Subterrene

Pronounced like submarine, and fairly obvious when you think about it, just not the type of thing you figure anyone gets around to building anytime after you stopped reading comic books or science fiction. Truth, however, is very often stranger than fiction.

ABSTRACT A tunneling machine for producing large tunnels in rock by progressive detachment of the tunnel core by thermal melting a boundary kerf into the tunnel face and simultaneously forming an initial tunnel wall support by deflecting the molten materials against the tunnel walls to provide, when solidified, a continuous liner; and fragmenting the tunnel core circumscribed by the kerf by thermal stress fracturing and in which the heat required for such operations is supplied by a compact nuclear reactor.

DESCRIPTION OF THE PRIOR ART The utilization of the basic concept of melting earth materials to dig a hole or small tunnel is taught in the prior art. For example, U.S. Pat. No. 3,357,505 issued 15 to Armstrong et al. in 1967, disclosed an electrically heated rock drill. U.S. Pat. No. 3,396,806 issued August 1968 to Benson disclosed a unitized machine for thermal earth drilling utilizing a nuclear reactor for supplying the melting energy requirements. This patent 20 also suggests that the hole could be melted to a larger diameter than required for the finished hole so that melt material would provide the hole casing. U.S. Pat. No. 3,693,731 issued Sept. 1972 to Armstrong et al. also discloses a nuclear reactor pow- 25 ered earth boring machine and melt material is used as structural hole lining material. However, this patent, like others that disclose machines for drilling tunnels by melting the earth, is a solid front machine which creates an amount of melt equal to the tunnel cross sec- 30 tion. 3-* tion of such large tunnels requires large heat flow rates and creates excessive costs of the heat generating and supply system. The most economical method is for the machine to thermally melt just enough material to detach the core, and to provide adequate tunnel lining The machine of the present invention is particularly adapted to excavate large tunnels, that is, having a cross-sectional measurement in the range of 2 to 12 metres and larger. The melting of the entire cross sec- 40 material. The core materials can be mechanically fractured for disposal. However, in hard rock the disintegration of the core material is best done by heated thermal stress fracturing penetrators.