Fast and large-capacity electric traction rail transit in cities. Trains run on fully enclosed lines, the lines located in the central city are basically located in underground tunnels, and the lines outside the central city are generally located on viaducts or on the ground.
Subway covers all kinds of urban rail transit systems with exclusive underground and above-ground road rights, high density and high volume in urban areas. China Taiwan Province Metro is referred to as MRT.
In addition to the subway, it also includes elevated railways or railways laid on roads. Therefore, the subway is the exclusive right of way, and there is no grade crossing, which is also the fundamental sign that the subway is different from the light rail transit system. The earliest (and first) subway in the world is the Metropolitan Subway in London, England, which was built at 1863.
Extended data:
The subway model is determined by the vehicle model used in the subway. Generally speaking, there is no uniform standard for subway models all over the world, and they are often tailored to the needs of a subway in a certain place, such as the A system and B system of new york subway. In Chinese mainland, subway models are usually divided into three types: A type, B type, C type and L type.
According to the construction method, the foundation pit of subway station can be divided into open excavation and cover excavation, underground excavation and cover excavation. According to the construction sequence, it can be divided into forward excavation method and reverse excavation method. Construction generally adopts the following common methods.
Cut and cover: Suitable for foundation pits or trenches with dense buildings and narrow site conditions. For example, the foundation pit is deep, the groundwater level is high, the stratum basically has no bearing capacity, and the environmental protection requirements are high. Slope excavation is difficult to ensure the safety and stability of foundation pit. When retaining piles and walls can be built, vertical excavation and covering are used for construction.
References:
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