Scrabble?! TUNNELINGS

Definitions of TUNNELINGS in various dictionaries:

A tunnelling shield is a protective structure used during the excavation of large, man-made tunnels. When excavating through ground that is soft, liquid, or otherwise unstable, there is a risk to workers and the project itself from falling materials and/or a cave-in. A tunnelling shield serves as a temporary support structure. It is in place for the usually short time from when the tunnel section is excavated until it can be lined with a permanent support structure. The permanent structure may be made up of, depending on the period, bricks, concrete, cast iron, or steel. Although modern shields are commonly cylindrical, the first "shield", designed by Marc Isambard Brunel, was actually a large, rectangular, scaffold-like iron structure with three levels and twelve sections per level and a solid weight-bearing top — see picture to the right. The structure nevertheless protected the men from cave-ins as they laboured within it, digging the tunnel out in front of themselves.