Tunneling shield for tunnel construction and mining.
Tunneling shield used in the construction of tunnels for various purposes, as well as in the development of mineral deposits by underground method.
A tunneling shield is a movable design, in the head construction of the tunnel and ensure the safe development of rock in the mine, loading it on nutritionally transport and erection of the lining (lining). Tunnel shields typically have a circular cross section, but are rectangular, elliptical, horseshoe, including unconfined.
Tunneling shield used in the construction of tunnels for various purposes, as well as in the development of mineral deposits underground way.
Tunnel shields can be used in all geological conditions, however, they are most effective in soft soils.
Tunnel shields for better handling should have the necessary agility, which is characterized, in particular, the ratio of length to transverse size.
The size of the boards is divided into shields large (7 m), medium (5 to 7) and of small cross section (less than 5 m). Diameter of resulting tunnel can range from 1 to 19 m.
A type of tunneling machine is underground robot multi-purpose “Geokhod”.
– increase the pace of work and productivity in 2-2,5 times,
– reducing the cost of the tunnelling works,
the relief and security of the workers – drifters,
– the combination of a large number of main and auxiliary working operations
– mechanization of working operations
Main parts of the shields are: cutter ring, bearing ring, shield jacks, mud jacks, platform jacks, tubes, ballasts, horizontal and vertical partitions.
The knife ring is used for partial cutting of soft and friable rocks, and prevention of the fall of the breed. Under the protection of the knife ring is carried out the excavation of rock. Support ring, directly adjacent to the knife, is the basis of the bearing design of the shield and serves for placing of switchboard jacks, pipes and remote control mechanisms of the shield. In the rear part of the shield erect permanent lining (the lining).
The movement of the shield, and in soft rocks, its penetration into the array for the purpose of development of the breed is carried out using a panel of hydraulic jacks.
Shields up to 2 m does not have partitions. With increasing diameter up to 3 m boards are equipped with one horizontal partition. The shields large size set of several horizontal and vertical walls to increase the rigidity and strength of the shield. Horizontal and vertical partitions divide the cross section of the shield on the independent working cells, to ensure ease and safety of doing pornostaritaliana work on the entire face.
In necessary cases the mounting face of development is carried out using a downhole Jack. Partitions mounted as retractable platforms with jacks (jacks platform), which will lead the development of the breed in the cells of the shield.
Working bodies of the existing shields affect the bottom mainly by means of pressing, cutting or combined method.
Method of pressing is effective in loose (sandy) and malokomplektnyh cohesive (clayey and silty) soils. Indentation of a running head consisting of the cutter ring and cutter strips or aperture Windows that the soil in the form of talus or briquettes transported into the tunnel shield.
Method of cutting in the mine are effective in stable cohesive soils, especially in tight clays and shales. For cutting mainly used in rotary, planetary and milling working bodies.