How the subway was built, how the subway was built

The subway, as the most popular mode of railway transportation that is not easy to get stuck in traffic, mainly runs underground, so how is the subway built?

The subway does not need to go around the river, and can cross the river from under the riverbed, and generally speaking, the subway passes under the riverShield methodThis is achieved by digging tunnels underground.

The subway shield uses the subway shield machine to excavate underground, and the excavation and lining operations of the tunnel are safely carried out in the machine while preventing the collapse of the soft foundation excavation face or keeping the excavation face stable. The construction process needs to first excavate a shaft or foundation pit at one end of a certain section of the tunnel, lift the subway shield machine into and install it, and the subway shield machine starts to excavate from the wall opening of the shaft or foundation pit and advances along the design tunnel line until it reaches the end point of another shaft or tunnel in the tunnel line.

Station construction. According to the construction method, the foundation pit of the subway station can be divided into open excavation method, hidden excavation method and cover excavation method construction; According to the order of construction, it can be divided into forward excavation method and reverse excavation method. Construction is generally built using the following common methods:

1. Cut-and-cover method: suitable for foundation pits or trenches with dense buildings and narrow site conditions, such as large foundation pit depth, high groundwater level, basic no bearing capacity of the stratum, high environmental protection requirements, and slope grading.

Excavation is difficult to ensure the safety and stability of the foundation pit, and when the enclosure pile and wall can be constructed, the vertical open cut method is used for construction.

2, the foundation pit cover excavation method: suitable for the building is more dense, the ground traffic is busy, the site conditions are relatively narrow and the scale of the foundation pit engineering, for the excavation range is larger, the groundwater level is high, the formation self-stability ability is poor, the precipitation is more difficult to underground engineering or the use of open excavation is difficult to ensure the construction and environmental safety, can be considered to use the cover excavation method.

3. Foundation pit cover excavation reverse method.

The reverse method of cover excavation is generally suitable for the construction of deep and large foundation pits or complex plane shapes with dense buildings, busy ground traffic and narrow site conditions.

1. Cut-and-cover backfill method: The simplest and most direct method is cut-and-cover (cut-and-cover backfill). This method is usually to dig a large pit in the street and then construct a tunnel structure underneath it, and the tunnel will have sufficient support to resurface the road surface.

In addition to the road being excavated, other underground structures such as power lines, ** lines, water pipes, etc. need to be reconfigured. The materials used to build such tunnels are generally concrete or steel, but older systems also use brick and iron.

2. Drilling method: Another method is to dig a shaft somewhere on the ground first, and then dig a tunnel at the bottom of the shaft. The most common method is to use a boring machine (submersible shield, shield machine) to install the pre-prepared components on the tunnel wall while excavating.

For places with a high density of buildings, such as Hong Kong Island in Hong Kong, drilling is even the only feasible construction method.

The steps for the construction of the subway are as follows:

Material preparation: construction team, a selected subway line, reinforcement mesh, concrete, boards, cables and mechanical and electrical equipment, etc.

1. First of all, it is necessary to explore the soil reform and disturbance of the subway line that needs to be built, and choose different excavation methods according to the exploration, including open cut and backfill method, shield method, and different methods need to be selected according to different exposed conditions.

2. When digging the soil, the reinforcement mesh is erected at the same time, and the water contained in the soil is discharged to ensure the firmness of the frame and prevent accidents on both sides.

3. Inject concrete into the built steel mesh, and build the bottom plate, side wall, middle plate and roof plate in turn after the concrete is solidified.

4. After the completion of a series of nuclear bench projects, it is necessary to lay tracks, cables, optical cables, communication and other equipment in the subway tunnel.

5. After installing a series of mechanical and electrical equipment, it is also necessary to decorate the station, install mechanical and electrical equipment, system commissioning, acceptance and other related links. After the above links are completed, the subway can be officially operated, but the operation of the subway must be monitored at any time to avoid accidents, and it is also necessary to regularly repair the subway-related equipment to prevent the aging of the equipment.

There are many reasons for the construction of the subway, but the main reason for this is traffic congestion. The number of city dwellers is increasing, and so is the number of cars. Even cities with vast roads are facing traffic paralysis.

In this case, the advent of the metro becomes a more efficient solution.

The subway system operates differently than buses, which generally follow the road and need to follow the traffic rules on the road. Metros, on the other hand, run on an underground rail system, which is faster and more efficient without road congestion. In addition, subways generally have relatively fixed routes and schedules, which also makes it easier for passengers to plan their trips and arrive at their destinations on time.

Therefore, the construction of subways can effectively alleviate the problem of urban traffic congestion and improve the efficiency of urban travel.

At the same time, in order to promote low-carbon travel, many cities have also begun to build subway systems. Compared with traditional buses or taxis, subways are more energy-efficient and environmentally friendly, reducing exhaust and noise emissions. Low-carbon travel can not only reduce environmental pollution, but also bring a healthier lifestyle to urban residents.

In addition, the construction of the subway is also aimed at improving the city's image and attracting investment. With the continuous development of the economy, the image of the city is becoming more and more important for investors. The construction of the subway can not only improve the city's traffic efficiency and ecological environment, but also increase the city's aesthetics and urbanization level.

Therefore, the construction of the subway can not only solve the city's traffic problems, but also improve the city's image and environmental protection. In the future, in the process of economic development and urbanization, the subway will be more important. <>

The subway has been an important transportation facility in modern cities for about 100 years. In 1863, the world's first underground began running in the UK. By the early 90s of the 20th century, more than 200 subways had been built in 88 cities in 39 countries in the world, and more than 50 million people took them every day.

What was the reason for the construction of the underground railway? Practice has shown that the subway has various characteristics such as the speed of vehicles running quite fast, the number of trains is very large, the passenger volume is large, convenient and comfortable. In wartime, the underground railroad was also a fairly good anti-aircraft shelter.

Let's take the Shanghai subway as an example to go to the superiority of the subway. Aokai.com.

1.It's very fast. Shanghai Metro Line 1 is about 1 kilometer long and has a total of 13 stations. The speed of the subway is about twice as fast as that of the bus, and it takes only 20 minutes to take the subway, which would have taken 1 hour. Aokai.com.

2.There are a lot of trains. The interval is approximately 2 minutes. Aokai.com.

3.The passenger traffic is quite large, and it is convenient and comfortable. Shanghai metro cars are mainly imported from Germany.

The carriages are about 23 meters long and 3 meters wide and can carry more than 400 passengers, and the compartments are more relaxed than the buses, and at the peak, 5 6 people per square meter stand, but the bus is 12 people. Aokai.com.

In Shanghai's metro stations, which are usually air-conditioned, equipped with closed-circuit television, radio and automatic fire alarm systems, and department stores, it is a very safe place to use as an ideal air defense place in wartime. Aokai.com.

Because the subway has so many advantages, for this reason, many of the world's largest cities have subways.