A few years ago I worked as a mining master in the Moscow Metrostro, on the site number six. The site was engaged in rollback. At my disposal were mine electric locomotives – small, but powerful cars. There was a “team” consisting of a lower reception site and drivers of electric locomotives and their assistants. We were engaged in the delivery of building materials. Delivery of various materials was carried out through the barrel with a depth of sixty meters. So, perhaps you will be interested in the story of what elements and building materials are used in the construction of the subway. The first and probably the most important is, of course, tubing. Tubings are the basis of metro tunnels.
The tubing ring has different sections, from five to eleven meters. Tubing is a segment, a kind of ring, one meter wide. It is made of cast iron, which is more expensive, or from reinforced concrete, which is several times cheaper than cast iron. Tubing rings are lining is carried out both in tunnels and at the station itself, with orientation on stiffness, which can be designed for a higher load due to a certain location of the tubing position in the ring. For example, tubing at the top have much more powerful stiffener ribs than those that are at the bottom of the tubing ring. Tubing have special holes for fastening with bolts. In the center of the base of the tubing, there is a hole designed to escalate the cement mortar into the voids located in the breed behind the tubing ring.
The first thing to say about here is about the use of a concrete solution for injection for a tubing ring, which allows the ring to firmly connect to the breed, and the solution is to fill the voids formed by brown -explosive work. Concrete is also used in the construction of the concrete monolithic floor of the station. A significant part of the concrete is the basis for the railway track, according to which trains will walk in the near future. It is poured after the installation of composite sleepers. Since the reinforcement is the basis of all the reinforced concrete and the fourth rate of the structures, it is used in metro construction no less often than in the construction of multi -storey buildings. Tons of reinforcement descend into the dungeon to become buried forever in concrete. The reinforcement increases the strength of concrete several times, which is important enough with such serious construction.
In general, the catalog of reinforced concrete products here is the presence in its full abundance. For the construction of wells, special large reinforced concrete rings are made (Eurobond), and monolithic bottoms, covers; For the removal of water masses, a system of pipes is laid, often also made of reinforced concrete.
Bolts and nuts are used to fasten tubing among themselves. Depending on the diameter of the ring and the tubing themselves, bolts of the required size are selected. They are of different lengths and sections. Basic bolts with a diameter of thirty to forty -two millimeters are mainly used. Bolts withstand very large loads, which explains their unusually large values. Washers are also used. There are two types of washers: ordinary metal ones used temporarily, and asbesto-bitumen, which are already used constantly and exclude the penetration of groundwater into the tunnel. Concrete is an equally important component of the construction of a modern metro than all other materials. For laying engineering communications, reinforced concrete trays fastened with special bolts are used, plus they are covered with lids.
A reinforcement can be of two types: smooth and corrugated. It has a different diameter. The size of the cross section of the reinforcement used in the metro construction is usually from ten to forty -two millimeters. Metal sheets are used mainly at the transitions and for the conjugation of the tunnel. This activity is called metal insulation. Depending on the load, which will subsequently experience insulating metal, sheets of different thicknesses are used. Most often, metal sheets have a thickness of 8 to 10 millimeters. Marble is the “face” of the station. Explanatory material, most often delivered from other countries. Laid the floor and walls of the future station with marble. The external finish for the metro station is very important. Fragile marble requires special accuracy in delivery and installation.
Perhaps the main materials that are used in metro construction were already mentioned here, but they are not the only. During the construction of such a magnificent structure, boards, wire, cable, paint, various varnishes, and other all kinds of building materials are used. In particular, when finishing work, tiles and bricks are used inside technical rooms.