It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and …

Dec 19, 2025 · Tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by nature’s action in dissolving a soluble rock. Tunnels …

TUNNEL definition: an underground passage. See examples of tunnel used in a sentence.

TUNNEL meaning: 1. a long passage under or through the ground, especially one made by people: 2. the long passage…. Learn more.

Jan 9, 2015 · The meaning of TUNNEL is a covered passageway; specifically : a horizontal passageway through or under an obstruction. How to use tunnel in a sentence.

In general, tunnels are at least twice as long as they are wide and are completely enclosed on all sides, save for the openings at each end. A tunnel may be used by pedestrians, cyclists, motor …

Today, engineers know that there are three basic steps to building a stable tunnel. The first step is excavation: engineers dig through the earth with a reliable tool or technique. The second...