Tunnel connecting parallel tunnels - has pilot hole drilled between tunnels and boring tool pulled back to enlarge bore

Abstract

Abstract The tunnel connects two parallel traffic tunnels or roadways. The traffic tunnels are dug past the point at which the connecting tunnel is to be located. Subsequently the traffic tunnels are provided with reinforced entrances of a smaller section than the section of the connecting tunnel. One of the entrances is then used as a starting point for drilling a pilot hole towards the other entrance by means of a trepanner head followed by a transport worm for removing the cut material. When the pilot hole is completed the trepanner head is replaced by a boring tool of a slightly smaller diemeter than the entry section. Both the boring tool and the transport worm are pulled by drilling rods back to the starting point, widening the pilot hole as they return.

Inventors

• 👤 Fridrich Wilhelm Paurat

Bibliographic Details