Tunnelling shield

Abstract

Tunnel Boring Machines (TBMs) are known that comprise a large metal cylindrical shield fronted by a rotating cutting wheel and containing a chamber where the excavated soil is deposited (and optionally mixed with slurry for extraction, depending on the type of geological/soil conditions). However, TBMs have various disadvantages including the stop-start nature of their tunnelling, and that a single TBM cannot easily transition between different rock/soil types (especially heavily fractured and sheared rock layers). The invention provides a tunnelling shield provided with jet grouting tools arranged to project from a leading edge thereof. In this way, the quality of the geological material into which the tunnel is being excavated may be improved dynamically as part of the excavation process.

Dependencies are inferred from the claim text.