Before answering this question, you must first understand how the subway is excavated . Shield machine is a professional construction machinery for tunnel digging. It is widely used in large projects such as subway, railway, and municipalities. It is also known as the "king of engineering machinery". It played a key role in digging the tunnel. For example, it is difficult to excavate the hard rocks, or the soil is soft, and the shield machine can be solved. Its emergence has increased the efficiency of tunnels by about 10 times. So how does the shield machine "eliminate" soil?

The head of the shield machine is a circular turntable full of blade, which can cut the soil in front of it during runtime. Some of these soils will be very solid around the tunnel, which not only reduces the cost of transportation soil, but also increases the firmness of the subway tunnel. In addition, in the process of excavating the tunnel, there may be caves and places to be filled. At this time, those reserved soils are used in martial arts.

In addition, in order to ensure that the subway does not collapse, a large amount of dirt is also needed to strengthen the road. Therefore, the workers will directly fill the dug out of the soil back to the subway during the operation process. building. Of course, if there is still a dug out of the soil, it will not be wasted casually.

The Municipal Council will directly transport these soils to the construction of other cities or be put into the construction of green belts. In this way, the resource utilization rate has also been improved. On the one hand, the use of this soil backfilling method has saved the cost of subway construction, and on the other hand, it also facilitates the work of workers to shorten the construction period. However, in order to minimize the harassment of residents of the surrounding cities, these transport vehicles usually work at night, so it is difficult to see the soil of digging the subway.

Having said so much, do you know how much money does it cost to build a subway?

The external cost of the subway is extremely expensive, and the price of one kilometer in some cities has reached 8 to 100 billion. Although the cost is expensive, it is relatively simple to use, and it is relatively simple to maintain it later. It is still worth it in the later period. Take the Moscow's subway, for example, their subway is in their 80s, and it is still used after simple maintenance and upgrading. If there are no geological disasters, their general life span can reach at least four or five hundred years. Of course, in the process, people must continue to upgrade it.