fill, flowable mortar, plastic soil-cement, K-Krete, and other names *A mixture of thickening agent, oxidizers, and water used to form a gel explosive *A mixture of pyroclastic material, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Tunnel
The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone (Kent, England, UK) with Coquelles ( Hauts-de-France, France) beneath the English Channel at the Strait of Dover. It is the only fixed link between the island of Great Britain and the European mainland. At its lowest point, it is deep below the sea bed and below sea level. At , it has the longest underwater section of any tunnel in the world, and is the third longest railway tunnel in the world. The speed limit for trains through the tunnel is . The tunnel is owned and operated by the company Getlink, formerly "Groupe Eurotunnel". The tunnel carries high-speed Eurostar passenger trains, the Eurotunnel Shuttle for road vehicles and international freight trains. It connects end-to-end with the high-speed railway lines of the LGV Nord in France and High Speed 1 in England. In 2017, through rail services carried 10.3 million passengers and 1.22 milli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames Water Ring Main
The Thames Water Ring Main (TWRM, formerly the London Water Ring Main) is a system of approximately of concrete tunnels which transfer drinking water from water treatment works in the Thames and River Lea catchments for distribution within central London. A major part of London's water supply infrastructure, the initial ring was constructed by Thames Water between 1988 and 1993 at a cost of £ (equivalent to £ in ), and when completed, it was the longest tunnel in the UK. Two extensions were constructed between 2007 and 2010. Overview The ring main comprises a major loop linking the Hampton, Walton, Ashford and Kempton water treatment works clustered in west London, to central London by a southern branch via Brixton and northern branch via Kew. Spurs run to Coppermills Water Treatment Works near Walthamstow, and to the reservoir and pumping station at Honor Oak. The total transfer capacity of the system is 1.8 gigalitres (1.8 × 109 litres) per day. The ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Underground
The London Underground (also known simply as the Underground or by its nickname the Tube) is a rapid transit system serving Greater London and some parts of the adjacent ceremonial counties of England, counties of Buckinghamshire, Essex and Hertfordshire in England. The Underground has its origins in the Metropolitan Railway, the world's first underground passenger railway. Opened on 10 January 1863, it is now part of the Circle line (London Underground), Circle, District line, District, Hammersmith & City line, Hammersmith & City and Metropolitan lines. The first line to operate underground electric locomotive, electric traction trains, the City & South London Railway in 1890, is now part of the Northern line. The network has expanded to 11 lines, and in 2020/21 was used for 296 million passenger journeys, making it List of metro systems, one of the world's busiest metro systems. The 11 lines collectively handle up to 5 million passenger journeys a day and serve 272 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid Transit
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be called a subway, tube, or underground. Unlike buses or trams, rapid transit systems are railways (usually electric railway, electric) that operate on an exclusive right-of-way (transportation), right-of-way, which cannot be accessed by pedestrians or other vehicles, and which is often grade-separated in tunnels or on elevated railways. Modern services on rapid transit systems are provided on designated lines between rapid transit station, stations typically using electric multiple units on rail tracks, although some systems use guided rubber tires, magnetic levitation (''maglev''), or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slurry Balance
A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pump. The size of solid particles may vary from 1 micrometre up to hundreds of millimetres. The particles may settle below a certain transport velocity and the mixture can behave like a Newtonian or non-Newtonian fluid. Depending on the mixture, the slurry may be abrasive and/or corrosive. Examples Examples of slurries include: *Cement slurry, a mixture of cement, water, and assorted dry and liquid additives used in the petroleum and other industries *Soil/cement slurry, also called Controlled Low-Strength Material (CLSM), flowable fill, controlled density fill, flowable mortar, plastic soil-cement, K-Krete, and other names *A mixture of thickening agent, oxidizers, and water used to form a gel explosive *A mixture of pyroclastic material, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Boring Machine
A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore through hard rock, wet or dry soil, or sand. Tunnel diameters can range from (micro-TBMs) to to date. Tunnels of less than a metre or so in diameter are typically done using trenchless construction methods or horizontal directional drilling rather than TBMs. TBMs can be designed to excavate non-circular tunnels, including u-shaped, horseshoe, square or rectangular tunnels. Tunnel boring machines are used as an alternative to drilling and blasting (D&B) methods in rock and conventional "hand mining" in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in urban areas. The major disadvan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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