EDUCATION:

     Mining Industry University, Leningrad, Russia.

         Engineering background. - Bachelor's Degree in Mechanical Engineering.

     JVC Vacational Training, CA, USA. 1995

          AutoCAD 

          Pro/Engineer R2000

      Autodesk Training Center, CDM Institute, NJ, 1999

         AutoCAD  

         CNC Computer Numerical Control

National University of mineral resource "Mountain".

(Before Leningradski gorni institute)

Национальный минерально-сырьевой университет «Горный»

(Ленинградский Горный институт) 

Graduate Project: "Shield".

When tunneling clay or unstable rock, a steel tube, called a shield, which is slightly larger than the intended diameter of the finished tunnel, is used. The shield is lowered in pieces down a shaft and assembled in a specially tunneled work area either in line with or adjacent to the proposed train tunnel. The top of the shield at the end nearest the excavation or face, as it is called, is extended to prevent loose material from falling into the work area. At the other end of the shield, called the tail, workers install the the cast-iron or precast concrete liners that create the finished inner surface of the tunnel. Each cylindrical section of liner is composed of several segments.

As each two or three feet of the face is excavated, the shield is pushed forward with powerful jacks braced against the closest of lining. As the shield moves, it leaves a small space between the actual surface of the soil as soon as the shield has been moved. In either case the tunnel is permanently locked into the earth. A tunnel cut through solid rock doesn't need a shield and it is sometimes left unlined. To reduce the building time, excavation crews will work simultaneously from several different shafts.

The face of tunnel can excavated in many ways. If necessary it can be dug by hand, but usually powerfull drills or a single large boring machine are used. When the tunnel is going through rock or very hard clay, the drill holes are filled with explosives, which, when ignited, reduce the face to rubble. As soon as the ventilation system has created the air, the muck is carried in small carts along a narrow track or along a conveyor belt to the nearest shaft.

When the material through which the tunnel is to bedug contains a lot of water, the pressure at the tunnel face must be increased to prevent that water from pouring in. First a thick concrete wall is built behind the shield to seal the tunnel. It is in the space between this wall and the face that the pressure will be increased.

Then a second concrete wall is built about ten feet behind the first, which also fits against the sides of the tunnel to create an airtight seal.

The space between the walls is called a compression chamber and is entered through heavy steel door located in both walls.

Because of the difference between the pressure at the face and pressure in the rest of the tunnel, workers traveling from one area to the other must spend a certain amount of time in the chamber. This way their bodies can adjust gradually as the pressure in the chamber is slowly changed to equal either the higher pressure at the face or the normal pressure towards the shaft.

Special air locks built into the chamber enable equipment and muck to be passed through without breaking the seal between the two areas.