How do dig tunnels for the metro

• How do dig tunnels for the metro

Traditionally tunnel boring machine given female names. This custom appeared with a light hand, Richard Lovat - founder of the world famous company LOVAT. He decided that his company boards will carry women's names in honor of the patron saint of underground works of Saint Barbara. Today, heavy men's work in the subway perform "Alan", "Almira", "Anastasia", "Natalia", "Claudia", "Olga", "Eve", "Svetlana", "Victory", "Polina" and other " ladies. "

The average distance between stations - 2-2, 5 kilometers. The train passes them for three minutes, and the tunnel boring machine overcomes per day 12 meters. Pass during the construction of a tunnel of 350 meters in a month - a good indicator. Despite the difficult geological conditions, some of the "ladies" to cope faster. For example, "Tatiana" was held for more than 2, 8 kilometers for a few months ahead of time, connecting the station "Ochakovo" and "Michurinsk prospectus" right tunnels.

Shield is brought to the construction site and assembled in parts already in place in a special pit, which the builders called mounting the camera. Its size is smaller than a football field - 60 to 70 meters. It will be the beginning of a new tunnel. The machine will finish its way in the same chamber, but with a different name - Remover. There she will disassemble and taken away for the construction of a new tunnel.

The length of the shield, like the worm can reach 100 meters. The head portion - a cutting mechanism, which is called the rotor. On it - Special cutters. They literally bite into the rock, paving the way. Immediately behind the rotor is drive which starts the cutting mechanism.

The shield is required to have a closed container for cement mortar filling the voids between the tubings (prefabricated fastening element underground constructions (shafts, tunnels and so on.).) And the ground. And yet - decompression chamber, jacks, driver's cab of the tunnel complex, and even lounge builders. The latter, too, is not superfluous, because the work is going around the clock. Workers working in three shifts; day one shield serve about 30 people.

The complex is paving the way with the help of a precision navigation electronics. switchboard operator constantly checks the coordinates of the route, because tunneling system may deviate from the set parameters are not more than eight millimeters. For each mechanism make the schedule to know where he ends up drifting, when will pass to the next stage.

Future space of the tunnel formed tubing - concrete blocks. When he is ready, the builders laid rails and a supply network engineering. Where the soil stack? He goes to a special shield pockets, out on a conveyor belt - into trucks plying on temporary rails, and then - on the surface. Trolley removal of soil and supply the necessary details, such as tubing. On-site soil is long, it is sent to a special landfill. In day one shield takes 30 trucks for export ground.

Metrostroevtsy sometimes have to improvise. The reason most often in the lack of free sites for construction. For example, in the "Moscow City", when they built the station "Business Center" yellow branches, the car was mounted on the patch is no longer a school gym. The shield had to build under the ground, dropping the ring for the ring.

But on the court, "Petrovsky Park" assembly mechanism had very little time. Usually installation panel takes a month or two, and to build it quickly, the head of the weight of about 150 tons are not dismantled and lowered completely to a depth of 28 meters. For this purpose, the pit brow installed 450-500-ton crane. Experts have spent a lot of calculations to make sure that it does not bring down the pit.

Have Moscow builders and their inventions. They were the first in the world paved by a shield tunnels under the escalators. Know-how used in the station "Marina Grove" light green branches. Abroad, this practice has not spread, because in Europe station mainly built on shallow tunnels and escalators to dig by hand.

The Shield "Lily" works for a two - building a tunnel directly to the two paths. It weighs more than 1,600 tons, the girth of "waist" - more than 10 meters, and "growth" - 66 meters. One such Tunneling mechanized complex, or shield, as it is called builders can replace two six-meter. Its main advantage - speed. If the standard six-meter shield runs about 250 running meters per month, the "Lily" - 350-400.

Giant "Lily" is needed to build a double-track tunnels. Train them go against each other. If the normal station rails extend on both sides of a single platform, then the new path in the two sides will be in the middle of the hall, and the two will be placed on the sides of the platform. Therefore, they are called double-track.

The main advantage of double-track tunnel that uses a single 10-meter giant shield, rather than two six-meter. Also, this method of construction reduces the number of workers on the construction site: for sinking two tunnels need 200 workers and one - 130. This technology reduces costs by about 30 percent.

Today, machines are ten times faster. Tunnels are paving the-art German shields Herrenknecht, Canadian and American LOVAT Robbins. By the way, the new "Lily", the creation of which went for almost a year, also a German, as well as "Anastasia" with "Almira". It was brought from Germany in April.